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+/* -*- C++ -*- */
+
+//=============================================================================
+/**
+ *  @file    Dump.h
+ *
+ *  $Id$
+ *
+ *
+ * A prototype mechanism that allow all ACE objects to be registered
+ * with a central in-memory "database" that can dump the state of all
+ * live ACE objects (e.g., from within a debugger).
+ *
+ * The macros which allow easy registration and removal of objects to be
+ * dumped (ACE_REGISTER_OBJECT and ACE_REMOVE_OBJECT) are turned into
+ * no-ops by compiling with the ACE_NDEBUG macro defined. This allows
+ * usage to be removed in "release mode" builds without changing code.
+ *
+ * There are several interesting aspects to this design:
+ *
+ * 1. It uses the External Polymorphism pattern to avoid having to
+ *  derive all ACE classes from a common base class that has virtual
+ *  methods (this is crucial to avoid unnecessary overhead).  In
+ *  addition, there is no additional space added to ACE objects
+ *  (this is crucial to maintain binary layout compatibility).
+ *
+ * 2. This mechanism can be conditionally compiled in order to
+ *  completely disable this feature entirely.  Moreover, by
+ *  using macros there are relatively few changes to ACE code.
+ *
+ * 3. This mechanism copes with single-inheritance hierarchies of
+ *  dumpable classes.  In such cases we typically want only one
+ *  dump, corresponding to the most derived instance.  Thanks to
+ *  Christian Millour (chris@etca.fr) for illustrating how to do
+ *  this.  Note, however, that this scheme doesn't generalize to
+ *  work with multiple-inheritance or virtual base classes.
+ *
+ * Future work includes:
+ *
+ * 1. Using a dynamic object table rather than a static table
+ *
+ * 2. Adding support to allow particular classes of objects to
+ *  be selectively dumped.
+ *
+ *
+ *  @author Doug Schmidt
+ */
+//=============================================================================
+
+
+#ifndef ACE_DUMP_H
+#define ACE_DUMP_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_Dumpable
+ *
+ * @brief Base class that defines a uniform interface for all object
+ * dumping.
+ */
+class ACE_Export ACE_Dumpable
+{
+public:
+  friend class ACE_ODB;
+  friend class ACE_Dumpable_Ptr;
+
+  /// Constructor.
+  ACE_Dumpable (const void *);
+
+  /// This pure virtual method must be filled in by a subclass.
+  virtual void dump (void) const = 0;
+
+protected:
+  virtual ~ACE_Dumpable (void);
+
+private:
+  /// Pointer to the object that is being stored.
+  const void *this_;
+};
+
+/**
+ * @class ACE_Dumpable_Ptr
+ *
+ * @brief A smart pointer stored in the in-memory object database
+ * ACE_ODB.  The pointee (if any) is deleted when reassigned.
+ */
+class ACE_Export ACE_Dumpable_Ptr
+{
+public:
+  ACE_Dumpable_Ptr (const ACE_Dumpable *dumper = 0);
+  const ACE_Dumpable *operator->() const;
+  void operator= (const ACE_Dumpable *dumper) const;
+
+private:
+  /// "Real" pointer to the underlying abstract base class
+  /// pointer that does the real work.
+  const ACE_Dumpable *dumper_;
+};
+
+/**
+ * @class ACE_ODB
+ *
+ * @brief This is the object database (ODB) that keeps track of all
+ * live ACE objects.
+ */
+class ACE_Export ACE_ODB
+{
+public:
+  /// @todo This is clearly inadequate and should be dynamic...
+  enum {MAX_TABLE_SIZE = 100000};
+
+  /// Iterates through the entire set of registered objects and
+  /// dumps their state.
+  void dump_objects (void);
+
+  /// Add the tuple <dumper, this_> to the list of registered ACE objects.
+  void register_object (const ACE_Dumpable *dumper);
+
+  /// Use <this_> to locate and remove the associated <dumper> from the
+  /// list of registered ACE objects.
+  void remove_object (const void *this_);
+
+  /// Interface to the Singleton instance of the object database.
+  static ACE_ODB *instance (void);
+
+private:
+  ACE_ODB (void); // Ensure we have a Singleton...
+
+  struct Tuple
+  {
+    /// Pointer to the object that is registered.
+    const void *this_;
+
+    /// Smart pointer to the ACE_Dumpable object associated with this_.
+    /// This uses an ACE_Dumpable_Ptr, instead of a bare pointer, to
+    /// cope with hierarchies of dumpable classes.  In such cases we
+    /// typically want only one dump, corresponding to the most derived
+    /// instance. To achieve this, the handle registered for the
+    /// subobject corresponding to the base class is destroyed (hence
+    /// on destruction of the subobject its handle won't exist anymore
+    /// and we'll have to check for that).
+    const ACE_Dumpable_Ptr dumper_;
+
+    Tuple (void) : dumper_(0) {}
+  };
+
+  /// Singleton instance of this class.
+  static ACE_ODB *instance_;
+
+  /// The current implementation is very simple-minded and will be
+  /// changed to be dynamic.
+  Tuple object_table_[ACE_ODB::MAX_TABLE_SIZE];
+
+  /// Current size of <object_table_>.
+  int current_size_;
+};
+
+ACE_END_VERSIONED_NAMESPACE_DECL
+
+// Include the templates classes at this point.
+#include "ace/Dump_T.h"
+
+#include /**/ "ace/post.h"
+#endif /* ACE_DUMP_H */