src/StoreEntryStream.h

   1
   2 /*
   3  * $Id: StoreEntryStream.h,v 1.1 2006/05/03 14:04:44 robertc Exp $
   4  *
   5  *
   6  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   7  * ----------------------------------------------------------
   8  *
   9  *  Squid is the result of efforts by numerous individuals from
  10  *  the Internet community; see the CONTRIBUTORS file for full
  11  *  details.   Many organizations have provided support for Squid's
  12  *  development; see the SPONSORS file for full details.  Squid is
  13  *  Copyrighted (C) 2001 by the Regents of the University of
  14  *  California; see the COPYRIGHT file for full details.  Squid
  15  *  incorporates software developed and/or copyrighted by other
  16  *  sources; see the CREDITS file for full details.
  17  *
  18  *  This program is free software; you can redistribute it and/or modify
  19  *  it under the terms of the GNU General Public License as published by
  20  *  the Free Software Foundation; either version 2 of the License, or
  21  *  (at your option) any later version.
  22  *
  23  *  This program is distributed in the hope that it will be useful,
  24  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  25  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  26  *  GNU General Public License for more details.
  27  *
  28  *  You should have received a copy of the GNU General Public License
  29  *  along with this program; if not, write to the Free Software
  30  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  31  *
  32  */
  33
  34 #ifndef SQUID_STORE_ENTRY_STREAM_H
  35 #define SQUID_STORE_ENTRY_STREAM_H
  36
  37 #include "Store.h"
  38
  39 #include <ostream>
  40
  41 /*
  42  * This class provides a streambuf interface for writing
  43  * to StoreEntries. Typical use is via a StoreEntryStream
  44  * rather than direct manipulation
  45  */
  46
  47 class StoreEntryStreamBuf : public std::streambuf
  48 {
  49
  50 public:
  51     StoreEntryStreamBuf(StoreEntry *anEntry) : anEntry(anEntry)
  52     {
  53
  54         anEntry->lock()
  55
  56         ;
  57         anEntry->buffer();
  58     }
  59
  60     ~StoreEntryStreamBuf()
  61     {
  62         anEntry->unlock();
  63     }
  64
  65 protected:
  66     /* flush the current buffer and the character that is overflowing
  67      * to the store entry.
  68      */
  69     virtual char overflow(char aChar = traits_type::eof())
  70     {
  71         std::streamsize pending(pptr() - pbase());
  72
  73         if (pending && sync ())
  74             return traits_type::eof();
  75
  76         if (aChar != traits_type::eof()) {
  77             char chars[1] = {aChar};
  78
  79             if (aChar != traits_type::eof())
  80                 anEntry->append(chars, 1);
  81         }
  82
  83         pbump (-pending);  // Reset pptr().
  84         return aChar;
  85     }
  86
  87     /* push the buffer to the store */
  88     virtual int sync()
  89     {
  90         std::streamsize pending(pptr() - pbase());
  91
  92         if (pending)
  93             anEntry->append(pbase(), pending);
  94
  95         anEntry->flush();
  96
  97         return 0;
  98     }
  99
 100     /* write multiple characters to the store entry
 101      * - this is an optimisation method.
 102      */
 103     virtual std::streamsize xsputn(const char * chars, std::streamsize number)
 104     {
 105         if (number)
 106             anEntry->append(chars, number);
 107
 108         return number;
 109     }
 110
 111 private:
 112     StoreEntry *anEntry;
 113
 114 };
 115
 116 class StoreEntryStream : public std::ostream
 117 {
 118
 119 public:
 120     /* create a stream for writing text etc into anEntry */
 121     StoreEntryStream(StoreEntry *anEntry) : _buffer(anEntry) { this->init(&_buffer);}
 122
 123 private:
 124     StoreEntryStreamBuf _buffer;
 125
 126 public:
 127     StoreEntryStreamBuf * rdbuf() const { return const_cast<StoreEntryStreamBuf *>(&_buffer); }
 128 };
 129
 130 #endif /* SQUID_STORE_ENTRY_STREAM_H */