ChangeLogTag:Fri Dec 8 10:34:32 2000 Douglas C. Schmidt <schmidt@ace.cs.wustl.edu>

1 files changed, 174 insertions, 0 deletions

diff --git a/ace/Refcounted_Auto_Ptr.h b/ace/Refcounted_Auto_Ptr.h
new file mode 100644
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+++ b/ace/Refcounted_Auto_Ptr.h
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+/* -*- C++ -*- */
+
+//=============================================================================
+/**
+ *  @file    Refcounted_Auto_Ptr.h
+ *
+ *  $Id$
+ *
+ *  @author John Tucker <JTucker@infoglide.com>
+ */
+//=============================================================================
+
+
+#ifndef ACE_REFCOUNTED_AUTO_PTR_H
+#define ACE_REFCOUNTED_AUTO_PTR_H
+#include "ace/pre.h"
+
+#include "ace/OS.h"
+
+#if !defined (ACE_LACKS_PRAGMA_ONCE)
+# pragma once
+#endif /* ACE_LACKS_PRAGMA_ONCE */
+
+// Forward decl.
+template <class X, class ACE_LOCK> class ACE_Refcounted_Auto_Ptr_Rep;
+template <class X, class ACE_LOCK> class ACE_Refcounted_Auto_Ptr;
+
+/**
+ * @class ACE_Refcounted_Auto_Ptr
+ *
+ * @brief This class implements support for a reference counted auto_ptr.
+ * Assigning or copying instances of an ACE_Refcounted_Auto_Ptr
+ * will automatically increment the reference count. When the last
+ * instance that references a ACE_Refcounted_Auto_Ptr instance is
+ * destroyed or overwritten, it will invoke delete on its underlying
+ * pointer.
+ */
+template <class X, class ACE_LOCK>
+class ACE_Refcounted_Auto_Ptr
+{
+public:
+
+  // = Initialization and termination methods.
+
+  /// Constructor that initializes an <ACE_Refcounted_Auto_Ptr> to
+  /// point to the result <r> immediately.
+  ACE_Refcounted_Auto_Ptr (X *p = 0);
+
+  /// Copy constructor binds <this> and <r> to the same 
+  /// <ACE_Refcounted_Auto_Ptr_Rep>. An <ACE_Refcounted_Auto_Ptr_Rep> 
+  /// is created if necessary.
+  ACE_Refcounted_Auto_Ptr (const ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> &r);
+
+  /// Destructor.
+  ~ACE_Refcounted_Auto_Ptr (void);
+
+  /// Assignment operator that binds <this> and <r> to the same 
+  /// <ACE_Refcounted_Auto_Ptr_Rep>. An <ACE_Refcounted_Auto_Ptr_Rep> 
+  /// is created if necessary.
+  void operator = (const ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> &r);
+
+  /// Equality operator that returns 1 if both 
+  /// ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> objects point to the same 
+  /// ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> object.  Attention: It 
+  /// also returns 1 if both objects have just been instantiated and 
+  /// not used yet.
+  int operator == (const ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> &r) const;
+
+  /// Inequality operator, which is the opposite of equality.
+  int operator != (const ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> &r) const;
+
+  /// Redirection operator
+  X *operator-> (void) const;
+
+  // = Accessor methods.
+
+  X &operator *() const;
+
+  /// Sets the pointer value to 0 and returns its old value.
+  X *release (void);
+  
+  /// Invokes delete on the previous pointer value and then sets the
+  /// pointer value to the specified value.
+  void reset (X *p = 0);
+
+  /// Get the pointer value.
+  X *get (void);
+
+  /// Declare the dynamic allocation hooks.
+  ACE_ALLOC_HOOK_DECLARE;
+
+private:
+  /// the ACE_Refcounted_Auto_Ptr_Rep
+  typedef ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> AUTO_REFCOUNTED_PTR_REP;
+
+  /// Protect operations on the <ACE_Refcounted_Auto_Ptr>.
+  AUTO_REFCOUNTED_PTR_REP *rep_;
+};
+
+/**
+ * @class ACE_Refcounted_Auto_Ptr_Rep
+ *
+ * @brief An ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> object
+ * incapsulates a pointer to an object of type X.  It is pointed to by
+ * ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> object[s] and only accessible
+ * through them. 
+ */
+template <class X, class ACE_LOCK>
+class ACE_Refcounted_Auto_Ptr_Rep
+{
+private:
+  friend class ACE_Refcounted_Auto_Ptr<X, ACE_LOCK>;
+
+  /// Sets the pointer value to 0 and returns its old value.
+  X *release (void);
+
+  /// Invokes delete on the previous pointer value and then
+  /// sets the pointer value to the specified value.
+  void reset (X *p = 0);
+
+  /// Get the pointer value.
+  X *get (void);
+
+  /// Declare the dynamic allocation hooks.
+  ACE_ALLOC_HOOK_DECLARE;
+
+  // = Encapsulate reference count and object lifetime of instances.
+  // These methods must go after the others to work around a bug with
+  // Borland's C++ Builder...
+
+  /// Create a ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> and initialize
+  /// the reference count.
+  static ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *create (X *p);
+
+  /// Increase the reference count and return argument. Uses the
+  /// attribute "ace_lock_" to synchronize reference count updating.
+  ///
+  /// Precondition (rep != 0).
+  static ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *attach (ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *&rep);
+
+  /// Decreases the reference count and and deletes rep if there are no
+  /// more references to rep.
+  ///
+  /// Precondition (rep != 0)
+  static void detach (ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *&rep);
+
+  /// Decreases the rep's reference count and and deletes rep if there
+  /// are no more references to rep. Then assigns new_rep to rep.
+  ///
+  /// Precondition (rep != 0 && new_rep != 0)
+  static void assign (ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *&rep,
+                      ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *new_rep);
+
+  /// Pointer to the result.
+  ACE_Auto_Basic_Ptr<X> ptr_;
+
+  /// Reference count.
+  int ref_count_;
+
+  // = Mutex variable to protect the <ptr_>.
+
+  /// Synchronization variable for the MT_SAFE <ACE_Hash_Map_Manager_Ex>.
+  ACE_LOCK lock_;
+
+private:
+  // = Constructor and destructor private.
+  ACE_Refcounted_Auto_Ptr_Rep (X *p = 0);
+  ~ACE_Refcounted_Auto_Ptr_Rep (void);
+};
+
+#include "ace/Refcounted_Auto_Ptr.i"
+
+#include "ace/post.h"
+#endif /* ACE_AUTO_PTR_H */