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/*
* Copyright (C) 2007 The Android Open Source Project
*
* 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
*
* http://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 _LIBS_UTILS_THREAD_H
#define _LIBS_UTILS_THREAD_H
#include <stdint.h>
#include <sys/types.h>
#include <time.h>
#if defined(HAVE_PTHREADS)
# include <pthread.h>
#endif
#include <utils/Condition.h>
#include <utils/Errors.h>
#include <utils/Mutex.h>
#include <utils/RefBase.h>
#include <utils/Timers.h>
#include <utils/ThreadDefs.h>
// ---------------------------------------------------------------------------
namespace android {
// ---------------------------------------------------------------------------
class Thread : virtual public RefBase
{
public:
// Create a Thread object, but doesn't create or start the associated
// thread. See the run() method.
Thread(bool canCallJava = true);
virtual ~Thread();
// Start the thread in threadLoop() which needs to be implemented.
virtual status_t run( const char* name = 0,
int32_t priority = PRIORITY_DEFAULT,
size_t stack = 0);
// Ask this object's thread to exit. This function is asynchronous, when the
// function returns the thread might still be running. Of course, this
// function can be called from a different thread.
virtual void requestExit();
// Good place to do one-time initializations
virtual status_t readyToRun();
// Call requestExit() and wait until this object's thread exits.
// BE VERY CAREFUL of deadlocks. In particular, it would be silly to call
// this function from this object's thread. Will return WOULD_BLOCK in
// that case.
status_t requestExitAndWait();
// Wait until this object's thread exits. Returns immediately if not yet running.
// Do not call from this object's thread; will return WOULD_BLOCK in that case.
status_t join();
// Indicates whether this thread is running or not.
bool isRunning() const;
#ifdef HAVE_ANDROID_OS
// Return the thread's kernel ID, same as the thread itself calling gettid() or
// androidGetTid(), or -1 if the thread is not running.
pid_t getTid() const;
#endif
protected:
// exitPending() returns true if requestExit() has been called.
bool exitPending() const;
private:
// Derived class must implement threadLoop(). The thread starts its life
// here. There are two ways of using the Thread object:
// 1) loop: if threadLoop() returns true, it will be called again if
// requestExit() wasn't called.
// 2) once: if threadLoop() returns false, the thread will exit upon return.
virtual bool threadLoop() = 0;
private:
Thread& operator=(const Thread&);
static int _threadLoop(void* user);
const bool mCanCallJava;
// always hold mLock when reading or writing
thread_id_t mThread;
mutable Mutex mLock;
Condition mThreadExitedCondition;
status_t mStatus;
// note that all accesses of mExitPending and mRunning need to hold mLock
volatile bool mExitPending;
volatile bool mRunning;
sp<Thread> mHoldSelf;
#ifdef HAVE_ANDROID_OS
// legacy for debugging, not used by getTid() as it is set by the child thread
// and so is not initialized until the child reaches that point
pid_t mTid;
#endif
};
}; // namespace android
// ---------------------------------------------------------------------------
#endif // _LIBS_UTILS_THREAD_H
// ---------------------------------------------------------------------------
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