TAO/tao/Synch_Queued_Message.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file Synch_Queued_Message.h
   6  *
   7  *  @author Carlos O'Ryan <coryan@uci.edu>
   8  */
   9 //=============================================================================
  10
  11 #ifndef TAO_SYNCH_QUEUED_MESSAGE_H
  12 #define TAO_SYNCH_QUEUED_MESSAGE_H
  13
  14 #include /**/ "ace/pre.h"
  15
  16 #include "tao/Queued_Message.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 # pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  23
  24 /**
  25  * @class TAO_Synch_Queued_Message
  26  *
  27  * @brief Specialize TAO_Queued_Message for synchronous requests,
  28  *        i.e. twoways and oneways sent with reliability better than
  29  *        SYNC_NONE.
  30  *
  31  * Reliable requests block the sending thread until the message is
  32  * sent, likewise, the sending thread must be informed if the
  33  * connection is closed or the message times out.
  34  *
  35  * In contrast oneway (and AMI) requests sent with the SYNC_NONE
  36  * policy are simple discarded if the connection fails or they
  37  * timeout.
  38  *
  39  * Another important difference is the management of the data buffer:
  40  * one SYNC_NONE messages the buffer is immediately copied into a
  41  * newly allocated buffer, and must be deallocated.  Other types of
  42  * requests use the memory allocated by the sending thread.
  43  */
  44 class TAO_Export TAO_Synch_Queued_Message : public TAO_Queued_Message
  45 {
  46 public:
  47   /// Constructor
  48   /**
  49    * @param contents The message block chain that must be sent.
  50    *
  51    * @param alloc The allocator that is used to allocate objects of
  52    *        this type.
  53    */
  54   TAO_Synch_Queued_Message (const ACE_Message_Block *contents,
  55                             TAO_ORB_Core *oc,
  56                             ACE_Allocator *alloc = 0,
  57                             bool is_heap_allocated = false);
  58
  59   /// Destructor
  60   virtual ~TAO_Synch_Queued_Message ();
  61
  62   const ACE_Message_Block *current_block () const;
  63
  64   /** @name Implement the Template Methods from TAO_Queued_Message
  65    */
  66   //@{
  67   virtual size_t message_length () const;
  68   virtual int all_data_sent () const;
  69   virtual void fill_iov (int iovcnt_max, int &iovcnt, iovec iov[]) const;
  70   virtual void bytes_transferred (size_t &byte_count);
  71   virtual TAO_Queued_Message *clone (ACE_Allocator *alloc);
  72   virtual void destroy ();
  73   virtual void copy_if_necessary (const ACE_Message_Block* chain);
  74   //@}
  75
  76 private:
  77   /// The contents of the message.
  78   /**
  79    * The message is normally generated by a TAO_OutputCDR stream.  The
  80    * application marshals the payload, possibly generating a chain of
  81    * message block connected via the 'cont()' field.
  82    */
  83   ACE_Message_Block *contents_;
  84
  85   /// The current message block
  86   /**
  87    * The message may be set in multiple writev() operations.  This
  88    * point keeps track of the next message to send out.
  89    */
  90   ACE_Message_Block *current_block_;
  91
  92   /// Do we own the contents_ message block?
  93   /**
  94    * This flag differs from the is_heap_allocated_ flag in that it only
  95    * applies to the contents_ message block and not the
  96    * TAO_Synch_Queued_Message object itself.
  97    */
  98   bool own_contents_;
  99 };
 100
 101 TAO_END_VERSIONED_NAMESPACE_DECL
 102
 103 #include /**/ "ace/post.h"
 104
 105 #endif  /* TAO_QUEUED_MESSAGE_H */