michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  *
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: 
michael@0: #ifndef _nsDiskCacheBinding_h_
michael@0: #define _nsDiskCacheBinding_h_
michael@0: 
michael@0: #include "mozilla/MemoryReporting.h"
michael@0: #include "nspr.h"
michael@0: #include "pldhash.h"
michael@0: 
michael@0: #include "nsISupports.h"
michael@0: #include "nsCacheEntry.h"
michael@0: 
michael@0: #include "nsDiskCacheMap.h"
michael@0: #include "nsDiskCacheStreams.h"
michael@0: 
michael@0: 
michael@0: /******************************************************************************
michael@0:  *  nsDiskCacheBinding
michael@0:  *
michael@0:  *  Created for disk cache specific data and stored in nsCacheEntry.mData as
michael@0:  *  an nsISupports.  Also stored in nsDiskCacheHashTable, with collisions
michael@0:  *  linked by the PRCList.
michael@0:  *
michael@0:  *****************************************************************************/
michael@0: 
michael@0: class nsDiskCacheDeviceDeactivateEntryEvent;
michael@0: 
michael@0: class nsDiskCacheBinding : public nsISupports, public PRCList {
michael@0: public:
michael@0:     NS_DECL_THREADSAFE_ISUPPORTS
michael@0: 
michael@0:     nsDiskCacheBinding(nsCacheEntry* entry, nsDiskCacheRecord * record);
michael@0:     virtual ~nsDiskCacheBinding();
michael@0: 
michael@0:     nsresult EnsureStreamIO();
michael@0:     bool     IsActive() { return mCacheEntry != nullptr;}
michael@0: 
michael@0: // XXX make friends
michael@0: public:
michael@0:     nsCacheEntry*           mCacheEntry;    // back pointer to parent nsCacheEntry
michael@0:     nsDiskCacheRecord       mRecord;
michael@0:     nsDiskCacheStreamIO*    mStreamIO;      // strong reference
michael@0:     bool                    mDoomed;        // record is not stored in cache map
michael@0:     uint8_t                 mGeneration;    // possibly just reservation
michael@0: 
michael@0:     // If set, points to a pending event which will deactivate |mCacheEntry|.
michael@0:     // If not set then either |mCacheEntry| is not deactivated, or it has been
michael@0:     // deactivated but the device returned it from FindEntry() before the event
michael@0:     // fired. In both two latter cases this binding is to be considered valid.
michael@0:     nsDiskCacheDeviceDeactivateEntryEvent *mDeactivateEvent;
michael@0: };
michael@0: 
michael@0: 
michael@0: /******************************************************************************
michael@0:  *  Utility Functions
michael@0:  *****************************************************************************/
michael@0: 
michael@0: nsDiskCacheBinding *   GetCacheEntryBinding(nsCacheEntry * entry);
michael@0: 
michael@0: 
michael@0: 
michael@0: /******************************************************************************
michael@0:  *  nsDiskCacheBindery
michael@0:  *
michael@0:  *  Used to keep track of nsDiskCacheBinding associated with active/bound (and
michael@0:  *  possibly doomed) entries.  Lookups on 4 byte disk hash to find collisions
michael@0:  *  (which need to be doomed, instead of just evicted.  Collisions are linked
michael@0:  *  using a PRCList to keep track of current generation number.
michael@0:  *
michael@0:  *  Used to detect hash number collisions, and find available generation numbers.
michael@0:  *
michael@0:  *  Not all nsDiskCacheBinding have a generation number.
michael@0:  *
michael@0:  *  Generation numbers may be aquired late, or lost (when data fits in block file)
michael@0:  *
michael@0:  *  Collisions can occur:
michael@0:  *      BindEntry()       - hashnumbers collide (possibly different keys)
michael@0:  *
michael@0:  *  Generation number required:
michael@0:  *      DeactivateEntry() - metadata written to disk, may require file
michael@0:  *      GetFileForEntry() - force data to require file
michael@0:  *      writing to stream - data size may require file
michael@0:  *
michael@0:  *  Binding can be kept in PRCList in order of generation numbers.
michael@0:  *  Binding with no generation number can be Appended to PRCList (last).
michael@0:  *
michael@0:  *****************************************************************************/
michael@0: 
michael@0: class nsDiskCacheBindery {
michael@0: public:
michael@0:     nsDiskCacheBindery();
michael@0:     ~nsDiskCacheBindery();
michael@0: 
michael@0:     nsresult                Init();
michael@0:     void                    Reset();
michael@0: 
michael@0:     nsDiskCacheBinding *    CreateBinding(nsCacheEntry *       entry,
michael@0:                                           nsDiskCacheRecord *  record);
michael@0: 
michael@0:     nsDiskCacheBinding *    FindActiveBinding(uint32_t  hashNumber);
michael@0:     void                    RemoveBinding(nsDiskCacheBinding * binding);
michael@0:     bool                    ActiveBindings();
michael@0: 
michael@0:     size_t                 SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf);
michael@0: 
michael@0: private:
michael@0:     nsresult                AddBinding(nsDiskCacheBinding * binding);
michael@0: 
michael@0:     // member variables
michael@0:     static const PLDHashTableOps ops;
michael@0:     PLDHashTable           table;
michael@0:     bool                   initialized;
michael@0: };
michael@0: 
michael@0: #endif /* _nsDiskCacheBinding_h_ */