src/MemObject.h

   1 /*
   2  * Copyright (C) 1996-2016 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 "SquidString.h"
  17 #include "stmem.h"
  18 #include "StoreIOBuffer.h"
  19 #include "StoreIOState.h"
  20 #include "typedefs.h" //for IRCB
  21
  22 #if USE_DELAY_POOLS
  23 #include "DelayId.h"
  24 #endif
  25
  26 typedef void STMCB (void *data, StoreIOBuffer wroteBuffer);
  27 typedef void STABH(void *);
  28
  29 class store_client;
  30 class HttpRequest;
  31 class HttpReply;
  32
  33 class MemObject
  34 {
  35     MEMPROXY_CLASS(MemObject);
  36
  37 public:
  38     static size_t inUseCount();
  39
  40     void dump() const;
  41     MemObject();
  42     ~MemObject();
  43
  44     /// sets store ID, log URI, and request method; TODO: find a better name
  45     void setUris(char const *aStoreId, char const *aLogUri, const HttpRequestMethod &aMethod);
  46
  47     /// whether setUris() has been called
  48     bool hasUris() const;
  49
  50     void write(const StoreIOBuffer &buf);
  51     void unlinkRequest();
  52     HttpReply const *getReply() const;
  53     void replaceHttpReply(HttpReply *newrep);
  54     void stat (MemBuf * mb) const;
  55     int64_t endOffset () const;
  56     void markEndOfReplyHeaders(); ///< sets _reply->hdr_sz to endOffset()
  57     /// negative if unknown; otherwise, expected object_sz, expected endOffset
  58     /// maximum, and stored reply headers+body size (all three are the same)
  59     int64_t expectedReplySize() const;
  60     int64_t size() const;
  61     void reset();
  62     int64_t lowestMemReaderOffset() const;
  63     bool readAheadPolicyCanRead() const;
  64     void addClient(store_client *);
  65     /* XXX belongs in MemObject::swapout, once swaphdrsz is managed
  66      * better
  67      */
  68     int64_t objectBytesOnDisk() const;
  69     int64_t policyLowestOffsetToKeep(bool swap) const;
  70     int64_t availableForSwapOut() const; ///< buffered bytes we have not swapped out yet
  71     void trimSwappable();
  72     void trimUnSwappable();
  73     bool isContiguous() const;
  74     int mostBytesWanted(int max, bool ignoreDelayPools) const;
  75     void setNoDelay(bool const newValue);
  76 #if USE_DELAY_POOLS
  77     DelayId mostBytesAllowed() const;
  78 #endif
  79
  80 #if URL_CHECKSUM_DEBUG
  81
  82     void checkUrlChecksum() const;
  83 #endif
  84
  85     /// Before StoreID, code assumed that MemObject stores Request URI.
  86     /// After StoreID, some old code still incorrectly assumes that.
  87     /// Use this method to mark that incorrect assumption.
  88     const char *urlXXX() const { return storeId(); }
  89
  90     /// Entry StoreID (usually just Request URI); if a buggy code requests this
  91     /// before the information is available, returns an "[unknown_URI]" string.
  92     const char *storeId() const;
  93
  94     /// client request URI used for logging; storeId() by default
  95     const char *logUri() const;
  96
  97     HttpRequestMethod method;
  98     mem_hdr data_hdr;
  99     int64_t inmem_lo;
 100     dlink_list clients;
 101
 102     size_t clientCount() const {return nclients;}
 103
 104     bool clientIsFirst(void *sc) const {return (clients.head && sc == clients.head->data);}
 105
 106     int nclients;
 107
 108     class SwapOut
 109     {
 110     public:
 111         SwapOut() : queue_offset(0), decision(swNeedsCheck) {}
 112
 113         int64_t queue_offset; ///< number of bytes sent to SwapDir for writing
 114         StoreIOState::Pointer sio;
 115
 116         /// Decision states for StoreEntry::swapoutPossible() and related code.
 117         typedef enum { swNeedsCheck = 0, swImpossible = -1, swPossible = +1, swStarted } Decision;
 118         Decision decision; ///< current decision state
 119     };
 120
 121     SwapOut swapout;
 122
 123     /// cache "I/O" direction and status
 124     typedef enum { ioUndecided, ioWriting, ioReading, ioDone } Io;
 125
 126     /// State of an entry with regards to the [shared] in-transit table.
 127     class XitTable
 128     {
 129     public:
 130         XitTable(): index(-1), io(ioUndecided) {}
 131
 132         int32_t index; ///< entry position inside the in-transit table
 133         Io io; ///< current I/O state
 134     };
 135     XitTable xitTable; ///< current [shared] memory caching state for the entry
 136
 137     /// State of an entry with regards to the [shared] memory caching.
 138     class MemCache
 139     {
 140     public:
 141         MemCache(): index(-1), offset(0), io(ioUndecided) {}
 142
 143         int32_t index; ///< entry position inside the memory cache
 144         int64_t offset; ///< bytes written/read to/from the memory cache so far
 145
 146         Io io; ///< current I/O state
 147     };
 148     MemCache memCache; ///< current [shared] memory caching state for the entry
 149
 150     bool smpCollapsed; ///< whether this entry gets data from another worker
 151
 152     /* Read only - this reply must be preserved by store clients */
 153     /* The original reply. possibly with updated metadata. */
 154     HttpRequest *request;
 155
 156     struct timeval start_ping;
 157     IRCB *ping_reply_callback;
 158     void *ircb_data;
 159
 160     struct {
 161         STABH *callback;
 162         void *data;
 163     } abort;
 164     RemovalPolicyNode repl;
 165     int id;
 166     int64_t object_sz;
 167     size_t swap_hdr_sz;
 168 #if URL_CHECKSUM_DEBUG
 169
 170     unsigned int chksum;
 171 #endif
 172
 173     const char *vary_headers;
 174
 175     void delayRead(DeferredRead const &);
 176     void kickReads();
 177
 178 private:
 179     HttpReply *_reply;
 180
 181     mutable String storeId_; ///< StoreId for our entry (usually request URI)
 182     mutable String logUri_;  ///< URI used for logging (usually request URI)
 183
 184     DeferredReadManager deferredReads;
 185 };
 186
 187 /** global current memory removal policy */
 188 extern RemovalPolicy *mem_policy;
 189
 190 #endif /* SQUID_MEMOBJECT_H */
 191