TAO/tao/Incoming_Message_Queue.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file Incoming_Message_Queue.h
   6  *
   7  *  @author Balachandran Natarajan <bala@cs.wustl.edu>
   8  */
   9 //=============================================================================
  10
  11 #ifndef TAO_INCOMING_MESSAGE_QUEUE_H
  12 #define TAO_INCOMING_MESSAGE_QUEUE_H
  13
  14 #include /**/ "ace/pre.h"
  15
  16 #include "tao/Pluggable_Messaging_Utils.h"
  17 #include "ace/Message_Block.h"
  18
  19 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  20 # pragma once
  21 #endif /* ACE_LACKS_PRAGMA_ONCE */
  22
  23 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  24
  25 class TAO_ORB_Core;
  26 class TAO_Queued_Data;
  27 class TAO_Transport;
  28
  29 /**
  30  * @class TAO_Incoming_Message_Queue
  31  *
  32  * @brief A queue of the messages in the incoming data path.
  33  *
  34  * Please read the documentation in the TAO_Transport class to find
  35  * out more about the design of the incoming data path.
  36  *
  37  * Under certain conditions TAO may have to maintain a queue
  38  * per-connection. This queue is drained by the pluggable
  39  * protocols framework, normally under control of the ACE_Reactor, but
  40  * other configurations are conceivable.
  41  *
  42  * The memory that is allocated for holding the messages comes from
  43  * the global pool for the following reasons
  44  *
  45  * - the thread that reads a part of the message would not be the same
  46  *   thread that reads and fills the rest of the message
  47  * - the thread that actually processes the message can be totally
  48  *   different.
  49  */
  50 class TAO_Export TAO_Incoming_Message_Queue
  51 {
  52 public:
  53   /// Constructor.
  54   TAO_Incoming_Message_Queue (TAO_ORB_Core *orb_core);
  55
  56   /// Destructor.
  57   ~TAO_Incoming_Message_Queue ();
  58
  59   /// Adding and deleting a node from the queue.
  60   TAO_Queued_Data *dequeue_head ();
  61   TAO_Queued_Data *dequeue_tail ();
  62   int enqueue_tail (TAO_Queued_Data *nd);
  63
  64   /// Return the length of the queue..
  65   CORBA::ULong queue_length () const;
  66
  67 private:
  68   friend class TAO_Transport;
  69
  70 private:
  71   /*!
  72     \brief A circular linked list of messages awaiting processing.
  73
  74     \a last_message_added_ points to the most recent message added to
  75     the list.  The earliest addition can be easily accessed via
  76     \a last_message_added_->next_.
  77    */
  78   TAO_Queued_Data *last_added_;
  79
  80   /// The size of the queue
  81   CORBA::ULong size_;
  82
  83   /// Copy of our ORB Core
  84   TAO_ORB_Core *orb_core_;
  85 };
  86
  87 /// Constant value indicating that the correct value is unknown yet,
  88 /// probably parsing the header failed due to insufficient data in buffer.
  89 const size_t TAO_MISSING_DATA_UNDEFINED = ~((size_t) 0); // MAX_SIZE_T
  90
  91 TAO_END_VERSIONED_NAMESPACE_DECL
  92
  93 #if defined (__ACE_INLINE__)
  94 # include "tao/Incoming_Message_Queue.inl"
  95 #endif /* __ACE_INLINE__ */
  96
  97 #include /**/ "ace/post.h"
  98 #endif /*TAO_INCOMING_MESSAGE_QUEUE_H*/