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