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/* -*- C++ -*- */
/** @file Mem_Map_Stream.h
*
* @author Douglas C. Schmidt <d.schmidt@vanderbilt.edu>
* @author Krishnakumar B <kitty@cs.wustl.edu>
*/
#ifndef _ACEXML_MEM_MAP_STREAM_H
#define _ACEXML_MEM_MAP_STREAM_H
#include /**/ "ace/pre.h"
#include "ACEXML/common/ACEXML_Export.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
#pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#include "ace/SOCK_Stream.h"
#include "ace/Mem_Map.h"
#include "ace/SOCK_Connector.h"
#include "ace/Connector.h"
#include "ace/Svc_Handler.h"
#include "ACEXML/common/XML_Types.h"
typedef ACE_Svc_Handler<ACE_SOCK_STREAM, ACE_NULL_SYNCH> Svc_Handler;
typedef ACE_Connector<Svc_Handler, ACE_SOCK_CONNECTOR> Connector;
/**
* @class ACEXML_Mem_Map_Stream
*
* @brief Provides a memory-mapped stream abstraction to simplify parsing
* of tokens.
*
* This class makes it possible to treat an connection as a stream of
* bytes, similar to the C library stdio streams. The contents of the
* connection are buffered incrementally in a memory-mapped file. This
* class maintains pointers to two positions in the stream:
*
* 1. The <recv> position, which keeps track of the beginning of a
* token that is in the stream.
*
* 2. The <get> position, which moves along character-by-character
* until the end of the token is reached.
*
* Once a token has been located, it can be extracted from the stream by
* calling the <recv>. The length of the token, i.e., the <recv_len>, is
* the length in bytes between the <get> position and the <recv> position.
* Once the token has been extracted, the <recv> and <get> positions can be
* updated by the <seek> method.
*/
class ACEXML_Export ACEXML_Mem_Map_Stream
{
public:
/// Default constructor
ACEXML_Mem_Map_Stream (void);
/// Initialize this object.
virtual int open (Connector *connector,
const ACE_INET_Addr &);
/// Destructor.
virtual ~ACEXML_Mem_Map_Stream (void);
/// Returns the underlying <ACE_SOCK_Stream>.
ACE_SOCK_Stream &stream (void);
/**
* Send <size> bytes in <buf> to the connected peer. This is a
* completely unbuffered call.
*/
virtual ssize_t send_n (const void *buf,
size_t size,
ACE_Time_Value *tv = 0);
/**
* Return the next character in the stream and advance the <get>
* position. Returns EOF when the <get> position reaches the end of the
* HTTP stream.
*/
virtual int get_char (void);
/**
* Returns a pointer to array of at most <len> characters starting at
* the <recv> position. If the <recv> position + <len> extends past the
* EOF then <len> is set to the number of characters between the <recv>
* position and the EOF and both the <get> and <recv> positions are
* advanced by <len>. Returns 0 if the <recv> position is at the EOF.
*/
virtual const char *recv (size_t &len);
/**
* Returns a pointer to array of characters starting at the <recv>
* position.
*/
virtual const char *recv (void) const;
/**
* Returns the length in bytes between the <get> position and the <recv>
* position.
*/
virtual size_t recv_len (void) const;
/**
* Returns the no. of bytes available in the stream.
*/
virtual size_t available (void) const;
/**
* Resets the <get> and <recv> positions to the beginning of the stream.
* This works since all the data has been cached in the memory-mapped
* backing store.
*/
virtual void rewind (void);
/**
* Returns the nth character <offset> from the <get> position in the
* stream without advancing the <get> position. Automatically extends
* the backing store if necessary. Returns EOF if <offset> is past the
* end of the stream.
*/
virtual int peek_char (size_t offset);
/**
* Return a pointer to an array of <size> characters starting at
* <offset> characters from the <get> position in the stream without
* advancing the <get> position. Automatically extends the backing store
* if necessary. Returns 0 if <offset> or <offset + size> is past the
* end of the stream.
*/
virtual const char *peek_str (size_t offset, size_t size);
/**
* Sets the <get> and <recv> positions as follows:
* o If <whence> is <SEEK_SET>, the positions are set to <offset>
* bytes from the start of the stream.
* o If <whence> is <SEEK_CUR>, the positions are set to the
* current <get> position plus <offset>.
* o If <whence> is <SEEK_END>, the positions are set to the size
* of the stream plus <offset>.
*
* If offset is greater than EOF, both <get> and <recv> are set to EOF.
* Note special return value is returned to indicate this condition.
*/
virtual ACE_OFF_T seek (ACE_OFF_T offset, int whence = SEEK_CUR);
/// Returns 1 if we're at the end of the HTTP stream, else 0.
virtual int eof (void) const;
/// Returns the underlying service handler.
Svc_Handler *svc_handler (void);
private:
/**
* Grow the file by reading another chunk from the HTTP socket and
* extend the mapping to cover this chunk. Returns -1 on failure or
* EOF, else 0.
*/
int grow_file_and_remap (void);
/**
* Connection to peer. The granularity is at the Svc_Handler level.
* The Svc_Handler has an SOCK_Stream.
*/
Svc_Handler *svc_handler_;
/// Memory-mapped file that we're iterating over.
ACE_Mem_Map mem_map_;
/// Pointer to the address where the next <recv> method will start.
char *recv_pos_;
/**
* Pointer to the address where the next <get_char> method will
* start.
*/
char *get_pos_;
/// Address at the end of the file mapping.
char *end_of_mapping_plus1_;
};
#include /**/ "ace/post.h"
#endif /* _ACEXML_MEM_MAP_STREAM_H */
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