diff options
| author | Bernard Normier <bernard@zeroc.com> | 2005-04-14 15:49:51 +0000 |
|---|---|---|
| committer | Bernard Normier <bernard@zeroc.com> | 2005-04-14 15:49:51 +0000 |
| commit | be347a7c38f42b6c00d90ac536bd0ce8253a225d (patch) | |
| tree | bcbcdf01659d7f6da1c584adbfb9347bc30fc85f /cpp/include/IceUtil/StaticMutex.h | |
| parent | Removed more stuff (diff) | |
| download | ice-be347a7c38f42b6c00d90ac536bd0ce8253a225d.tar.bz2 ice-be347a7c38f42b6c00d90ac536bd0ce8253a225d.tar.xz ice-be347a7c38f42b6c00d90ac536bd0ce8253a225d.zip | |
Improved Double-Check Locking with memory barriers
(InterlockedCompareExchangePointer)
Diffstat (limited to 'cpp/include/IceUtil/StaticMutex.h')
| -rw-r--r-- | cpp/include/IceUtil/StaticMutex.h | 40 |
1 files changed, 31 insertions, 9 deletions
diff --git a/cpp/include/IceUtil/StaticMutex.h b/cpp/include/IceUtil/StaticMutex.h index bb34a97f80e..bc44e401bb3 100644 --- a/cpp/include/IceUtil/StaticMutex.h +++ b/cpp/include/IceUtil/StaticMutex.h @@ -14,6 +14,16 @@ #include <IceUtil/Lock.h> #include <IceUtil/ThreadException.h> +#if defined(_MSC_VER) && (_MSC_VER < 1300) +// +// Old versions of the Platform SDK don't have InterlockedCompareExchangePointer +// +# ifndef InterlockedCompareExchangePointer +# define InterlockedCompareExchangePointer(Destination, ExChange, Comperand) \ + InterlockedCompareExchange(Destination, ExChange, Comperand) +# endif +#endif + namespace IceUtil { @@ -55,7 +65,6 @@ public: #ifdef _WIN32 - mutable bool _mutexInitialized; # if defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x0400 mutable CRITICAL_SECTION* _mutex; # else @@ -94,6 +103,7 @@ private: void lock(LockState&) const; #ifdef _WIN32 + inline bool initialized() const; ICE_UTIL_API void initialize() const; #endif @@ -104,7 +114,7 @@ private: }; #ifdef _WIN32 -# define ICE_STATIC_MUTEX_INITIALIZER { false } +# define ICE_STATIC_MUTEX_INITIALIZER { 0 } #else # define ICE_STATIC_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER } #endif @@ -121,12 +131,23 @@ extern ICE_UTIL_API StaticMutex globalMutex; #ifdef _WIN32 +inline bool +StaticMutex::initialized() const +{ + // + // Read mutex and then inserts a memory barrier to ensure we can't + // see tmp != 0 before we see the initialized object + // + void* tmp = _mutex; + return InterlockedCompareExchangePointer(reinterpret_cast<void**>(&tmp), 0, 0) != 0; +} + # if defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x0400 inline void StaticMutex::lock() const { - if (!_mutexInitialized) + if(!initialized()) { initialize(); } @@ -137,7 +158,7 @@ StaticMutex::lock() const inline bool StaticMutex::tryLock() const { - if (!_mutexInitialized) + if(!initialized()) { initialize(); } @@ -156,7 +177,7 @@ StaticMutex::tryLock() const inline void StaticMutex::unlock() const { - assert(_mutexInitialized); + assert(_mutex != 0); assert(_mutex->RecursionCount == 1); LeaveCriticalSection(_mutex); } @@ -164,14 +185,15 @@ StaticMutex::unlock() const inline void StaticMutex::unlock(LockState&) const { - assert(_mutexInitialized); + assert(_mutex != 0); + assert(_mutex->RecursionCount == 1); LeaveCriticalSection(_mutex); } inline void StaticMutex::lock(LockState&) const { - if (!_mutexInitialized) + if(!initialized()) { initialize(); } @@ -183,7 +205,7 @@ StaticMutex::lock(LockState&) const inline void StaticMutex::lock() const { - if (!_mutexInitialized) + if(!initialized()) { initialize(); } @@ -207,7 +229,7 @@ StaticMutex::lock() const inline bool StaticMutex::tryLock() const { - if (!_mutexInitialized) + if(!initialized()) { initialize(); } |