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Fr4nz D13trich 2025-11-22 14:04:28 +01:00
parent 81b91f4139
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22732 changed files with 4815320 additions and 2 deletions

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//
// Copyright 2020 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/flags/internal/commandlineflag.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
FlagStateInterface::~FlagStateInterface() = default;
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_FLAGS_INTERNAL_COMMANDLINEFLAG_H_
#define ABSL_FLAGS_INTERNAL_COMMANDLINEFLAG_H_
#include "absl/base/config.h"
#include "absl/base/internal/fast_type_id.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
// An alias for flag fast type id. This value identifies the flag value type
// similarly to typeid(T), without relying on RTTI being available. In most
// cases this id is enough to uniquely identify the flag's value type. In a few
// cases we'll have to resort to using actual RTTI implementation if it is
// available.
using FlagFastTypeId = absl::base_internal::FastTypeIdType;
// Options that control SetCommandLineOptionWithMode.
enum FlagSettingMode {
// update the flag's value unconditionally (can call this multiple times).
SET_FLAGS_VALUE,
// update the flag's value, but *only if* it has not yet been updated
// with SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef".
SET_FLAG_IF_DEFAULT,
// set the flag's default value to this. If the flag has not been updated
// yet (via SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef")
// change the flag's current value to the new default value as well.
SET_FLAGS_DEFAULT
};
// Options that control ParseFrom: Source of a value.
enum ValueSource {
// Flag is being set by value specified on a command line.
kCommandLine,
// Flag is being set by value specified in the code.
kProgrammaticChange,
};
// Handle to FlagState objects. Specific flag state objects will restore state
// of a flag produced this flag state from method CommandLineFlag::SaveState().
class FlagStateInterface {
public:
virtual ~FlagStateInterface();
// Restores the flag originated this object to the saved state.
virtual void Restore() const = 0;
};
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_FLAGS_INTERNAL_COMMANDLINEFLAG_H_

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/flags/internal/flag.h"
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <array>
#include <atomic>
#include <cstring>
#include <memory>
#include <string>
#include <typeinfo>
#include <vector>
#include "absl/base/attributes.h"
#include "absl/base/call_once.h"
#include "absl/base/casts.h"
#include "absl/base/config.h"
#include "absl/base/const_init.h"
#include "absl/base/dynamic_annotations.h"
#include "absl/base/no_destructor.h"
#include "absl/base/optimization.h"
#include "absl/base/thread_annotations.h"
#include "absl/flags/config.h"
#include "absl/flags/internal/commandlineflag.h"
#include "absl/flags/usage_config.h"
#include "absl/memory/memory.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include "absl/synchronization/mutex.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
// The help message indicating that the commandline flag has been stripped. It
// will not show up when doing "-help" and its variants. The flag is stripped
// if ABSL_FLAGS_STRIP_HELP is set to 1 before including absl/flags/flag.h
const char kStrippedFlagHelp[] = "\001\002\003\004 (unknown) \004\003\002\001";
namespace {
// Currently we only validate flag values for user-defined flag types.
bool ShouldValidateFlagValue(FlagFastTypeId flag_type_id) {
#define DONT_VALIDATE(T, _) \
if (flag_type_id == base_internal::FastTypeId<T>()) return false;
ABSL_FLAGS_INTERNAL_SUPPORTED_TYPES(DONT_VALIDATE)
#undef DONT_VALIDATE
return true;
}
// RAII helper used to temporarily unlock and relock `absl::Mutex`.
// This is used when we need to ensure that locks are released while
// invoking user supplied callbacks and then reacquired, since callbacks may
// need to acquire these locks themselves.
class MutexRelock {
public:
explicit MutexRelock(absl::Mutex& mu) : mu_(mu) { mu_.Unlock(); }
~MutexRelock() { mu_.Lock(); }
MutexRelock(const MutexRelock&) = delete;
MutexRelock& operator=(const MutexRelock&) = delete;
private:
absl::Mutex& mu_;
};
// This is a freelist of leaked flag values and guard for its access.
// When we can't guarantee it is safe to reuse the memory for flag values,
// we move the memory to the freelist where it lives indefinitely, so it can
// still be safely accessed. This also prevents leak checkers from complaining
// about the leaked memory that can no longer be accessed through any pointer.
absl::Mutex* FreelistMutex() {
static absl::NoDestructor<absl::Mutex> mutex;
return mutex.get();
}
ABSL_CONST_INIT std::vector<void*>* s_freelist ABSL_GUARDED_BY(FreelistMutex())
ABSL_PT_GUARDED_BY(FreelistMutex()) = nullptr;
void AddToFreelist(void* p) {
absl::MutexLock l(FreelistMutex());
if (!s_freelist) {
s_freelist = new std::vector<void*>;
}
s_freelist->push_back(p);
}
} // namespace
///////////////////////////////////////////////////////////////////////////////
uint64_t NumLeakedFlagValues() {
absl::MutexLock l(FreelistMutex());
return s_freelist == nullptr ? 0u : s_freelist->size();
}
///////////////////////////////////////////////////////////////////////////////
// Persistent state of the flag data.
class FlagImpl;
class FlagState : public flags_internal::FlagStateInterface {
public:
template <typename V>
FlagState(FlagImpl& flag_impl, const V& v, bool modified,
bool on_command_line, int64_t counter)
: flag_impl_(flag_impl),
value_(v),
modified_(modified),
on_command_line_(on_command_line),
counter_(counter) {}
~FlagState() override {
if (flag_impl_.ValueStorageKind() != FlagValueStorageKind::kHeapAllocated &&
flag_impl_.ValueStorageKind() != FlagValueStorageKind::kSequenceLocked)
return;
flags_internal::Delete(flag_impl_.op_, value_.heap_allocated);
}
private:
friend class FlagImpl;
// Restores the flag to the saved state.
void Restore() const override {
if (!flag_impl_.RestoreState(*this)) return;
ABSL_INTERNAL_LOG(INFO,
absl::StrCat("Restore saved value of ", flag_impl_.Name(),
" to: ", flag_impl_.CurrentValue()));
}
// Flag and saved flag data.
FlagImpl& flag_impl_;
union SavedValue {
explicit SavedValue(void* v) : heap_allocated(v) {}
explicit SavedValue(int64_t v) : one_word(v) {}
void* heap_allocated;
int64_t one_word;
} value_;
bool modified_;
bool on_command_line_;
int64_t counter_;
};
///////////////////////////////////////////////////////////////////////////////
// Flag implementation, which does not depend on flag value type.
DynValueDeleter::DynValueDeleter(FlagOpFn op_arg) : op(op_arg) {}
void DynValueDeleter::operator()(void* ptr) const {
if (op == nullptr) return;
Delete(op, ptr);
}
MaskedPointer::MaskedPointer(ptr_t rhs, bool is_candidate) : ptr_(rhs) {
if (is_candidate) {
ApplyMask(kUnprotectedReadCandidate);
}
}
bool MaskedPointer::IsUnprotectedReadCandidate() const {
return CheckMask(kUnprotectedReadCandidate);
}
bool MaskedPointer::HasBeenRead() const { return CheckMask(kHasBeenRead); }
void MaskedPointer::Set(FlagOpFn op, const void* src, bool is_candidate) {
flags_internal::Copy(op, src, Ptr());
if (is_candidate) {
ApplyMask(kUnprotectedReadCandidate);
}
}
void MaskedPointer::MarkAsRead() { ApplyMask(kHasBeenRead); }
void MaskedPointer::ApplyMask(mask_t mask) {
ptr_ = reinterpret_cast<ptr_t>(reinterpret_cast<mask_t>(ptr_) | mask);
}
bool MaskedPointer::CheckMask(mask_t mask) const {
return (reinterpret_cast<mask_t>(ptr_) & mask) != 0;
}
void FlagImpl::Init() {
new (&data_guard_) absl::Mutex;
auto def_kind = static_cast<FlagDefaultKind>(def_kind_);
switch (ValueStorageKind()) {
case FlagValueStorageKind::kValueAndInitBit:
case FlagValueStorageKind::kOneWordAtomic: {
alignas(int64_t) std::array<char, sizeof(int64_t)> buf{};
if (def_kind == FlagDefaultKind::kGenFunc) {
(*default_value_.gen_func)(buf.data());
} else {
assert(def_kind != FlagDefaultKind::kDynamicValue);
std::memcpy(buf.data(), &default_value_, Sizeof(op_));
}
if (ValueStorageKind() == FlagValueStorageKind::kValueAndInitBit) {
// We presume here the memory layout of FlagValueAndInitBit struct.
uint8_t initialized = 1;
std::memcpy(buf.data() + Sizeof(op_), &initialized,
sizeof(initialized));
}
// Type can contain valid uninitialized bits, e.g. padding.
ABSL_ANNOTATE_MEMORY_IS_INITIALIZED(buf.data(), buf.size());
OneWordValue().store(absl::bit_cast<int64_t>(buf),
std::memory_order_release);
break;
}
case FlagValueStorageKind::kSequenceLocked: {
// For this storage kind the default_value_ always points to gen_func
// during initialization.
assert(def_kind == FlagDefaultKind::kGenFunc);
(*default_value_.gen_func)(AtomicBufferValue());
break;
}
case FlagValueStorageKind::kHeapAllocated:
// For this storage kind the default_value_ always points to gen_func
// during initialization.
assert(def_kind == FlagDefaultKind::kGenFunc);
// Flag value initially points to the internal buffer.
MaskedPointer ptr_value = PtrStorage().load(std::memory_order_acquire);
(*default_value_.gen_func)(ptr_value.Ptr());
// Default value is a candidate for an unprotected read.
PtrStorage().store(MaskedPointer(ptr_value.Ptr(), true),
std::memory_order_release);
break;
}
seq_lock_.MarkInitialized();
}
absl::Mutex* FlagImpl::DataGuard() const {
absl::call_once(const_cast<FlagImpl*>(this)->init_control_, &FlagImpl::Init,
const_cast<FlagImpl*>(this));
// data_guard_ is initialized inside Init.
return reinterpret_cast<absl::Mutex*>(&data_guard_);
}
void FlagImpl::AssertValidType(FlagFastTypeId rhs_type_id,
const std::type_info* (*gen_rtti)()) const {
FlagFastTypeId lhs_type_id = flags_internal::FastTypeId(op_);
// `rhs_type_id` is the fast type id corresponding to the declaration
// visible at the call site. `lhs_type_id` is the fast type id
// corresponding to the type specified in flag definition. They must match
// for this operation to be well-defined.
if (ABSL_PREDICT_TRUE(lhs_type_id == rhs_type_id)) return;
const std::type_info* lhs_runtime_type_id =
flags_internal::RuntimeTypeId(op_);
const std::type_info* rhs_runtime_type_id = (*gen_rtti)();
if (lhs_runtime_type_id == rhs_runtime_type_id) return;
#ifdef ABSL_INTERNAL_HAS_RTTI
if (*lhs_runtime_type_id == *rhs_runtime_type_id) return;
#endif
ABSL_INTERNAL_LOG(
FATAL, absl::StrCat("Flag '", Name(),
"' is defined as one type and declared as another"));
}
std::unique_ptr<void, DynValueDeleter> FlagImpl::MakeInitValue() const {
void* res = nullptr;
switch (DefaultKind()) {
case FlagDefaultKind::kDynamicValue:
res = flags_internal::Clone(op_, default_value_.dynamic_value);
break;
case FlagDefaultKind::kGenFunc:
res = flags_internal::Alloc(op_);
(*default_value_.gen_func)(res);
break;
default:
res = flags_internal::Clone(op_, &default_value_);
break;
}
return {res, DynValueDeleter{op_}};
}
void FlagImpl::StoreValue(const void* src, ValueSource source) {
switch (ValueStorageKind()) {
case FlagValueStorageKind::kValueAndInitBit:
case FlagValueStorageKind::kOneWordAtomic: {
// Load the current value to avoid setting 'init' bit manually.
int64_t one_word_val = OneWordValue().load(std::memory_order_acquire);
std::memcpy(&one_word_val, src, Sizeof(op_));
OneWordValue().store(one_word_val, std::memory_order_release);
seq_lock_.IncrementModificationCount();
break;
}
case FlagValueStorageKind::kSequenceLocked: {
seq_lock_.Write(AtomicBufferValue(), src, Sizeof(op_));
break;
}
case FlagValueStorageKind::kHeapAllocated:
MaskedPointer ptr_value = PtrStorage().load(std::memory_order_acquire);
if (ptr_value.IsUnprotectedReadCandidate() && ptr_value.HasBeenRead()) {
// If current value is a candidate for an unprotected read and if it was
// already read at least once, follow up reads (if any) are done without
// mutex protection. We can't guarantee it is safe to reuse this memory
// since it may have been accessed by another thread concurrently, so
// instead we move the memory to a freelist so it can still be safely
// accessed, and allocate a new one for the new value.
AddToFreelist(ptr_value.Ptr());
ptr_value = MaskedPointer(Clone(op_, src), source == kCommandLine);
} else {
// Current value either was set programmatically or was never read.
// We can reuse the memory since all accesses to this value (if any)
// were protected by mutex. That said, if a new value comes from command
// line it now becomes a candidate for an unprotected read.
ptr_value.Set(op_, src, source == kCommandLine);
}
PtrStorage().store(ptr_value, std::memory_order_release);
seq_lock_.IncrementModificationCount();
break;
}
modified_ = true;
InvokeCallback();
}
absl::string_view FlagImpl::Name() const { return name_; }
absl::string_view FlagImpl::TypeName() const { return type_name_; }
std::string FlagImpl::Filename() const {
return flags_internal::GetUsageConfig().normalize_filename(filename_);
}
std::string FlagImpl::Help() const {
return HelpSourceKind() == FlagHelpKind::kLiteral ? help_.literal
: help_.gen_func();
}
FlagFastTypeId FlagImpl::TypeId() const {
return flags_internal::FastTypeId(op_);
}
int64_t FlagImpl::ModificationCount() const {
return seq_lock_.ModificationCount();
}
bool FlagImpl::IsSpecifiedOnCommandLine() const {
absl::MutexLock l(DataGuard());
return on_command_line_;
}
std::string FlagImpl::DefaultValue() const {
absl::MutexLock l(DataGuard());
auto obj = MakeInitValue();
return flags_internal::Unparse(op_, obj.get());
}
std::string FlagImpl::CurrentValue() const {
auto* guard = DataGuard(); // Make sure flag initialized
switch (ValueStorageKind()) {
case FlagValueStorageKind::kValueAndInitBit:
case FlagValueStorageKind::kOneWordAtomic: {
const auto one_word_val =
absl::bit_cast<std::array<char, sizeof(int64_t)>>(
OneWordValue().load(std::memory_order_acquire));
return flags_internal::Unparse(op_, one_word_val.data());
}
case FlagValueStorageKind::kSequenceLocked: {
std::unique_ptr<void, DynValueDeleter> cloned(flags_internal::Alloc(op_),
DynValueDeleter{op_});
ReadSequenceLockedData(cloned.get());
return flags_internal::Unparse(op_, cloned.get());
}
case FlagValueStorageKind::kHeapAllocated: {
absl::MutexLock l(guard);
return flags_internal::Unparse(
op_, PtrStorage().load(std::memory_order_acquire).Ptr());
}
}
return "";
}
void FlagImpl::SetCallback(const FlagCallbackFunc mutation_callback) {
absl::MutexLock l(DataGuard());
if (callback_ == nullptr) {
callback_ = new FlagCallback;
}
callback_->func = mutation_callback;
InvokeCallback();
}
void FlagImpl::InvokeCallback() const {
if (!callback_) return;
// Make a copy of the C-style function pointer that we are about to invoke
// before we release the lock guarding it.
FlagCallbackFunc cb = callback_->func;
// If the flag has a mutation callback this function invokes it. While the
// callback is being invoked the primary flag's mutex is unlocked and it is
// re-locked back after call to callback is completed. Callback invocation is
// guarded by flag's secondary mutex instead which prevents concurrent
// callback invocation. Note that it is possible for other thread to grab the
// primary lock and update flag's value at any time during the callback
// invocation. This is by design. Callback can get a value of the flag if
// necessary, but it might be different from the value initiated the callback
// and it also can be different by the time the callback invocation is
// completed. Requires that *primary_lock be held in exclusive mode; it may be
// released and reacquired by the implementation.
MutexRelock relock(*DataGuard());
absl::MutexLock lock(&callback_->guard);
cb();
}
std::unique_ptr<FlagStateInterface> FlagImpl::SaveState() {
absl::MutexLock l(DataGuard());
bool modified = modified_;
bool on_command_line = on_command_line_;
switch (ValueStorageKind()) {
case FlagValueStorageKind::kValueAndInitBit:
case FlagValueStorageKind::kOneWordAtomic: {
return absl::make_unique<FlagState>(
*this, OneWordValue().load(std::memory_order_acquire), modified,
on_command_line, ModificationCount());
}
case FlagValueStorageKind::kSequenceLocked: {
void* cloned = flags_internal::Alloc(op_);
// Read is guaranteed to be successful because we hold the lock.
bool success =
seq_lock_.TryRead(cloned, AtomicBufferValue(), Sizeof(op_));
assert(success);
static_cast<void>(success);
return absl::make_unique<FlagState>(*this, cloned, modified,
on_command_line, ModificationCount());
}
case FlagValueStorageKind::kHeapAllocated: {
return absl::make_unique<FlagState>(
*this,
flags_internal::Clone(
op_, PtrStorage().load(std::memory_order_acquire).Ptr()),
modified, on_command_line, ModificationCount());
}
}
return nullptr;
}
bool FlagImpl::RestoreState(const FlagState& flag_state) {
absl::MutexLock l(DataGuard());
if (flag_state.counter_ == ModificationCount()) {
return false;
}
switch (ValueStorageKind()) {
case FlagValueStorageKind::kValueAndInitBit:
case FlagValueStorageKind::kOneWordAtomic:
StoreValue(&flag_state.value_.one_word, kProgrammaticChange);
break;
case FlagValueStorageKind::kSequenceLocked:
case FlagValueStorageKind::kHeapAllocated:
StoreValue(flag_state.value_.heap_allocated, kProgrammaticChange);
break;
}
modified_ = flag_state.modified_;
on_command_line_ = flag_state.on_command_line_;
return true;
}
template <typename StorageT>
StorageT* FlagImpl::OffsetValue() const {
char* p = reinterpret_cast<char*>(const_cast<FlagImpl*>(this));
// The offset is deduced via Flag value type specific op_.
ptrdiff_t offset = flags_internal::ValueOffset(op_);
return reinterpret_cast<StorageT*>(p + offset);
}
std::atomic<uint64_t>* FlagImpl::AtomicBufferValue() const {
assert(ValueStorageKind() == FlagValueStorageKind::kSequenceLocked);
return OffsetValue<std::atomic<uint64_t>>();
}
std::atomic<int64_t>& FlagImpl::OneWordValue() const {
assert(ValueStorageKind() == FlagValueStorageKind::kOneWordAtomic ||
ValueStorageKind() == FlagValueStorageKind::kValueAndInitBit);
return OffsetValue<FlagOneWordValue>()->value;
}
std::atomic<MaskedPointer>& FlagImpl::PtrStorage() const {
assert(ValueStorageKind() == FlagValueStorageKind::kHeapAllocated);
return OffsetValue<FlagMaskedPointerValue>()->value;
}
// Attempts to parse supplied `value` string using parsing routine in the `flag`
// argument. If parsing successful, this function replaces the dst with newly
// parsed value. In case if any error is encountered in either step, the error
// message is stored in 'err'
std::unique_ptr<void, DynValueDeleter> FlagImpl::TryParse(
absl::string_view value, std::string& err) const {
std::unique_ptr<void, DynValueDeleter> tentative_value = MakeInitValue();
std::string parse_err;
if (!flags_internal::Parse(op_, value, tentative_value.get(), &parse_err)) {
absl::string_view err_sep = parse_err.empty() ? "" : "; ";
err = absl::StrCat("Illegal value '", value, "' specified for flag '",
Name(), "'", err_sep, parse_err);
return nullptr;
}
return tentative_value;
}
void FlagImpl::Read(void* dst) const {
auto* guard = DataGuard(); // Make sure flag initialized
switch (ValueStorageKind()) {
case FlagValueStorageKind::kValueAndInitBit:
case FlagValueStorageKind::kOneWordAtomic: {
const int64_t one_word_val =
OneWordValue().load(std::memory_order_acquire);
std::memcpy(dst, &one_word_val, Sizeof(op_));
break;
}
case FlagValueStorageKind::kSequenceLocked: {
ReadSequenceLockedData(dst);
break;
}
case FlagValueStorageKind::kHeapAllocated: {
absl::MutexLock l(guard);
MaskedPointer ptr_value = PtrStorage().load(std::memory_order_acquire);
flags_internal::CopyConstruct(op_, ptr_value.Ptr(), dst);
// For unprotected read candidates, mark that the value as has been read.
if (ptr_value.IsUnprotectedReadCandidate() && !ptr_value.HasBeenRead()) {
ptr_value.MarkAsRead();
PtrStorage().store(ptr_value, std::memory_order_release);
}
break;
}
}
}
int64_t FlagImpl::ReadOneWord() const {
assert(ValueStorageKind() == FlagValueStorageKind::kOneWordAtomic ||
ValueStorageKind() == FlagValueStorageKind::kValueAndInitBit);
auto* guard = DataGuard(); // Make sure flag initialized
(void)guard;
return OneWordValue().load(std::memory_order_acquire);
}
bool FlagImpl::ReadOneBool() const {
assert(ValueStorageKind() == FlagValueStorageKind::kValueAndInitBit);
auto* guard = DataGuard(); // Make sure flag initialized
(void)guard;
return absl::bit_cast<FlagValueAndInitBit<bool>>(
OneWordValue().load(std::memory_order_acquire))
.value;
}
void FlagImpl::ReadSequenceLockedData(void* dst) const {
size_t size = Sizeof(op_);
// Attempt to read using the sequence lock.
if (ABSL_PREDICT_TRUE(seq_lock_.TryRead(dst, AtomicBufferValue(), size))) {
return;
}
// We failed due to contention. Acquire the lock to prevent contention
// and try again.
absl::ReaderMutexLock l(DataGuard());
bool success = seq_lock_.TryRead(dst, AtomicBufferValue(), size);
assert(success);
static_cast<void>(success);
}
void FlagImpl::Write(const void* src) {
absl::MutexLock l(DataGuard());
if (ShouldValidateFlagValue(flags_internal::FastTypeId(op_))) {
std::unique_ptr<void, DynValueDeleter> obj{flags_internal::Clone(op_, src),
DynValueDeleter{op_}};
std::string ignored_error;
std::string src_as_str = flags_internal::Unparse(op_, src);
if (!flags_internal::Parse(op_, src_as_str, obj.get(), &ignored_error)) {
ABSL_INTERNAL_LOG(ERROR, absl::StrCat("Attempt to set flag '", Name(),
"' to invalid value ", src_as_str));
}
}
StoreValue(src, kProgrammaticChange);
}
// Sets the value of the flag based on specified string `value`. If the flag
// was successfully set to new value, it returns true. Otherwise, sets `err`
// to indicate the error, leaves the flag unchanged, and returns false. There
// are three ways to set the flag's value:
// * Update the current flag value
// * Update the flag's default value
// * Update the current flag value if it was never set before
// The mode is selected based on 'set_mode' parameter.
bool FlagImpl::ParseFrom(absl::string_view value, FlagSettingMode set_mode,
ValueSource source, std::string& err) {
absl::MutexLock l(DataGuard());
switch (set_mode) {
case SET_FLAGS_VALUE: {
// set or modify the flag's value
auto tentative_value = TryParse(value, err);
if (!tentative_value) return false;
StoreValue(tentative_value.get(), source);
if (source == kCommandLine) {
on_command_line_ = true;
}
break;
}
case SET_FLAG_IF_DEFAULT: {
// set the flag's value, but only if it hasn't been set by someone else
if (modified_) {
// TODO(rogeeff): review and fix this semantic. Currently we do not fail
// in this case if flag is modified. This is misleading since the flag's
// value is not updated even though we return true.
// *err = absl::StrCat(Name(), " is already set to ",
// CurrentValue(), "\n");
// return false;
return true;
}
auto tentative_value = TryParse(value, err);
if (!tentative_value) return false;
StoreValue(tentative_value.get(), source);
break;
}
case SET_FLAGS_DEFAULT: {
auto tentative_value = TryParse(value, err);
if (!tentative_value) return false;
if (DefaultKind() == FlagDefaultKind::kDynamicValue) {
void* old_value = default_value_.dynamic_value;
default_value_.dynamic_value = tentative_value.release();
tentative_value.reset(old_value);
} else {
default_value_.dynamic_value = tentative_value.release();
def_kind_ = static_cast<uint8_t>(FlagDefaultKind::kDynamicValue);
}
if (!modified_) {
// Need to set both default value *and* current, in this case.
StoreValue(default_value_.dynamic_value, source);
modified_ = false;
}
break;
}
}
return true;
}
void FlagImpl::CheckDefaultValueParsingRoundtrip() const {
std::string v = DefaultValue();
absl::MutexLock lock(DataGuard());
auto dst = MakeInitValue();
std::string error;
if (!flags_internal::Parse(op_, v, dst.get(), &error)) {
ABSL_INTERNAL_LOG(
FATAL,
absl::StrCat("Flag ", Name(), " (from ", Filename(),
"): string form of default value '", v,
"' could not be parsed; error=", error));
}
// We do not compare dst to def since parsing/unparsing may make
// small changes, e.g., precision loss for floating point types.
}
bool FlagImpl::ValidateInputValue(absl::string_view value) const {
absl::MutexLock l(DataGuard());
auto obj = MakeInitValue();
std::string ignored_error;
return flags_internal::Parse(op_, value, obj.get(), &ignored_error);
}
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl

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@ -0,0 +1,969 @@
//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_FLAGS_INTERNAL_FLAG_H_
#define ABSL_FLAGS_INTERNAL_FLAG_H_
#include <stddef.h>
#include <stdint.h>
#include <atomic>
#include <cstring>
#include <memory>
#include <string>
#include <type_traits>
#include <typeinfo>
#include "absl/base/attributes.h"
#include "absl/base/call_once.h"
#include "absl/base/casts.h"
#include "absl/base/config.h"
#include "absl/base/optimization.h"
#include "absl/base/thread_annotations.h"
#include "absl/flags/commandlineflag.h"
#include "absl/flags/config.h"
#include "absl/flags/internal/commandlineflag.h"
#include "absl/flags/internal/registry.h"
#include "absl/flags/internal/sequence_lock.h"
#include "absl/flags/marshalling.h"
#include "absl/meta/type_traits.h"
#include "absl/strings/string_view.h"
#include "absl/synchronization/mutex.h"
#include "absl/utility/utility.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
///////////////////////////////////////////////////////////////////////////////
// Forward declaration of absl::Flag<T> public API.
namespace flags_internal {
template <typename T>
class Flag;
} // namespace flags_internal
template <typename T>
using Flag = flags_internal::Flag<T>;
template <typename T>
ABSL_MUST_USE_RESULT T GetFlag(const absl::Flag<T>& flag);
template <typename T>
void SetFlag(absl::Flag<T>* flag, const T& v);
template <typename T, typename V>
void SetFlag(absl::Flag<T>* flag, const V& v);
template <typename U>
const CommandLineFlag& GetFlagReflectionHandle(const absl::Flag<U>& f);
///////////////////////////////////////////////////////////////////////////////
// Flag value type operations, eg., parsing, copying, etc. are provided
// by function specific to that type with a signature matching FlagOpFn.
namespace flags_internal {
enum class FlagOp {
kAlloc,
kDelete,
kCopy,
kCopyConstruct,
kSizeof,
kFastTypeId,
kRuntimeTypeId,
kParse,
kUnparse,
kValueOffset,
};
using FlagOpFn = void* (*)(FlagOp, const void*, void*, void*);
// Forward declaration for Flag value specific operations.
template <typename T>
void* FlagOps(FlagOp op, const void* v1, void* v2, void* v3);
// Allocate aligned memory for a flag value.
inline void* Alloc(FlagOpFn op) {
return op(FlagOp::kAlloc, nullptr, nullptr, nullptr);
}
// Deletes memory interpreting obj as flag value type pointer.
inline void Delete(FlagOpFn op, void* obj) {
op(FlagOp::kDelete, nullptr, obj, nullptr);
}
// Copies src to dst interpreting as flag value type pointers.
inline void Copy(FlagOpFn op, const void* src, void* dst) {
op(FlagOp::kCopy, src, dst, nullptr);
}
// Construct a copy of flag value in a location pointed by dst
// based on src - pointer to the flag's value.
inline void CopyConstruct(FlagOpFn op, const void* src, void* dst) {
op(FlagOp::kCopyConstruct, src, dst, nullptr);
}
// Makes a copy of flag value pointed by obj.
inline void* Clone(FlagOpFn op, const void* obj) {
void* res = flags_internal::Alloc(op);
flags_internal::CopyConstruct(op, obj, res);
return res;
}
// Returns true if parsing of input text is successful.
inline bool Parse(FlagOpFn op, absl::string_view text, void* dst,
std::string* error) {
return op(FlagOp::kParse, &text, dst, error) != nullptr;
}
// Returns string representing supplied value.
inline std::string Unparse(FlagOpFn op, const void* val) {
std::string result;
op(FlagOp::kUnparse, val, &result, nullptr);
return result;
}
// Returns size of flag value type.
inline size_t Sizeof(FlagOpFn op) {
// This sequence of casts reverses the sequence from
// `flags_internal::FlagOps()`
return static_cast<size_t>(reinterpret_cast<intptr_t>(
op(FlagOp::kSizeof, nullptr, nullptr, nullptr)));
}
// Returns fast type id corresponding to the value type.
inline FlagFastTypeId FastTypeId(FlagOpFn op) {
return reinterpret_cast<FlagFastTypeId>(
op(FlagOp::kFastTypeId, nullptr, nullptr, nullptr));
}
// Returns fast type id corresponding to the value type.
inline const std::type_info* RuntimeTypeId(FlagOpFn op) {
return reinterpret_cast<const std::type_info*>(
op(FlagOp::kRuntimeTypeId, nullptr, nullptr, nullptr));
}
// Returns offset of the field value_ from the field impl_ inside of
// absl::Flag<T> data. Given FlagImpl pointer p you can get the
// location of the corresponding value as:
// reinterpret_cast<char*>(p) + ValueOffset().
inline ptrdiff_t ValueOffset(FlagOpFn op) {
// This sequence of casts reverses the sequence from
// `flags_internal::FlagOps()`
return static_cast<ptrdiff_t>(reinterpret_cast<intptr_t>(
op(FlagOp::kValueOffset, nullptr, nullptr, nullptr)));
}
// Returns an address of RTTI's typeid(T).
template <typename T>
inline const std::type_info* GenRuntimeTypeId() {
#ifdef ABSL_INTERNAL_HAS_RTTI
return &typeid(T);
#else
return nullptr;
#endif
}
///////////////////////////////////////////////////////////////////////////////
// Flag help auxiliary structs.
// This is help argument for absl::Flag encapsulating the string literal pointer
// or pointer to function generating it as well as enum descriminating two
// cases.
using HelpGenFunc = std::string (*)();
template <size_t N>
struct FixedCharArray {
char value[N];
template <size_t... I>
static constexpr FixedCharArray<N> FromLiteralString(
absl::string_view str, absl::index_sequence<I...>) {
return (void)str, FixedCharArray<N>({{str[I]..., '\0'}});
}
};
template <typename Gen, size_t N = Gen::Value().size()>
constexpr FixedCharArray<N + 1> HelpStringAsArray(int) {
return FixedCharArray<N + 1>::FromLiteralString(
Gen::Value(), absl::make_index_sequence<N>{});
}
template <typename Gen>
constexpr std::false_type HelpStringAsArray(char) {
return std::false_type{};
}
union FlagHelpMsg {
constexpr explicit FlagHelpMsg(const char* help_msg) : literal(help_msg) {}
constexpr explicit FlagHelpMsg(HelpGenFunc help_gen) : gen_func(help_gen) {}
const char* literal;
HelpGenFunc gen_func;
};
enum class FlagHelpKind : uint8_t { kLiteral = 0, kGenFunc = 1 };
struct FlagHelpArg {
FlagHelpMsg source;
FlagHelpKind kind;
};
extern const char kStrippedFlagHelp[];
// These two HelpArg overloads allows us to select at compile time one of two
// way to pass Help argument to absl::Flag. We'll be passing
// AbslFlagHelpGenFor##name as Gen and integer 0 as a single argument to prefer
// first overload if possible. If help message is evaluatable on constexpr
// context We'll be able to make FixedCharArray out of it and we'll choose first
// overload. In this case the help message expression is immediately evaluated
// and is used to construct the absl::Flag. No additional code is generated by
// ABSL_FLAG Otherwise SFINAE kicks in and first overload is dropped from the
// consideration, in which case the second overload will be used. The second
// overload does not attempt to evaluate the help message expression
// immediately and instead delays the evaluation by returning the function
// pointer (&T::NonConst) generating the help message when necessary. This is
// evaluatable in constexpr context, but the cost is an extra function being
// generated in the ABSL_FLAG code.
template <typename Gen, size_t N>
constexpr FlagHelpArg HelpArg(const FixedCharArray<N>& value) {
return {FlagHelpMsg(value.value), FlagHelpKind::kLiteral};
}
template <typename Gen>
constexpr FlagHelpArg HelpArg(std::false_type) {
return {FlagHelpMsg(&Gen::NonConst), FlagHelpKind::kGenFunc};
}
///////////////////////////////////////////////////////////////////////////////
// Flag default value auxiliary structs.
// Signature for the function generating the initial flag value (usually
// based on default value supplied in flag's definition)
using FlagDfltGenFunc = void (*)(void*);
union FlagDefaultSrc {
constexpr explicit FlagDefaultSrc(FlagDfltGenFunc gen_func_arg)
: gen_func(gen_func_arg) {}
#define ABSL_FLAGS_INTERNAL_DFLT_FOR_TYPE(T, name) \
T name##_value; \
constexpr explicit FlagDefaultSrc(T value) : name##_value(value) {} // NOLINT
ABSL_FLAGS_INTERNAL_BUILTIN_TYPES(ABSL_FLAGS_INTERNAL_DFLT_FOR_TYPE)
#undef ABSL_FLAGS_INTERNAL_DFLT_FOR_TYPE
void* dynamic_value;
FlagDfltGenFunc gen_func;
};
enum class FlagDefaultKind : uint8_t {
kDynamicValue = 0,
kGenFunc = 1,
kOneWord = 2 // for default values UP to one word in size
};
struct FlagDefaultArg {
FlagDefaultSrc source;
FlagDefaultKind kind;
};
// This struct and corresponding overload to InitDefaultValue are used to
// facilitate usage of {} as default value in ABSL_FLAG macro.
// TODO(rogeeff): Fix handling types with explicit constructors.
struct EmptyBraces {};
template <typename T>
constexpr T InitDefaultValue(T t) {
return t;
}
template <typename T>
constexpr T InitDefaultValue(EmptyBraces) {
return T{};
}
template <typename ValueT, typename GenT,
typename std::enable_if<std::is_integral<ValueT>::value, int>::type =
((void)GenT{}, 0)>
constexpr FlagDefaultArg DefaultArg(int) {
return {FlagDefaultSrc(GenT{}.value), FlagDefaultKind::kOneWord};
}
template <typename ValueT, typename GenT>
constexpr FlagDefaultArg DefaultArg(char) {
return {FlagDefaultSrc(&GenT::Gen), FlagDefaultKind::kGenFunc};
}
///////////////////////////////////////////////////////////////////////////////
// Flag storage selector traits. Each trait indicates what kind of storage kind
// to use for the flag value.
template <typename T>
using FlagUseValueAndInitBitStorage =
std::integral_constant<bool, std::is_trivially_copyable<T>::value &&
std::is_default_constructible<T>::value &&
(sizeof(T) < 8)>;
template <typename T>
using FlagUseOneWordStorage =
std::integral_constant<bool, std::is_trivially_copyable<T>::value &&
(sizeof(T) <= 8)>;
template <class T>
using FlagUseSequenceLockStorage =
std::integral_constant<bool, std::is_trivially_copyable<T>::value &&
(sizeof(T) > 8)>;
enum class FlagValueStorageKind : uint8_t {
kValueAndInitBit = 0,
kOneWordAtomic = 1,
kSequenceLocked = 2,
kHeapAllocated = 3,
};
// This constexpr function returns the storage kind for the given flag value
// type.
template <typename T>
static constexpr FlagValueStorageKind StorageKind() {
return FlagUseValueAndInitBitStorage<T>::value
? FlagValueStorageKind::kValueAndInitBit
: FlagUseOneWordStorage<T>::value
? FlagValueStorageKind::kOneWordAtomic
: FlagUseSequenceLockStorage<T>::value
? FlagValueStorageKind::kSequenceLocked
: FlagValueStorageKind::kHeapAllocated;
}
// This is a base class for the storage classes used by kOneWordAtomic and
// kValueAndInitBit storage kinds. It literally just stores the one word value
// as an atomic. By default, it is initialized to a magic value that is unlikely
// a valid value for the flag value type.
struct FlagOneWordValue {
constexpr static int64_t Uninitialized() {
return static_cast<int64_t>(0xababababababababll);
}
constexpr FlagOneWordValue() : value(Uninitialized()) {}
constexpr explicit FlagOneWordValue(int64_t v) : value(v) {}
std::atomic<int64_t> value;
};
// This class represents a memory layout used by kValueAndInitBit storage kind.
template <typename T>
struct alignas(8) FlagValueAndInitBit {
T value;
// Use an int instead of a bool to guarantee that a non-zero value has
// a bit set.
uint8_t init;
};
// This class implements an aligned pointer with two options stored via masks
// in unused bits of the pointer value (due to alignment requirement).
// - IsUnprotectedReadCandidate - indicates that the value can be switched to
// unprotected read without a lock.
// - HasBeenRead - indicates that the value has been read at least once.
// - AllowsUnprotectedRead - combination of the two options above and indicates
// that the value can now be read without a lock.
// Further details of these options and their use is covered in the description
// of the FlagValue<T, FlagValueStorageKind::kHeapAllocated> specialization.
class MaskedPointer {
public:
using mask_t = uintptr_t;
using ptr_t = void*;
static constexpr int RequiredAlignment() { return 4; }
constexpr MaskedPointer() : ptr_(nullptr) {}
constexpr explicit MaskedPointer(ptr_t rhs) : ptr_(rhs) {}
MaskedPointer(ptr_t rhs, bool is_candidate);
MaskedPointer(const MaskedPointer& rhs) = default;
MaskedPointer& operator=(const MaskedPointer& rhs) = default;
void* Ptr() const {
return reinterpret_cast<void*>(reinterpret_cast<mask_t>(ptr_) &
kPtrValueMask);
}
bool AllowsUnprotectedRead() const {
return (reinterpret_cast<mask_t>(ptr_) & kAllowsUnprotectedRead) ==
kAllowsUnprotectedRead;
}
bool IsUnprotectedReadCandidate() const;
bool HasBeenRead() const;
void Set(FlagOpFn op, const void* src, bool is_candidate);
void MarkAsRead();
private:
// Masks
// Indicates that the flag value either default or originated from command
// line.
static constexpr mask_t kUnprotectedReadCandidate = 0x1u;
// Indicates that flag has been read.
static constexpr mask_t kHasBeenRead = 0x2u;
static constexpr mask_t kAllowsUnprotectedRead =
kUnprotectedReadCandidate | kHasBeenRead;
static constexpr mask_t kPtrValueMask = ~kAllowsUnprotectedRead;
void ApplyMask(mask_t mask);
bool CheckMask(mask_t mask) const;
ptr_t ptr_;
};
// This class implements a type erased storage of the heap allocated flag value.
// It is used as a base class for the storage class for kHeapAllocated storage
// kind. The initial_buffer is expected to have an alignment of at least
// MaskedPointer::RequiredAlignment(), so that the bits used by the
// MaskedPointer to store masks are set to 0. This guarantees that value starts
// in an uninitialized state.
struct FlagMaskedPointerValue {
constexpr explicit FlagMaskedPointerValue(MaskedPointer::ptr_t initial_buffer)
: value(MaskedPointer(initial_buffer)) {}
std::atomic<MaskedPointer> value;
};
// This is the forward declaration for the template that represents a storage
// for the flag values. This template is expected to be explicitly specialized
// for each storage kind and it does not have a generic default
// implementation.
template <typename T,
FlagValueStorageKind Kind = flags_internal::StorageKind<T>()>
struct FlagValue;
// This specialization represents the storage of flag values types with the
// kValueAndInitBit storage kind. It is based on the FlagOneWordValue class
// and relies on memory layout in FlagValueAndInitBit<T> to indicate that the
// value has been initialized or not.
template <typename T>
struct FlagValue<T, FlagValueStorageKind::kValueAndInitBit> : FlagOneWordValue {
constexpr FlagValue() : FlagOneWordValue(0) {}
bool Get(const SequenceLock&, T& dst) const {
int64_t storage = value.load(std::memory_order_acquire);
if (ABSL_PREDICT_FALSE(storage == 0)) {
// This assert is to ensure that the initialization inside FlagImpl::Init
// is able to set init member correctly.
static_assert(offsetof(FlagValueAndInitBit<T>, init) == sizeof(T),
"Unexpected memory layout of FlagValueAndInitBit");
return false;
}
dst = absl::bit_cast<FlagValueAndInitBit<T>>(storage).value;
return true;
}
};
// This specialization represents the storage of flag values types with the
// kOneWordAtomic storage kind. It is based on the FlagOneWordValue class
// and relies on the magic uninitialized state of default constructed instead of
// FlagOneWordValue to indicate that the value has been initialized or not.
template <typename T>
struct FlagValue<T, FlagValueStorageKind::kOneWordAtomic> : FlagOneWordValue {
constexpr FlagValue() : FlagOneWordValue() {}
bool Get(const SequenceLock&, T& dst) const {
int64_t one_word_val = value.load(std::memory_order_acquire);
if (ABSL_PREDICT_FALSE(one_word_val == FlagOneWordValue::Uninitialized())) {
return false;
}
std::memcpy(&dst, static_cast<const void*>(&one_word_val), sizeof(T));
return true;
}
};
// This specialization represents the storage of flag values types with the
// kSequenceLocked storage kind. This storage is used by trivially copyable
// types with size greater than 8 bytes. This storage relies on uninitialized
// state of the SequenceLock to indicate that the value has been initialized or
// not. This storage also provides lock-free read access to the underlying
// value once it is initialized.
template <typename T>
struct FlagValue<T, FlagValueStorageKind::kSequenceLocked> {
bool Get(const SequenceLock& lock, T& dst) const {
return lock.TryRead(&dst, value_words, sizeof(T));
}
static constexpr int kNumWords =
flags_internal::AlignUp(sizeof(T), sizeof(uint64_t)) / sizeof(uint64_t);
alignas(T) alignas(
std::atomic<uint64_t>) std::atomic<uint64_t> value_words[kNumWords];
};
// This specialization represents the storage of flag values types with the
// kHeapAllocated storage kind. This is a storage of last resort and is used
// if none of other storage kinds are applicable.
//
// Generally speaking the values with this storage kind can't be accessed
// atomically and thus can't be read without holding a lock. If we would ever
// want to avoid the lock, we'd need to leak the old value every time new flag
// value is being set (since we are in danger of having a race condition
// otherwise).
//
// Instead of doing that, this implementation attempts to cater to some common
// use cases by allowing at most 2 values to be leaked - default value and
// value set from the command line.
//
// This specialization provides an initial buffer for the first flag value. This
// is where the default value is going to be stored. We attempt to reuse this
// buffer if possible, including storing the value set from the command line
// there.
//
// As long as we only read this value, we can access it without a lock (in
// practice we still use the lock for the very first read to be able set
// "has been read" option on this flag).
//
// If flag is specified on the command line we store the parsed value either
// in the internal buffer (if the default value never been read) or we leak the
// default value and allocate the new storage for the parse value. This value is
// also a candidate for an unprotected read. If flag is set programmatically
// after the command line is parsed, the storage for this value is going to be
// leaked. Note that in both scenarios we are not going to have a real leak.
// Instead we'll store the leaked value pointers in the internal freelist to
// avoid triggering the memory leak checker complains.
//
// If the flag is ever set programmatically, it stops being the candidate for an
// unprotected read, and any follow up access to the flag value requires a lock.
// Note that if the value if set programmatically before the command line is
// parsed, we can switch back to enabling unprotected reads for that value.
template <typename T>
struct FlagValue<T, FlagValueStorageKind::kHeapAllocated>
: FlagMaskedPointerValue {
// We const initialize the value with unmasked pointer to the internal buffer,
// making sure it is not a candidate for unprotected read. This way we can
// ensure Init is done before any access to the flag value.
constexpr FlagValue() : FlagMaskedPointerValue(&buffer[0]) {}
bool Get(const SequenceLock&, T& dst) const {
MaskedPointer ptr_value = value.load(std::memory_order_acquire);
if (ABSL_PREDICT_TRUE(ptr_value.AllowsUnprotectedRead())) {
::new (static_cast<void*>(&dst)) T(*static_cast<T*>(ptr_value.Ptr()));
return true;
}
return false;
}
alignas(MaskedPointer::RequiredAlignment()) alignas(
T) char buffer[sizeof(T)]{};
};
///////////////////////////////////////////////////////////////////////////////
// Flag callback auxiliary structs.
// Signature for the mutation callback used by watched Flags
// The callback is noexcept.
// TODO(rogeeff): add noexcept after C++17 support is added.
using FlagCallbackFunc = void (*)();
struct FlagCallback {
FlagCallbackFunc func;
absl::Mutex guard; // Guard for concurrent callback invocations.
};
///////////////////////////////////////////////////////////////////////////////
// Flag implementation, which does not depend on flag value type.
// The class encapsulates the Flag's data and access to it.
struct DynValueDeleter {
explicit DynValueDeleter(FlagOpFn op_arg = nullptr);
void operator()(void* ptr) const;
FlagOpFn op;
};
class FlagState;
// These are only used as constexpr global objects.
// They do not use a virtual destructor to simplify their implementation.
// They are not destroyed except at program exit, so leaks do not matter.
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
#endif
class FlagImpl final : public CommandLineFlag {
public:
constexpr FlagImpl(const char* name, const char* type_name,
const char* filename, FlagOpFn op, FlagHelpArg help,
FlagValueStorageKind value_kind,
FlagDefaultArg default_arg)
: name_(name),
type_name_(type_name),
filename_(filename),
op_(op),
help_(help.source),
help_source_kind_(static_cast<uint8_t>(help.kind)),
value_storage_kind_(static_cast<uint8_t>(value_kind)),
def_kind_(static_cast<uint8_t>(default_arg.kind)),
modified_(false),
on_command_line_(false),
callback_(nullptr),
default_value_(default_arg.source),
data_guard_{} {}
// Constant access methods
int64_t ReadOneWord() const ABSL_LOCKS_EXCLUDED(*DataGuard());
bool ReadOneBool() const ABSL_LOCKS_EXCLUDED(*DataGuard());
void Read(void* dst) const override ABSL_LOCKS_EXCLUDED(*DataGuard());
void Read(bool* value) const ABSL_LOCKS_EXCLUDED(*DataGuard()) {
*value = ReadOneBool();
}
template <typename T,
absl::enable_if_t<flags_internal::StorageKind<T>() ==
FlagValueStorageKind::kOneWordAtomic,
int> = 0>
void Read(T* value) const ABSL_LOCKS_EXCLUDED(*DataGuard()) {
int64_t v = ReadOneWord();
std::memcpy(value, static_cast<const void*>(&v), sizeof(T));
}
template <typename T,
typename std::enable_if<flags_internal::StorageKind<T>() ==
FlagValueStorageKind::kValueAndInitBit,
int>::type = 0>
void Read(T* value) const ABSL_LOCKS_EXCLUDED(*DataGuard()) {
*value = absl::bit_cast<FlagValueAndInitBit<T>>(ReadOneWord()).value;
}
// Mutating access methods
void Write(const void* src) ABSL_LOCKS_EXCLUDED(*DataGuard());
// Interfaces to operate on callbacks.
void SetCallback(const FlagCallbackFunc mutation_callback)
ABSL_LOCKS_EXCLUDED(*DataGuard());
void InvokeCallback() const ABSL_EXCLUSIVE_LOCKS_REQUIRED(*DataGuard());
// Used in read/write operations to validate source/target has correct type.
// For example if flag is declared as absl::Flag<int> FLAGS_foo, a call to
// absl::GetFlag(FLAGS_foo) validates that the type of FLAGS_foo is indeed
// int. To do that we pass the assumed type id (which is deduced from type
// int) as an argument `type_id`, which is in turn is validated against the
// type id stored in flag object by flag definition statement.
void AssertValidType(FlagFastTypeId type_id,
const std::type_info* (*gen_rtti)()) const;
private:
template <typename T>
friend class Flag;
friend class FlagState;
// Ensures that `data_guard_` is initialized and returns it.
absl::Mutex* DataGuard() const
ABSL_LOCK_RETURNED(reinterpret_cast<absl::Mutex*>(data_guard_));
// Returns heap allocated value of type T initialized with default value.
std::unique_ptr<void, DynValueDeleter> MakeInitValue() const
ABSL_EXCLUSIVE_LOCKS_REQUIRED(*DataGuard());
// Flag initialization called via absl::call_once.
void Init();
// Offset value access methods. One per storage kind. These methods to not
// respect const correctness, so be very careful using them.
// This is a shared helper routine which encapsulates most of the magic. Since
// it is only used inside the three routines below, which are defined in
// flag.cc, we can define it in that file as well.
template <typename StorageT>
StorageT* OffsetValue() const;
// The same as above, but used for sequencelock-protected storage.
std::atomic<uint64_t>* AtomicBufferValue() const;
// This is an accessor for a value stored as one word atomic. Returns a
// mutable reference to an atomic value.
std::atomic<int64_t>& OneWordValue() const;
std::atomic<MaskedPointer>& PtrStorage() const;
// Attempts to parse supplied `value` string. If parsing is successful,
// returns new value. Otherwise returns nullptr.
std::unique_ptr<void, DynValueDeleter> TryParse(absl::string_view value,
std::string& err) const
ABSL_EXCLUSIVE_LOCKS_REQUIRED(*DataGuard());
// Stores the flag value based on the pointer to the source.
void StoreValue(const void* src, ValueSource source)
ABSL_EXCLUSIVE_LOCKS_REQUIRED(*DataGuard());
// Copy the flag data, protected by `seq_lock_` into `dst`.
//
// REQUIRES: ValueStorageKind() == kSequenceLocked.
void ReadSequenceLockedData(void* dst) const
ABSL_LOCKS_EXCLUDED(*DataGuard());
FlagHelpKind HelpSourceKind() const {
return static_cast<FlagHelpKind>(help_source_kind_);
}
FlagValueStorageKind ValueStorageKind() const {
return static_cast<FlagValueStorageKind>(value_storage_kind_);
}
FlagDefaultKind DefaultKind() const
ABSL_EXCLUSIVE_LOCKS_REQUIRED(*DataGuard()) {
return static_cast<FlagDefaultKind>(def_kind_);
}
// CommandLineFlag interface implementation
absl::string_view Name() const override;
absl::string_view TypeName() const override;
std::string Filename() const override;
std::string Help() const override;
FlagFastTypeId TypeId() const override;
bool IsSpecifiedOnCommandLine() const override
ABSL_LOCKS_EXCLUDED(*DataGuard());
std::string DefaultValue() const override ABSL_LOCKS_EXCLUDED(*DataGuard());
std::string CurrentValue() const override ABSL_LOCKS_EXCLUDED(*DataGuard());
bool ValidateInputValue(absl::string_view value) const override
ABSL_LOCKS_EXCLUDED(*DataGuard());
void CheckDefaultValueParsingRoundtrip() const override
ABSL_LOCKS_EXCLUDED(*DataGuard());
int64_t ModificationCount() const ABSL_EXCLUSIVE_LOCKS_REQUIRED(*DataGuard());
// Interfaces to save and restore flags to/from persistent state.
// Returns current flag state or nullptr if flag does not support
// saving and restoring a state.
std::unique_ptr<FlagStateInterface> SaveState() override
ABSL_LOCKS_EXCLUDED(*DataGuard());
// Restores the flag state to the supplied state object. If there is
// nothing to restore returns false. Otherwise returns true.
bool RestoreState(const FlagState& flag_state)
ABSL_LOCKS_EXCLUDED(*DataGuard());
bool ParseFrom(absl::string_view value, FlagSettingMode set_mode,
ValueSource source, std::string& error) override
ABSL_LOCKS_EXCLUDED(*DataGuard());
// Immutable flag's state.
// Flags name passed to ABSL_FLAG as second arg.
const char* const name_;
// Flags type passed to ABSL_FLAG as first arg.
const char* const type_name_;
// The file name where ABSL_FLAG resides.
const char* const filename_;
// Type-specific operations vtable.
const FlagOpFn op_;
// Help message literal or function to generate it.
const FlagHelpMsg help_;
// Indicates if help message was supplied as literal or generator func.
const uint8_t help_source_kind_ : 1;
// Kind of storage this flag is using for the flag's value.
const uint8_t value_storage_kind_ : 2;
uint8_t : 0; // The bytes containing the const bitfields must not be
// shared with bytes containing the mutable bitfields.
// Mutable flag's state (guarded by `data_guard_`).
// def_kind_ is not guard by DataGuard() since it is accessed in Init without
// locks.
uint8_t def_kind_ : 2;
// Has this flag's value been modified?
bool modified_ : 1 ABSL_GUARDED_BY(*DataGuard());
// Has this flag been specified on command line.
bool on_command_line_ : 1 ABSL_GUARDED_BY(*DataGuard());
// Unique tag for absl::call_once call to initialize this flag.
absl::once_flag init_control_;
// Sequence lock / mutation counter.
flags_internal::SequenceLock seq_lock_;
// Optional flag's callback and absl::Mutex to guard the invocations.
FlagCallback* callback_ ABSL_GUARDED_BY(*DataGuard());
// Either a pointer to the function generating the default value based on the
// value specified in ABSL_FLAG or pointer to the dynamically set default
// value via SetCommandLineOptionWithMode. def_kind_ is used to distinguish
// these two cases.
FlagDefaultSrc default_value_;
// This is reserved space for an absl::Mutex to guard flag data. It will be
// initialized in FlagImpl::Init via placement new.
// We can't use "absl::Mutex data_guard_", since this class is not literal.
// We do not want to use "absl::Mutex* data_guard_", since this would require
// heap allocation during initialization, which is both slows program startup
// and can fail. Using reserved space + placement new allows us to avoid both
// problems.
alignas(absl::Mutex) mutable char data_guard_[sizeof(absl::Mutex)];
};
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic pop
#endif
///////////////////////////////////////////////////////////////////////////////
// The Flag object parameterized by the flag's value type. This class implements
// flag reflection handle interface.
template <typename T>
class Flag {
public:
constexpr Flag(const char* name, const char* type_name, const char* filename,
FlagHelpArg help, const FlagDefaultArg default_arg)
: impl_(name, type_name, filename, &FlagOps<T>, help,
flags_internal::StorageKind<T>(), default_arg),
value_() {}
// CommandLineFlag interface
absl::string_view Name() const { return impl_.Name(); }
std::string Filename() const { return impl_.Filename(); }
std::string Help() const { return impl_.Help(); }
// Do not use. To be removed.
bool IsSpecifiedOnCommandLine() const {
return impl_.IsSpecifiedOnCommandLine();
}
std::string DefaultValue() const { return impl_.DefaultValue(); }
std::string CurrentValue() const { return impl_.CurrentValue(); }
private:
template <typename, bool>
friend class FlagRegistrar;
friend class FlagImplPeer;
T Get() const {
// See implementation notes in CommandLineFlag::Get().
union U {
T value;
U() {}
~U() { value.~T(); }
};
U u;
#if !defined(NDEBUG)
impl_.AssertValidType(base_internal::FastTypeId<T>(), &GenRuntimeTypeId<T>);
#endif
if (ABSL_PREDICT_FALSE(!value_.Get(impl_.seq_lock_, u.value))) {
impl_.Read(&u.value);
}
return std::move(u.value);
}
void Set(const T& v) {
impl_.AssertValidType(base_internal::FastTypeId<T>(), &GenRuntimeTypeId<T>);
impl_.Write(&v);
}
// Access to the reflection.
const CommandLineFlag& Reflect() const { return impl_; }
// Flag's data
// The implementation depends on value_ field to be placed exactly after the
// impl_ field, so that impl_ can figure out the offset to the value and
// access it.
FlagImpl impl_;
FlagValue<T> value_;
};
///////////////////////////////////////////////////////////////////////////////
// Trampoline for friend access
class FlagImplPeer {
public:
template <typename T, typename FlagType>
static T InvokeGet(const FlagType& flag) {
return flag.Get();
}
template <typename FlagType, typename T>
static void InvokeSet(FlagType& flag, const T& v) {
flag.Set(v);
}
template <typename FlagType>
static const CommandLineFlag& InvokeReflect(const FlagType& f) {
return f.Reflect();
}
};
///////////////////////////////////////////////////////////////////////////////
// Implementation of Flag value specific operations routine.
template <typename T>
void* FlagOps(FlagOp op, const void* v1, void* v2, void* v3) {
struct AlignedSpace {
alignas(MaskedPointer::RequiredAlignment()) alignas(T) char buf[sizeof(T)];
};
using Allocator = std::allocator<AlignedSpace>;
switch (op) {
case FlagOp::kAlloc: {
Allocator alloc;
return std::allocator_traits<Allocator>::allocate(alloc, 1);
}
case FlagOp::kDelete: {
T* p = static_cast<T*>(v2);
p->~T();
Allocator alloc;
std::allocator_traits<Allocator>::deallocate(
alloc, reinterpret_cast<AlignedSpace*>(p), 1);
return nullptr;
}
case FlagOp::kCopy:
*static_cast<T*>(v2) = *static_cast<const T*>(v1);
return nullptr;
case FlagOp::kCopyConstruct:
new (v2) T(*static_cast<const T*>(v1));
return nullptr;
case FlagOp::kSizeof:
return reinterpret_cast<void*>(static_cast<uintptr_t>(sizeof(T)));
case FlagOp::kFastTypeId:
return const_cast<void*>(base_internal::FastTypeId<T>());
case FlagOp::kRuntimeTypeId:
return const_cast<std::type_info*>(GenRuntimeTypeId<T>());
case FlagOp::kParse: {
// Initialize the temporary instance of type T based on current value in
// destination (which is going to be flag's default value).
T temp(*static_cast<T*>(v2));
if (!absl::ParseFlag<T>(*static_cast<const absl::string_view*>(v1), &temp,
static_cast<std::string*>(v3))) {
return nullptr;
}
*static_cast<T*>(v2) = std::move(temp);
return v2;
}
case FlagOp::kUnparse:
*static_cast<std::string*>(v2) =
absl::UnparseFlag<T>(*static_cast<const T*>(v1));
return nullptr;
case FlagOp::kValueOffset: {
// Round sizeof(FlagImp) to a multiple of alignof(FlagValue<T>) to get the
// offset of the data.
size_t round_to = alignof(FlagValue<T>);
size_t offset = (sizeof(FlagImpl) + round_to - 1) / round_to * round_to;
return reinterpret_cast<void*>(offset);
}
}
return nullptr;
}
///////////////////////////////////////////////////////////////////////////////
// This class facilitates Flag object registration and tail expression-based
// flag definition, for example:
// ABSL_FLAG(int, foo, 42, "Foo help").OnUpdate(NotifyFooWatcher);
struct FlagRegistrarEmpty {};
template <typename T, bool do_register>
class FlagRegistrar {
public:
constexpr explicit FlagRegistrar(Flag<T>& flag, const char* filename)
: flag_(flag) {
if (do_register)
flags_internal::RegisterCommandLineFlag(flag_.impl_, filename);
}
FlagRegistrar OnUpdate(FlagCallbackFunc cb) && {
flag_.impl_.SetCallback(cb);
return *this;
}
// Makes the registrar die gracefully as an empty struct on a line where
// registration happens. Registrar objects are intended to live only as
// temporary.
constexpr operator FlagRegistrarEmpty() const { return {}; } // NOLINT
private:
Flag<T>& flag_; // Flag being registered (not owned).
};
///////////////////////////////////////////////////////////////////////////////
// Test only API
uint64_t NumLeakedFlagValues();
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_FLAGS_INTERNAL_FLAG_H_

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_FLAGS_INTERNAL_PARSE_H_
#define ABSL_FLAGS_INTERNAL_PARSE_H_
#include <iostream>
#include <ostream>
#include <string>
#include <vector>
#include "absl/base/config.h"
#include "absl/flags/declare.h"
#include "absl/flags/internal/usage.h"
#include "absl/strings/string_view.h"
ABSL_DECLARE_FLAG(std::vector<std::string>, flagfile);
ABSL_DECLARE_FLAG(std::vector<std::string>, fromenv);
ABSL_DECLARE_FLAG(std::vector<std::string>, tryfromenv);
ABSL_DECLARE_FLAG(std::vector<std::string>, undefok);
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
enum class UsageFlagsAction { kHandleUsage, kIgnoreUsage };
enum class OnUndefinedFlag {
kIgnoreUndefined,
kReportUndefined,
kAbortIfUndefined
};
// This is not a public interface. This interface exists to expose the ability
// to change help output stream in case of parsing errors. This is used by
// internal unit tests to validate expected outputs.
// When this was written, `EXPECT_EXIT` only supported matchers on stderr,
// but not on stdout.
std::vector<char*> ParseCommandLineImpl(
int argc, char* argv[], UsageFlagsAction usage_flag_action,
OnUndefinedFlag undef_flag_action,
std::ostream& error_help_output = std::cout);
// --------------------------------------------------------------------
// Inspect original command line
// Returns true if flag with specified name was either present on the original
// command line or specified in flag file present on the original command line.
bool WasPresentOnCommandLine(absl::string_view flag_name);
// Return existing flags similar to the parameter, in order to help in case of
// misspellings.
std::vector<std::string> GetMisspellingHints(absl::string_view flag);
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_FLAGS_INTERNAL_PARSE_H_

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_FLAGS_INTERNAL_PATH_UTIL_H_
#define ABSL_FLAGS_INTERNAL_PATH_UTIL_H_
#include "absl/base/config.h"
#include "absl/strings/string_view.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
// A portable interface that returns the basename of the filename passed as an
// argument. It is similar to basename(3)
// <https://linux.die.net/man/3/basename>.
// For example:
// flags_internal::Basename("a/b/prog/file.cc")
// returns "file.cc"
// flags_internal::Basename("file.cc")
// returns "file.cc"
inline absl::string_view Basename(absl::string_view filename) {
auto last_slash_pos = filename.find_last_of("/\\");
return last_slash_pos == absl::string_view::npos
? filename
: filename.substr(last_slash_pos + 1);
}
// A portable interface that returns the directory name of the filename
// passed as an argument, including the trailing slash.
// Returns the empty string if a slash is not found in the input file name.
// For example:
// flags_internal::Package("a/b/prog/file.cc")
// returns "a/b/prog/"
// flags_internal::Package("file.cc")
// returns ""
inline absl::string_view Package(absl::string_view filename) {
auto last_slash_pos = filename.find_last_of("/\\");
return last_slash_pos == absl::string_view::npos
? absl::string_view()
: filename.substr(0, last_slash_pos + 1);
}
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_FLAGS_INTERNAL_PATH_UTIL_H_

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/flags/internal/path_util.h"
#include "gtest/gtest.h"
namespace {
namespace flags = absl::flags_internal;
TEST(FlagsPathUtilTest, TestBasename) {
EXPECT_EQ(flags::Basename(""), "");
EXPECT_EQ(flags::Basename("a.cc"), "a.cc");
EXPECT_EQ(flags::Basename("dir/a.cc"), "a.cc");
EXPECT_EQ(flags::Basename("dir1/dir2/a.cc"), "a.cc");
EXPECT_EQ(flags::Basename("../dir1/dir2/a.cc"), "a.cc");
EXPECT_EQ(flags::Basename("/dir1/dir2/a.cc"), "a.cc");
EXPECT_EQ(flags::Basename("/dir1/dir2/../dir3/a.cc"), "a.cc");
}
// --------------------------------------------------------------------
TEST(FlagsPathUtilTest, TestPackage) {
EXPECT_EQ(flags::Package(""), "");
EXPECT_EQ(flags::Package("a.cc"), "");
EXPECT_EQ(flags::Package("dir/a.cc"), "dir/");
EXPECT_EQ(flags::Package("dir1/dir2/a.cc"), "dir1/dir2/");
EXPECT_EQ(flags::Package("../dir1/dir2/a.cc"), "../dir1/dir2/");
EXPECT_EQ(flags::Package("/dir1/dir2/a.cc"), "/dir1/dir2/");
EXPECT_EQ(flags::Package("/dir1/dir2/../dir3/a.cc"), "/dir1/dir2/../dir3/");
}
} // namespace

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//
// Copyright 2020 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/flags/internal/private_handle_accessor.h"
#include <memory>
#include <string>
#include "absl/base/config.h"
#include "absl/flags/commandlineflag.h"
#include "absl/flags/internal/commandlineflag.h"
#include "absl/strings/string_view.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
FlagFastTypeId PrivateHandleAccessor::TypeId(const CommandLineFlag& flag) {
return flag.TypeId();
}
std::unique_ptr<FlagStateInterface> PrivateHandleAccessor::SaveState(
CommandLineFlag& flag) {
return flag.SaveState();
}
bool PrivateHandleAccessor::IsSpecifiedOnCommandLine(
const CommandLineFlag& flag) {
return flag.IsSpecifiedOnCommandLine();
}
bool PrivateHandleAccessor::ValidateInputValue(const CommandLineFlag& flag,
absl::string_view value) {
return flag.ValidateInputValue(value);
}
void PrivateHandleAccessor::CheckDefaultValueParsingRoundtrip(
const CommandLineFlag& flag) {
flag.CheckDefaultValueParsingRoundtrip();
}
bool PrivateHandleAccessor::ParseFrom(CommandLineFlag& flag,
absl::string_view value,
flags_internal::FlagSettingMode set_mode,
flags_internal::ValueSource source,
std::string& error) {
return flag.ParseFrom(value, set_mode, source, error);
}
absl::string_view PrivateHandleAccessor::TypeName(const CommandLineFlag& flag) {
return flag.TypeName();
}
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// Copyright 2020 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_FLAGS_INTERNAL_PRIVATE_HANDLE_ACCESSOR_H_
#define ABSL_FLAGS_INTERNAL_PRIVATE_HANDLE_ACCESSOR_H_
#include <memory>
#include <string>
#include "absl/base/config.h"
#include "absl/flags/commandlineflag.h"
#include "absl/flags/internal/commandlineflag.h"
#include "absl/strings/string_view.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
// This class serves as a trampoline to access private methods of
// CommandLineFlag. This class is intended for use exclusively internally inside
// of the Abseil Flags implementation.
class PrivateHandleAccessor {
public:
// Access to CommandLineFlag::TypeId.
static FlagFastTypeId TypeId(const CommandLineFlag& flag);
// Access to CommandLineFlag::SaveState.
static std::unique_ptr<FlagStateInterface> SaveState(CommandLineFlag& flag);
// Access to CommandLineFlag::IsSpecifiedOnCommandLine.
static bool IsSpecifiedOnCommandLine(const CommandLineFlag& flag);
// Access to CommandLineFlag::ValidateInputValue.
static bool ValidateInputValue(const CommandLineFlag& flag,
absl::string_view value);
// Access to CommandLineFlag::CheckDefaultValueParsingRoundtrip.
static void CheckDefaultValueParsingRoundtrip(const CommandLineFlag& flag);
static bool ParseFrom(CommandLineFlag& flag, absl::string_view value,
flags_internal::FlagSettingMode set_mode,
flags_internal::ValueSource source, std::string& error);
// Access to CommandLineFlag::TypeName.
static absl::string_view TypeName(const CommandLineFlag& flag);
};
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_FLAGS_INTERNAL_PRIVATE_HANDLE_ACCESSOR_H_

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/flags/internal/program_name.h"
#include <string>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/no_destructor.h"
#include "absl/base/thread_annotations.h"
#include "absl/flags/internal/path_util.h"
#include "absl/strings/string_view.h"
#include "absl/synchronization/mutex.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
static absl::Mutex* ProgramNameMutex() {
static absl::NoDestructor<absl::Mutex> mutex;
return mutex.get();
}
ABSL_CONST_INIT static std::string* program_name ABSL_GUARDED_BY(
ProgramNameMutex()) ABSL_PT_GUARDED_BY(ProgramNameMutex()) = nullptr;
std::string ProgramInvocationName() {
absl::MutexLock l(ProgramNameMutex());
return program_name ? *program_name : "UNKNOWN";
}
std::string ShortProgramInvocationName() {
absl::MutexLock l(ProgramNameMutex());
return program_name ? std::string(flags_internal::Basename(*program_name))
: "UNKNOWN";
}
void SetProgramInvocationName(absl::string_view prog_name_str) {
absl::MutexLock l(ProgramNameMutex());
if (!program_name) {
program_name = new std::string(prog_name_str);
} else {
program_name->assign(prog_name_str.data(), prog_name_str.size());
}
}
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_FLAGS_INTERNAL_PROGRAM_NAME_H_
#define ABSL_FLAGS_INTERNAL_PROGRAM_NAME_H_
#include <string>
#include "absl/base/config.h"
#include "absl/strings/string_view.h"
// --------------------------------------------------------------------
// Program name
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
// Returns program invocation name or "UNKNOWN" if `SetProgramInvocationName()`
// is never called. At the moment this is always set to argv[0] as part of
// library initialization.
std::string ProgramInvocationName();
// Returns base name for program invocation name. For example, if
// ProgramInvocationName() == "a/b/mybinary"
// then
// ShortProgramInvocationName() == "mybinary"
std::string ShortProgramInvocationName();
// Sets program invocation name to a new value. Should only be called once
// during program initialization, before any threads are spawned.
void SetProgramInvocationName(absl::string_view prog_name_str);
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_FLAGS_INTERNAL_PROGRAM_NAME_H_

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/flags/internal/program_name.h"
#include <string>
#include "gtest/gtest.h"
#include "absl/strings/match.h"
#include "absl/strings/string_view.h"
namespace {
namespace flags = absl::flags_internal;
TEST(FlagsPathUtilTest, TestProgamNameInterfaces) {
flags::SetProgramInvocationName("absl/flags/program_name_test");
std::string program_name = flags::ProgramInvocationName();
for (char& c : program_name)
if (c == '\\') c = '/';
#if !defined(__wasm__) && !defined(__asmjs__)
const std::string expect_name = "absl/flags/program_name_test";
const std::string expect_basename = "program_name_test";
#else
// For targets that generate javascript or webassembly the invocation name
// has the special value below.
const std::string expect_name = "this.program";
const std::string expect_basename = "this.program";
#endif
EXPECT_TRUE(absl::EndsWith(program_name, expect_name)) << program_name;
EXPECT_EQ(flags::ShortProgramInvocationName(), expect_basename);
flags::SetProgramInvocationName("a/my_test");
EXPECT_EQ(flags::ProgramInvocationName(), "a/my_test");
EXPECT_EQ(flags::ShortProgramInvocationName(), "my_test");
absl::string_view not_null_terminated("absl/aaa/bbb");
not_null_terminated = not_null_terminated.substr(1, 10);
flags::SetProgramInvocationName(not_null_terminated);
EXPECT_EQ(flags::ProgramInvocationName(), "bsl/aaa/bb");
EXPECT_EQ(flags::ShortProgramInvocationName(), "bb");
}
} // namespace

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_FLAGS_INTERNAL_REGISTRY_H_
#define ABSL_FLAGS_INTERNAL_REGISTRY_H_
#include <functional>
#include "absl/base/config.h"
#include "absl/flags/commandlineflag.h"
#include "absl/flags/internal/commandlineflag.h"
#include "absl/strings/string_view.h"
// --------------------------------------------------------------------
// Global flags registry API.
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
// Executes specified visitor for each non-retired flag in the registry. While
// callback are executed, the registry is locked and can't be changed.
void ForEachFlag(std::function<void(CommandLineFlag&)> visitor);
//-----------------------------------------------------------------------------
bool RegisterCommandLineFlag(CommandLineFlag&, const char* filename);
void FinalizeRegistry();
//-----------------------------------------------------------------------------
// Retired registrations:
//
// Retired flag registrations are treated specially. A 'retired' flag is
// provided only for compatibility with automated invocations that still
// name it. A 'retired' flag:
// - is not bound to a C++ FLAGS_ reference.
// - has a type and a value, but that value is intentionally inaccessible.
// - does not appear in --help messages.
// - is fully supported by _all_ flag parsing routines.
// - consumes args normally, and complains about type mismatches in its
// argument.
// - emits a complaint but does not die (e.g. LOG(ERROR)) if it is
// accessed by name through the flags API for parsing or otherwise.
//
// The registrations for a flag happen in an unspecified order as the
// initializers for the namespace-scope objects of a program are run.
// Any number of weak registrations for a flag can weakly define the flag.
// One non-weak registration will upgrade the flag from weak to non-weak.
// Further weak registrations of a non-weak flag are ignored.
//
// This mechanism is designed to support moving dead flags into a
// 'graveyard' library. An example migration:
//
// 0: Remove references to this FLAGS_flagname in the C++ codebase.
// 1: Register as 'retired' in old_lib.
// 2: Make old_lib depend on graveyard.
// 3: Add a redundant 'retired' registration to graveyard.
// 4: Remove the old_lib 'retired' registration.
// 5: Eventually delete the graveyard registration entirely.
//
// Retire flag with name "name" and type indicated by ops.
void Retire(const char* name, FlagFastTypeId type_id, char* buf);
constexpr size_t kRetiredFlagObjSize = 3 * sizeof(void*);
constexpr size_t kRetiredFlagObjAlignment = alignof(void*);
// Registered a retired flag with name 'flag_name' and type 'T'.
template <typename T>
class RetiredFlag {
public:
void Retire(const char* flag_name) {
flags_internal::Retire(flag_name, base_internal::FastTypeId<T>(), buf_);
}
private:
alignas(kRetiredFlagObjAlignment) char buf_[kRetiredFlagObjSize];
};
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_FLAGS_INTERNAL_REGISTRY_H_

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//
// Copyright 2020 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_FLAGS_INTERNAL_SEQUENCE_LOCK_H_
#define ABSL_FLAGS_INTERNAL_SEQUENCE_LOCK_H_
#include <stddef.h>
#include <stdint.h>
#include <atomic>
#include <cassert>
#include <cstring>
#include "absl/base/optimization.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
// Align 'x' up to the nearest 'align' bytes.
inline constexpr size_t AlignUp(size_t x, size_t align) {
return align * ((x + align - 1) / align);
}
// A SequenceLock implements lock-free reads. A sequence counter is incremented
// before and after each write, and readers access the counter before and after
// accessing the protected data. If the counter is verified to not change during
// the access, and the sequence counter value was even, then the reader knows
// that the read was race-free and valid. Otherwise, the reader must fall back
// to a Mutex-based code path.
//
// This particular SequenceLock starts in an "uninitialized" state in which
// TryRead() returns false. It must be enabled by calling MarkInitialized().
// This serves as a marker that the associated flag value has not yet been
// initialized and a slow path needs to be taken.
//
// The memory reads and writes protected by this lock must use the provided
// `TryRead()` and `Write()` functions. These functions behave similarly to
// `memcpy()`, with one oddity: the protected data must be an array of
// `std::atomic<uint64>`. This is to comply with the C++ standard, which
// considers data races on non-atomic objects to be undefined behavior. See "Can
// Seqlocks Get Along With Programming Language Memory Models?"[1] by Hans J.
// Boehm for more details.
//
// [1] https://www.hpl.hp.com/techreports/2012/HPL-2012-68.pdf
class SequenceLock {
public:
constexpr SequenceLock() : lock_(kUninitialized) {}
// Mark that this lock is ready for use.
void MarkInitialized() {
assert(lock_.load(std::memory_order_relaxed) == kUninitialized);
lock_.store(0, std::memory_order_release);
}
// Copy "size" bytes of data from "src" to "dst", protected as a read-side
// critical section of the sequence lock.
//
// Unlike traditional sequence lock implementations which loop until getting a
// clean read, this implementation returns false in the case of concurrent
// calls to `Write`. In such a case, the caller should fall back to a
// locking-based slow path.
//
// Returns false if the sequence lock was not yet marked as initialized.
//
// NOTE: If this returns false, "dst" may be overwritten with undefined
// (potentially uninitialized) data.
bool TryRead(void* dst, const std::atomic<uint64_t>* src, size_t size) const {
// Acquire barrier ensures that no loads done by f() are reordered
// above the first load of the sequence counter.
int64_t seq_before = lock_.load(std::memory_order_acquire);
if (ABSL_PREDICT_FALSE(seq_before & 1) == 1) return false;
RelaxedCopyFromAtomic(dst, src, size);
// Another acquire fence ensures that the load of 'lock_' below is
// strictly ordered after the RelaxedCopyToAtomic call above.
std::atomic_thread_fence(std::memory_order_acquire);
int64_t seq_after = lock_.load(std::memory_order_relaxed);
return ABSL_PREDICT_TRUE(seq_before == seq_after);
}
// Copy "size" bytes from "src" to "dst" as a write-side critical section
// of the sequence lock. Any concurrent readers will be forced to retry
// until they get a read that does not conflict with this write.
//
// This call must be externally synchronized against other calls to Write,
// but may proceed concurrently with reads.
void Write(std::atomic<uint64_t>* dst, const void* src, size_t size) {
// We can use relaxed instructions to increment the counter since we
// are extenally synchronized. The std::atomic_thread_fence below
// ensures that the counter updates don't get interleaved with the
// copy to the data.
int64_t orig_seq = lock_.load(std::memory_order_relaxed);
assert((orig_seq & 1) == 0); // Must be initially unlocked.
lock_.store(orig_seq + 1, std::memory_order_relaxed);
// We put a release fence between update to lock_ and writes to shared data.
// Thus all stores to shared data are effectively release operations and
// update to lock_ above cannot be re-ordered past any of them. Note that
// this barrier is not for the fetch_add above. A release barrier for the
// fetch_add would be before it, not after.
std::atomic_thread_fence(std::memory_order_release);
RelaxedCopyToAtomic(dst, src, size);
// "Release" semantics ensure that none of the writes done by
// RelaxedCopyToAtomic() can be reordered after the following modification.
lock_.store(orig_seq + 2, std::memory_order_release);
}
// Return the number of times that Write() has been called.
//
// REQUIRES: This must be externally synchronized against concurrent calls to
// `Write()` or `IncrementModificationCount()`.
// REQUIRES: `MarkInitialized()` must have been previously called.
int64_t ModificationCount() const {
int64_t val = lock_.load(std::memory_order_relaxed);
assert(val != kUninitialized && (val & 1) == 0);
return val / 2;
}
// REQUIRES: This must be externally synchronized against concurrent calls to
// `Write()` or `ModificationCount()`.
// REQUIRES: `MarkInitialized()` must have been previously called.
void IncrementModificationCount() {
int64_t val = lock_.load(std::memory_order_relaxed);
assert(val != kUninitialized);
lock_.store(val + 2, std::memory_order_relaxed);
}
private:
// Perform the equivalent of "memcpy(dst, src, size)", but using relaxed
// atomics.
static void RelaxedCopyFromAtomic(void* dst, const std::atomic<uint64_t>* src,
size_t size) {
char* dst_byte = static_cast<char*>(dst);
while (size >= sizeof(uint64_t)) {
uint64_t word = src->load(std::memory_order_relaxed);
std::memcpy(dst_byte, &word, sizeof(word));
dst_byte += sizeof(word);
src++;
size -= sizeof(word);
}
if (size > 0) {
uint64_t word = src->load(std::memory_order_relaxed);
std::memcpy(dst_byte, &word, size);
}
}
// Perform the equivalent of "memcpy(dst, src, size)", but using relaxed
// atomics.
static void RelaxedCopyToAtomic(std::atomic<uint64_t>* dst, const void* src,
size_t size) {
const char* src_byte = static_cast<const char*>(src);
while (size >= sizeof(uint64_t)) {
uint64_t word;
std::memcpy(&word, src_byte, sizeof(word));
dst->store(word, std::memory_order_relaxed);
src_byte += sizeof(word);
dst++;
size -= sizeof(word);
}
if (size > 0) {
uint64_t word = 0;
std::memcpy(&word, src_byte, size);
dst->store(word, std::memory_order_relaxed);
}
}
static constexpr int64_t kUninitialized = -1;
std::atomic<int64_t> lock_;
};
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_FLAGS_INTERNAL_SEQUENCE_LOCK_H_

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// Copyright 2020 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/flags/internal/sequence_lock.h"
#include <algorithm>
#include <atomic>
#include <thread> // NOLINT(build/c++11)
#include <tuple>
#include <vector>
#include "gtest/gtest.h"
#include "absl/base/internal/sysinfo.h"
#include "absl/container/fixed_array.h"
#include "absl/time/clock.h"
namespace {
namespace flags = absl::flags_internal;
class ConcurrentSequenceLockTest
: public testing::TestWithParam<std::tuple<int, int>> {
public:
ConcurrentSequenceLockTest()
: buf_bytes_(std::get<0>(GetParam())),
num_threads_(std::get<1>(GetParam())) {}
protected:
const int buf_bytes_;
const int num_threads_;
};
TEST_P(ConcurrentSequenceLockTest, ReadAndWrite) {
const int buf_words =
flags::AlignUp(buf_bytes_, sizeof(uint64_t)) / sizeof(uint64_t);
// The buffer that will be protected by the SequenceLock.
absl::FixedArray<std::atomic<uint64_t>> protected_buf(buf_words);
for (auto& v : protected_buf) v = -1;
flags::SequenceLock seq_lock;
std::atomic<bool> stop{false};
std::atomic<int64_t> bad_reads{0};
std::atomic<int64_t> good_reads{0};
std::atomic<int64_t> unsuccessful_reads{0};
// Start a bunch of threads which read 'protected_buf' under the sequence
// lock. The main thread will concurrently update 'protected_buf'. The updates
// always consist of an array of identical integers. The reader ensures that
// any data it reads matches that pattern (i.e. the reads are not "torn").
std::vector<std::thread> threads;
for (int i = 0; i < num_threads_; i++) {
threads.emplace_back([&]() {
absl::FixedArray<char> local_buf(buf_bytes_);
while (!stop.load(std::memory_order_relaxed)) {
if (seq_lock.TryRead(local_buf.data(), protected_buf.data(),
buf_bytes_)) {
bool good = true;
for (const auto& v : local_buf) {
if (v != local_buf[0]) good = false;
}
if (good) {
good_reads.fetch_add(1, std::memory_order_relaxed);
} else {
bad_reads.fetch_add(1, std::memory_order_relaxed);
}
} else {
unsuccessful_reads.fetch_add(1, std::memory_order_relaxed);
}
}
});
}
while (unsuccessful_reads.load(std::memory_order_relaxed) < num_threads_) {
absl::SleepFor(absl::Milliseconds(1));
}
seq_lock.MarkInitialized();
// Run a maximum of 5 seconds. On Windows, the scheduler behavior seems
// somewhat unfair and without an explicit timeout for this loop, the tests
// can run a long time.
absl::Time deadline = absl::Now() + absl::Seconds(5);
for (int i = 0; i < 100 && absl::Now() < deadline; i++) {
absl::FixedArray<char> writer_buf(buf_bytes_);
for (auto& v : writer_buf) v = i;
seq_lock.Write(protected_buf.data(), writer_buf.data(), buf_bytes_);
absl::SleepFor(absl::Microseconds(10));
}
stop.store(true, std::memory_order_relaxed);
for (auto& t : threads) t.join();
ASSERT_GE(good_reads, 0);
ASSERT_EQ(bad_reads, 0);
}
// Simple helper for generating a range of thread counts.
// Generates [low, low*scale, low*scale^2, ...high)
// (even if high is between low*scale^k and low*scale^(k+1)).
std::vector<int> MultiplicativeRange(int low, int high, int scale) {
std::vector<int> result;
for (int current = low; current < high; current *= scale) {
result.push_back(current);
}
result.push_back(high);
return result;
}
#ifndef ABSL_HAVE_THREAD_SANITIZER
const int kMaxThreads = absl::base_internal::NumCPUs();
#else
// With TSAN, a lot of threads contending for atomic access on the sequence
// lock make this test run too slowly.
const int kMaxThreads = std::min(absl::base_internal::NumCPUs(), 4);
#endif
// Return all of the interesting buffer sizes worth testing:
// powers of two and adjacent values.
std::vector<int> InterestingBufferSizes() {
std::vector<int> ret;
for (int v : MultiplicativeRange(1, 128, 2)) {
ret.push_back(v);
if (v > 1) {
ret.push_back(v - 1);
}
ret.push_back(v + 1);
}
return ret;
}
INSTANTIATE_TEST_SUITE_P(
TestManyByteSizes, ConcurrentSequenceLockTest,
testing::Combine(
// Buffer size (bytes).
testing::ValuesIn(InterestingBufferSizes()),
// Number of reader threads.
testing::ValuesIn(MultiplicativeRange(1, kMaxThreads, 2))));
// Simple single-threaded test, parameterized by the size of the buffer to be
// protected.
class SequenceLockTest : public testing::TestWithParam<int> {};
TEST_P(SequenceLockTest, SingleThreaded) {
const int size = GetParam();
absl::FixedArray<std::atomic<uint64_t>> protected_buf(
flags::AlignUp(size, sizeof(uint64_t)) / sizeof(uint64_t));
flags::SequenceLock seq_lock;
seq_lock.MarkInitialized();
std::vector<char> src_buf(size, 'x');
seq_lock.Write(protected_buf.data(), src_buf.data(), size);
std::vector<char> dst_buf(size, '0');
ASSERT_TRUE(seq_lock.TryRead(dst_buf.data(), protected_buf.data(), size));
ASSERT_EQ(src_buf, dst_buf);
}
INSTANTIATE_TEST_SUITE_P(TestManyByteSizes, SequenceLockTest,
// Buffer size (bytes).
testing::Range(1, 128));
} // namespace

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/flags/internal/usage.h"
#include <stdint.h>
#include <algorithm>
#include <cstdlib>
#include <functional>
#include <iterator>
#include <map>
#include <ostream>
#include <string>
#include <utility>
#include <vector>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/no_destructor.h"
#include "absl/base/thread_annotations.h"
#include "absl/flags/commandlineflag.h"
#include "absl/flags/flag.h"
#include "absl/flags/internal/flag.h"
#include "absl/flags/internal/path_util.h"
#include "absl/flags/internal/private_handle_accessor.h"
#include "absl/flags/internal/program_name.h"
#include "absl/flags/internal/registry.h"
#include "absl/flags/usage_config.h"
#include "absl/strings/match.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_split.h"
#include "absl/strings/string_view.h"
#include "absl/strings/strip.h"
#include "absl/synchronization/mutex.h"
// Dummy global variables to prevent anyone else defining these.
bool FLAGS_help = false;
bool FLAGS_helpfull = false;
bool FLAGS_helpshort = false;
bool FLAGS_helppackage = false;
bool FLAGS_version = false;
bool FLAGS_only_check_args = false;
bool FLAGS_helpon = false;
bool FLAGS_helpmatch = false;
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
namespace {
using PerFlagFilter = std::function<bool(const absl::CommandLineFlag&)>;
// Maximum length size in a human readable format.
constexpr size_t kHrfMaxLineLength = 80;
// This class is used to emit an XML element with `tag` and `text`.
// It adds opening and closing tags and escapes special characters in the text.
// For example:
// std::cout << XMLElement("title", "Milk & Cookies");
// prints "<title>Milk &amp; Cookies</title>"
class XMLElement {
public:
XMLElement(absl::string_view tag, absl::string_view txt)
: tag_(tag), txt_(txt) {}
friend std::ostream& operator<<(std::ostream& out,
const XMLElement& xml_elem) {
out << "<" << xml_elem.tag_ << ">";
for (auto c : xml_elem.txt_) {
switch (c) {
case '"':
out << "&quot;";
break;
case '\'':
out << "&apos;";
break;
case '&':
out << "&amp;";
break;
case '<':
out << "&lt;";
break;
case '>':
out << "&gt;";
break;
case '\n':
case '\v':
case '\f':
case '\t':
out << " ";
break;
default:
if (IsValidXmlCharacter(static_cast<unsigned char>(c))) {
out << c;
}
break;
}
}
return out << "</" << xml_elem.tag_ << ">";
}
private:
static bool IsValidXmlCharacter(unsigned char c) { return c >= 0x20; }
absl::string_view tag_;
absl::string_view txt_;
};
// --------------------------------------------------------------------
// Helper class to pretty-print info about a flag.
class FlagHelpPrettyPrinter {
public:
// Pretty printer holds on to the std::ostream& reference to direct an output
// to that stream.
FlagHelpPrettyPrinter(size_t max_line_len, size_t min_line_len,
size_t wrapped_line_indent, std::ostream& out)
: out_(out),
max_line_len_(max_line_len),
min_line_len_(min_line_len),
wrapped_line_indent_(wrapped_line_indent),
line_len_(0),
first_line_(true) {}
void Write(absl::string_view str, bool wrap_line = false) {
// Empty string - do nothing.
if (str.empty()) return;
std::vector<absl::string_view> tokens;
if (wrap_line) {
for (auto line : absl::StrSplit(str, absl::ByAnyChar("\n\r"))) {
if (!tokens.empty()) {
// Keep line separators in the input string.
tokens.emplace_back("\n");
}
for (auto token :
absl::StrSplit(line, absl::ByAnyChar(" \t"), absl::SkipEmpty())) {
tokens.push_back(token);
}
}
} else {
tokens.push_back(str);
}
for (auto token : tokens) {
bool new_line = (line_len_ == 0);
// Respect line separators in the input string.
if (token == "\n") {
EndLine();
continue;
}
// Write the token, ending the string first if necessary/possible.
if (!new_line && (line_len_ + token.size() >= max_line_len_)) {
EndLine();
new_line = true;
}
if (new_line) {
StartLine();
} else {
out_ << ' ';
++line_len_;
}
out_ << token;
line_len_ += token.size();
}
}
void StartLine() {
if (first_line_) {
line_len_ = min_line_len_;
first_line_ = false;
} else {
line_len_ = min_line_len_ + wrapped_line_indent_;
}
out_ << std::string(line_len_, ' ');
}
void EndLine() {
out_ << '\n';
line_len_ = 0;
}
private:
std::ostream& out_;
const size_t max_line_len_;
const size_t min_line_len_;
const size_t wrapped_line_indent_;
size_t line_len_;
bool first_line_;
};
void FlagHelpHumanReadable(const CommandLineFlag& flag, std::ostream& out) {
FlagHelpPrettyPrinter printer(kHrfMaxLineLength, 4, 2, out);
// Flag name.
printer.Write(absl::StrCat("--", flag.Name()));
// Flag help.
printer.Write(absl::StrCat("(", flag.Help(), ");"), /*wrap_line=*/true);
// The listed default value will be the actual default from the flag
// definition in the originating source file, unless the value has
// subsequently been modified using SetCommandLineOption() with mode
// SET_FLAGS_DEFAULT.
std::string dflt_val = flag.DefaultValue();
std::string curr_val = flag.CurrentValue();
bool is_modified = curr_val != dflt_val;
if (flag.IsOfType<std::string>()) {
dflt_val = absl::StrCat("\"", dflt_val, "\"");
}
printer.Write(absl::StrCat("default: ", dflt_val, ";"));
if (is_modified) {
if (flag.IsOfType<std::string>()) {
curr_val = absl::StrCat("\"", curr_val, "\"");
}
printer.Write(absl::StrCat("currently: ", curr_val, ";"));
}
printer.EndLine();
}
// Shows help for every filename which matches any of the filters
// If filters are empty, shows help for every file.
// If a flag's help message has been stripped (e.g. by adding '#define
// STRIP_FLAG_HELP 1' then this flag will not be displayed by '--help'
// and its variants.
void FlagsHelpImpl(std::ostream& out, PerFlagFilter filter_cb,
HelpFormat format, absl::string_view program_usage_message) {
if (format == HelpFormat::kHumanReadable) {
out << flags_internal::ShortProgramInvocationName() << ": "
<< program_usage_message << "\n\n";
} else {
// XML schema is not a part of our public API for now.
out << "<?xml version=\"1.0\"?>\n"
<< "<!-- This output should be used with care. We do not report type "
"names for flags with user defined types -->\n"
<< "<!-- Prefer flag only_check_args for validating flag inputs -->\n"
// The document.
<< "<AllFlags>\n"
// The program name and usage.
<< XMLElement("program", flags_internal::ShortProgramInvocationName())
<< '\n'
<< XMLElement("usage", program_usage_message) << '\n';
}
// Ordered map of package name to
// map of file name to
// vector of flags in the file.
// This map is used to output matching flags grouped by package and file
// name.
std::map<std::string,
std::map<std::string, std::vector<const absl::CommandLineFlag*>>>
matching_flags;
flags_internal::ForEachFlag([&](absl::CommandLineFlag& flag) {
// Ignore retired flags.
if (flag.IsRetired()) return;
// If the flag has been stripped, pretend that it doesn't exist.
if (flag.Help() == flags_internal::kStrippedFlagHelp) return;
// Make sure flag satisfies the filter
if (!filter_cb(flag)) return;
std::string flag_filename = flag.Filename();
matching_flags[std::string(flags_internal::Package(flag_filename))]
[flag_filename]
.push_back(&flag);
});
absl::string_view package_separator; // controls blank lines between packages
absl::string_view file_separator; // controls blank lines between files
for (auto& package : matching_flags) {
if (format == HelpFormat::kHumanReadable) {
out << package_separator;
package_separator = "\n\n";
}
file_separator = "";
for (auto& flags_in_file : package.second) {
if (format == HelpFormat::kHumanReadable) {
out << file_separator << " Flags from " << flags_in_file.first
<< ":\n";
file_separator = "\n";
}
std::sort(std::begin(flags_in_file.second),
std::end(flags_in_file.second),
[](const CommandLineFlag* lhs, const CommandLineFlag* rhs) {
return lhs->Name() < rhs->Name();
});
for (const auto* flag : flags_in_file.second) {
flags_internal::FlagHelp(out, *flag, format);
}
}
}
if (format == HelpFormat::kHumanReadable) {
FlagHelpPrettyPrinter printer(kHrfMaxLineLength, 0, 0, out);
if (filter_cb && matching_flags.empty()) {
printer.Write("No flags matched.\n", true);
}
printer.EndLine();
printer.Write(
"Try --helpfull to get a list of all flags or --help=substring "
"shows help for flags which include specified substring in either "
"in the name, or description or path.\n",
true);
} else {
// The end of the document.
out << "</AllFlags>\n";
}
}
void FlagsHelpImpl(std::ostream& out,
flags_internal::FlagKindFilter filename_filter_cb,
HelpFormat format, absl::string_view program_usage_message) {
FlagsHelpImpl(
out,
[&](const absl::CommandLineFlag& flag) {
return filename_filter_cb && filename_filter_cb(flag.Filename());
},
format, program_usage_message);
}
} // namespace
// --------------------------------------------------------------------
// Produces the help message describing specific flag.
void FlagHelp(std::ostream& out, const CommandLineFlag& flag,
HelpFormat format) {
if (format == HelpFormat::kHumanReadable)
flags_internal::FlagHelpHumanReadable(flag, out);
}
// --------------------------------------------------------------------
// Produces the help messages for all flags matching the filename filter.
// If filter is empty produces help messages for all flags.
void FlagsHelp(std::ostream& out, absl::string_view filter, HelpFormat format,
absl::string_view program_usage_message) {
flags_internal::FlagKindFilter filter_cb = [&](absl::string_view filename) {
return filter.empty() || absl::StrContains(filename, filter);
};
flags_internal::FlagsHelpImpl(out, filter_cb, format, program_usage_message);
}
// --------------------------------------------------------------------
// Checks all the 'usage' command line flags to see if any have been set.
// If so, handles them appropriately.
HelpMode HandleUsageFlags(std::ostream& out,
absl::string_view program_usage_message) {
switch (GetFlagsHelpMode()) {
case HelpMode::kNone:
break;
case HelpMode::kImportant:
flags_internal::FlagsHelpImpl(
out, flags_internal::GetUsageConfig().contains_help_flags,
GetFlagsHelpFormat(), program_usage_message);
break;
case HelpMode::kShort:
flags_internal::FlagsHelpImpl(
out, flags_internal::GetUsageConfig().contains_helpshort_flags,
GetFlagsHelpFormat(), program_usage_message);
break;
case HelpMode::kFull:
flags_internal::FlagsHelp(out, "", GetFlagsHelpFormat(),
program_usage_message);
break;
case HelpMode::kPackage:
flags_internal::FlagsHelpImpl(
out, flags_internal::GetUsageConfig().contains_helppackage_flags,
GetFlagsHelpFormat(), program_usage_message);
break;
case HelpMode::kMatch: {
std::string substr = GetFlagsHelpMatchSubstr();
if (substr.empty()) {
// show all options
flags_internal::FlagsHelp(out, substr, GetFlagsHelpFormat(),
program_usage_message);
} else {
auto filter_cb = [&substr](const absl::CommandLineFlag& flag) {
if (absl::StrContains(flag.Name(), substr)) return true;
if (absl::StrContains(flag.Filename(), substr)) return true;
if (absl::StrContains(flag.Help(), substr)) return true;
return false;
};
flags_internal::FlagsHelpImpl(
out, filter_cb, HelpFormat::kHumanReadable, program_usage_message);
}
break;
}
case HelpMode::kVersion:
if (flags_internal::GetUsageConfig().version_string)
out << flags_internal::GetUsageConfig().version_string();
// Unlike help, we may be asking for version in a script, so return 0
break;
case HelpMode::kOnlyCheckArgs:
break;
}
return GetFlagsHelpMode();
}
// --------------------------------------------------------------------
// Globals representing usage reporting flags
namespace {
absl::Mutex* HelpAttributesMutex() {
static absl::NoDestructor<absl::Mutex> mutex;
return mutex.get();
}
ABSL_CONST_INIT std::string* match_substr ABSL_GUARDED_BY(HelpAttributesMutex())
ABSL_PT_GUARDED_BY(HelpAttributesMutex()) = nullptr;
ABSL_CONST_INIT HelpMode help_mode ABSL_GUARDED_BY(HelpAttributesMutex()) =
HelpMode::kNone;
ABSL_CONST_INIT HelpFormat help_format ABSL_GUARDED_BY(HelpAttributesMutex()) =
HelpFormat::kHumanReadable;
} // namespace
std::string GetFlagsHelpMatchSubstr() {
absl::MutexLock l(HelpAttributesMutex());
if (match_substr == nullptr) return "";
return *match_substr;
}
void SetFlagsHelpMatchSubstr(absl::string_view substr) {
absl::MutexLock l(HelpAttributesMutex());
if (match_substr == nullptr) match_substr = new std::string;
match_substr->assign(substr.data(), substr.size());
}
HelpMode GetFlagsHelpMode() {
absl::MutexLock l(HelpAttributesMutex());
return help_mode;
}
void SetFlagsHelpMode(HelpMode mode) {
absl::MutexLock l(HelpAttributesMutex());
help_mode = mode;
}
HelpFormat GetFlagsHelpFormat() {
absl::MutexLock l(HelpAttributesMutex());
return help_format;
}
void SetFlagsHelpFormat(HelpFormat format) {
absl::MutexLock l(HelpAttributesMutex());
help_format = format;
}
// Deduces usage flags from the input argument in a form --name=value or
// --name. argument is already split into name and value before we call this
// function.
bool DeduceUsageFlags(absl::string_view name, absl::string_view value) {
if (absl::ConsumePrefix(&name, "help")) {
if (name.empty()) {
if (value.empty()) {
SetFlagsHelpMode(HelpMode::kImportant);
} else {
SetFlagsHelpMode(HelpMode::kMatch);
SetFlagsHelpMatchSubstr(value);
}
return true;
}
if (name == "match") {
SetFlagsHelpMode(HelpMode::kMatch);
SetFlagsHelpMatchSubstr(value);
return true;
}
if (name == "on") {
SetFlagsHelpMode(HelpMode::kMatch);
SetFlagsHelpMatchSubstr(absl::StrCat("/", value, "."));
return true;
}
if (name == "full") {
SetFlagsHelpMode(HelpMode::kFull);
return true;
}
if (name == "short") {
SetFlagsHelpMode(HelpMode::kShort);
return true;
}
if (name == "package") {
SetFlagsHelpMode(HelpMode::kPackage);
return true;
}
return false;
}
if (name == "version") {
SetFlagsHelpMode(HelpMode::kVersion);
return true;
}
if (name == "only_check_args") {
SetFlagsHelpMode(HelpMode::kOnlyCheckArgs);
return true;
}
return false;
}
// --------------------------------------------------------------------
void MaybeExit(HelpMode mode) {
switch (mode) {
case flags_internal::HelpMode::kNone:
return;
case flags_internal::HelpMode::kOnlyCheckArgs:
case flags_internal::HelpMode::kVersion:
std::exit(0);
default: // For all the other modes we exit with 1
std::exit(1);
}
}
// --------------------------------------------------------------------
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_FLAGS_INTERNAL_USAGE_H_
#define ABSL_FLAGS_INTERNAL_USAGE_H_
#include <iosfwd>
#include <ostream>
#include <string>
#include "absl/base/config.h"
#include "absl/flags/commandlineflag.h"
#include "absl/strings/string_view.h"
// --------------------------------------------------------------------
// Usage reporting interfaces
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
// The format to report the help messages in.
enum class HelpFormat {
kHumanReadable,
};
// The kind of usage help requested.
enum class HelpMode {
kNone,
kImportant,
kShort,
kFull,
kPackage,
kMatch,
kVersion,
kOnlyCheckArgs
};
// Streams the help message describing `flag` to `out`.
// The default value for `flag` is included in the output.
void FlagHelp(std::ostream& out, const CommandLineFlag& flag,
HelpFormat format = HelpFormat::kHumanReadable);
// Produces the help messages for all flags matching the filter. A flag matches
// the filter if it is defined in a file with a filename which includes
// filter string as a substring. You can use '/' and '.' to restrict the
// matching to a specific file names. For example:
// FlagsHelp(out, "/path/to/file.");
// restricts help to only flags which resides in files named like:
// .../path/to/file.<ext>
// for any extension 'ext'. If the filter is empty this function produces help
// messages for all flags.
void FlagsHelp(std::ostream& out, absl::string_view filter,
HelpFormat format, absl::string_view program_usage_message);
// --------------------------------------------------------------------
// If any of the 'usage' related command line flags (listed on the bottom of
// this file) has been set this routine produces corresponding help message in
// the specified output stream and returns HelpMode that was handled. Otherwise
// it returns HelpMode::kNone.
HelpMode HandleUsageFlags(std::ostream& out,
absl::string_view program_usage_message);
// --------------------------------------------------------------------
// Encapsulates the logic of exiting the binary depending on handled help mode.
void MaybeExit(HelpMode mode);
// --------------------------------------------------------------------
// Globals representing usage reporting flags
// Returns substring to filter help output (--help=substr argument)
std::string GetFlagsHelpMatchSubstr();
// Returns the requested help mode.
HelpMode GetFlagsHelpMode();
// Returns the requested help format.
HelpFormat GetFlagsHelpFormat();
// These are corresponding setters to the attributes above.
void SetFlagsHelpMatchSubstr(absl::string_view);
void SetFlagsHelpMode(HelpMode);
void SetFlagsHelpFormat(HelpFormat);
// Deduces usage flags from the input argument in a form --name=value or
// --name. argument is already split into name and value before we call this
// function.
bool DeduceUsageFlags(absl::string_view name, absl::string_view value);
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_FLAGS_INTERNAL_USAGE_H_

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//
// Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/flags/internal/usage.h"
#include <stdint.h>
#include <sstream>
#include <string>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/flags/config.h"
#include "absl/flags/flag.h"
#include "absl/flags/internal/parse.h"
#include "absl/flags/internal/program_name.h"
#include "absl/flags/reflection.h"
#include "absl/flags/usage.h"
#include "absl/flags/usage_config.h"
#include "absl/strings/match.h"
#include "absl/strings/string_view.h"
ABSL_FLAG(int, usage_reporting_test_flag_01, 101,
"usage_reporting_test_flag_01 help message");
ABSL_FLAG(bool, usage_reporting_test_flag_02, false,
"usage_reporting_test_flag_02 help message");
ABSL_FLAG(double, usage_reporting_test_flag_03, 1.03,
"usage_reporting_test_flag_03 help message");
ABSL_FLAG(int64_t, usage_reporting_test_flag_04, 1000000000000004L,
"usage_reporting_test_flag_04 help message");
ABSL_FLAG(std::string, usage_reporting_test_flag_07, "\r\n\f\v\a\b\t ",
"usage_reporting_test_flag_07 help \r\n\f\v\a\b\t ");
static const char kTestUsageMessage[] = "Custom usage message";
struct UDT {
UDT() = default;
UDT(const UDT&) = default;
UDT& operator=(const UDT&) = default;
};
static bool AbslParseFlag(absl::string_view, UDT*, std::string*) {
return true;
}
static std::string AbslUnparseFlag(const UDT&) { return "UDT{}"; }
ABSL_FLAG(UDT, usage_reporting_test_flag_05, {},
"usage_reporting_test_flag_05 help message");
ABSL_FLAG(
std::string, usage_reporting_test_flag_06, {},
"usage_reporting_test_flag_06 help message.\n"
"\n"
"Some more help.\n"
"Even more long long long long long long long long long long long long "
"help message.");
namespace {
namespace flags = absl::flags_internal;
static std::string NormalizeFileName(absl::string_view fname) {
#ifdef _WIN32
std::string normalized(fname);
std::replace(normalized.begin(), normalized.end(), '\\', '/');
fname = normalized;
#endif
auto absl_pos = fname.rfind("absl/");
if (absl_pos != absl::string_view::npos) {
fname = fname.substr(absl_pos);
}
return std::string(fname);
}
class UsageReportingTest : public testing::Test {
protected:
UsageReportingTest() {
// Install default config for the use on this unit test.
// Binary may install a custom config before tests are run.
absl::FlagsUsageConfig default_config;
default_config.normalize_filename = &NormalizeFileName;
absl::SetFlagsUsageConfig(default_config);
}
~UsageReportingTest() override {
flags::SetFlagsHelpMode(flags::HelpMode::kNone);
flags::SetFlagsHelpMatchSubstr("");
flags::SetFlagsHelpFormat(flags::HelpFormat::kHumanReadable);
}
void SetUp() override {
#if ABSL_FLAGS_STRIP_NAMES
GTEST_SKIP() << "This test requires flag names to be present";
#endif
}
private:
absl::FlagSaver flag_saver_;
};
// --------------------------------------------------------------------
using UsageReportingDeathTest = UsageReportingTest;
TEST_F(UsageReportingDeathTest, TestSetProgramUsageMessage) {
#if !defined(GTEST_HAS_ABSL) || !GTEST_HAS_ABSL
// Check for kTestUsageMessage set in main() below.
EXPECT_EQ(absl::ProgramUsageMessage(), kTestUsageMessage);
#else
// Check for part of the usage message set by GoogleTest.
EXPECT_THAT(absl::ProgramUsageMessage(),
::testing::HasSubstr(
"This program contains tests written using Google Test"));
#endif
EXPECT_DEATH_IF_SUPPORTED(
absl::SetProgramUsageMessage("custom usage message"),
::testing::HasSubstr("SetProgramUsageMessage() called twice"));
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_01) {
const auto* flag = absl::FindCommandLineFlag("usage_reporting_test_flag_01");
std::stringstream test_buf;
flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable);
EXPECT_EQ(
test_buf.str(),
R"( --usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message);
default: 101;
)");
}
TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_02) {
const auto* flag = absl::FindCommandLineFlag("usage_reporting_test_flag_02");
std::stringstream test_buf;
flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable);
EXPECT_EQ(
test_buf.str(),
R"( --usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message);
default: false;
)");
}
TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_03) {
const auto* flag = absl::FindCommandLineFlag("usage_reporting_test_flag_03");
std::stringstream test_buf;
flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable);
EXPECT_EQ(
test_buf.str(),
R"( --usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message);
default: 1.03;
)");
}
TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_04) {
const auto* flag = absl::FindCommandLineFlag("usage_reporting_test_flag_04");
std::stringstream test_buf;
flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable);
EXPECT_EQ(
test_buf.str(),
R"( --usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message);
default: 1000000000000004;
)");
}
TEST_F(UsageReportingTest, TestFlagHelpHRF_on_flag_05) {
const auto* flag = absl::FindCommandLineFlag("usage_reporting_test_flag_05");
std::stringstream test_buf;
flags::FlagHelp(test_buf, *flag, flags::HelpFormat::kHumanReadable);
EXPECT_EQ(
test_buf.str(),
R"( --usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
default: UDT{};
)");
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestFlagsHelpHRF) {
std::string usage_test_flags_out =
R"(usage_test: Custom usage message
Flags from absl/flags/internal/usage_test.cc:
--usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message);
default: 101;
--usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message);
default: false;
--usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message);
default: 1.03;
--usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message);
default: 1000000000000004;
--usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
default: UDT{};
--usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
Some more help.
Even more long long long long long long long long long long long long help
message.); default: "";)"
"\n --usage_reporting_test_flag_07 (usage_reporting_test_flag_07 "
"help\n\n \f\v\a\b ); default: \"\r\n\f\v\a\b\t \";\n"
R"(
Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.
)";
std::stringstream test_buf_01;
flags::FlagsHelp(test_buf_01, "usage_test.cc",
flags::HelpFormat::kHumanReadable, kTestUsageMessage);
EXPECT_EQ(test_buf_01.str(), usage_test_flags_out);
std::stringstream test_buf_02;
flags::FlagsHelp(test_buf_02, "flags/internal/usage_test.cc",
flags::HelpFormat::kHumanReadable, kTestUsageMessage);
EXPECT_EQ(test_buf_02.str(), usage_test_flags_out);
std::stringstream test_buf_03;
flags::FlagsHelp(test_buf_03, "usage_test", flags::HelpFormat::kHumanReadable,
kTestUsageMessage);
EXPECT_EQ(test_buf_03.str(), usage_test_flags_out);
std::stringstream test_buf_04;
flags::FlagsHelp(test_buf_04, "flags/invalid_file_name.cc",
flags::HelpFormat::kHumanReadable, kTestUsageMessage);
EXPECT_EQ(test_buf_04.str(),
R"(usage_test: Custom usage message
No flags matched.
Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.
)");
std::stringstream test_buf_05;
flags::FlagsHelp(test_buf_05, "", flags::HelpFormat::kHumanReadable,
kTestUsageMessage);
std::string test_out = test_buf_05.str();
absl::string_view test_out_str(test_out);
EXPECT_TRUE(
absl::StartsWith(test_out_str, "usage_test: Custom usage message"));
EXPECT_TRUE(absl::StrContains(
test_out_str, "Flags from absl/flags/internal/usage_test.cc:"));
EXPECT_TRUE(
absl::StrContains(test_out_str, "-usage_reporting_test_flag_01 "));
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestNoUsageFlags) {
std::stringstream test_buf;
EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage),
flags::HelpMode::kNone);
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestUsageFlag_helpshort) {
flags::SetFlagsHelpMode(flags::HelpMode::kShort);
std::stringstream test_buf;
EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage),
flags::HelpMode::kShort);
EXPECT_EQ(
test_buf.str(),
R"(usage_test: Custom usage message
Flags from absl/flags/internal/usage_test.cc:
--usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message);
default: 101;
--usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message);
default: false;
--usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message);
default: 1.03;
--usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message);
default: 1000000000000004;
--usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
default: UDT{};
--usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
Some more help.
Even more long long long long long long long long long long long long help
message.); default: "";)"
"\n --usage_reporting_test_flag_07 (usage_reporting_test_flag_07 "
"help\n\n \f\v\a\b ); default: \"\r\n\f\v\a\b\t \";\n"
R"(
Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.
)");
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestUsageFlag_help_simple) {
flags::SetFlagsHelpMode(flags::HelpMode::kImportant);
std::stringstream test_buf;
EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage),
flags::HelpMode::kImportant);
EXPECT_EQ(
test_buf.str(),
R"(usage_test: Custom usage message
Flags from absl/flags/internal/usage_test.cc:
--usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message);
default: 101;
--usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message);
default: false;
--usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message);
default: 1.03;
--usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message);
default: 1000000000000004;
--usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
default: UDT{};
--usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
Some more help.
Even more long long long long long long long long long long long long help
message.); default: "";)"
"\n --usage_reporting_test_flag_07 (usage_reporting_test_flag_07 "
"help\n\n \f\v\a\b ); default: \"\r\n\f\v\a\b\t \";\n"
R"(
Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.
)");
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestUsageFlag_help_one_flag) {
flags::SetFlagsHelpMode(flags::HelpMode::kMatch);
flags::SetFlagsHelpMatchSubstr("usage_reporting_test_flag_06");
std::stringstream test_buf;
EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage),
flags::HelpMode::kMatch);
EXPECT_EQ(test_buf.str(),
R"(usage_test: Custom usage message
Flags from absl/flags/internal/usage_test.cc:
--usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
Some more help.
Even more long long long long long long long long long long long long help
message.); default: "";
Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.
)");
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestUsageFlag_help_multiple_flag) {
flags::SetFlagsHelpMode(flags::HelpMode::kMatch);
flags::SetFlagsHelpMatchSubstr("test_flag");
std::stringstream test_buf;
EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage),
flags::HelpMode::kMatch);
EXPECT_EQ(
test_buf.str(),
R"(usage_test: Custom usage message
Flags from absl/flags/internal/usage_test.cc:
--usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message);
default: 101;
--usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message);
default: false;
--usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message);
default: 1.03;
--usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message);
default: 1000000000000004;
--usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
default: UDT{};
--usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
Some more help.
Even more long long long long long long long long long long long long help
message.); default: "";)"
"\n --usage_reporting_test_flag_07 (usage_reporting_test_flag_07 "
"help\n\n \f\v\a\b ); default: \"\r\n\f\v\a\b\t \";\n"
R"(
Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.
)");
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestUsageFlag_helppackage) {
flags::SetFlagsHelpMode(flags::HelpMode::kPackage);
std::stringstream test_buf;
EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage),
flags::HelpMode::kPackage);
EXPECT_EQ(
test_buf.str(),
R"(usage_test: Custom usage message
Flags from absl/flags/internal/usage_test.cc:
--usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message);
default: 101;
--usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message);
default: false;
--usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message);
default: 1.03;
--usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message);
default: 1000000000000004;
--usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
default: UDT{};
--usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
Some more help.
Even more long long long long long long long long long long long long help
message.); default: "";)"
"\n --usage_reporting_test_flag_07 (usage_reporting_test_flag_07 "
"help\n\n \f\v\a\b ); default: \"\r\n\f\v\a\b\t \";\n"
R"(
Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.
)");
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestUsageFlag_version) {
flags::SetFlagsHelpMode(flags::HelpMode::kVersion);
std::stringstream test_buf;
EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage),
flags::HelpMode::kVersion);
#ifndef NDEBUG
EXPECT_EQ(test_buf.str(), "usage_test\nDebug build (NDEBUG not #defined)\n");
#else
EXPECT_EQ(test_buf.str(), "usage_test\n");
#endif
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestUsageFlag_only_check_args) {
flags::SetFlagsHelpMode(flags::HelpMode::kOnlyCheckArgs);
std::stringstream test_buf;
EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage),
flags::HelpMode::kOnlyCheckArgs);
EXPECT_EQ(test_buf.str(), "");
}
// --------------------------------------------------------------------
TEST_F(UsageReportingTest, TestUsageFlag_helpon) {
flags::SetFlagsHelpMode(flags::HelpMode::kMatch);
flags::SetFlagsHelpMatchSubstr("/bla-bla.");
std::stringstream test_buf_01;
EXPECT_EQ(flags::HandleUsageFlags(test_buf_01, kTestUsageMessage),
flags::HelpMode::kMatch);
EXPECT_EQ(test_buf_01.str(),
R"(usage_test: Custom usage message
No flags matched.
Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.
)");
flags::SetFlagsHelpMatchSubstr("/usage_test.");
std::stringstream test_buf_02;
EXPECT_EQ(flags::HandleUsageFlags(test_buf_02, kTestUsageMessage),
flags::HelpMode::kMatch);
EXPECT_EQ(
test_buf_02.str(),
R"(usage_test: Custom usage message
Flags from absl/flags/internal/usage_test.cc:
--usage_reporting_test_flag_01 (usage_reporting_test_flag_01 help message);
default: 101;
--usage_reporting_test_flag_02 (usage_reporting_test_flag_02 help message);
default: false;
--usage_reporting_test_flag_03 (usage_reporting_test_flag_03 help message);
default: 1.03;
--usage_reporting_test_flag_04 (usage_reporting_test_flag_04 help message);
default: 1000000000000004;
--usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
default: UDT{};
--usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
Some more help.
Even more long long long long long long long long long long long long help
message.); default: "";)"
"\n --usage_reporting_test_flag_07 (usage_reporting_test_flag_07 "
"help\n\n \f\v\a\b ); default: \"\r\n\f\v\a\b\t \";\n"
R"(
Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.
)");
}
// --------------------------------------------------------------------
} // namespace
int main(int argc, char* argv[]) {
(void)absl::GetFlag(FLAGS_undefok); // Force linking of parse.cc
flags::SetProgramInvocationName("usage_test");
#if !defined(GTEST_HAS_ABSL) || !GTEST_HAS_ABSL
// GoogleTest calls absl::SetProgramUsageMessage() already.
absl::SetProgramUsageMessage(kTestUsageMessage);
#endif
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}