src/MemObject.h

   1 /*
   2  * Copyright (C) 1996-2017 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 "sbuf/SBuf.h"
  17 #include "SquidString.h"
  18 #include "stmem.h"
  19 #include "StoreIOBuffer.h"
  20 #include "StoreIOState.h"
  21 #include "typedefs.h" //for IRCB
  22
  23 #if USE_DELAY_POOLS
  24 #include "DelayId.h"
  25 #endif
  26
  27 typedef void STMCB (void *data, StoreIOBuffer wroteBuffer);
  28 typedef void STABH(void *);
  29
  30 class store_client;
  31 class HttpRequest;
  32 class HttpReply;
  33
  34 class MemObject
  35 {
  36     MEMPROXY_CLASS(MemObject);
  37
  38 public:
  39     static size_t inUseCount();
  40
  41     void dump() const;
  42     MemObject();
  43     ~MemObject();
  44
  45     /// sets store ID, log URI, and request method; TODO: find a better name
  46     void setUris(char const *aStoreId, char const *aLogUri, const HttpRequestMethod &aMethod);
  47
  48     /// whether setUris() has been called
  49     bool hasUris() const;
  50
  51     void write(const StoreIOBuffer &buf);
  52     void unlinkRequest();
  53     HttpReply const *getReply() const;
  54     void replaceHttpReply(HttpReply *newrep);
  55     void stat (MemBuf * mb) const;
  56     int64_t endOffset () const;
  57     void markEndOfReplyHeaders(); ///< sets _reply->hdr_sz to endOffset()
  58     /// negative if unknown; otherwise, expected object_sz, expected endOffset
  59     /// maximum, and stored reply headers+body size (all three are the same)
  60     int64_t expectedReplySize() const;
  61     int64_t size() const;
  62     void reset();
  63     int64_t lowestMemReaderOffset() const;
  64     bool readAheadPolicyCanRead() const;
  65     void addClient(store_client *);
  66     /* XXX belongs in MemObject::swapout, once swaphdrsz is managed
  67      * better
  68      */
  69     int64_t objectBytesOnDisk() const;
  70     int64_t policyLowestOffsetToKeep(bool swap) const;
  71     int64_t availableForSwapOut() const; ///< buffered bytes we have not swapped out yet
  72     void trimSwappable();
  73     void trimUnSwappable();
  74     bool isContiguous() const;
  75     int mostBytesWanted(int max, bool ignoreDelayPools) const;
  76     void setNoDelay(bool const newValue);
  77 #if USE_DELAY_POOLS
  78     DelayId mostBytesAllowed() const;
  79 #endif
  80
  81 #if URL_CHECKSUM_DEBUG
  82
  83     void checkUrlChecksum() const;
  84 #endif
  85
  86     /// Before StoreID, code assumed that MemObject stores Request URI.
  87     /// After StoreID, some old code still incorrectly assumes that.
  88     /// Use this method to mark that incorrect assumption.
  89     const char *urlXXX() const { return storeId(); }
  90
  91     /// Entry StoreID (usually just Request URI); if a buggy code requests this
  92     /// before the information is available, returns an "[unknown_URI]" string.
  93     const char *storeId() const;
  94
  95     /// client request URI used for logging; storeId() by default
  96     const char *logUri() const;
  97
  98     HttpRequestMethod method;
  99     mem_hdr data_hdr;
 100     int64_t inmem_lo;
 101     dlink_list clients;
 102
 103     size_t clientCount() const {return nclients;}
 104
 105     bool clientIsFirst(void *sc) const {return (clients.head && sc == clients.head->data);}
 106
 107     int nclients;
 108
 109     class SwapOut
 110     {
 111     public:
 112         SwapOut() : queue_offset(0), decision(swNeedsCheck) {}
 113
 114         int64_t queue_offset; ///< number of bytes sent to SwapDir for writing
 115         StoreIOState::Pointer sio;
 116
 117         /// Decision states for StoreEntry::swapoutPossible() and related code.
 118         typedef enum { swNeedsCheck = 0, swImpossible = -1, swPossible = +1, swStarted } Decision;
 119         Decision decision; ///< current decision state
 120     };
 121
 122     SwapOut swapout;
 123
 124     /// cache "I/O" direction and status
 125     typedef enum { ioUndecided, ioWriting, ioReading, ioDone } Io;
 126
 127     /// State of an entry with regards to the [shared] in-transit table.
 128     class XitTable
 129     {
 130     public:
 131         XitTable(): index(-1), io(ioUndecided) {}
 132
 133         int32_t index; ///< entry position inside the in-transit table
 134         Io io; ///< current I/O state
 135     };
 136     XitTable xitTable; ///< current [shared] memory caching state for the entry
 137
 138     /// State of an entry with regards to the [shared] memory caching.
 139     class MemCache
 140     {
 141     public:
 142         MemCache(): index(-1), offset(0), io(ioUndecided) {}
 143
 144         int32_t index; ///< entry position inside the memory cache
 145         int64_t offset; ///< bytes written/read to/from the memory cache so far
 146
 147         Io io; ///< current I/O state
 148     };
 149     MemCache memCache; ///< current [shared] memory caching state for the entry
 150
 151     bool smpCollapsed; ///< whether this entry gets data from another worker
 152
 153     /* Read only - this reply must be preserved by store clients */
 154     /* The original reply. possibly with updated metadata. */
 155     HttpRequest *request;
 156
 157     struct timeval start_ping;
 158     IRCB *ping_reply_callback;
 159     void *ircb_data;
 160
 161     struct {
 162         STABH *callback;
 163         void *data;
 164     } abort;
 165     RemovalPolicyNode repl;
 166     int id;
 167     int64_t object_sz;
 168     size_t swap_hdr_sz;
 169 #if URL_CHECKSUM_DEBUG
 170
 171     unsigned int chksum;
 172 #endif
 173
 174     SBuf vary_headers;
 175
 176     void delayRead(DeferredRead const &);
 177     void kickReads();
 178
 179 private:
 180     HttpReply *_reply;
 181
 182     mutable String storeId_; ///< StoreId for our entry (usually request URI)
 183     mutable String logUri_;  ///< URI used for logging (usually request URI)
 184
 185     DeferredReadManager deferredReads;
 186 };
 187
 188 /** global current memory removal policy */
 189 extern RemovalPolicy *mem_policy;
 190
 191 #endif /* SQUID_MEMOBJECT_H */
 192