From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 21:33:14 +0200 Subject: Adding upstream version 115.7.0esr. Signed-off-by: Daniel Baumann --- intl/icu/source/common/umutex.h | 313 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 313 insertions(+) create mode 100644 intl/icu/source/common/umutex.h (limited to 'intl/icu/source/common/umutex.h') diff --git a/intl/icu/source/common/umutex.h b/intl/icu/source/common/umutex.h new file mode 100644 index 0000000000..f084a20bf8 --- /dev/null +++ b/intl/icu/source/common/umutex.h @@ -0,0 +1,313 @@ +// © 2016 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html +/* +********************************************************************** +* Copyright (C) 1997-2015, International Business Machines +* Corporation and others. All Rights Reserved. +********************************************************************** +* +* File UMUTEX.H +* +* Modification History: +* +* Date Name Description +* 04/02/97 aliu Creation. +* 04/07/99 srl rewrite - C interface, multiple mutices +* 05/13/99 stephen Changed to umutex (from cmutex) +****************************************************************************** +*/ + +#ifndef UMUTEX_H +#define UMUTEX_H + +#ifndef __wasi__ +#include +#include +#include +#endif + +#include + +#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|| defined(U_USER_MUTEX_H) +// Support for including an alternate implementation of atomic & mutex operations has been withdrawn.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 + +#ifndef __wasi__ + +// Export an explicit template instantiation of std::atomic. +// 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. +// +// Similar story for std::atomic, and the exported UMutex class. +#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; +template struct U_COMMON_API std::atomic; + #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; +template struct std::atomic; +#endif +#endif + +#endif + +U_NAMESPACE_BEGIN + +/**************************************************************************** + * + * Low Level Atomic Operations, ICU wrappers for. + * + ****************************************************************************/ + +#ifndef __wasi__ + +typedef std::atomic u_atomic_int32_t; + +inline int32_t umtx_loadAcquire(u_atomic_int32_t &var) { + return var.load(std::memory_order_acquire); +} + +inline void umtx_storeRelease(u_atomic_int32_t &var, int32_t val) { + var.store(val, std::memory_order_release); +} + +inline int32_t umtx_atomic_inc(u_atomic_int32_t *var) { + return var->fetch_add(1) + 1; +} + +inline int32_t umtx_atomic_dec(u_atomic_int32_t *var) { + return var->fetch_sub(1) - 1; +} + +#else + +typedef int32_t u_atomic_int32_t; +#define ATOMIC_INT32_T_INITIALIZER(val) val + +inline int32_t umtx_loadAcquire(u_atomic_int32_t &var) { + return var; +} + +inline void umtx_storeRelease(u_atomic_int32_t &var, int32_t val) { + var = val; +} + +inline int32_t umtx_atomic_inc(u_atomic_int32_t *var) { + return ++(*var); +} + +inline int32_t umtx_atomic_dec(u_atomic_int32_t *var) { + return --(*var); +} + +#endif + +/************************************************************************************************* + * + * UInitOnce Definitions. + * + *************************************************************************************************/ + +struct U_COMMON_API UInitOnce { + u_atomic_int32_t fState {0}; + UErrorCode fErrCode {U_ZERO_ERROR}; + 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_COMMON_API UBool U_EXPORT2 umtx_initImplPreInit(UInitOnce &); +U_COMMON_API void U_EXPORT2 umtx_initImplPostInit(UInitOnce &); + +template void umtx_initOnce(UInitOnce &uio, T *obj, void (U_CALLCONV T::*fp)()) { + if (umtx_loadAcquire(uio.fState) == 2) { + return; + } + if (umtx_initImplPreInit(uio)) { + (obj->*fp)(); + umtx_initImplPostInit(uio); + } +} + + +// umtx_initOnce variant for plain functions, or static class functions. +// No context parameter. +inline void umtx_initOnce(UInitOnce &uio, void (U_CALLCONV *fp)()) { + if (umtx_loadAcquire(uio.fState) == 2) { + return; + } + if (umtx_initImplPreInit(uio)) { + (*fp)(); + umtx_initImplPostInit(uio); + } +} + +// umtx_initOnce variant for plain functions, or static class functions. +// With ErrorCode, No context parameter. +inline void umtx_initOnce(UInitOnce &uio, void (U_CALLCONV *fp)(UErrorCode &), UErrorCode &errCode) { + if (U_FAILURE(errCode)) { + return; + } + if (umtx_loadAcquire(uio.fState) != 2 && umtx_initImplPreInit(uio)) { + // We run the initialization. + (*fp)(errCode); + uio.fErrCode = errCode; + umtx_initImplPostInit(uio); + } else { + // Someone else already ran the initialization. + if (U_FAILURE(uio.fErrCode)) { + errCode = uio.fErrCode; + } + } +} + +// umtx_initOnce variant for plain functions, or static class functions, +// with a context parameter. +template void umtx_initOnce(UInitOnce &uio, void (U_CALLCONV *fp)(T), T context) { + if (umtx_loadAcquire(uio.fState) == 2) { + return; + } + if (umtx_initImplPreInit(uio)) { + (*fp)(context); + umtx_initImplPostInit(uio); + } +} + +// umtx_initOnce variant for plain functions, or static class functions, +// with a context parameter and an error code. +template void umtx_initOnce(UInitOnce &uio, void (U_CALLCONV *fp)(T, UErrorCode &), T context, UErrorCode &errCode) { + if (U_FAILURE(errCode)) { + return; + } + if (umtx_loadAcquire(uio.fState) != 2 && umtx_initImplPreInit(uio)) { + // We run the initialization. + (*fp)(context, errCode); + uio.fErrCode = errCode; + umtx_initImplPostInit(uio); + } else { + // Someone else already ran the initialization. + if (U_FAILURE(uio.fErrCode)) { + errCode = uio.fErrCode; + } + } +} + +// UMutex should be constexpr-constructible, so that no initialization code +// is run during startup. +// This works on all C++ libraries except MS VS before VS2019. +#if (defined(_CPPLIB_VER) && !defined(_MSVC_STL_VERSION)) || \ + (defined(_MSVC_STL_VERSION) && _MSVC_STL_VERSION < 142) + // (VS std lib older than VS2017) || (VS std lib version < VS2019) +# define UMUTEX_CONSTEXPR +#else +# define UMUTEX_CONSTEXPR constexpr +#endif + +/** + * UMutex - ICU Mutex class. + * + * This is the preferred Mutex class for use within ICU implementation code. + * It is a thin wrapper over C++ std::mutex, with these additions: + * - Static instances are safe, not triggering static construction or destruction, + * and the associated order of construction or destruction issues. + * - Plumbed into u_cleanup() for destructing the underlying std::mutex, + * which frees any OS level resources they may be holding. + * + * Limitations: + * - Static or global instances only. Cannot be heap allocated. Cannot appear as a + * member of another class. + * - No condition variables or other advanced features. If needed, you will need to use + * std::mutex and std::condition_variable directly. For an example, see unifiedcache.cpp + * + * Typical Usage: + * static UMutex myMutex; + * + * { + * Mutex lock(myMutex); + * ... // Do stuff that is protected by myMutex; + * } // myMutex is released when lock goes out of scope. + */ + +class U_COMMON_API UMutex { +public: + UMUTEX_CONSTEXPR UMutex() {} + ~UMutex() = default; + + UMutex(const UMutex &other) = delete; + UMutex &operator =(const UMutex &other) = delete; + void *operator new(size_t) = delete; + + // requirements for C++ BasicLockable, allows UMutex to work with std::lock_guard + void lock() { +#ifndef __wasi__ + std::mutex *m = fMutex.load(std::memory_order_acquire); + if (m == nullptr) { m = getMutex(); } + m->lock(); +#endif + } + void unlock() { +#ifndef __wasi__ + fMutex.load(std::memory_order_relaxed)->unlock(); +#endif + } + + static void cleanup(); + +private: +#ifndef __wasi__ + alignas(std::mutex) char fStorage[sizeof(std::mutex)] {}; + std::atomic fMutex { nullptr }; +#endif + + /** All initialized UMutexes are kept in a linked list, so that they can be found, + * and the underlying std::mutex destructed, by u_cleanup(). + */ + UMutex *fListLink { nullptr }; + static UMutex *gListHead; + + /** Out-of-line function to lazily initialize a UMutex on first use. + * Initial fast check is inline, in lock(). The returned value may never + * be nullptr. + */ +#ifndef __wasi__ + std::mutex *getMutex(); +#endif +}; + + +/* Lock a mutex. + * @param mutex The given mutex to be locked. Pass NULL to specify + * the global ICU mutex. Recursive locks are an error + * and may cause a deadlock on some platforms. + */ +U_CAPI void U_EXPORT2 umtx_lock(UMutex* mutex); + +/* Unlock a mutex. + * @param mutex The given mutex to be unlocked. Pass NULL to specify + * the global ICU mutex. + */ +U_CAPI void U_EXPORT2 umtx_unlock (UMutex* mutex); + + +U_NAMESPACE_END + +#endif /* UMUTEX_H */ +/*eof*/ -- cgit v1.2.3