wtf/Threading.h

   1 /*
   2  * Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
   3  * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1.  Redistributions of source code must retain the above copyright
  10  *     notice, this list of conditions and the following disclaimer.
  11  * 2.  Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  15  *     its contributors may be used to endorse or promote products derived
  16  *     from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  22  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  24  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  25  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  *
  29  *
  30  * Note: The implementations of InterlockedIncrement and InterlockedDecrement are based
  31  * on atomic_increment and atomic_exchange_and_add from the Boost C++ Library. The license
  32  * is virtually identical to the Apple license above but is included here for completeness.
  33  *
  34  * Boost Software License - Version 1.0 - August 17th, 2003
  35  *
  36  * Permission is hereby granted, free of charge, to any person or organization
  37  * obtaining a copy of the software and accompanying documentation covered by
  38  * this license (the "Software") to use, reproduce, display, distribute,
  39  * execute, and transmit the Software, and to prepare derivative works of the
  40  * Software, and to permit third-parties to whom the Software is furnished to
  41  * do so, all subject to the following:
  42  *
  43  * The copyright notices in the Software and this entire statement, including
  44  * the above license grant, this restriction and the following disclaimer,
  45  * must be included in all copies of the Software, in whole or in part, and
  46  * all derivative works of the Software, unless such copies or derivative
  47  * works are solely in the form of machine-executable object code generated by
  48  * a source language processor.
  49  *
  50  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  51  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  52  * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  53  * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  54  * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  55  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  56  * DEALINGS IN THE SOFTWARE.
  57  */
  58
  59 #ifndef Threading_h
  60 #define Threading_h
  61
  62 #if PLATFORM(WINCE)
  63 #include <windows.h>
  64 #endif
  65
  66 #include <wtf/Assertions.h>
  67 #include <wtf/Locker.h>
  68 #include <wtf/Noncopyable.h>
  69
  70 #if PLATFORM(WIN_OS) && !PLATFORM(WINCE)
  71 #include <windows.h>
  72 #elif PLATFORM(DARWIN)
  73 #include <libkern/OSAtomic.h>
  74 #elif COMPILER(GCC)
  75 #if (__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 2))
  76 #include <ext/atomicity.h>
  77 #else
  78 #include <bits/atomicity.h>
  79 #endif
  80 #endif
  81
  82 #if USE(PTHREADS)
  83 #include <pthread.h>
  84 #elif PLATFORM(GTK)
  85 #include <wtf/GOwnPtr.h>
  86 typedef struct _GMutex GMutex;
  87 typedef struct _GCond GCond;
  88 #endif
  89
  90 #if PLATFORM(QT)
  91 #include <qglobal.h>
  92 QT_BEGIN_NAMESPACE
  93 class QMutex;
  94 class QWaitCondition;
  95 QT_END_NAMESPACE
  96 #endif
  97
  98 #include <stdint.h>
  99
 100 // For portability, we do not use thread-safe statics natively supported by some compilers (e.g. gcc).
 101 #define AtomicallyInitializedStatic(T, name) \
 102     WTF::lockAtomicallyInitializedStaticMutex(); \
 103     static T name; \
 104     WTF::unlockAtomicallyInitializedStaticMutex();
 105
 106 namespace WTF {
 107
 108 typedef uint32_t ThreadIdentifier;
 109 typedef void* (*ThreadFunction)(void* argument);
 110
 111 // Returns 0 if thread creation failed.
 112 // The thread name must be a literal since on some platforms it's passed in to the thread.
 113 ThreadIdentifier createThread(ThreadFunction, void*, const char* threadName);
 114
 115 // Internal platform-specific createThread implementation.
 116 ThreadIdentifier createThreadInternal(ThreadFunction, void*, const char* threadName);
 117
 118 // Called in the thread during initialization.
 119 // Helpful for platforms where the thread name must be set from within the thread.
 120 void setThreadNameInternal(const char* threadName);
 121
 122 ThreadIdentifier currentThread();
 123 bool isMainThread();
 124 int waitForThreadCompletion(ThreadIdentifier, void**);
 125 void detachThread(ThreadIdentifier);
 126
 127 #if USE(PTHREADS)
 128 typedef pthread_mutex_t PlatformMutex;
 129 typedef pthread_rwlock_t PlatformReadWriteLock;
 130 typedef pthread_cond_t PlatformCondition;
 131 #elif PLATFORM(GTK)
 132 typedef GOwnPtr<GMutex> PlatformMutex;
 133 typedef void* PlatformReadWriteLock; // FIXME: Implement.
 134 typedef GOwnPtr<GCond> PlatformCondition;
 135 #elif PLATFORM(QT)
 136 typedef QT_PREPEND_NAMESPACE(QMutex)* PlatformMutex;
 137 typedef void* PlatformReadWriteLock; // FIXME: Implement.
 138 typedef QT_PREPEND_NAMESPACE(QWaitCondition)* PlatformCondition;
 139 #elif PLATFORM(WIN_OS)
 140 struct PlatformMutex {
 141     CRITICAL_SECTION m_internalMutex;
 142     size_t m_recursionCount;
 143 };
 144 typedef void* PlatformReadWriteLock; // FIXME: Implement.
 145 struct PlatformCondition {
 146     size_t m_waitersGone;
 147     size_t m_waitersBlocked;
 148     size_t m_waitersToUnblock;
 149     HANDLE m_blockLock;
 150     HANDLE m_blockQueue;
 151     HANDLE m_unblockLock;
 152
 153     bool timedWait(PlatformMutex&, DWORD durationMilliseconds);
 154     void signal(bool unblockAll);
 155 };
 156 #else
 157 typedef void* PlatformMutex;
 158 typedef void* PlatformReadWriteLock;
 159 typedef void* PlatformCondition;
 160 #endif
 161
 162 class Mutex : Noncopyable {
 163 public:
 164     Mutex();
 165     ~Mutex();
 166
 167     void lock();
 168     bool tryLock();
 169     void unlock();
 170
 171 public:
 172     PlatformMutex& impl() { return m_mutex; }
 173 private:
 174     PlatformMutex m_mutex;
 175 };
 176
 177 typedef Locker<Mutex> MutexLocker;
 178
 179 class ReadWriteLock : Noncopyable {
 180 public:
 181     ReadWriteLock();
 182     ~ReadWriteLock();
 183
 184     void readLock();
 185     bool tryReadLock();
 186
 187     void writeLock();
 188     bool tryWriteLock();
 189
 190     void unlock();
 191
 192 private:
 193     PlatformReadWriteLock m_readWriteLock;
 194 };
 195
 196 class ThreadCondition : Noncopyable {
 197 public:
 198     ThreadCondition();
 199     ~ThreadCondition();
 200
 201     void wait(Mutex& mutex);
 202     // Returns true if the condition was signaled before absoluteTime, false if the absoluteTime was reached or is in the past.
 203     // The absoluteTime is in seconds, starting on January 1, 1970. The time is assumed to use the same time zone as WTF::currentTime().
 204     bool timedWait(Mutex&, double absoluteTime);
 205     void signal();
 206     void broadcast();
 207
 208 private:
 209     PlatformCondition m_condition;
 210 };
 211
 212 #if PLATFORM(WIN_OS)
 213 #define WTF_USE_LOCKFREE_THREADSAFESHARED 1
 214
 215 #if COMPILER(MINGW) || COMPILER(MSVC7) || PLATFORM(WINCE)
 216 inline void atomicIncrement(int* addend) { InterlockedIncrement(reinterpret_cast<long*>(addend)); }
 217 inline int atomicDecrement(int* addend) { return InterlockedDecrement(reinterpret_cast<long*>(addend)); }
 218 #else
 219 inline void atomicIncrement(int volatile* addend) { InterlockedIncrement(reinterpret_cast<long volatile*>(addend)); }
 220 inline int atomicDecrement(int volatile* addend) { return InterlockedDecrement(reinterpret_cast<long volatile*>(addend)); }
 221 #endif
 222
 223 #elif PLATFORM(DARWIN)
 224 #define WTF_USE_LOCKFREE_THREADSAFESHARED 1
 225
 226 inline void atomicIncrement(int volatile* addend) { OSAtomicIncrement32Barrier(const_cast<int*>(addend)); }
 227 inline int atomicDecrement(int volatile* addend) { return OSAtomicDecrement32Barrier(const_cast<int*>(addend)); }
 228
 229 #elif COMPILER(GCC)
 230 #define WTF_USE_LOCKFREE_THREADSAFESHARED 1
 231
 232 inline void atomicIncrement(int volatile* addend) { __gnu_cxx::__atomic_add(addend, 1); }
 233 inline int atomicDecrement(int volatile* addend) { return __gnu_cxx::__exchange_and_add(addend, -1) - 1; }
 234
 235 #endif
 236
 237 class ThreadSafeSharedBase : Noncopyable {
 238 public:
 239     ThreadSafeSharedBase(int initialRefCount = 1)
 240         : m_refCount(initialRefCount)
 241     {
 242     }
 243
 244     void ref()
 245     {
 246 #if USE(LOCKFREE_THREADSAFESHARED)
 247         atomicIncrement(&m_refCount);
 248 #else
 249         MutexLocker locker(m_mutex);
 250         ++m_refCount;
 251 #endif
 252     }
 253
 254     bool hasOneRef()
 255     {
 256         return refCount() == 1;
 257     }
 258
 259     int refCount() const
 260     {
 261 #if !USE(LOCKFREE_THREADSAFESHARED)
 262         MutexLocker locker(m_mutex);
 263 #endif
 264         return static_cast<int const volatile &>(m_refCount);
 265     }
 266
 267 protected:
 268     // Returns whether the pointer should be freed or not.
 269     bool derefBase()
 270     {
 271 #if USE(LOCKFREE_THREADSAFESHARED)
 272         if (atomicDecrement(&m_refCount) <= 0)
 273             return true;
 274 #else
 275         int refCount;
 276         {
 277             MutexLocker locker(m_mutex);
 278             --m_refCount;
 279             refCount = m_refCount;
 280         }
 281         if (refCount <= 0)
 282             return true;
 283 #endif
 284         return false;
 285     }
 286
 287 private:
 288     template<class T>
 289     friend class CrossThreadRefCounted;
 290
 291     int m_refCount;
 292 #if !USE(LOCKFREE_THREADSAFESHARED)
 293     mutable Mutex m_mutex;
 294 #endif
 295 };
 296
 297 template<class T> class ThreadSafeShared : public ThreadSafeSharedBase {
 298 public:
 299     ThreadSafeShared(int initialRefCount = 1)
 300         : ThreadSafeSharedBase(initialRefCount)
 301     {
 302     }
 303
 304     void deref()
 305     {
 306         if (derefBase())
 307             delete static_cast<T*>(this);
 308     }
 309 };
 310
 311 // This function must be called from the main thread. It is safe to call it repeatedly.
 312 // Darwin is an exception to this rule: it is OK to call it from any thread, the only requirement is that the calls are not reentrant.
 313 void initializeThreading();
 314
 315 void lockAtomicallyInitializedStaticMutex();
 316 void unlockAtomicallyInitializedStaticMutex();
 317
 318 } // namespace WTF
 319
 320 using WTF::Mutex;
 321 using WTF::MutexLocker;
 322 using WTF::ThreadCondition;
 323 using WTF::ThreadIdentifier;
 324 using WTF::ThreadSafeShared;
 325
 326 using WTF::createThread;
 327 using WTF::currentThread;
 328 using WTF::isMainThread;
 329 using WTF::detachThread;
 330 using WTF::waitForThreadCompletion;
 331
 332 #endif // Threading_h