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// Copyright (c) 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.
// WARNING: You should *NOT* be using this class directly. PlatformThread is
// the low-level platform-specific abstraction to the OS's threading interface.
// You should instead be using a message-loop driven Thread, see thread.h.
#ifndef BASE_THREADING_PLATFORM_THREAD_H_
#define BASE_THREADING_PLATFORM_THREAD_H_
#pragma once
#include "base/base_export.h"
#include "base/basictypes.h"
#include "build/build_config.h"
#if defined(OS_WIN)
#include <windows.h>
#elif defined(OS_POSIX)
#include <pthread.h>
#if defined(OS_MACOSX)
#include <mach/mach.h>
#else // OS_POSIX && !OS_MACOSX
#include <unistd.h>
#endif
#endif
namespace base {
// PlatformThreadHandle should not be assumed to be a numeric type, since the
// standard intends to allow pthread_t to be a structure. This means you
// should not initialize it to a value, like 0. If it's a member variable, the
// constructor can safely "value initialize" using () in the initializer list.
#if defined(OS_WIN)
typedef DWORD PlatformThreadId;
typedef void* PlatformThreadHandle; // HANDLE
const PlatformThreadHandle kNullThreadHandle = NULL;
#elif defined(OS_POSIX)
typedef pthread_t PlatformThreadHandle;
const PlatformThreadHandle kNullThreadHandle = 0;
#if defined(OS_MACOSX)
typedef mach_port_t PlatformThreadId;
#else // OS_POSIX && !OS_MACOSX
typedef pid_t PlatformThreadId;
#endif
#endif
const PlatformThreadId kInvalidThreadId = 0;
// Valid values for SetThreadPriority()
enum ThreadPriority{
kThreadPriority_Normal,
// Suitable for low-latency, glitch-resistant audio.
kThreadPriority_RealtimeAudio
};
// A namespace for low-level thread functions.
class BASE_EXPORT PlatformThread {
public:
// Implement this interface to run code on a background thread. Your
// ThreadMain method will be called on the newly created thread.
class BASE_EXPORT Delegate {
public:
virtual ~Delegate() {}
virtual void ThreadMain() = 0;
};
// Gets the current thread id, which may be useful for logging purposes.
static PlatformThreadId CurrentId();
// Yield the current thread so another thread can be scheduled.
static void YieldCurrentThread();
// Sleeps for the specified duration (units are milliseconds).
static void Sleep(int duration_ms);
// Sets the thread name visible to debuggers/tools. This has no effect
// otherwise. This name pointer is not copied internally. Thus, it must stay
// valid until the thread ends.
static void SetName(const char* name);
// Gets the thread name, if previously set by SetName.
static const char* GetName();
// Creates a new thread. The |stack_size| parameter can be 0 to indicate
// that the default stack size should be used. Upon success,
// |*thread_handle| will be assigned a handle to the newly created thread,
// and |delegate|'s ThreadMain method will be executed on the newly created
// thread.
// NOTE: When you are done with the thread handle, you must call Join to
// release system resources associated with the thread. You must ensure that
// the Delegate object outlives the thread.
static bool Create(size_t stack_size, Delegate* delegate,
PlatformThreadHandle* thread_handle);
// CreateNonJoinable() does the same thing as Create() except the thread
// cannot be Join()'d. Therefore, it also does not output a
// PlatformThreadHandle.
static bool CreateNonJoinable(size_t stack_size, Delegate* delegate);
// Joins with a thread created via the Create function. This function blocks
// the caller until the designated thread exits. This will invalidate
// |thread_handle|.
static void Join(PlatformThreadHandle thread_handle);
static void SetThreadPriority(PlatformThreadHandle handle,
ThreadPriority priority);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(PlatformThread);
};
} // namespace base
#endif // BASE_THREADING_PLATFORM_THREAD_H_
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