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/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
// System independant wrapper for spawning threads
// Note: the spawned thread will loop over the callback function until stopped.
// Note: The callback function is expected to return every 2 seconds or more
// often.
#ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_THREAD_WRAPPER_H_
#define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_THREAD_WRAPPER_H_
#if defined(WEBRTC_WIN)
#include <windows.h>
#endif
#include "webrtc/base/scoped_ptr.h"
#include "webrtc/common_types.h"
#include "webrtc/typedefs.h"
namespace webrtc {
// Callback function that the spawned thread will enter once spawned.
// A return value of false is interpreted as that the function has no
// more work to do and that the thread can be released.
typedef bool(*ThreadRunFunction)(void*);
enum ThreadPriority {
#ifdef WEBRTC_WIN
kLowPriority = THREAD_PRIORITY_BELOW_NORMAL,
kNormalPriority = THREAD_PRIORITY_NORMAL,
kHighPriority = THREAD_PRIORITY_ABOVE_NORMAL,
kHighestPriority = THREAD_PRIORITY_HIGHEST,
kRealtimePriority = THREAD_PRIORITY_TIME_CRITICAL
#else
kLowPriority = 1,
kNormalPriority = 2,
kHighPriority = 3,
kHighestPriority = 4,
kRealtimePriority = 5
#endif
};
// Represents a simple worker thread. The implementation must be assumed
// to be single threaded, meaning that all methods of the class, must be
// called from the same thread, including instantiation.
// TODO(tommi): There's no need for this to be a virtual interface since there's
// only ever a single implementation of it.
class ThreadWrapper {
public:
virtual ~ThreadWrapper() {}
// Factory method. Constructor disabled.
//
// func Pointer to a, by user, specified callback function.
// obj Object associated with the thread. Passed in the callback
// function.
// prio Thread priority. May require root/admin rights.
// thread_name NULL terminated thread name, will be visable in the Windows
// debugger.
static rtc::scoped_ptr<ThreadWrapper> CreateThread(ThreadRunFunction func,
void* obj, const char* thread_name);
// Get the current thread's thread ID.
// NOTE: This is a static method. It returns the id of the calling thread,
// *not* the id of the worker thread that a ThreadWrapper instance represents.
// TODO(tommi): Move outside of the ThreadWrapper class to avoid confusion.
static uint32_t GetThreadId();
// Tries to spawns a thread and returns true if that was successful.
// Additionally, it tries to set thread priority according to the priority
// from when CreateThread was called. However, failure to set priority will
// not result in a false return value.
virtual bool Start() = 0;
// Stops the spawned thread and waits for it to be reclaimed with a timeout
// of two seconds. Will return false if the thread was not reclaimed.
// Multiple tries to Stop are allowed (e.g. to wait longer than 2 seconds).
// It's ok to call Stop() even if the spawned thread has been reclaimed.
virtual bool Stop() = 0;
// Set the priority of the worker thread. Must be called when thread
// is running.
virtual bool SetPriority(ThreadPriority priority) = 0;
};
} // namespace webrtc
#endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_THREAD_WRAPPER_H_
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