/*
**********************************************************************
* Copyright (C) 1997-2012, 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
#include "unicode/utypes.h"
#include "unicode/uclean.h"
#include "putilimp.h"
/* For _ReadWriteBarrier(). */
#if defined(_MSC_VER) && _MSC_VER >= 1500
# include <intrin.h>
#endif
/* For CRITICAL_SECTION */
#if U_PLATFORM_HAS_WIN32_API
#if 0
/* TODO(andy): Why doesn't windows.h compile in all files? It does in some.
* The intent was to include windows.h here, and have struct UMutex
* have an embedded CRITICAL_SECTION when building on Windows.
* The workaround is to put some char[] storage in UMutex instead,
* avoiding the need to include windows.h everwhere this header is included.
*/
# define WIN32_LEAN_AND_MEAN
# define VC_EXTRALEAN
# define NOUSER
# define NOSERVICE
# define NOIME
# define NOMCX
# include <windows.h>
#endif /* 0 */
#define U_WINDOWS_CRIT_SEC_SIZE 64
#endif /* win32 */
#if U_PLATFORM_IS_DARWIN_BASED
#if defined(__STRICT_ANSI__)
#define UPRV_REMAP_INLINE
#define inline
#endif
#include <libkern/OSAtomic.h>
#define USE_MAC_OS_ATOMIC_INCREMENT 1
#if defined(UPRV_REMAP_INLINE)
#undef inline
#undef UPRV_REMAP_INLINE
#endif
#endif
/*
* If we do not compile with dynamic_annotations.h then define
* empty annotation macros.
* See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations
*/
#ifndef ANNOTATE_HAPPENS_BEFORE
# define ANNOTATE_HAPPENS_BEFORE(obj)
# define ANNOTATE_HAPPENS_AFTER(obj)
# define ANNOTATE_UNPROTECTED_READ(x) (x)
#endif
#ifndef UMTX_FULL_BARRIER
# if U_HAVE_GCC_ATOMICS
# define UMTX_FULL_BARRIER __sync_synchronize();
# elif defined(_MSC_VER) && _MSC_VER >= 1500
/* From MSVC intrin.h. Use _ReadWriteBarrier() only on MSVC 9 and higher. */
# define UMTX_FULL_BARRIER _ReadWriteBarrier();
# elif U_PLATFORM_IS_DARWIN_BASED
# define UMTX_FULL_BARRIER OSMemoryBarrier();
# else
# define UMTX_FULL_BARRIER \
{ \
umtx_lock(NULL); \
umtx_unlock(NULL); \
}
# endif
#endif
#ifndef UMTX_ACQUIRE_BARRIER
# define UMTX_ACQUIRE_BARRIER UMTX_FULL_BARRIER
#endif
#ifndef UMTX_RELEASE_BARRIER
# define UMTX_RELEASE_BARRIER UMTX_FULL_BARRIER
#endif
/**
* \def UMTX_CHECK
* Encapsulates a safe check of an expression
* for use with double-checked lazy inititialization.
* Either memory barriers or mutexes are required, to prevent both the hardware
* and the compiler from reordering operations across the check.
* The expression must involve only a _single_ variable, typically
* a possibly null pointer or a boolean that indicates whether some service
* is initialized or not.
* The setting of the variable involved in the test must be the last step of
* the initialization process.
*
* @internal
*/
#define UMTX_CHECK(pMutex, expression, result) \
{ \
(result)=(expression); \
UMTX_ACQUIRE_BARRIER; \
}
/*
* TODO: Replace all uses of UMTX_CHECK and surrounding code
* with SimpleSingleton or TriStateSingleton, and remove UMTX_CHECK.
*/
/*
* Code within ICU that accesses shared static or global data should
* instantiate a Mutex object while doing so. The unnamed global mutex
* is used throughout ICU, so keep locking short and sweet.
*
* For example:
*
* void Function(int arg1, int arg2)
* {
* static Object* foo; // Shared read-write object
* umtx_lock(NULL); // Lock the ICU global mutex
* foo->Method();
* umtx_unlock(NULL);
* }
*
* an alternative C++ mutex API is defined in the file common/mutex.h
*/
/*
* UMutex - Mutexes for use by ICU implementation code.
* Must be declared as static or globals. They cannot appear as members
* of other objects.
* UMutex structs must be initialized.
* Example:
* static UMutex = U_MUTEX_INITIALIZER;
* The declaration of struct UMutex is platform dependent.
*/
#if U_PLATFORM_HAS_WIN32_API
/* U_INIT_ONCE mimics the windows API INIT_ONCE, which exists on Windows Vista and newer.
* When ICU no longer needs to support older Windows platforms (XP) that do not have
* a native INIT_ONCE, switch this implementation over to wrap the native Windows APIs.
*/
typedef struct U_INIT_ONCE {
long fState;
void *fContext;
} U_INIT_ONCE;
#define U_INIT_ONCE_STATIC_INIT {0, NULL}
typedef struct UMutex {
U_INIT_ONCE fInitOnce;
UMTX fUserMutex;
UBool fInitialized; /* Applies to fUserMutex only. */
/* CRITICAL_SECTION fCS; */ /* See note above. Unresolved problems with including
* Windows.h, which would allow using CRITICAL_SECTION
* directly here. */
char fCS[U_WINDOWS_CRIT_SEC_SIZE];
} UMutex;
/* Initializer for a static UMUTEX. Deliberately contains no value for the
* CRITICAL_SECTION.
*/
#define U_MUTEX_INITIALIZER {U_INIT_ONCE_STATIC_INIT, NULL, FALSE}
#elif U_PLATFORM_IMPLEMENTS_POSIX
#include <pthread.h>
struct UMutex {
pthread_mutex_t fMutex;
UMTX fUserMutex;
UBool fInitialized;
};
#define U_MUTEX_INITIALIZER {PTHREAD_MUTEX_INITIALIZER, NULL, FALSE}
#else
/* Unknow platform type. */
struct UMutex {
void *fMutex;
};
#define U_MUTEX_INITIALIZER {NULL}
#error Unknown Platform.
#endif
#if (U_PLATFORM != U_PF_CYGWIN && U_PLATFORM != U_PF_MINGW) || defined(CYGWINMSVC)
typedef struct UMutex UMutex;
#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);
/*
* Atomic Increment and Decrement of an int32_t value.
*
* Return Values:
* If the result of the operation is zero, the return zero.
* If the result of the operation is not zero, the sign of returned value
* is the same as the sign of the result, but the returned value itself may
* be different from the result of the operation.
*/
U_CAPI int32_t U_EXPORT2 umtx_atomic_inc(int32_t *);
U_CAPI int32_t U_EXPORT2 umtx_atomic_dec(int32_t *);
#endif /*_CMUTEX*/
/*eof*/