Repo created

TMessagesProj/jni/voip/webrtc/base/location.h

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+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_LOCATION_H_
+#define BASE_LOCATION_H_
+
+#include <stddef.h>
+
+#include <cassert>
+#include <functional>
+#include <string>
+
+#include "base/base_export.h"
+#include "base/debug/debugging_buildflags.h"
+#include "base/hash/hash.h"
+#include "build/build_config.h"
+
+namespace base {
+
+#if defined(__has_builtin)
+// Clang allows detection of these builtins.
+#define SUPPORTS_LOCATION_BUILTINS                                       \
+  (__has_builtin(__builtin_FUNCTION) && __has_builtin(__builtin_FILE) && \
+   __has_builtin(__builtin_LINE))
+#elif defined(COMPILER_GCC) && __GNUC__ >= 7
+// GCC has supported these for a long time, but they point at the function
+// declaration in the case of default arguments, rather than at the call site.
+#define SUPPORTS_LOCATION_BUILTINS 1
+#else
+#define SUPPORTS_LOCATION_BUILTINS 0
+#endif
+
+// Location provides basic info where of an object was constructed, or was
+// significantly brought to life.
+class BASE_EXPORT Location {
+ public:
+  Location();
+  Location(const Location& other);
+
+  // Only initializes the file name and program counter, the source information
+  // will be null for the strings, and -1 for the line number.
+  // TODO(http://crbug.com/760702) remove file name from this constructor.
+  Location(const char* file_name, const void* program_counter);
+
+  // Constructor should be called with a long-lived char*, such as __FILE__.
+  // It assumes the provided value will persist as a global constant, and it
+  // will not make a copy of it.
+  Location(const char* function_name,
+           const char* file_name,
+           int line_number,
+           const void* program_counter);
+
+  // Comparator for hash map insertion. The program counter should uniquely
+  // identify a location.
+  bool operator==(const Location& other) const {
+    return program_counter_ == other.program_counter_;
+  }
+
+  // Returns true if there is source code location info. If this is false,
+  // the Location object only contains a program counter or is
+  // default-initialized (the program counter is also null).
+  bool has_source_info() const { return function_name_ && file_name_; }
+
+  // Will be nullptr for default initialized Location objects and when source
+  // names are disabled.
+  const char* function_name() const { return function_name_; }
+
+  // Will be nullptr for default initialized Location objects and when source
+  // names are disabled.
+  const char* file_name() const { return file_name_; }
+
+  // Will be -1 for default initialized Location objects and when source names
+  // are disabled.
+  int line_number() const { return line_number_; }
+
+  // The address of the code generating this Location object. Should always be
+  // valid except for default initialized Location objects, which will be
+  // nullptr.
+  const void* program_counter() const { return program_counter_; }
+
+  // Converts to the most user-readable form possible. If function and filename
+  // are not available, this will return "pc:<hex address>".
+  std::string ToString() const;
+
+#if !BUILDFLAG(FROM_HERE_USES_LOCATION_BUILTINS)
+#if !BUILDFLAG(ENABLE_LOCATION_SOURCE)
+  static Location CreateFromHere(const char* file_name);
+#else
+  static Location CreateFromHere(const char* function_name,
+                                 const char* file_name,
+                                 int line_number);
+#endif
+#endif
+
+#if SUPPORTS_LOCATION_BUILTINS && BUILDFLAG(ENABLE_LOCATION_SOURCE)
+  static Location Current(const char* function_name = __builtin_FUNCTION(),
+                          const char* file_name = __builtin_FILE(),
+                          int line_number = __builtin_LINE());
+#elif SUPPORTS_LOCATION_BUILTINS
+  static Location Current(const char* file_name = __builtin_FILE());
+#else
+  static Location Current();
+#endif
+
+ private:
+  const char* function_name_ = nullptr;
+  const char* file_name_ = nullptr;
+  int line_number_ = -1;
+  const void* program_counter_ = nullptr;
+};
+
+BASE_EXPORT const void* GetProgramCounter();
+
+#if BUILDFLAG(FROM_HERE_USES_LOCATION_BUILTINS)
+
+#define FROM_HERE ::base::Location::Current()
+
+// The macros defined here will expand to the current function.
+#elif BUILDFLAG(ENABLE_LOCATION_SOURCE)
+
+// Full source information should be included.
+#define FROM_HERE ::base::Location::CreateFromHere(__func__, __FILE__, __LINE__)
+
+#else
+
+// TODO(http://crbug.com/760702) remove the __FILE__ argument from these calls.
+#define FROM_HERE ::base::Location::CreateFromHere(__FILE__)
+
+#endif
+
+}  // namespace base
+
+namespace std {
+
+// Specialization for using Location in hash tables.
+template <>
+struct hash<::base::Location> {
+  std::size_t operator()(const ::base::Location& loc) const {
+    const void* program_counter = loc.program_counter();
+    return base::FastHash(base::as_bytes(base::make_span(&program_counter, 1)));
+  }
+};
+
+}  // namespace std
+
+#endif  // BASE_LOCATION_H_