src/MemObject.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_MEMOBJECT_H
  32 #define SQUID_MEMOBJECT_H
  33
  34 #include "CommRead.h"
  35 #include "dlink.h"
  36 #include "HttpRequestMethod.h"
  37 #include "RemovalPolicy.h"
  38 #include "stmem.h"
  39 #include "StoreIOBuffer.h"
  40 #include "StoreIOState.h"
  41
  42 #if USE_DELAY_POOLS
  43 #include "DelayId.h"
  44 #endif
  45
  46 typedef void STMCB (void *data, StoreIOBuffer wroteBuffer);
  47
  48 class store_client;
  49 class HttpRequest;
  50 class HttpReply;
  51
  52 class MemObject
  53 {
  54
  55 public:
  56     static size_t inUseCount();
  57     MEMPROXY_CLASS(MemObject);
  58
  59     void dump() const;
  60     MemObject(char const *, char const *);
  61     ~MemObject();
  62
  63     /// replaces construction-time URLs with correct ones; see hidden_mem_obj
  64     void resetUrls(char const *aUrl, char const *aLog_url);
  65
  66     void write(StoreIOBuffer, STMCB *, void *);
  67     void unlinkRequest();
  68     HttpReply const *getReply() const;
  69     void replaceHttpReply(HttpReply *newrep);
  70     void stat (MemBuf * mb) const;
  71     int64_t endOffset () const;
  72     void markEndOfReplyHeaders(); ///< sets _reply->hdr_sz to endOffset()
  73     /// negative if unknown; otherwise, expected object_sz, expected endOffset
  74     /// maximum, and stored reply headers+body size (all three are the same)
  75     int64_t expectedReplySize() const;
  76     int64_t size() const;
  77     void reset();
  78     int64_t lowestMemReaderOffset() const;
  79     bool readAheadPolicyCanRead() const;
  80     void addClient(store_client *);
  81     /* XXX belongs in MemObject::swapout, once swaphdrsz is managed
  82      * better
  83      */
  84     int64_t objectBytesOnDisk() const;
  85     int64_t policyLowestOffsetToKeep(bool swap) const;
  86     int64_t availableForSwapOut() const; ///< buffered bytes we have not swapped out yet
  87     void trimSwappable();
  88     void trimUnSwappable();
  89     bool isContiguous() const;
  90     int mostBytesWanted(int max, bool ignoreDelayPools) const;
  91     void setNoDelay(bool const newValue);
  92 #if USE_DELAY_POOLS
  93     DelayId mostBytesAllowed() const;
  94 #endif
  95
  96 #if URL_CHECKSUM_DEBUG
  97
  98     void checkUrlChecksum() const;
  99 #endif
 100
 101     HttpRequestMethod method;
 102     char *url;
 103     mem_hdr data_hdr;
 104     int64_t inmem_lo;
 105     dlink_list clients;
 106
 107     /** \todo move into .cc or .cci */
 108     size_t clientCount() const {return nclients;}
 109
 110     bool clientIsFirst(void *sc) const {return (clients.head && sc == clients.head->data);}
 111
 112     int nclients;
 113
 114     class SwapOut
 115     {
 116
 117     public:
 118         int64_t queue_offset; ///< number of bytes sent to SwapDir for writing
 119         StoreIOState::Pointer sio;
 120
 121         /// Decision states for StoreEntry::swapoutPossible() and related code.
 122         typedef enum { swNeedsCheck = 0, swImpossible = -1, swPossible = +1 } Decision;
 123         Decision decision; ///< current decision state
 124     };
 125
 126     SwapOut swapout;
 127
 128     /* Read only - this reply must be preserved by store clients */
 129     /* The original reply. possibly with updated metadata. */
 130     HttpRequest *request;
 131
 132     struct timeval start_ping;
 133     IRCB *ping_reply_callback;
 134     void *ircb_data;
 135
 136     struct {
 137         STABH *callback;
 138         void *data;
 139     } abort;
 140     char *log_url;
 141     RemovalPolicyNode repl;
 142     int id;
 143     int64_t object_sz;
 144     size_t swap_hdr_sz;
 145 #if URL_CHECKSUM_DEBUG
 146
 147     unsigned int chksum;
 148 #endif
 149
 150     const char *vary_headers;
 151
 152     void delayRead(DeferredRead const &);
 153     void kickReads();
 154
 155 private:
 156     HttpReply *_reply;
 157
 158     DeferredReadManager deferredReads;
 159 };
 160
 161 MEMPROXY_CLASS_INLINE(MemObject);
 162
 163 /** global current memory removal policy */
 164 extern RemovalPolicy *mem_policy;
 165
 166 #endif /* SQUID_MEMOBJECT_H */