src/store/Controller.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_STORE_CONTROLLER_H
  10 #define SQUID_STORE_CONTROLLER_H
  11
  12 #include "store/Storage.h"
  13
  14 class MemObject;
  15 class RequestFlags;
  16 class HttpRequestMethod;
  17
  18 namespace Store {
  19
  20 /// Public Store interface. Coordinates the work of memory/disk/transient stores
  21 /// and hides their individual existence/differences from the callers.
  22 class Controller: public Storage
  23 {
  24 public:
  25     Controller();
  26     virtual ~Controller() override;
  27
  28     /* Storage API */
  29     virtual void create() override;
  30     virtual void init() override;
  31     virtual StoreEntry *get(const cache_key *) override;
  32     virtual uint64_t maxSize() const override;
  33     virtual uint64_t minSize() const override;
  34     virtual uint64_t currentSize() const override;
  35     virtual uint64_t currentCount() const override;
  36     virtual int64_t maxObjectSize() const override;
  37     virtual void getStats(StoreInfoStats &stats) const override;
  38     virtual void stat(StoreEntry &) const override;
  39     virtual void sync() override;
  40     virtual void maintain() override;
  41     virtual void markForUnlink(StoreEntry &) override;
  42     virtual void unlink(StoreEntry &) override;
  43     virtual int callback() override;
  44
  45     /// called when the entry is no longer needed by any transaction
  46     void handleIdleEntry(StoreEntry &);
  47
  48     /// called to get rid of no longer needed entry data in RAM, if any
  49     void memoryOut(StoreEntry &, const bool preserveSwappable);
  50
  51     /// makes the entry available for collapsing future requests
  52     void allowCollapsing(StoreEntry *, const RequestFlags &, const HttpRequestMethod &);
  53
  54     /// marks the entry completed for collapsed requests
  55     void transientsCompleteWriting(StoreEntry &);
  56
  57     /// Update local intransit entry after changes made by appending worker.
  58     void syncCollapsed(const sfileno);
  59
  60     /// calls Root().transients->abandon() if transients are tracked
  61     void transientsAbandon(StoreEntry &);
  62
  63     /// number of the transient entry readers some time ago
  64     int transientReaders(const StoreEntry &) const;
  65
  66     /// disassociates the entry from the intransit table
  67     void transientsDisconnect(MemObject &);
  68
  69     /// removes the entry from the memory cache
  70     void memoryUnlink(StoreEntry &);
  71
  72     /// disassociates the entry from the memory cache, preserving cached data
  73     void memoryDisconnect(StoreEntry &);
  74
  75     /// \returns an iterator for all Store entries
  76     StoreSearch *search();
  77
  78     /// the number of cache_dirs being rebuilt; TODO: move to Disks::Rebuilding
  79     static int store_dirs_rebuilding;
  80
  81 private:
  82     /// update reference counters of the recently touched entry
  83     void referenceBusy(StoreEntry &e);
  84     /// dereference() an idle entry and return true if the entry should be deleted
  85     bool dereferenceIdle(StoreEntry &, bool wantsLocalMemory);
  86
  87     StoreEntry *find(const cache_key *key);
  88     bool keepForLocalMemoryCache(StoreEntry &e) const;
  89     bool anchorCollapsed(StoreEntry &, bool &inSync);
  90
  91     Disks *swapDir; ///< summary view of all disk caches
  92     Memory *memStore; ///< memory cache
  93
  94     /// A shared table of public store entries that do not know whether they
  95     /// will belong to a memory cache, a disk cache, or will be uncachable
  96     /// when the response header comes. Used for SMP collapsed forwarding.
  97     Transients *transients;
  98 };
  99
 100 /// safely access controller singleton
 101 extern Controller &Root();
 102
 103 /// initialize the storage module; a custom root is used by unit tests only
 104 extern void Init(Controller *root = nullptr);
 105
 106 /// undo Init()
 107 extern void FreeMemory();
 108
 109 } // namespace Store
 110
 111 #endif /* SQUID_STORE_CONTROLLER_H */
 112