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Diffstat (limited to 'include/utils/Thread.h')
-rw-r--r-- | include/utils/Thread.h | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/include/utils/Thread.h b/include/utils/Thread.h new file mode 100644 index 0000000..4a34abd --- /dev/null +++ b/include/utils/Thread.h @@ -0,0 +1,113 @@ +/* + * 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(); + +#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 +// --------------------------------------------------------------------------- |