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       1             : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
       2             :  *
       3             :  * This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : 
       8             : #ifndef _nsDiskCacheBinding_h_
       9             : #define _nsDiskCacheBinding_h_
      10             : 
      11             : #include "mozilla/MemoryReporting.h"
      12             : #include "nspr.h"
      13             : #include "PLDHashTable.h"
      14             : 
      15             : #include "nsISupports.h"
      16             : #include "nsCacheEntry.h"
      17             : 
      18             : #include "nsDiskCacheMap.h"
      19             : #include "nsDiskCacheStreams.h"
      20             : 
      21             : 
      22             : /******************************************************************************
      23             :  *  nsDiskCacheBinding
      24             :  *
      25             :  *  Created for disk cache specific data and stored in nsCacheEntry.mData as
      26             :  *  an nsISupports.  Also stored in nsDiskCacheHashTable, with collisions
      27             :  *  linked by the PRCList.
      28             :  *
      29             :  *****************************************************************************/
      30             : 
      31             : class nsDiskCacheDeviceDeactivateEntryEvent;
      32             : 
      33             : class nsDiskCacheBinding : public nsISupports, public PRCList {
      34             :     virtual ~nsDiskCacheBinding();
      35             : 
      36             : public:
      37             :     NS_DECL_THREADSAFE_ISUPPORTS
      38             : 
      39             :     nsDiskCacheBinding(nsCacheEntry* entry, nsDiskCacheRecord * record);
      40             : 
      41             :     nsresult EnsureStreamIO();
      42           0 :     bool     IsActive() { return mCacheEntry != nullptr;}
      43             : 
      44             : // XXX make friends
      45             : public:
      46             :     nsCacheEntry*           mCacheEntry;    // back pointer to parent nsCacheEntry
      47             :     nsDiskCacheRecord       mRecord;
      48             :     nsDiskCacheStreamIO*    mStreamIO;      // strong reference
      49             :     bool                    mDoomed;        // record is not stored in cache map
      50             :     uint8_t                 mGeneration;    // possibly just reservation
      51             : 
      52             :     // If set, points to a pending event which will deactivate |mCacheEntry|.
      53             :     // If not set then either |mCacheEntry| is not deactivated, or it has been
      54             :     // deactivated but the device returned it from FindEntry() before the event
      55             :     // fired. In both two latter cases this binding is to be considered valid.
      56             :     nsDiskCacheDeviceDeactivateEntryEvent *mDeactivateEvent;
      57             : };
      58             : 
      59             : 
      60             : /******************************************************************************
      61             :  *  Utility Functions
      62             :  *****************************************************************************/
      63             : 
      64             : nsDiskCacheBinding *   GetCacheEntryBinding(nsCacheEntry * entry);
      65             : 
      66             : 
      67             : 
      68             : /******************************************************************************
      69             :  *  nsDiskCacheBindery
      70             :  *
      71             :  *  Used to keep track of nsDiskCacheBinding associated with active/bound (and
      72             :  *  possibly doomed) entries.  Lookups on 4 byte disk hash to find collisions
      73             :  *  (which need to be doomed, instead of just evicted.  Collisions are linked
      74             :  *  using a PRCList to keep track of current generation number.
      75             :  *
      76             :  *  Used to detect hash number collisions, and find available generation numbers.
      77             :  *
      78             :  *  Not all nsDiskCacheBinding have a generation number.
      79             :  *
      80             :  *  Generation numbers may be aquired late, or lost (when data fits in block file)
      81             :  *
      82             :  *  Collisions can occur:
      83             :  *      BindEntry()       - hashnumbers collide (possibly different keys)
      84             :  *
      85             :  *  Generation number required:
      86             :  *      DeactivateEntry() - metadata written to disk, may require file
      87             :  *      GetFileForEntry() - force data to require file
      88             :  *      writing to stream - data size may require file
      89             :  *
      90             :  *  Binding can be kept in PRCList in order of generation numbers.
      91             :  *  Binding with no generation number can be Appended to PRCList (last).
      92             :  *
      93             :  *****************************************************************************/
      94             : 
      95             : class nsDiskCacheBindery {
      96             : public:
      97             :     nsDiskCacheBindery();
      98             :     ~nsDiskCacheBindery();
      99             : 
     100             :     void                    Init();
     101             :     void                    Reset();
     102             : 
     103             :     nsDiskCacheBinding *    CreateBinding(nsCacheEntry *       entry,
     104             :                                           nsDiskCacheRecord *  record);
     105             : 
     106             :     nsDiskCacheBinding *    FindActiveBinding(uint32_t  hashNumber);
     107             :     void                    RemoveBinding(nsDiskCacheBinding * binding);
     108             :     bool                    ActiveBindings();
     109             : 
     110             :     size_t                 SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf);
     111             : 
     112             : private:
     113             :     nsresult                AddBinding(nsDiskCacheBinding * binding);
     114             : 
     115             :     // member variables
     116             :     static const PLDHashTableOps ops;
     117             :     PLDHashTable           table;
     118             :     bool                   initialized;
     119             : 
     120             :     static const uint32_t kInitialTableLength = 0;
     121             : };
     122             : 
     123             : #endif /* _nsDiskCacheBinding_h_ */