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author | William R. Otte <wotte@dre.vanderbilt.edu> | 2008-03-04 14:51:23 +0000 |
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committer | William R. Otte <wotte@dre.vanderbilt.edu> | 2008-03-04 14:51:23 +0000 |
commit | 99aa8c60282c7b8072eb35eb9ac815702f5bf586 (patch) | |
tree | bda96bf8c3a4c2875a083d7b16720533c8ffeaf4 /ACE/ace/Thread_Mutex.h | |
parent | c4078c377d74290ebe4e66da0b4975da91732376 (diff) | |
download | ATCD-99aa8c60282c7b8072eb35eb9ac815702f5bf586.tar.gz |
undoing accidental deletion
Diffstat (limited to 'ACE/ace/Thread_Mutex.h')
-rw-r--r-- | ACE/ace/Thread_Mutex.h | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/ACE/ace/Thread_Mutex.h b/ACE/ace/Thread_Mutex.h new file mode 100644 index 00000000000..d8f5369b01a --- /dev/null +++ b/ACE/ace/Thread_Mutex.h @@ -0,0 +1,175 @@ +// -*- C++ -*- + +//========================================================================== +/** + * @file Thread_Mutex.h + * + * $Id$ + * + * Moved from Synch.h. + * + * @author Douglas C. Schmidt <schmidt@cs.wustl.edu> + */ +//========================================================================== + +#ifndef ACE_THREAD_MUTEX_H +#define ACE_THREAD_MUTEX_H +#include /**/ "ace/pre.h" + +#include /**/ "ace/config-all.h" + +#if !defined (ACE_LACKS_PRAGMA_ONCE) +# pragma once +#endif /* ACE_LACKS_PRAGMA_ONCE */ + +#if !defined (ACE_HAS_THREADS) +# include "ace/Null_Mutex.h" +#else /* ACE_HAS_THREADS */ +// ACE platform supports some form of threading. + +#include /**/ "ace/ACE_export.h" +#include "ace/OS_NS_Thread.h" + +ACE_BEGIN_VERSIONED_NAMESPACE_DECL + +/** + * @class ACE_Thread_Mutex + * + * @brief ACE_Thread_Mutex wrapper (only valid for threads in the same + * process). + * + * This implementation is optimized for locking threads that are + * in the same process. It maps to <CRITICAL_SECTION>s on NT + * and <ACE_mutex_t> with <type> set to <USYNC_THREAD> on UNIX. + * ACE_Thread_Mutex is recursive on some platforms (like + * Win32). However, on most platforms (like Solaris) it is not + * recursive. To be totally safe and portable, developers + * should use ACE_Recursive_Thread_Mutex when they need a + * recursive mutex. + */ +class ACE_Export ACE_Thread_Mutex +{ + friend class ACE_Condition_Thread_Mutex; +public: + /// Constructor. + ACE_Thread_Mutex (const ACE_TCHAR *name = 0, + ACE_mutexattr_t *attributes = 0); + + /// Implicitly destroy the mutex. + ~ACE_Thread_Mutex (void); + + /** + * Explicitly destroy the mutex. Note that only one thread should + * call this method since it doesn't protect against race + * conditions. + */ + int remove (void); + + /// Acquire lock ownership (wait on queue if necessary). + int acquire (void); + + /** + * Block the thread until we acquire the mutex or until @a tv times + * out, in which case -1 is returned with @c errno == @c ETIME. Note + * that @a tv is assumed to be in "absolute" rather than "relative" + * time. The value of @a tv is updated upon return to show the + * actual (absolute) acquisition time. + */ + int acquire (ACE_Time_Value &tv); + + /** + * If @a tv == 0 the call <acquire()> directly. Otherwise, Block the + * thread until we acquire the mutex or until @a tv times out, in + * which case -1 is returned with @c errno == @c ETIME. Note that + * @a tv is assumed to be in "absolute" rather than "relative" time. + * The value of @a tv is updated upon return to show the actual + * (absolute) acquisition time. + */ + int acquire (ACE_Time_Value *tv); + + /** + * Conditionally acquire lock (i.e., don't wait on queue). Returns + * -1 on failure. If we "failed" because someone else already had + * the lock, @c errno is set to @c EBUSY. + */ + int tryacquire (void); + + /// Release lock and unblock a thread at head of queue. + int release (void); + + /** + * Acquire mutex ownership. This calls acquire() and is only here + * to make the ACE_Thread_Mutex interface consistent with the + * other synchronization APIs. + */ + int acquire_read (void); + + /** + * Acquire mutex ownership. This calls acquire() and is only here + * to make the ACE_Thread_Mutex interface consistent with the + * other synchronization APIs. + */ + int acquire_write (void); + + /** + * Conditionally acquire mutex (i.e., won't block). This calls + * tryacquire() and is only here to make the ACE_Thread_Mutex + * interface consistent with the other synchronization APIs. + * Returns -1 on failure. If we "failed" because someone else + * already had the lock, @c errno is set to @c EBUSY. + */ + int tryacquire_read (void); + + /** + * Conditionally acquire mutex (i.e., won't block). This calls + * tryacquire() and is only here to make the ACE_Thread_Mutex + * interface consistent with the other synchronization APIs. + * Returns -1 on failure. If we "failed" because someone else + * already had the lock, @c errno is set to @c EBUSY. + */ + int tryacquire_write (void); + + /** + * This is only here to make the ACE_Thread_Mutex + * interface consistent with the other synchronization APIs. + * Assumes the caller has already acquired the mutex using one of + * the above calls, and returns 0 (success) always. + */ + int tryacquire_write_upgrade (void); + + /// Return the underlying mutex. + const ACE_thread_mutex_t &lock (void) const; + + /// Dump the state of an object. + void dump (void) const; + + /// Declare the dynamic allocation hooks. + ACE_ALLOC_HOOK_DECLARE; + + // protected: + /// Mutex type that supports single-process locking efficiently. + ACE_thread_mutex_t lock_; + + /// Keeps track of whether remove() has been called yet to avoid + /// multiple <remove> calls, e.g., explicitly and implicitly in the + /// destructor. This flag isn't protected by a lock, so make sure + /// that you don't have multiple threads simultaneously calling + /// <remove> on the same object, which is a bad idea anyway... + bool removed_; + +private: + // = Prevent assignment and initialization. + void operator= (const ACE_Thread_Mutex &); + ACE_Thread_Mutex (const ACE_Thread_Mutex &); +}; + +ACE_END_VERSIONED_NAMESPACE_DECL + +#if defined (__ACE_INLINE__) +#include "ace/Thread_Mutex.inl" +#endif /* __ACE_INLINE__ */ + +#endif /* !ACE_HAS_THREADS */ + +#include /**/ "ace/post.h" +#endif /* ACE_THREAD_MUTEX_H */ |