TAO/examples/Content_Server/AMI_Iterator/Iterator_Handler.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file     Iterator_Handler.h
   6  *
   7  *   Header file for the Web_Server::AMI_Content_IteratorHandler
   8  *   implementation.
   9  *
  10  *  @author  Ossama Othman <ossama@uci.edu>
  11  */
  12 //=============================================================================
  13
  14
  15 #ifndef ITERATOR_HANDLER_H
  16 #define ITERATOR_HANDLER_H
  17
  18 #include "ace/FILE_Addr.h"
  19 #include "ace/FILE_IO.h"
  20 #include "Web_ServerS.h"
  21
  22 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  23 # pragma once
  24 #endif /* ACE_LACKS_PRAGMA_ONCE */
  25
  26 class Iterator_Handler
  27   : public virtual POA_Web_Server::AMI_Content_IteratorHandler
  28 {
  29   // = TITLE
  30   //    The AMI reply handler for replies from the Content_Iterator.
  31   //
  32   // = DESCRIPTION
  33   //    This class handles all asynchronously received replies from
  34   //    the Content_Iterator on the server side.  Once a reply is
  35   //    handled, another asynchronous request is made to the
  36   //    Content_Iterator.  This ensures that chunks of data are
  37   //    received in the proper order, and also takes advantage of
  38   //    asyncronous method invocations.
  39
  40   /// Dummy friend class declaration to quiet down a warning.
  41   friend class Iterator_Handler_Friend;
  42
  43 public:
  44   /// Constructor that creates a content iterator corresponding to the
  45   /// name of the file being retrieved from the web server.
  46   Iterator_Handler ();
  47
  48   virtual void next_chunk (CORBA::Boolean pending_data,
  49                    const Web_Server::Chunk_Type & chunk);
  50
  51   virtual void next_chunk_excep (
  52       ::Messaging::ExceptionHolder *)
  53     {}
  54
  55   virtual void destroy ();
  56
  57   virtual void destroy_excep (
  58       ::Messaging::ExceptionHolder *)
  59     {}
  60
  61   /**
  62    * Activate and run this Reply Handler.  The contents (not the
  63    * pointer itself) of the <request_count> parameter will be
  64    * incremented when file retrieval begins, and decremented when file
  65    * retrieval completes.
  66    */
  67   void run (int *request_count,
  68             const char *pathname,
  69             Web_Server::Iterator_Factory_ptr factory);
  70
  71 private:
  72   /// Destructor (private to ensure that Iterator_Handler is allocated
  73   /// on the heap).
  74   ~Iterator_Handler ();
  75
  76   /// Initialize the Content Iterator used to retrieve the file.
  77   void initialize_content_iterator (const char *pathname,
  78                                     Web_Server::Iterator_Factory_ptr factory);
  79
  80   /// Deactivate this reply handler.
  81   void deactivate ();
  82
  83   /// Get the name of the viewer associated with the file being
  84   /// retrieved.
  85   int get_viewer (char *viewer, size_t length);
  86
  87   /// Spawn an external view to display the retrieved file.
  88   int spawn_viewer ();
  89
  90 private:
  91   /// The Addr corresponding to the retrieved file.
  92   ACE_FILE_Addr file_;
  93
  94   /// The object that provides all file related IO operations
  95   /// (e.g. read, write, etc).
  96   ACE_FILE_IO file_io_;
  97
  98   /// The iterator used to obtain individual chunks of data from the
  99   /// web server.
 100   Web_Server::Content_Iterator_var contents_;
 101
 102   /// The metadata associated with the file being retrieved from the
 103   /// web server.
 104   Web_Server::Metadata_Type_var metadata_;
 105
 106   /// The offset from the beginning of the file, the next chunk of data
 107   /// should be read from.
 108   CORBA::ULong offset_;
 109
 110   /// Reference to this Reply Handler's self.
 111   Web_Server::AMI_Content_IteratorHandler_var ami_handler_;
 112
 113   /**
 114    * Pointer to external status monitoring variable. The contents (not
 115    * the pointer itself) of the<pending_data> parameter will be
 116    * decremented when file retrieval has completed.
 117    */
 118   int *request_count_;
 119 };
 120
 121 #endif  /* ITERATOR_HAHNDLER_H */