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

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+// Copyright 2011 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_PROCESS_PROCESS_H_
+#define BASE_PROCESS_PROCESS_H_
+
+#include "base/base_export.h"
+#include "base/macros.h"
+#include "base/process/process_handle.h"
+#include "base/time/time.h"
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include "base/win/scoped_handle.h"
+#endif
+
+#if defined(OS_FUCHSIA)
+#include <lib/zx/process.h>
+#endif
+
+#if defined(OS_MACOSX)
+#include "base/feature_list.h"
+#include "base/process/port_provider_mac.h"
+#endif
+
+namespace base {
+
+#if defined(OS_MACOSX)
+extern const Feature kMacAllowBackgroundingProcesses;
+#endif
+
+// Provides a move-only encapsulation of a process.
+//
+// This object is not tied to the lifetime of the underlying process: the
+// process may be killed and this object may still around, and it will still
+// claim to be valid. The actual behavior in that case is OS dependent like so:
+//
+// Windows: The underlying ProcessHandle will be valid after the process dies
+// and can be used to gather some information about that process, but most
+// methods will obviously fail.
+//
+// POSIX: The underlying ProcessHandle is not guaranteed to remain valid after
+// the process dies, and it may be reused by the system, which means that it may
+// end up pointing to the wrong process.
+class BASE_EXPORT Process {
+ public:
+  // On Windows, this takes ownership of |handle|. On POSIX, this does not take
+  // ownership of |handle|.
+  explicit Process(ProcessHandle handle = kNullProcessHandle);
+
+  Process(Process&& other);
+
+  // The destructor does not terminate the process.
+  ~Process();
+
+  Process& operator=(Process&& other);
+
+  // Returns an object for the current process.
+  static Process Current();
+
+  // Returns a Process for the given |pid|.
+  static Process Open(ProcessId pid);
+
+  // Returns a Process for the given |pid|. On Windows the handle is opened
+  // with more access rights and must only be used by trusted code (can read the
+  // address space and duplicate handles).
+  static Process OpenWithExtraPrivileges(ProcessId pid);
+
+#if defined(OS_WIN)
+  // Returns a Process for the given |pid|, using some |desired_access|.
+  // See ::OpenProcess documentation for valid |desired_access|.
+  static Process OpenWithAccess(ProcessId pid, DWORD desired_access);
+#endif
+
+  // Creates an object from a |handle| owned by someone else.
+  // Don't use this for new code. It is only intended to ease the migration to
+  // a strict ownership model.
+  // TODO(rvargas) crbug.com/417532: Remove this code.
+  static Process DeprecatedGetProcessFromHandle(ProcessHandle handle);
+
+  // Returns true if processes can be backgrounded.
+  static bool CanBackgroundProcesses();
+
+  // Terminates the current process immediately with |exit_code|.
+  [[noreturn]] static void TerminateCurrentProcessImmediately(int exit_code);
+
+  // Returns true if this objects represents a valid process.
+  bool IsValid() const;
+
+  // Returns a handle for this process. There is no guarantee about when that
+  // handle becomes invalid because this object retains ownership.
+  ProcessHandle Handle() const;
+
+  // Returns a second object that represents this process.
+  Process Duplicate() const;
+
+  // Get the PID for this process.
+  ProcessId Pid() const;
+
+#if !defined(OS_ANDROID)
+  // Get the creation time for this process. Since the Pid can be reused after a
+  // process dies, it is useful to use both the Pid and the creation time to
+  // uniquely identify a process.
+  //
+  // Not available on Android because /proc/stat/ cannot be accessed on O+.
+  // https://issuetracker.google.com/issues/37140047
+  Time CreationTime() const;
+#endif  // !defined(OS_ANDROID)
+
+  // Returns true if this process is the current process.
+  bool is_current() const;
+
+  // Close the process handle. This will not terminate the process.
+  void Close();
+
+  // Returns true if this process is still running. This is only safe on Windows
+  // (and maybe Fuchsia?), because the ProcessHandle will keep the zombie
+  // process information available until itself has been released. But on Posix,
+  // the OS may reuse the ProcessId.
+#if defined(OS_WIN)
+  bool IsRunning() const {
+    return !WaitForExitWithTimeout(base::TimeDelta(), nullptr);
+  }
+#endif
+
+  // Terminates the process with extreme prejudice. The given |exit_code| will
+  // be the exit code of the process. If |wait| is true, this method will wait
+  // for up to one minute for the process to actually terminate.
+  // Returns true if the process terminates within the allowed time.
+  // NOTE: On POSIX |exit_code| is ignored.
+  bool Terminate(int exit_code, bool wait) const;
+
+#if defined(OS_WIN)
+  enum class WaitExitStatus {
+    PROCESS_EXITED,
+    STOP_EVENT_SIGNALED,
+    FAILED,
+  };
+
+  // Waits for the process to exit, or the specified |stop_event_handle| to be
+  // set. Returns value indicating which event was set. The given |exit_code|
+  // will be the exit code of the process.
+  WaitExitStatus WaitForExitOrEvent(
+      const base::win::ScopedHandle& stop_event_handle,
+      int* exit_code) const;
+#endif  // OS_WIN
+
+  // Waits for the process to exit. Returns true on success.
+  // On POSIX, if the process has been signaled then |exit_code| is set to -1.
+  // On Linux this must be a child process, however on Mac and Windows it can be
+  // any process.
+  // NOTE: |exit_code| is optional, nullptr can be passed if the exit code is
+  // not required.
+  bool WaitForExit(int* exit_code) const;
+
+  // Same as WaitForExit() but only waits for up to |timeout|.
+  // NOTE: |exit_code| is optional, nullptr can be passed if the exit code
+  // is not required.
+  bool WaitForExitWithTimeout(TimeDelta timeout, int* exit_code) const;
+
+  // Indicates that the process has exited with the specified |exit_code|.
+  // This should be called if process exit is observed outside of this class.
+  // (i.e. Not because Terminate or WaitForExit, above, was called.)
+  // Note that nothing prevents this being called multiple times for a dead
+  // process though that should be avoided.
+  void Exited(int exit_code) const;
+
+#if defined(OS_MACOSX)
+  // The Mac needs a Mach port in order to manipulate a process's priority,
+  // and there's no good way to get that from base given the pid. These Mac
+  // variants of the IsProcessBackgrounded and SetProcessBackgrounded API take
+  // a port provider for this reason. See crbug.com/460102
+  //
+  // A process is backgrounded when its task priority is
+  // |TASK_BACKGROUND_APPLICATION|.
+  //
+  // Returns true if the port_provider can locate a task port for the process
+  // and it is backgrounded. If port_provider is null, returns false.
+  bool IsProcessBackgrounded(PortProvider* port_provider) const;
+
+  // Set the process as backgrounded. If value is
+  // true, the priority of the associated task will be set to
+  // TASK_BACKGROUND_APPLICATION. If value is false, the
+  // priority of the process will be set to TASK_FOREGROUND_APPLICATION.
+  //
+  // Returns true if the priority was changed, false otherwise. If
+  // |port_provider| is null, this is a no-op and it returns false.
+  bool SetProcessBackgrounded(PortProvider* port_provider, bool value);
+#else
+  // A process is backgrounded when it's priority is lower than normal.
+  // Return true if this process is backgrounded, false otherwise.
+  bool IsProcessBackgrounded() const;
+
+  // Set a process as backgrounded. If value is true, the priority of the
+  // process will be lowered. If value is false, the priority of the process
+  // will be made "normal" - equivalent to default process priority.
+  // Returns true if the priority was changed, false otherwise.
+  bool SetProcessBackgrounded(bool value);
+#endif  // defined(OS_MACOSX)
+  // Returns an integer representing the priority of a process. The meaning
+  // of this value is OS dependent.
+  int GetPriority() const;
+
+#if defined(OS_CHROMEOS)
+  // Get the PID in its PID namespace.
+  // If the process is not in a PID namespace or /proc/<pid>/status does not
+  // report NSpid, kNullProcessId is returned.
+  ProcessId GetPidInNamespace() const;
+#endif
+
+ private:
+#if defined(OS_WIN)
+  win::ScopedHandle process_;
+#elif defined(OS_FUCHSIA)
+  zx::process process_;
+#else
+  ProcessHandle process_;
+#endif
+
+#if defined(OS_WIN) || defined(OS_FUCHSIA)
+  bool is_current_process_;
+#endif
+
+  DISALLOW_COPY_AND_ASSIGN(Process);
+};
+
+#if defined(OS_CHROMEOS)
+// Exposed for testing.
+// Given the contents of the /proc/<pid>/cgroup file, determine whether the
+// process is backgrounded or not.
+BASE_EXPORT bool IsProcessBackgroundedCGroup(
+    const StringPiece& cgroup_contents);
+#endif  // defined(OS_CHROMEOS)
+
+}  // namespace base
+
+#endif  // BASE_PROCESS_PROCESS_H_