+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
/*
******************************************************************************
*
-* Copyright (C) 1997-2015, International Business Machines
+* Copyright (C) 1997-2016, International Business Machines
* Corporation and others. All Rights Reserved.
*
******************************************************************************
#include "uassert.h"
#include "cmemory.h"
+U_NAMESPACE_BEGIN
-// The ICU global mutex. Used when ICU implementation code passes NULL for the mutex pointer.
-static UMutex globalMutex = U_MUTEX_INITIALIZER;
-
-/*
- * ICU Mutex wrappers. Wrap operating system mutexes, giving the rest of ICU a
- * platform independent set of mutex operations. For internal ICU use only.
- */
#if defined(U_USER_MUTEX_CPP)
-// Build time user mutex hook: #include "U_USER_MUTEX_CPP"
-#include U_MUTEX_XSTR(U_USER_MUTEX_CPP)
-
-#elif U_PLATFORM_HAS_WIN32_API
-
-//-------------------------------------------------------------------------------------------
-//
-// Windows Specific Definitions
-//
-// Note: Cygwin (and possibly others) have both WIN32 and POSIX.
-// Prefer Win32 in these cases. (Win32 comes ahead in the #if chain)
-//
-//-------------------------------------------------------------------------------------------
-
-#if defined U_NO_PLATFORM_ATOMICS
-#error ICU on Win32 requires support for low level atomic operations.
-// Visual Studio, gcc, clang are OK. Shouldn't get here.
-#endif
-
-
-// This function is called when a test of a UInitOnce::fState reveals that
-// initialization has not completed, that we either need to call the
-// function on this thread, or wait for some other thread to complete.
-//
-// The actual call to the init function is made inline by template code
-// that knows the C++ types involved. This function returns TRUE if
-// the caller needs to call the Init function.
-//
-
-U_NAMESPACE_BEGIN
-
-U_COMMON_API UBool U_EXPORT2 umtx_initImplPreInit(UInitOnce &uio) {
- for (;;) {
- int32_t previousState = InterlockedCompareExchange(
-#if (U_PLATFORM == U_PF_MINGW) || (U_PLATFORM == U_PF_CYGWIN) || defined(__clang__)
- (LONG volatile *) // this is the type given in the API doc for this function.
+// Support for including an alternate implementation of mutexes has been withdrawn.
+// See issue ICU-20185.
+#error U_USER_MUTEX_CPP not supported
#endif
- &uio.fState, // Destination
- 1, // Exchange Value
- 0); // Compare value
-
- if (previousState == 0) {
- return true; // Caller will next call the init function.
- // Current state == 1.
- } else if (previousState == 2) {
- // Another thread already completed the initialization.
- // We can simply return FALSE, indicating no
- // further action is needed by the caller.
- return FALSE;
- } else {
- // Another thread is currently running the initialization.
- // Wait until it completes.
- do {
- Sleep(1);
- previousState = umtx_loadAcquire(uio.fState);
- } while (previousState == 1);
- }
- }
-}
-
-// This function is called by the thread that ran an initialization function,
-// just after completing the function.
-
-U_COMMON_API void U_EXPORT2 umtx_initImplPostInit(UInitOnce &uio) {
- umtx_storeRelease(uio.fState, 2);
-}
-
-U_NAMESPACE_END
-
-static void winMutexInit(CRITICAL_SECTION *cs) {
- InitializeCriticalSection(cs);
- return;
-}
-
-U_CAPI void U_EXPORT2
-umtx_lock(UMutex *mutex) {
- if (mutex == NULL) {
- mutex = &globalMutex;
- }
- CRITICAL_SECTION *cs = &mutex->fCS;
- umtx_initOnce(mutex->fInitOnce, winMutexInit, cs);
- EnterCriticalSection(cs);
-}
-U_CAPI void U_EXPORT2
-umtx_unlock(UMutex* mutex)
-{
- if (mutex == NULL) {
- mutex = &globalMutex;
- }
- LeaveCriticalSection(&mutex->fCS);
-}
-
-
-U_CAPI void U_EXPORT2
-umtx_condBroadcast(UConditionVar *condition) {
- // We require that the associated mutex be held by the caller,
- // so access to fWaitCount is protected and safe. No other thread can
- // call condWait() while we are here.
- if (condition->fWaitCount == 0) {
- return;
- }
- ResetEvent(condition->fExitGate);
- SetEvent(condition->fEntryGate);
-}
+/*************************************************************************************************
+ *
+ * ICU Mutex wrappers.
+ *
+ *************************************************************************************************/
-U_CAPI void U_EXPORT2
-umtx_condSignal(UConditionVar *condition) {
- // Function not implemented. There is no immediate requirement from ICU to have it.
- // Once ICU drops support for Windows XP and Server 2003, ICU Condition Variables will be
- // changed to be thin wrappers on native Windows CONDITION_VARIABLEs, and this function
- // becomes trivial to provide.
- U_ASSERT(FALSE);
-}
-
-U_CAPI void U_EXPORT2
-umtx_condWait(UConditionVar *condition, UMutex *mutex) {
- if (condition->fEntryGate == NULL) {
- // Note: because the associated mutex must be locked when calling
- // wait, we know that there can not be multiple threads
- // running here with the same condition variable.
- // Meaning that lazy initialization is safe.
- U_ASSERT(condition->fExitGate == NULL);
- condition->fEntryGate = CreateEvent(NULL, // Security Attributes
- TRUE, // Manual Reset
- FALSE, // Initially reset
- NULL); // Name.
- U_ASSERT(condition->fEntryGate != NULL);
- condition->fExitGate = CreateEvent(NULL, TRUE, TRUE, NULL);
- U_ASSERT(condition->fExitGate != NULL);
- }
-
- condition->fWaitCount++;
- umtx_unlock(mutex);
- WaitForSingleObject(condition->fEntryGate, INFINITE);
- umtx_lock(mutex);
- condition->fWaitCount--;
- if (condition->fWaitCount == 0) {
- // All threads that were waiting at the entry gate have woken up
- // and moved through. Shut the entry gate and open the exit gate.
- ResetEvent(condition->fEntryGate);
- SetEvent(condition->fExitGate);
- } else {
- umtx_unlock(mutex);
- WaitForSingleObject(condition->fExitGate, INFINITE);
- umtx_lock(mutex);
- }
+// The ICU global mutex. Used when ICU implementation code passes NULL for the mutex pointer.
+static UMutex *globalMutex() {
+ static UMutex *m = STATIC_NEW(UMutex);
+ return m;
}
-
-#elif U_PLATFORM_IMPLEMENTS_POSIX
-
-//-------------------------------------------------------------------------------------------
-//
-// POSIX specific definitions
-//
-//-------------------------------------------------------------------------------------------
-
-# include <pthread.h>
-
-// Each UMutex consists of a pthread_mutex_t.
-// All are statically initialized and ready for use.
-// There is no runtime mutex initialization code needed.
-
U_CAPI void U_EXPORT2
umtx_lock(UMutex *mutex) {
- if (mutex == NULL) {
- mutex = &globalMutex;
+ if (mutex == nullptr) {
+ mutex = globalMutex();
}
- int sysErr = pthread_mutex_lock(&mutex->fMutex);
- (void)sysErr; // Suppress unused variable warnings.
- U_ASSERT(sysErr == 0);
+ mutex->fMutex.lock();
}
U_CAPI void U_EXPORT2
umtx_unlock(UMutex* mutex)
{
- if (mutex == NULL) {
- mutex = &globalMutex;
+ if (mutex == nullptr) {
+ mutex = globalMutex();
}
- int sysErr = pthread_mutex_unlock(&mutex->fMutex);
- (void)sysErr; // Suppress unused variable warnings.
- U_ASSERT(sysErr == 0);
+ mutex->fMutex.unlock();
}
-U_CAPI void U_EXPORT2
-umtx_condWait(UConditionVar *cond, UMutex *mutex) {
- if (mutex == NULL) {
- mutex = &globalMutex;
- }
- int sysErr = pthread_cond_wait(&cond->fCondition, &mutex->fMutex);
- (void)sysErr;
- U_ASSERT(sysErr == 0);
-}
+/*************************************************************************************************
+ *
+ * UInitOnce Implementation
+ *
+ *************************************************************************************************/
-U_CAPI void U_EXPORT2
-umtx_condBroadcast(UConditionVar *cond) {
- int sysErr = pthread_cond_broadcast(&cond->fCondition);
- (void)sysErr;
- U_ASSERT(sysErr == 0);
+static std::mutex &initMutex() {
+ static std::mutex *m = STATIC_NEW(std::mutex);
+ return *m;
}
-U_CAPI void U_EXPORT2
-umtx_condSignal(UConditionVar *cond) {
- int sysErr = pthread_cond_signal(&cond->fCondition);
- (void)sysErr;
- U_ASSERT(sysErr == 0);
+static std::condition_variable &initCondition() {
+ static std::condition_variable *cv = STATIC_NEW(std::condition_variable);
+ return *cv;
}
-
-U_NAMESPACE_BEGIN
-
-static pthread_mutex_t initMutex = PTHREAD_MUTEX_INITIALIZER;
-static pthread_cond_t initCondition = PTHREAD_COND_INITIALIZER;
-
-
// This function is called when a test of a UInitOnce::fState reveals that
-// initialization has not completed, that we either need to call the
+// initialization has not completed, that we either need to call the init
// function on this thread, or wait for some other thread to complete.
//
// The actual call to the init function is made inline by template code
-// that knows the C++ types involved. This function returns TRUE if
+// that knows the C++ types involved. This function returns true if
// the caller needs to call the Init function.
//
U_COMMON_API UBool U_EXPORT2
umtx_initImplPreInit(UInitOnce &uio) {
- pthread_mutex_lock(&initMutex);
- int32_t state = uio.fState;
- if (state == 0) {
+ std::unique_lock<std::mutex> lock(initMutex());
+
+ if (umtx_loadAcquire(uio.fState) == 0) {
umtx_storeRelease(uio.fState, 1);
- pthread_mutex_unlock(&initMutex);
- return TRUE; // Caller will next call the init function.
+ return true; // Caller will next call the init function.
} else {
- while (uio.fState == 1) {
+ while (umtx_loadAcquire(uio.fState) == 1) {
// Another thread is currently running the initialization.
// Wait until it completes.
- pthread_cond_wait(&initCondition, &initMutex);
+ initCondition().wait(lock);
}
- pthread_mutex_unlock(&initMutex);
U_ASSERT(uio.fState == 2);
- return FALSE;
+ return false;
}
}
-
// This function is called by the thread that ran an initialization function,
// just after completing the function.
// Some threads may be waiting on the condition, requiring the broadcast wakeup.
U_COMMON_API void U_EXPORT2
umtx_initImplPostInit(UInitOnce &uio) {
- pthread_mutex_lock(&initMutex);
- umtx_storeRelease(uio.fState, 2);
- pthread_cond_broadcast(&initCondition);
- pthread_mutex_unlock(&initMutex);
-}
-
-U_NAMESPACE_END
-
-// End of POSIX specific umutex implementation.
-
-#else // Platform #define chain.
-
-#error Unknown Platform
-
-#endif // Platform #define chain.
-
-
-//-------------------------------------------------------------------------------
-//
-// Atomic Operations, out-of-line versions.
-// These are conditional, only defined if better versions
-// were not available for the platform.
-//
-// These versions are platform neutral.
-//
-//--------------------------------------------------------------------------------
-
-#if defined U_NO_PLATFORM_ATOMICS
-static UMutex gIncDecMutex = U_MUTEX_INITIALIZER;
-
-U_NAMESPACE_BEGIN
-
-U_COMMON_API int32_t U_EXPORT2
-umtx_atomic_inc(u_atomic_int32_t *p) {
- int32_t retVal;
- umtx_lock(&gIncDecMutex);
- retVal = ++(*p);
- umtx_unlock(&gIncDecMutex);
- return retVal;
-}
-
-
-U_COMMON_API int32_t U_EXPORT2
-umtx_atomic_dec(u_atomic_int32_t *p) {
- int32_t retVal;
- umtx_lock(&gIncDecMutex);
- retVal = --(*p);
- umtx_unlock(&gIncDecMutex);
- return retVal;
-}
-
-U_COMMON_API int32_t U_EXPORT2
-umtx_loadAcquire(u_atomic_int32_t &var) {
- umtx_lock(&gIncDecMutex);
- int32_t val = var;
- umtx_unlock(&gIncDecMutex);
- return val;
-}
-
-U_COMMON_API void U_EXPORT2
-umtx_storeRelease(u_atomic_int32_t &var, int32_t val) {
- umtx_lock(&gIncDecMutex);
- var = val;
- umtx_unlock(&gIncDecMutex);
+ {
+ std::unique_lock<std::mutex> lock(initMutex());
+ umtx_storeRelease(uio.fState, 2);
+ }
+ initCondition().notify_all();
}
U_NAMESPACE_END
-#endif
-//--------------------------------------------------------------------------
-//
-// Deprecated functions for setting user mutexes.
-//
-//--------------------------------------------------------------------------
+/*************************************************************************************************
+ *
+ * Deprecated functions for setting user mutexes.
+ *
+ *************************************************************************************************/
U_DEPRECATED void U_EXPORT2
u_setMutexFunctions(const void * /*context */, UMtxInitFn *, UMtxFn *,
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