1 files changed, 161 insertions, 0 deletions
diff --git a/ACE/ace/Lock.h b/ACE/ace/Lock.h
new file mode 100644
index 00000000000..272683098c0
--- /dev/null
+++ b/ACE/ace/Lock.h
@@ -0,0 +1,161 @@
+// -*- C++ -*-
+
+//==========================================================================
+/**
+ *  @file    Lock.h
+ *
+ *  $Id$
+ *
+ *   Moved from Synch.h.
+ *
+ *  @author Douglas C. Schmidt <schmidt@cs.wustl.edu>
+ */
+//==========================================================================
+
+#ifndef ACE_LOCK_H
+#define ACE_LOCK_H
+#include /**/ "ace/pre.h"
+
+#include /**/ "ace/ACE_export.h"
+
+#if !defined (ACE_LACKS_PRAGMA_ONCE)
+# pragma once
+#endif /* ACE_LACKS_PRAGMA_ONCE */
+
+ACE_BEGIN_VERSIONED_NAMESPACE_DECL
+
+/**
+ * @class ACE_Lock
+ *
+ * @brief This is the abstract base class that contains the uniform
+ * locking API that is supported by all the ACE synchronization
+ * mechanisms.
+ *
+ * This class is typically used in conjunction with the
+ * ACE_Lock_Adapter in order to provide a polymorphic
+ * interface to the ACE synchronization mechanisms (e.g.,
+ * ACE_Mutex, ACE_Semaphore, ACE_RW_Mutex, etc).  Note that
+ * the reason that all of ACE doesn't use polymorphic locks is
+ * that (1) they add ~20% extra overhead for virtual function
+ * calls and (2) objects with virtual functions can't be placed
+ * into shared memory.
+ */
+class ACE_Export ACE_Lock
+{
+public:
+  /// CE needs a default ctor here.
+  ACE_Lock (void);
+
+  /// Noop virtual destructor
+  virtual ~ACE_Lock (void);
+
+  /**
+   * Explicitly destroy the lock.  Note that only one thread should
+   * call this method since it doesn't protect against race
+   * conditions.
+   */
+  virtual int remove (void) = 0;
+
+  /// Block the thread until the lock is acquired.  Returns -1 on
+  /// failure.
+  virtual int acquire (void) = 0;
+
+  /**
+   * 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>.
+   */
+  virtual int tryacquire (void) = 0;
+
+  /// Release the lock.  Returns -1 on failure.
+  virtual int release (void) = 0;
+
+  /**
+   * Block until the thread acquires a read lock.  If the locking
+   * mechanism doesn't support read locks then this just calls
+   * <acquire>.  Returns -1 on failure.
+   */
+  virtual int acquire_read (void) = 0;
+
+  /**
+   * Block until the thread acquires a write lock.  If the locking
+   * mechanism doesn't support read locks then this just calls
+   * <acquire>.  Returns -1 on failure.
+   */
+  virtual int acquire_write (void) = 0;
+
+  /**
+   * Conditionally acquire a read lock.  If the locking mechanism
+   * doesn't support read locks then this just calls <acquire>.
+   * Returns -1 on failure.  If we "failed" because someone else
+   * already had the lock, <errno> is set to <EBUSY>.
+   */
+  virtual int tryacquire_read (void) = 0;
+
+  /**
+   * Conditionally acquire a write lock.  If the locking mechanism
+   * doesn't support read locks then this just calls <acquire>.
+   * Returns -1 on failure.  If we "failed" because someone else
+   * already had the lock, <errno> is set to <EBUSY>.
+   */
+  virtual int tryacquire_write (void) = 0;
+
+  /**
+   * Conditionally try to upgrade a lock held for read to a write lock.
+   * If the locking mechanism doesn't support read locks then this just
+   * calls <acquire>. Returns 0 on success, -1 on failure.
+   */
+  virtual int tryacquire_write_upgrade (void) = 0;
+};
+
+/**
+ * @class ACE_Adaptive_Lock
+ *
+ * @brief An adaptive general locking class that defers the decision of
+ * lock type to run time.
+ *
+ * This class, as ACE_Lock, provide a set of general locking APIs.
+ * However, it defers our decision of what kind of lock to use
+ * to the run time and delegates all locking operations to the actual
+ * lock.  Users must define a constructor in their subclass to
+ * initialize <lock_>.
+ */
+class ACE_Export ACE_Adaptive_Lock : public ACE_Lock
+{
+public:
+  /// You must also override the destructor function to match with how
+  /// you construct the underneath <lock_>.
+  virtual ~ACE_Adaptive_Lock (void);
+
+  // = Lock/unlock operations.
+
+  virtual int remove (void);
+  virtual int acquire (void);
+  virtual int tryacquire (void);
+  virtual int release (void);
+  virtual int acquire_read (void);
+  virtual int acquire_write (void);
+  virtual int tryacquire_read (void);
+  virtual int tryacquire_write (void);
+  virtual int tryacquire_write_upgrade (void);
+  void dump (void) const;
+
+protected:
+  /**
+   * Create and initialize create the actual lcok used in the class.
+   * The default constructor simply set the <lock_> to 0 (null).  You
+   * must overwrite this method for this class to work.
+   */
+  ACE_Adaptive_Lock (void);
+
+  ACE_Lock *lock_;
+};
+
+ACE_END_VERSIONED_NAMESPACE_DECL
+
+#if defined (__ACE_INLINE__)
+#include "ace/Lock.inl"
+#endif /* __ACE_INLINE__ */
+
+#include /**/ "ace/post.h"
+#endif /* ACE_LOCK_H */