src/StoreEntryStream.h

   1 /*
   2  *
   3  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   4  * ----------------------------------------------------------
   5  *
   6  *  Squid is the result of efforts by numerous individuals from
   7  *  the Internet community; see the CONTRIBUTORS file for full
   8  *  details.   Many organizations have provided support for Squid's
   9  *  development; see the SPONSORS file for full details.  Squid is
  10  *  Copyrighted (C) 2001 by the Regents of the University of
  11  *  California; see the COPYRIGHT file for full details.  Squid
  12  *  incorporates software developed and/or copyrighted by other
  13  *  sources; see the CREDITS file for full details.
  14  *
  15  *  This program is free software; you can redistribute it and/or modify
  16  *  it under the terms of the GNU General Public License as published by
  17  *  the Free Software Foundation; either version 2 of the License, or
  18  *  (at your option) any later version.
  19  *
  20  *  This program is distributed in the hope that it will be useful,
  21  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  *  GNU General Public License for more details.
  24  *
  25  *  You should have received a copy of the GNU General Public License
  26  *  along with this program; if not, write to the Free Software
  27  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  28  *
  29  */
  30
  31 #ifndef SQUID_STORE_ENTRY_STREAM_H
  32 #define SQUID_STORE_ENTRY_STREAM_H
  33
  34 #include "Store.h"
  35
  36 #if HAVE_OSTREAM
  37 #include <ostream>
  38 #endif
  39
  40 /*
  41  * This class provides a streambuf interface for writing
  42  * to StoreEntries. Typical use is via a StoreEntryStream
  43  * rather than direct manipulation
  44  */
  45
  46 class StoreEntryStreamBuf : public std::streambuf
  47 {
  48
  49 public:
  50     StoreEntryStreamBuf(StoreEntry *anEntry) : theEntry(anEntry) {
  51         theEntry->lock("StoreEntryStreamBuf");
  52         theEntry->buffer();
  53     }
  54
  55     ~StoreEntryStreamBuf() {
  56         theEntry->unlock("StoreEntryStreamBuf");
  57     }
  58
  59 protected:
  60     /* flush the current buffer and the character that is overflowing
  61      * to the store entry.
  62      */
  63     virtual int_type overflow(int_type aChar = traits_type::eof()) {
  64         std::streamsize pending(pptr() - pbase());
  65
  66         if (pending && sync ())
  67             return traits_type::eof();
  68
  69         if (aChar != traits_type::eof()) {
  70             // NP: cast because GCC promotes int_type to 32-bit type
  71             //     std::basic_streambuf<char>::int_type {aka int}
  72             //     despite the definition with 8-bit type value.
  73             char chars[1] = {char(aChar)};
  74
  75             if (aChar != traits_type::eof())
  76                 theEntry->append(chars, 1);
  77         }
  78
  79         pbump (-pending);  // Reset pptr().
  80         return aChar;
  81     }
  82
  83     /* push the buffer to the store */
  84     virtual int sync() {
  85         std::streamsize pending(pptr() - pbase());
  86
  87         if (pending)
  88             theEntry->append(pbase(), pending);
  89
  90         theEntry->flush();
  91
  92         return 0;
  93     }
  94
  95     /* write multiple characters to the store entry
  96      * - this is an optimisation method.
  97      */
  98     virtual std::streamsize xsputn(const char * chars, std::streamsize number) {
  99         if (number)
 100             theEntry->append(chars, number);
 101
 102         return number;
 103     }
 104
 105 private:
 106     StoreEntry *theEntry;
 107
 108 };
 109
 110 class StoreEntryStream : public std::ostream
 111 {
 112
 113 public:
 114     /* create a stream for writing text etc into theEntry */
 115     // See http://www.codecomments.com/archive292-2005-2-396222.html
 116     StoreEntryStream(StoreEntry *entry): std::ostream(0), theBuffer(entry) {
 117         rdbuf(&theBuffer); // set the buffer to now-initialized theBuffer
 118         clear(); //clear badbit set by calling init(0)
 119     }
 120
 121 private:
 122     StoreEntryStreamBuf theBuffer;
 123 };
 124
 125 #endif /* SQUID_STORE_ENTRY_STREAM_H */