#ifndef UMUTEX_H
#define UMUTEX_H
+#include <atomic>
+#include <condition_variable>
+#include <mutex>
+
#include "unicode/utypes.h"
#include "unicode/uclean.h"
+#include "unicode/uobject.h"
+
#include "putilimp.h"
+#if defined(U_USER_ATOMICS_H) || defined(U_USER_MUTEX_H)
+// Support for including an alternate implementation of atomic & mutex operations has been withdrawn.
+// See issue ICU-20185.
+#error U_USER_ATOMICS and U_USER_MUTEX_H are not supported
+#endif
-// Forward Declarations. UMutex is not in the ICU namespace (yet) because
-// there are some remaining references from plain C.
-struct UMutex;
-struct UConditionVar;
+// Export an explicit template instantiation of std::atomic<int32_t>.
+// When building DLLs for Windows this is required as it is used as a data member of the exported SharedObject class.
+// See digitlst.h, pluralaffix.h, datefmt.h, and others for similar examples.
+#if U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_CYGWIN && !defined(U_IN_DOXYGEN)
+#if defined(__clang__) || defined(_MSC_VER)
+ #if defined(__clang__)
+ // Suppress the warning that the explicit instantiation after explicit specialization has no effect.
+ #pragma clang diagnostic push
+ #pragma clang diagnostic ignored "-Winstantiation-after-specialization"
+ #endif
+template struct U_COMMON_API std::atomic<int32_t>;
+ #if defined(__clang__)
+ #pragma clang diagnostic pop
+ #endif
+#elif defined(__GNUC__)
+// For GCC this class is already exported/visible, so no need for U_COMMON_API.
+template struct std::atomic<int32_t>;
+#endif
+#endif
-U_NAMESPACE_BEGIN
-struct UInitOnce;
-U_NAMESPACE_END
-// Stringify macros, to allow #include of user supplied atomic & mutex files.
-#define U_MUTEX_STR(s) #s
-#define U_MUTEX_XSTR(s) U_MUTEX_STR(s)
+U_NAMESPACE_BEGIN
/****************************************************************************
*
- * Low Level Atomic Operations.
- * Compiler dependent. Not operating system dependent.
+ * Low Level Atomic Operations, ICU wrappers for.
*
****************************************************************************/
-#if defined (U_USER_ATOMICS_H)
-#include U_MUTEX_XSTR(U_USER_ATOMICS_H)
-
-#elif U_HAVE_STD_ATOMICS
-
-// C++11 atomics are available.
-
-#include <atomic>
-
-U_NAMESPACE_BEGIN
typedef std::atomic<int32_t> u_atomic_int32_t;
#define ATOMIC_INT32_T_INITIALIZER(val) ATOMIC_VAR_INIT(val)
inline int32_t umtx_atomic_dec(u_atomic_int32_t *var) {
return var->fetch_sub(1) - 1;
}
-U_NAMESPACE_END
-
-#elif U_PLATFORM_HAS_WIN32_API
-
-// MSVC compiler. Reads and writes of volatile variables have
-// acquire and release memory semantics, respectively.
-// This is a Microsoft extension, not standard C++ behavior.
-//
-// Update: can't use this because of MinGW, built with gcc.
-// Original plan was to use gcc atomics for MinGW, but they
-// aren't supported, so we fold MinGW into this path.
-
-#ifndef WIN32_LEAN_AND_MEAN
-# define WIN32_LEAN_AND_MEAN
-#endif
-# define VC_EXTRALEAN
-# define NOUSER
-# define NOSERVICE
-# define NOIME
-# define NOMCX
-# ifndef NOMINMAX
-# define NOMINMAX
-# endif
-# include <windows.h>
-
-U_NAMESPACE_BEGIN
-typedef volatile LONG u_atomic_int32_t;
-#define ATOMIC_INT32_T_INITIALIZER(val) val
-
-inline int32_t umtx_loadAcquire(u_atomic_int32_t &var) {
- return InterlockedCompareExchange(&var, 0, 0);
-}
-
-inline void umtx_storeRelease(u_atomic_int32_t &var, int32_t val) {
- InterlockedExchange(&var, val);
-}
-
-
-inline int32_t umtx_atomic_inc(u_atomic_int32_t *var) {
- return InterlockedIncrement(var);
-}
-
-inline int32_t umtx_atomic_dec(u_atomic_int32_t *var) {
- return InterlockedDecrement(var);
-}
-U_NAMESPACE_END
-
-
-#elif U_HAVE_CLANG_ATOMICS
-/*
- * Clang __c11 atomic built-ins
- */
-
-U_NAMESPACE_BEGIN
-typedef _Atomic(int32_t) u_atomic_int32_t;
-#define ATOMIC_INT32_T_INITIALIZER(val) val
-
-inline int32_t umtx_loadAcquire(u_atomic_int32_t &var) {
- return __c11_atomic_load(&var, __ATOMIC_ACQUIRE);
-}
-
-inline void umtx_storeRelease(u_atomic_int32_t &var, int32_t val) {
- return __c11_atomic_store(&var, val, __ATOMIC_RELEASE);
-}
-
-inline int32_t umtx_atomic_inc(u_atomic_int32_t *var) {
- return __c11_atomic_fetch_add(var, 1, __ATOMIC_SEQ_CST) + 1;
-}
-
-inline int32_t umtx_atomic_dec(u_atomic_int32_t *var) {
- return __c11_atomic_fetch_sub(var, 1, __ATOMIC_SEQ_CST) - 1;
-}
-U_NAMESPACE_END
-
-
-#elif U_HAVE_GCC_ATOMICS
-/*
- * gcc atomic ops. These are available on several other compilers as well.
- */
-
-U_NAMESPACE_BEGIN
-typedef int32_t u_atomic_int32_t;
-#define ATOMIC_INT32_T_INITIALIZER(val) val
-
-inline int32_t umtx_loadAcquire(u_atomic_int32_t &var) {
- int32_t val = var;
- __sync_synchronize();
- return val;
-}
-
-inline void umtx_storeRelease(u_atomic_int32_t &var, int32_t val) {
- __sync_synchronize();
- var = val;
-}
-
-inline int32_t umtx_atomic_inc(u_atomic_int32_t *p) {
- return __sync_add_and_fetch(p, 1);
-}
-
-inline int32_t umtx_atomic_dec(u_atomic_int32_t *p) {
- return __sync_sub_and_fetch(p, 1);
-}
-U_NAMESPACE_END
-
-#else
-
-/*
- * Unknown Platform. Use out-of-line functions, which in turn use mutexes.
- * Slow but correct.
- */
-
-#define U_NO_PLATFORM_ATOMICS
-
-U_NAMESPACE_BEGIN
-typedef int32_t u_atomic_int32_t;
-#define ATOMIC_INT32_T_INITIALIZER(val) val
-
-U_COMMON_API int32_t U_EXPORT2
-umtx_loadAcquire(u_atomic_int32_t &var);
-
-U_COMMON_API void U_EXPORT2
-umtx_storeRelease(u_atomic_int32_t &var, int32_t val);
-
-U_COMMON_API int32_t U_EXPORT2
-umtx_atomic_inc(u_atomic_int32_t *p);
-
-U_COMMON_API int32_t U_EXPORT2
-umtx_atomic_dec(u_atomic_int32_t *p);
-
-U_NAMESPACE_END
-
-#endif /* Low Level Atomic Ops Platfrom Chain */
-
/*************************************************************************************************
*
* UInitOnce Definitions.
- * These are platform neutral.
*
*************************************************************************************************/
-U_NAMESPACE_BEGIN
-
struct UInitOnce {
u_atomic_int32_t fState;
UErrorCode fErrCode;
- void reset() {fState = 0;};
- UBool isReset() {return umtx_loadAcquire(fState) == 0;};
+ void reset() {fState = 0;}
+ UBool isReset() {return umtx_loadAcquire(fState) == 0;}
// Note: isReset() is used by service registration code.
// Thread safety of this usage needs review.
};
}
}
-U_NAMESPACE_END
-
-
-/*************************************************************************************************
+/**
+ * ICU Mutex wrappers. Originally wrapped operating system mutexes, giving the rest of ICU a
+ * platform independent set of mutex operations. Now vestigial, wrapping std::mutex only.
+ * For internal ICU use only.
*
- * Mutex Definitions. Platform Dependent, #if platform chain follows.
- * TODO: Add a C++11 version.
- * Need to convert all mutex using files to C++ first.
+ * Caution: do not directly declare static or global instances of UMutex. Doing so can introduce
+ * static initializers, which are disallowed in ICU library code. Instead, use the following
+ * idiom, which avoids static init and also avoids ordering issues on destruction
+ * (use after delete) by avoiding destruction altogether.
*
- *************************************************************************************************/
-
-#if defined(U_USER_MUTEX_H)
-// #inlcude "U_USER_MUTEX_H"
-#include U_MUTEX_XSTR(U_USER_MUTEX_H)
-
-#elif U_PLATFORM_USES_ONLY_WIN32_API
-
-/* For CRITICAL_SECTION */
-
-/*
- * Note: there is an earlier include of windows.h in this file, but it is in
- * different conditionals.
- * This one is needed if we are using C++11 for atomic ops, but
- * win32 APIs for Critical Sections.
- */
-
-#ifndef WIN32_LEAN_AND_MEAN
-# define WIN32_LEAN_AND_MEAN
-#endif
-# define VC_EXTRALEAN
-# define NOUSER
-# define NOSERVICE
-# define NOIME
-# define NOMCX
-# ifndef NOMINMAX
-# define NOMINMAX
-# endif
-# include <windows.h>
-
-
-typedef struct UMutex {
- icu::UInitOnce fInitOnce;
- CRITICAL_SECTION fCS;
-} UMutex;
-
-/* Initializer for a static UMUTEX. Deliberately contains no value for the
- * CRITICAL_SECTION.
- */
-#define U_MUTEX_INITIALIZER {U_INITONCE_INITIALIZER}
-
-struct UConditionVar {
- HANDLE fEntryGate;
- HANDLE fExitGate;
- int32_t fWaitCount;
-};
-
-#define U_CONDITION_INITIALIZER {NULL, NULL, 0}
-
-
-
-#elif U_PLATFORM_IMPLEMENTS_POSIX
-
-/*
- * POSIX platform
+ * UMutex *myMutex() {
+ * static UMutex *m = STATIC_NEW(UMutex);
+ * return m;
+ * }
+ * ...
+ *
+ * Mutex lock(myMutex()); // hold myMutex until the variable "lock" goes out of scope.
*/
-#include <pthread.h>
+struct UMutex : public icu::UMemory {
+ UMutex() = default;
+ ~UMutex() = default;
+ UMutex(const UMutex &other) = delete;
+ UMutex &operator =(const UMutex &other) = delete;
-struct UMutex {
- pthread_mutex_t fMutex;
+ std::mutex fMutex = {}; // Note: struct - pubic members - because most access is from
+ // // plain C style functions (umtx_lock(), etc.)
};
-typedef struct UMutex UMutex;
-#define U_MUTEX_INITIALIZER {PTHREAD_MUTEX_INITIALIZER}
-
-struct UConditionVar {
- pthread_cond_t fCondition;
-};
-#define U_CONDITION_INITIALIZER {PTHREAD_COND_INITIALIZER}
-
-#else
-
-/*
- * Unknow platform type.
- * This is an error condition. ICU requires mutexes.
- */
-
-#error Unknown Platform.
-
-#endif
-
-
-
-/**************************************************************************************
- *
- * Mutex Implementation function declaratations.
- * Declarations are platform neutral.
- * Implementations, in umutex.cpp, are platform specific.
- *
- ************************************************************************************/
/* Lock a mutex.
* @param mutex The given mutex to be locked. Pass NULL to specify
*/
U_INTERNAL void U_EXPORT2 umtx_unlock (UMutex* mutex);
-/*
- * Wait on a condition variable.
- * The calling thread will unlock the mutex and wait on the condition variable.
- * The mutex must be locked by the calling thread when invoking this function.
- *
- * @param cond the condition variable to wait on.
- * @param mutex the associated mutex.
- */
-U_INTERNAL void U_EXPORT2 umtx_condWait(UConditionVar *cond, UMutex *mutex);
-
-
-/*
- * Broadcast wakeup of all threads waiting on a Condition.
- * The associated mutex must be locked by the calling thread when calling
- * this function; this is a temporary ICU restriction.
- *
- * @param cond the condition variable.
- */
-U_INTERNAL void U_EXPORT2 umtx_condBroadcast(UConditionVar *cond);
-
-/*
- * Signal a condition variable, waking up one waiting thread.
- * CAUTION: Do not use. Place holder only. Not implemented for Windows.
- */
-U_INTERNAL void U_EXPORT2 umtx_condSignal(UConditionVar *cond);
+U_NAMESPACE_END
#endif /* UMUTEX_H */
/*eof*/
projects / apple / icu.git / blobdiff