src/store/Controlled.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_STORE_CONTROLLED_H
  10 #define SQUID_STORE_CONTROLLED_H
  11
  12 #include "store/Storage.h"
  13
  14 namespace Store {
  15
  16 /// Storage controlled by a Controller.
  17 /// This API is shared among Disks, Disk, Memory caches and Transients.
  18 class Controlled: public Storage
  19 {
  20 public:
  21     /// somebody needs this entry (many cache replacement policies need to know)
  22     virtual void reference(StoreEntry &e) = 0;
  23
  24     /// somebody no longer needs this entry (usually after calling reference())
  25     /// return false iff the idle entry should be destroyed
  26     virtual bool dereference(StoreEntry &e) = 0;
  27
  28     /// make stored metadata and HTTP headers the same as in the given entry
  29     virtual void updateHeaders(StoreEntry *) {}
  30
  31     /// If this storage cannot cache collapsed entries, return false.
  32     /// If the entry is not found, return false. Otherwise, return true after
  33     /// tying the entry to this cache and setting inSync to updateCollapsed().
  34     virtual bool anchorCollapsed(StoreEntry &, bool &/*inSync*/) { return false; }
  35
  36     /// Update a local collapsed entry with fresh info from this cache (if any).
  37     /// Return true iff the cache supports collapsed entries and
  38     /// the given local collapsed entry is now in sync with this storage.
  39     virtual bool updateCollapsed(StoreEntry &) { return false; }
  40 };
  41
  42 } // namespace Store
  43
  44 #endif /* SQUID_STORE_CONTROLLED_H */
  45