threads.h revision 1555436473afd296488235f0aa22bb17162a929f
1/* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#ifndef _LIBS_UTILS_THREADS_H 18#define _LIBS_UTILS_THREADS_H 19 20#include <stdint.h> 21#include <sys/types.h> 22#include <time.h> 23 24#if defined(HAVE_PTHREADS) 25# include <pthread.h> 26#endif 27 28// ------------------------------------------------------------------ 29// C API 30 31#ifdef __cplusplus 32extern "C" { 33#endif 34 35typedef void* android_thread_id_t; 36 37typedef int (*android_thread_func_t)(void*); 38 39enum { 40 /* 41 * *********************************************** 42 * ** Keep in sync with android.os.Process.java ** 43 * *********************************************** 44 * 45 * This maps directly to the "nice" priorites we use in Android. 46 * A thread priority should be chosen inverse-proportinally to 47 * the amount of work the thread is expected to do. The more work 48 * a thread will do, the less favorable priority it should get so that 49 * it doesn't starve the system. Threads not behaving properly might 50 * be "punished" by the kernel. 51 * Use the levels below when appropriate. Intermediate values are 52 * acceptable, preferably use the {MORE|LESS}_FAVORABLE constants below. 53 */ 54 ANDROID_PRIORITY_LOWEST = 19, 55 56 /* use for background tasks */ 57 ANDROID_PRIORITY_BACKGROUND = 10, 58 59 /* most threads run at normal priority */ 60 ANDROID_PRIORITY_NORMAL = 0, 61 62 /* threads currently running a UI that the user is interacting with */ 63 ANDROID_PRIORITY_FOREGROUND = -2, 64 65 /* the main UI thread has a slightly more favorable priority */ 66 ANDROID_PRIORITY_DISPLAY = -4, 67 68 /* ui service treads might want to run at a urgent display (uncommon) */ 69 ANDROID_PRIORITY_URGENT_DISPLAY = -8, 70 71 /* all normal audio threads */ 72 ANDROID_PRIORITY_AUDIO = -16, 73 74 /* service audio threads (uncommon) */ 75 ANDROID_PRIORITY_URGENT_AUDIO = -19, 76 77 /* should never be used in practice. regular process might not 78 * be allowed to use this level */ 79 ANDROID_PRIORITY_HIGHEST = -20, 80 81 ANDROID_PRIORITY_DEFAULT = ANDROID_PRIORITY_NORMAL, 82 ANDROID_PRIORITY_MORE_FAVORABLE = -1, 83 ANDROID_PRIORITY_LESS_FAVORABLE = +1, 84}; 85 86enum { 87 ANDROID_TGROUP_DEFAULT = 0, 88 ANDROID_TGROUP_BG_NONINTERACT = 1, 89 ANDROID_TGROUP_FG_BOOST = 2, 90 ANDROID_TGROUP_MAX = ANDROID_TGROUP_FG_BOOST, 91}; 92 93// Create and run a new thread. 94extern int androidCreateThread(android_thread_func_t, void *); 95 96// Create thread with lots of parameters 97extern int androidCreateThreadEtc(android_thread_func_t entryFunction, 98 void *userData, 99 const char* threadName, 100 int32_t threadPriority, 101 size_t threadStackSize, 102 android_thread_id_t *threadId); 103 104// Get some sort of unique identifier for the current thread. 105extern android_thread_id_t androidGetThreadId(); 106 107// Low-level thread creation -- never creates threads that can 108// interact with the Java VM. 109extern int androidCreateRawThreadEtc(android_thread_func_t entryFunction, 110 void *userData, 111 const char* threadName, 112 int32_t threadPriority, 113 size_t threadStackSize, 114 android_thread_id_t *threadId); 115 116// Used by the Java Runtime to control how threads are created, so that 117// they can be proper and lovely Java threads. 118typedef int (*android_create_thread_fn)(android_thread_func_t entryFunction, 119 void *userData, 120 const char* threadName, 121 int32_t threadPriority, 122 size_t threadStackSize, 123 android_thread_id_t *threadId); 124 125extern void androidSetCreateThreadFunc(android_create_thread_fn func); 126 127#ifdef __cplusplus 128} 129#endif 130 131// ------------------------------------------------------------------ 132// C++ API 133 134#ifdef __cplusplus 135 136#include <utils/Errors.h> 137#include <utils/RefBase.h> 138#include <utils/Timers.h> 139 140namespace android { 141 142typedef android_thread_id_t thread_id_t; 143 144typedef android_thread_func_t thread_func_t; 145 146enum { 147 PRIORITY_LOWEST = ANDROID_PRIORITY_LOWEST, 148 PRIORITY_BACKGROUND = ANDROID_PRIORITY_BACKGROUND, 149 PRIORITY_NORMAL = ANDROID_PRIORITY_NORMAL, 150 PRIORITY_FOREGROUND = ANDROID_PRIORITY_FOREGROUND, 151 PRIORITY_DISPLAY = ANDROID_PRIORITY_DISPLAY, 152 PRIORITY_URGENT_DISPLAY = ANDROID_PRIORITY_URGENT_DISPLAY, 153 PRIORITY_AUDIO = ANDROID_PRIORITY_AUDIO, 154 PRIORITY_URGENT_AUDIO = ANDROID_PRIORITY_URGENT_AUDIO, 155 PRIORITY_HIGHEST = ANDROID_PRIORITY_HIGHEST, 156 PRIORITY_DEFAULT = ANDROID_PRIORITY_DEFAULT, 157 PRIORITY_MORE_FAVORABLE = ANDROID_PRIORITY_MORE_FAVORABLE, 158 PRIORITY_LESS_FAVORABLE = ANDROID_PRIORITY_LESS_FAVORABLE, 159}; 160 161// Create and run a new thread. 162inline bool createThread(thread_func_t f, void *a) { 163 return androidCreateThread(f, a) ? true : false; 164} 165 166// Create thread with lots of parameters 167inline bool createThreadEtc(thread_func_t entryFunction, 168 void *userData, 169 const char* threadName = "android:unnamed_thread", 170 int32_t threadPriority = PRIORITY_DEFAULT, 171 size_t threadStackSize = 0, 172 thread_id_t *threadId = 0) 173{ 174 return androidCreateThreadEtc(entryFunction, userData, threadName, 175 threadPriority, threadStackSize, threadId) ? true : false; 176} 177 178// Get some sort of unique identifier for the current thread. 179inline thread_id_t getThreadId() { 180 return androidGetThreadId(); 181} 182 183/*****************************************************************************/ 184 185/* 186 * Simple mutex class. The implementation is system-dependent. 187 * 188 * The mutex must be unlocked by the thread that locked it. They are not 189 * recursive, i.e. the same thread can't lock it multiple times. 190 */ 191class Mutex { 192public: 193 Mutex(); 194 Mutex(const char* name); 195 ~Mutex(); 196 197 // lock or unlock the mutex 198 status_t lock(); 199 void unlock(); 200 201 // lock if possible; returns 0 on success, error otherwise 202 status_t tryLock(); 203 204 // Manages the mutex automatically. It'll be locked when Autolock is 205 // constructed and released when Autolock goes out of scope. 206 class Autolock { 207 public: 208 inline Autolock(Mutex& mutex) : mLock(mutex) { mLock.lock(); } 209 inline Autolock(Mutex* mutex) : mLock(*mutex) { mLock.lock(); } 210 inline ~Autolock() { mLock.unlock(); } 211 private: 212 Mutex& mLock; 213 }; 214 215private: 216 friend class Condition; 217 218 // A mutex cannot be copied 219 Mutex(const Mutex&); 220 Mutex& operator = (const Mutex&); 221 222#if defined(HAVE_PTHREADS) 223 pthread_mutex_t mMutex; 224#else 225 void _init(); 226 void* mState; 227#endif 228}; 229 230#if defined(HAVE_PTHREADS) 231 232inline Mutex::Mutex() { 233 pthread_mutex_init(&mMutex, NULL); 234} 235inline Mutex::Mutex(const char* name) { 236 pthread_mutex_init(&mMutex, NULL); 237} 238inline Mutex::~Mutex() { 239 pthread_mutex_destroy(&mMutex); 240} 241inline status_t Mutex::lock() { 242 return -pthread_mutex_lock(&mMutex); 243} 244inline void Mutex::unlock() { 245 pthread_mutex_unlock(&mMutex); 246} 247inline status_t Mutex::tryLock() { 248 return -pthread_mutex_trylock(&mMutex); 249} 250 251#endif // HAVE_PTHREADS 252 253/* 254 * Automatic mutex. Declare one of these at the top of a function. 255 * When the function returns, it will go out of scope, and release the 256 * mutex. 257 */ 258 259typedef Mutex::Autolock AutoMutex; 260 261/*****************************************************************************/ 262 263/* 264 * Condition variable class. The implementation is system-dependent. 265 * 266 * Condition variables are paired up with mutexes. Lock the mutex, 267 * call wait(), then either re-wait() if things aren't quite what you want, 268 * or unlock the mutex and continue. All threads calling wait() must 269 * use the same mutex for a given Condition. 270 */ 271class Condition { 272public: 273 Condition(); 274 ~Condition(); 275 // Wait on the condition variable. Lock the mutex before calling. 276 status_t wait(Mutex& mutex); 277 // same with relative timeout 278 status_t waitRelative(Mutex& mutex, nsecs_t reltime); 279 // Signal the condition variable, allowing one thread to continue. 280 void signal(); 281 // Signal the condition variable, allowing all threads to continue. 282 void broadcast(); 283 284private: 285#if defined(HAVE_PTHREADS) 286 pthread_cond_t mCond; 287#else 288 void* mState; 289#endif 290}; 291 292#if defined(HAVE_PTHREADS) 293 294inline Condition::Condition() { 295 pthread_cond_init(&mCond, NULL); 296} 297inline Condition::~Condition() { 298 pthread_cond_destroy(&mCond); 299} 300inline status_t Condition::wait(Mutex& mutex) { 301 return -pthread_cond_wait(&mCond, &mutex.mMutex); 302} 303inline status_t Condition::waitRelative(Mutex& mutex, nsecs_t reltime) { 304#if defined(HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE) 305 struct timespec ts; 306 ts.tv_sec = reltime/1000000000; 307 ts.tv_nsec = reltime%1000000000; 308 return -pthread_cond_timedwait_relative_np(&mCond, &mutex.mMutex, &ts); 309#else // HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE 310 struct timespec ts; 311#if defined(HAVE_POSIX_CLOCKS) 312 clock_gettime(CLOCK_REALTIME, &ts); 313#else // HAVE_POSIX_CLOCKS 314 // we don't support the clocks here. 315 struct timeval t; 316 gettimeofday(&t, NULL); 317 ts.tv_sec = t.tv_sec; 318 ts.tv_nsec= t.tv_usec*1000; 319#endif // HAVE_POSIX_CLOCKS 320 ts.tv_sec += reltime/1000000000; 321 ts.tv_nsec+= reltime%1000000000; 322 if (ts.tv_nsec >= 1000000000) { 323 ts.tv_nsec -= 1000000000; 324 ts.tv_sec += 1; 325 } 326 return -pthread_cond_timedwait(&mCond, &mutex.mMutex, &ts); 327#endif // HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE 328} 329inline void Condition::signal() { 330 pthread_cond_signal(&mCond); 331} 332inline void Condition::broadcast() { 333 pthread_cond_broadcast(&mCond); 334} 335 336#endif // HAVE_PTHREADS 337 338/*****************************************************************************/ 339 340/* 341 * This is our spiffy thread object! 342 */ 343 344class Thread : virtual public RefBase 345{ 346public: 347 // Create a Thread object, but doesn't create or start the associated 348 // thread. See the run() method. 349 Thread(bool canCallJava = true); 350 virtual ~Thread(); 351 352 // Start the thread in threadLoop() which needs to be implemented. 353 virtual status_t run( const char* name = 0, 354 int32_t priority = PRIORITY_DEFAULT, 355 size_t stack = 0); 356 357 // Ask this object's thread to exit. This function is asynchronous, when the 358 // function returns the thread might still be running. Of course, this 359 // function can be called from a different thread. 360 virtual void requestExit(); 361 362 // Good place to do one-time initializations 363 virtual status_t readyToRun(); 364 365 // Call requestExit() and wait until this object's thread exits. 366 // BE VERY CAREFUL of deadlocks. In particular, it would be silly to call 367 // this function from this object's thread. Will return WOULD_BLOCK in 368 // that case. 369 status_t requestExitAndWait(); 370 371protected: 372 // exitPending() returns true if requestExit() has been called. 373 bool exitPending() const; 374 375private: 376 // Derived class must implement threadLoop(). The thread starts its life 377 // here. There are two ways of using the Thread object: 378 // 1) loop: if threadLoop() returns true, it will be called again if 379 // requestExit() wasn't called. 380 // 2) once: if threadLoop() returns false, the thread will exit upon return. 381 virtual bool threadLoop() = 0; 382 383private: 384 Thread& operator=(const Thread&); 385 static int _threadLoop(void* user); 386 const bool mCanCallJava; 387 thread_id_t mThread; 388 Mutex mLock; 389 Condition mThreadExitedCondition; 390 status_t mStatus; 391 volatile bool mExitPending; 392 volatile bool mRunning; 393 sp<Thread> mHoldSelf; 394}; 395 396 397}; // namespace android 398 399#endif // __cplusplus 400 401#endif // _LIBS_UTILS_THREADS_H 402