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authorWilliam R. Otte <wotte@dre.vanderbilt.edu>2006-07-24 15:50:30 +0000
committerWilliam R. Otte <wotte@dre.vanderbilt.edu>2006-07-24 15:50:30 +0000
commitc44379cc7d9c7aa113989237ab0f56db12aa5219 (patch)
tree66a84b20d47f2269d8bdc6e0323f338763424d3a /ACE/ace/Thread_Mutex.h
parent3aff90f4a822fcf5d902bbfbcc9fa931d6191a8c (diff)
downloadATCD-c44379cc7d9c7aa113989237ab0f56db12aa5219.tar.gz
Repo restructuring
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+// -*- 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 <errno> == <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 <tv> times out, in
+ * which case -1 is returned with <errno> == <ETIME>. Note that
+ * <*tv> is assumed to be in "absolute" rather than "relative" time.
+ * The value of <*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, <errno> is set to <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, <errno> is set to <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, <errno> is set to <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...
+ int removed_;
+
+private:
+ // = Prevent assignment and initialization.
+ void operator= (const ACE_Thread_Mutex &);
+ ACE_Thread_Mutex (const ACE_Thread_Mutex &);
+};
+
+#if defined (ACE_USES_OBSOLETE_GUARD_CLASSES)
+/**
+ * @class ACE_Thread_Mutex_Guard
+ *
+ * @brief This data structure is meant to be used within a method or
+ * function... It performs automatic aquisition and release of
+ * an ACE_Thread_Mutex.
+ *
+ * This class is obsolete and should be replaced by
+ * ACE_Guard<ACE_Thread_Mutex>.
+ */
+class ACE_Export ACE_Thread_Mutex_Guard
+{
+public:
+ /// Implicitly and automatically acquire the lock.
+ ACE_Thread_Mutex_Guard (ACE_Thread_Mutex &m, int block = 1);
+
+ /// Implicitly release the lock.
+ ~ACE_Thread_Mutex_Guard (void);
+
+ /// 1 if locked, 0 if couldn't acquire the lock (errno will contain
+ /// the reason for this).
+ int locked (void);
+
+ /**
+ * Explicitly release the lock. Note that only one thread should
+ * call this method since it doesn't protect against race
+ * conditions.
+ */
+ int remove (void);
+
+ /// Explicitly acquire the lock.
+ int acquire (void);
+
+ /**
+ * Conditionally acquire the lock (i.e., won't block). Returns -1
+ * on failure. If we "failed" because someone else already had the
+ * lock, <errno> is set to <EBUSY>.
+ */
+ int tryacquire (void);
+
+ /// Explicitly release the lock.
+ int release (void);
+
+ /// Dump the state of an object.
+ void dump (void) const;
+
+ /// Declare the dynamic allocation hooks.
+ ACE_ALLOC_HOOK_DECLARE;
+
+protected:
+ /// Reference to the mutex.
+ ACE_Thread_Mutex &lock_;
+
+ /// Keeps track of whether we acquired the lock or failed.
+ int owner_;
+
+private:
+ // = Prevent assignment and initialization.
+ void operator= (const ACE_Thread_Mutex_Guard &);
+ ACE_Thread_Mutex_Guard (const ACE_Thread_Mutex_Guard &);
+};
+#endif /* ACE_USES_OBSOLETE_GUARD_CLASSES */
+
+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 */