src/StoreEntryStream.h

   1
   2 /*
   3  * $Id$
   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) : theEntry(anEntry) {
  52
  53         theEntry->lock();
  54         theEntry->buffer();
  55     }
  56
  57     ~StoreEntryStreamBuf() {
  58         theEntry->unlock();
  59     }
  60
  61 protected:
  62     /* flush the current buffer and the character that is overflowing
  63      * to the store entry.
  64      */
  65     virtual int_type overflow(int_type aChar = traits_type::eof()) {
  66         std::streamsize pending(pptr() - pbase());
  67
  68         if (pending && sync ())
  69             return traits_type::eof();
  70
  71         if (aChar != traits_type::eof()) {
  72             char chars[1] = {aChar};
  73
  74             if (aChar != traits_type::eof())
  75                 theEntry->append(chars, 1);
  76         }
  77
  78         pbump (-pending);  // Reset pptr().
  79         return aChar;
  80     }
  81
  82     /* push the buffer to the store */
  83     virtual int sync() {
  84         std::streamsize pending(pptr() - pbase());
  85
  86         if (pending)
  87             theEntry->append(pbase(), pending);
  88
  89         theEntry->flush();
  90
  91         return 0;
  92     }
  93
  94     /* write multiple characters to the store entry
  95      * - this is an optimisation method.
  96      */
  97     virtual std::streamsize xsputn(const char * chars, std::streamsize number) {
  98         if (number)
  99             theEntry->append(chars, number);
 100
 101         return number;
 102     }
 103
 104 private:
 105     StoreEntry *theEntry;
 106
 107 };
 108
 109 class StoreEntryStream : public std::ostream
 110 {
 111
 112 public:
 113     /* create a stream for writing text etc into theEntry */
 114     // See http://www.codecomments.com/archive292-2005-2-396222.html
 115     StoreEntryStream(StoreEntry *entry): std::ostream(0), theBuffer(entry) {
 116         rdbuf(&theBuffer); // set the buffer to now-initialized theBuffer
 117         clear(); //clear badbit set by calling init(0)
 118     }
 119
 120 private:
 121     StoreEntryStreamBuf theBuffer;
 122 };
 123
 124 #endif /* SQUID_STORE_ENTRY_STREAM_H */