src/MemObject.h

   1 /*
   2  * Copyright (C) 1996-2014 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_MEMOBJECT_H
  10 #define SQUID_MEMOBJECT_H
  11
  12 #include "CommRead.h"
  13 #include "dlink.h"
  14 #include "http/RequestMethod.h"
  15 #include "RemovalPolicy.h"
  16 #include "stmem.h"
  17 #include "StoreIOBuffer.h"
  18 #include "StoreIOState.h"
  19
  20 #if USE_DELAY_POOLS
  21 #include "DelayId.h"
  22 #endif
  23
  24 typedef void STMCB (void *data, StoreIOBuffer wroteBuffer);
  25
  26 class store_client;
  27 class HttpRequest;
  28 class HttpReply;
  29
  30 class MemObject
  31 {
  32     MEMPROXY_CLASS(MemObject);
  33
  34 public:
  35     static size_t inUseCount();
  36
  37     void dump() const;
  38     MemObject();
  39     ~MemObject();
  40
  41     /// sets store ID, log URI, and request method; TODO: find a better name
  42     void setUris(char const *aStoreId, char const *aLogUri, const HttpRequestMethod &aMethod);
  43
  44     /// whether setUris() has been called
  45     bool hasUris() const;
  46
  47     void write(const StoreIOBuffer &buf);
  48     void unlinkRequest();
  49     HttpReply const *getReply() const;
  50     void replaceHttpReply(HttpReply *newrep);
  51     void stat (MemBuf * mb) const;
  52     int64_t endOffset () const;
  53     void markEndOfReplyHeaders(); ///< sets _reply->hdr_sz to endOffset()
  54     /// negative if unknown; otherwise, expected object_sz, expected endOffset
  55     /// maximum, and stored reply headers+body size (all three are the same)
  56     int64_t expectedReplySize() const;
  57     int64_t size() const;
  58     void reset();
  59     int64_t lowestMemReaderOffset() const;
  60     bool readAheadPolicyCanRead() const;
  61     void addClient(store_client *);
  62     /* XXX belongs in MemObject::swapout, once swaphdrsz is managed
  63      * better
  64      */
  65     int64_t objectBytesOnDisk() const;
  66     int64_t policyLowestOffsetToKeep(bool swap) const;
  67     int64_t availableForSwapOut() const; ///< buffered bytes we have not swapped out yet
  68     void trimSwappable();
  69     void trimUnSwappable();
  70     bool isContiguous() const;
  71     int mostBytesWanted(int max, bool ignoreDelayPools) const;
  72     void setNoDelay(bool const newValue);
  73 #if USE_DELAY_POOLS
  74     DelayId mostBytesAllowed() const;
  75 #endif
  76
  77 #if URL_CHECKSUM_DEBUG
  78
  79     void checkUrlChecksum() const;
  80 #endif
  81
  82     /// Before StoreID, code assumed that MemObject stores Request URI.
  83     /// After StoreID, some old code still incorrectly assumes that.
  84     /// Use this method to mark that incorrect assumption.
  85     const char *urlXXX() const { return storeId(); }
  86
  87     /// Entry StoreID (usually just Request URI); if a buggy code requests this
  88     /// before the information is available, returns an "[unknown_URI]" string.
  89     const char *storeId() const;
  90
  91     /// client request URI used for logging; storeId() by default
  92     const char *logUri() const;
  93
  94     HttpRequestMethod method;
  95     mem_hdr data_hdr;
  96     int64_t inmem_lo;
  97     dlink_list clients;
  98
  99     /** \todo move into .cc or .cci */
 100     size_t clientCount() const {return nclients;}
 101
 102     bool clientIsFirst(void *sc) const {return (clients.head && sc == clients.head->data);}
 103
 104     int nclients;
 105
 106     class SwapOut
 107     {
 108
 109     public:
 110         int64_t queue_offset; ///< number of bytes sent to SwapDir for writing
 111         StoreIOState::Pointer sio;
 112
 113         /// Decision states for StoreEntry::swapoutPossible() and related code.
 114         typedef enum { swNeedsCheck = 0, swImpossible = -1, swPossible = +1, swStarted } Decision;
 115         Decision decision; ///< current decision state
 116     };
 117
 118     SwapOut swapout;
 119
 120     /// cache "I/O" direction and status
 121     typedef enum { ioUndecided, ioWriting, ioReading, ioDone } Io;
 122
 123     /// State of an entry with regards to the [shared] in-transit table.
 124     class XitTable
 125     {
 126     public:
 127         XitTable(): index(-1), io(ioUndecided) {}
 128
 129         int32_t index; ///< entry position inside the in-transit table
 130         Io io; ///< current I/O state
 131     };
 132     XitTable xitTable; ///< current [shared] memory caching state for the entry
 133
 134     /// State of an entry with regards to the [shared] memory caching.
 135     class MemCache
 136     {
 137     public:
 138         MemCache(): index(-1), offset(0), io(ioUndecided) {}
 139
 140         int32_t index; ///< entry position inside the memory cache
 141         int64_t offset; ///< bytes written/read to/from the memory cache so far
 142
 143         Io io; ///< current I/O state
 144     };
 145     MemCache memCache; ///< current [shared] memory caching state for the entry
 146
 147     bool smpCollapsed; ///< whether this entry gets data from another worker
 148
 149     /* Read only - this reply must be preserved by store clients */
 150     /* The original reply. possibly with updated metadata. */
 151     HttpRequest *request;
 152
 153     struct timeval start_ping;
 154     IRCB *ping_reply_callback;
 155     void *ircb_data;
 156
 157     struct {
 158         STABH *callback;
 159         void *data;
 160     } abort;
 161     RemovalPolicyNode repl;
 162     int id;
 163     int64_t object_sz;
 164     size_t swap_hdr_sz;
 165 #if URL_CHECKSUM_DEBUG
 166
 167     unsigned int chksum;
 168 #endif
 169
 170     const char *vary_headers;
 171
 172     void delayRead(DeferredRead const &);
 173     void kickReads();
 174
 175 private:
 176     HttpReply *_reply;
 177
 178     mutable String storeId_; ///< StoreId for our entry (usually request URI)
 179     mutable String logUri_;  ///< URI used for logging (usually request URI)
 180
 181     DeferredReadManager deferredReads;
 182 };
 183
 184 /** global current memory removal policy */
 185 extern RemovalPolicy *mem_policy;
 186
 187 #endif /* SQUID_MEMOBJECT_H */
 188