9447be65c3
The signal() method is useful to choose whether to wake up one or all threads. Change-Id: I062ab6d3ddd306a9fb735549ea140e2a76eed75a
117 lines
4.2 KiB
C++
117 lines
4.2 KiB
C++
/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef _LIBS_UTILS_THREAD_H
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#define _LIBS_UTILS_THREAD_H
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#include <stdint.h>
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#include <sys/types.h>
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#include <time.h>
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#if defined(HAVE_PTHREADS)
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# include <pthread.h>
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#endif
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#include <utils/Condition.h>
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#include <utils/Errors.h>
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#include <utils/Mutex.h>
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#include <utils/RefBase.h>
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#include <utils/Timers.h>
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#include <utils/ThreadDefs.h>
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// ---------------------------------------------------------------------------
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namespace android {
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// ---------------------------------------------------------------------------
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class Thread : virtual public RefBase
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{
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public:
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// Create a Thread object, but doesn't create or start the associated
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// thread. See the run() method.
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Thread(bool canCallJava = true);
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virtual ~Thread();
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// Start the thread in threadLoop() which needs to be implemented.
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virtual status_t run( const char* name = 0,
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int32_t priority = PRIORITY_DEFAULT,
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size_t stack = 0);
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// Ask this object's thread to exit. This function is asynchronous, when the
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// function returns the thread might still be running. Of course, this
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// function can be called from a different thread.
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virtual void requestExit();
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// Good place to do one-time initializations
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virtual status_t readyToRun();
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// Call requestExit() and wait until this object's thread exits.
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// BE VERY CAREFUL of deadlocks. In particular, it would be silly to call
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// this function from this object's thread. Will return WOULD_BLOCK in
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// that case.
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status_t requestExitAndWait();
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// Wait until this object's thread exits. Returns immediately if not yet running.
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// Do not call from this object's thread; will return WOULD_BLOCK in that case.
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status_t join();
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// Indicates whether this thread is running or not.
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bool isRunning() const;
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#ifdef HAVE_ANDROID_OS
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// Return the thread's kernel ID, same as the thread itself calling gettid() or
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// androidGetTid(), or -1 if the thread is not running.
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pid_t getTid() const;
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#endif
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protected:
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// exitPending() returns true if requestExit() has been called.
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bool exitPending() const;
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private:
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// Derived class must implement threadLoop(). The thread starts its life
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// here. There are two ways of using the Thread object:
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// 1) loop: if threadLoop() returns true, it will be called again if
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// requestExit() wasn't called.
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// 2) once: if threadLoop() returns false, the thread will exit upon return.
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virtual bool threadLoop() = 0;
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private:
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Thread& operator=(const Thread&);
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static int _threadLoop(void* user);
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const bool mCanCallJava;
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// always hold mLock when reading or writing
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thread_id_t mThread;
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mutable Mutex mLock;
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Condition mThreadExitedCondition;
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status_t mStatus;
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// note that all accesses of mExitPending and mRunning need to hold mLock
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volatile bool mExitPending;
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volatile bool mRunning;
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sp<Thread> mHoldSelf;
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#ifdef HAVE_ANDROID_OS
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// legacy for debugging, not used by getTid() as it is set by the child thread
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// and so is not initialized until the child reaches that point
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pid_t mTid;
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#endif
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};
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}; // namespace android
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// ---------------------------------------------------------------------------
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#endif // _LIBS_UTILS_THREAD_H
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// ---------------------------------------------------------------------------
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