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();
  61     ~MemObject();
  62
  63     /// sets store ID, log URI, and request method; TODO: find a better name
  64     void setUris(char const *aStoreId, char const *aLogUri, const HttpRequestMethod &aMethod);
  65
  66     /// whether setUris() has been called
  67     bool hasUris() const;
  68
  69     void write(const StoreIOBuffer &buf);
  70     void unlinkRequest();
  71     HttpReply const *getReply() const;
  72     void replaceHttpReply(HttpReply *newrep);
  73     void stat (MemBuf * mb) const;
  74     int64_t endOffset () const;
  75     void markEndOfReplyHeaders(); ///< sets _reply->hdr_sz to endOffset()
  76     /// negative if unknown; otherwise, expected object_sz, expected endOffset
  77     /// maximum, and stored reply headers+body size (all three are the same)
  78     int64_t expectedReplySize() const;
  79     int64_t size() const;
  80     void reset();
  81     int64_t lowestMemReaderOffset() const;
  82     bool readAheadPolicyCanRead() const;
  83     void addClient(store_client *);
  84     /* XXX belongs in MemObject::swapout, once swaphdrsz is managed
  85      * better
  86      */
  87     int64_t objectBytesOnDisk() const;
  88     int64_t policyLowestOffsetToKeep(bool swap) const;
  89     int64_t availableForSwapOut() const; ///< buffered bytes we have not swapped out yet
  90     void trimSwappable();
  91     void trimUnSwappable();
  92     bool isContiguous() const;
  93     int mostBytesWanted(int max, bool ignoreDelayPools) const;
  94     void setNoDelay(bool const newValue);
  95 #if USE_DELAY_POOLS
  96     DelayId mostBytesAllowed() const;
  97 #endif
  98
  99 #if URL_CHECKSUM_DEBUG
 100
 101     void checkUrlChecksum() const;
 102 #endif
 103
 104     /// Before StoreID, code assumed that MemObject stores Request URI.
 105     /// After StoreID, some old code still incorrectly assumes that.
 106     /// Use this method to mark that incorrect assumption.
 107     const char *urlXXX() const { return storeId(); }
 108
 109     /// Entry StoreID (usually just Request URI); if a buggy code requests this
 110     /// before the information is available, returns an "[unknown_URI]" string.
 111     const char *storeId() const;
 112
 113     /// client request URI used for logging; storeId() by default
 114     const char *logUri() const;
 115
 116     HttpRequestMethod method;
 117     mem_hdr data_hdr;
 118     int64_t inmem_lo;
 119     dlink_list clients;
 120
 121     /** \todo move into .cc or .cci */
 122     size_t clientCount() const {return nclients;}
 123
 124     bool clientIsFirst(void *sc) const {return (clients.head && sc == clients.head->data);}
 125
 126     int nclients;
 127
 128     class SwapOut
 129     {
 130
 131     public:
 132         int64_t queue_offset; ///< number of bytes sent to SwapDir for writing
 133         StoreIOState::Pointer sio;
 134
 135         /// Decision states for StoreEntry::swapoutPossible() and related code.
 136         typedef enum { swNeedsCheck = 0, swImpossible = -1, swPossible = +1, swStarted } Decision;
 137         Decision decision; ///< current decision state
 138     };
 139
 140     SwapOut swapout;
 141
 142     /// cache "I/O" direction and status
 143     typedef enum { ioUndecided, ioWriting, ioReading, ioDone } Io;
 144
 145     /// State of an entry with regards to the [shared] in-transit table.
 146     class XitTable {
 147     public:
 148         XitTable(): index(-1), io(ioUndecided) {}
 149
 150         int32_t index; ///< entry position inside the in-transit table
 151         Io io; ///< current I/O state
 152     };
 153     XitTable xitTable; ///< current [shared] memory caching state for the entry
 154
 155     /// State of an entry with regards to the [shared] memory caching.
 156     class MemCache {
 157     public:
 158         MemCache(): index(-1), offset(0), io(ioUndecided) {}
 159
 160         int32_t index; ///< entry position inside the memory cache
 161         int64_t offset; ///< bytes written/read to/from the memory cache so far
 162
 163         Io io; ///< current I/O state
 164     };
 165     MemCache memCache; ///< current [shared] memory caching state for the entry
 166
 167     bool smpCollapsed; ///< whether this entry gets data from another worker
 168
 169     /* Read only - this reply must be preserved by store clients */
 170     /* The original reply. possibly with updated metadata. */
 171     HttpRequest *request;
 172
 173     struct timeval start_ping;
 174     IRCB *ping_reply_callback;
 175     void *ircb_data;
 176
 177     struct {
 178         STABH *callback;
 179         void *data;
 180     } abort;
 181     RemovalPolicyNode repl;
 182     int id;
 183     int64_t object_sz;
 184     size_t swap_hdr_sz;
 185 #if URL_CHECKSUM_DEBUG
 186
 187     unsigned int chksum;
 188 #endif
 189
 190     const char *vary_headers;
 191
 192     void delayRead(DeferredRead const &);
 193     void kickReads();
 194
 195 private:
 196     HttpReply *_reply;
 197
 198     mutable String storeId_; ///< StoreId for our entry (usually request URI)
 199     mutable String logUri_;  ///< URI used for logging (usually request URI)
 200
 201     DeferredReadManager deferredReads;
 202 };
 203
 204 MEMPROXY_CLASS_INLINE(MemObject);
 205
 206 /** global current memory removal policy */
 207 extern RemovalPolicy *mem_policy;
 208
 209 #endif /* SQUID_MEMOBJECT_H */