1 files changed, 192 insertions, 0 deletions
diff --git a/ACE/ace/Barrier.h b/ACE/ace/Barrier.h
new file mode 100644
index 00000000000..562d4467f11
--- /dev/null
+++ b/ACE/ace/Barrier.h
@@ -0,0 +1,192 @@
+// -*- C++ -*-
+
+//==========================================================================
+/**
+ *  @file    Barrier.h
+ *
+ *  $Id$
+ *
+ *   Moved from Synch.h.
+ *
+ *  @author Douglas C. Schmidt <schmidt@cs.wustl.edu>
+ */
+//==========================================================================
+
+#ifndef ACE_BARRIER_H
+#define ACE_BARRIER_H
+#include /**/ "ace/pre.h"
+
+#include /**/ "ace/ACE_export.h"
+
+#if !defined (ACE_LACKS_PRAGMA_ONCE)
+# pragma once
+#endif /* ACE_LACKS_PRAGMA_ONCE */
+
+#include /**/ "ace/config-all.h"
+
+// ACE platform supports some form of threading.
+#if !defined (ACE_HAS_THREADS)
+
+#include "ace/OS_NS_errno.h"
+
+ACE_BEGIN_VERSIONED_NAMESPACE_DECL
+
+/**
+ * @class ACE_Barrier
+ *
+ * @brief This is a no-op to make ACE "syntactically consistent."
+ */
+class ACE_Export ACE_Barrier
+{
+public:
+  ACE_Barrier (unsigned int, const ACE_TCHAR * = 0, void * = 0) {}
+  ~ACE_Barrier (void) {}
+  int wait (void) { ACE_NOTSUP_RETURN (-1); }
+  void dump (void) const {}
+};
+
+ACE_END_VERSIONED_NAMESPACE_DECL
+
+#else /* ACE_HAS_THREADS */
+
+#include "ace/Condition_Thread_Mutex.h"
+
+ACE_BEGIN_VERSIONED_NAMESPACE_DECL
+
+struct ACE_Export ACE_Sub_Barrier
+{
+  // = Initialization.
+  ACE_Sub_Barrier (unsigned int count,
+                   ACE_Thread_Mutex &lock,
+                   const ACE_TCHAR *name = 0,
+                   void *arg = 0);
+
+  ~ACE_Sub_Barrier (void);
+
+  /// True if this generation of the barrier is done.
+  ACE_Condition_Thread_Mutex barrier_finished_;
+
+  /// Number of threads that are still running.
+  int running_threads_;
+
+  /// Dump the state of an object.
+  void dump (void) const;
+
+  /// Declare the dynamic allocation hooks.
+  ACE_ALLOC_HOOK_DECLARE;
+};
+
+/**
+ * @class ACE_Barrier
+ *
+ * @brief Implements "barrier synchronization".
+ *
+ * This class allows <count> number of threads to synchronize
+ * their completion of (one round of) a task, which is known as
+ * "barrier synchronization".   After all the threads call <wait()>
+ * on the barrier they are all atomically released and can begin a new
+ * round.
+ *
+ * This implementation uses a "sub-barrier generation numbering"
+ * scheme to avoid overhead and to ensure that all threads wait to
+ * leave the barrier correct.  This code is based on an article from
+ * SunOpsis Vol. 4, No. 1 by Richard Marejka
+ * (Richard.Marejka@canada.sun.com).
+ */
+class ACE_Export ACE_Barrier
+{
+public:
+  /// Initialize the barrier to synchronize @a count threads.
+  ACE_Barrier (unsigned int count,
+               const ACE_TCHAR *name = 0,
+               void *arg = 0);
+
+  /// Default destructor.
+  ~ACE_Barrier (void);
+
+  /// Block the caller until all @c count threads have called @c wait and
+  /// then allow all the caller threads to continue in parallel.
+  ///
+  /// @retval 0 after successfully waiting for all threads to wait.
+  /// @retval -1 if an error occurs or the barrier is shut
+  /// down (@sa shutdown ()).
+  int wait (void);
+
+  /// Shut the barrier down, aborting the wait of all waiting threads.
+  /// Any threads waiting on the barrier when it is shut down will return with
+  /// value -1, errno ESHUTDOWN.
+  ///
+  /// @retval 0 for success, -1 if already shut down.
+  ///
+  /// @since ACE beta 5.4.9.
+  int shutdown (void);
+
+  /// Dump the state of an object.
+  void dump (void) const;
+
+  /// Declare the dynamic allocation hooks.
+  ACE_ALLOC_HOOK_DECLARE;
+
+protected:
+  /// Serialize access to the barrier state.
+  ACE_Thread_Mutex lock_;
+
+  /// Either 0 or 1, depending on whether we are the first generation
+  /// of waiters or the next generation of waiters.
+  int current_generation_;
+
+  /// Total number of threads that can be waiting at any one time.
+  int count_;
+
+  /**
+   * We keep two @c sub_barriers, one for the first "generation" of
+   * waiters, and one for the next "generation" of waiters.  This
+   * efficiently solves the problem of what to do if all the first
+   * generation waiters don't leave the barrier before one of the
+   * threads calls wait() again (i.e., starts up the next generation
+   * barrier).
+   */
+  ACE_Sub_Barrier sub_barrier_1_;
+  ACE_Sub_Barrier sub_barrier_2_;
+  ACE_Sub_Barrier *sub_barrier_[2];
+
+private:
+  // = Prevent assignment and initialization.
+  void operator= (const ACE_Barrier &);
+  ACE_Barrier (const ACE_Barrier &);
+};
+
+/**
+ * @class ACE_Thread_Barrier
+ *
+ * @brief Implements "barrier synchronization" using ACE_Thread_Mutexes!
+ *
+ * This class is just a simple wrapper for ACE_Barrier that
+ * selects the USYNC_THREAD variant for the locks.
+ */
+class ACE_Export ACE_Thread_Barrier : public ACE_Barrier
+{
+public:
+  /// Create a Thread_Barrier, passing in the optional @a name.
+  ACE_Thread_Barrier (unsigned int count, const ACE_TCHAR *name = 0);
+
+  /// Default destructor.
+  ~ACE_Thread_Barrier (void);
+
+  /// Dump the state of an object.
+  void dump (void) const;
+
+  /// Declare the dynamic allocation hooks.
+  ACE_ALLOC_HOOK_DECLARE;
+};
+
+ACE_END_VERSIONED_NAMESPACE_DECL
+
+#if defined (__ACE_INLINE__)
+#include "ace/Barrier.inl"
+#endif /* __ACE_INLINE__ */
+
+#endif /* !ACE_HAS_THREADS */
+
+#include /**/ "ace/post.h"
+#endif /* ACE_BARRIER_H */