/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef _nsDiskCacheBinding_h_

#define _nsDiskCacheBinding_h_

#include "mozilla/MemoryReporting.h"

#include "nspr.h"

#include "PLDHashTable.h"

#include "nsISupports.h"

#include "nsCacheEntry.h"

#include "nsDiskCacheMap.h"

#include "nsDiskCacheStreams.h"

/******************************************************************************

 *  nsDiskCacheBinding

 *

 *  Created for disk cache specific data and stored in nsCacheEntry.mData as

 *  an nsISupports.  Also stored in nsDiskCacheHashTable, with collisions

 *  linked by the PRCList.

 *

 *****************************************************************************/

class nsDiskCacheDeviceDeactivateEntryEvent;

class nsDiskCacheBinding : public nsISupports, public PRCList {

    virtual ~nsDiskCacheBinding();

public:

    NS_DECL_THREADSAFE_ISUPPORTS

    nsDiskCacheBinding(nsCacheEntry* entry, nsDiskCacheRecord * record);

    nsresult EnsureStreamIO();

    bool     IsActive() { return mCacheEntry != nullptr;}

// XXX make friends

public:

    nsCacheEntry*           mCacheEntry;    // back pointer to parent nsCacheEntry

    nsDiskCacheRecord       mRecord;

    nsDiskCacheStreamIO*    mStreamIO;      // strong reference

    bool                    mDoomed;        // record is not stored in cache map

    uint8_t                 mGeneration;    // possibly just reservation

    // If set, points to a pending event which will deactivate |mCacheEntry|.

    // If not set then either |mCacheEntry| is not deactivated, or it has been

    // deactivated but the device returned it from FindEntry() before the event

    // fired. In both two latter cases this binding is to be considered valid.

    nsDiskCacheDeviceDeactivateEntryEvent *mDeactivateEvent;

};

/******************************************************************************

 *  Utility Functions

 *****************************************************************************/

nsDiskCacheBinding *   GetCacheEntryBinding(nsCacheEntry * entry);

/******************************************************************************

 *  nsDiskCacheBindery

 *

 *  Used to keep track of nsDiskCacheBinding associated with active/bound (and

 *  possibly doomed) entries.  Lookups on 4 byte disk hash to find collisions

 *  (which need to be doomed, instead of just evicted.  Collisions are linked

 *  using a PRCList to keep track of current generation number.

 *

 *  Used to detect hash number collisions, and find available generation numbers.

 *

 *  Not all nsDiskCacheBinding have a generation number.

 *

 *  Generation numbers may be aquired late, or lost (when data fits in block file)

 *

 *  Collisions can occur:

 *      BindEntry()       - hashnumbers collide (possibly different keys)

 *

 *  Generation number required:

 *      DeactivateEntry() - metadata written to disk, may require file

 *      GetFileForEntry() - force data to require file

 *      writing to stream - data size may require file

 *

 *  Binding can be kept in PRCList in order of generation numbers.

 *  Binding with no generation number can be Appended to PRCList (last).

 *

 *****************************************************************************/

class nsDiskCacheBindery {

public:

    nsDiskCacheBindery();

    ~nsDiskCacheBindery();

    void                    Init();

    void                    Reset();

    nsDiskCacheBinding *    CreateBinding(nsCacheEntry *       entry,

                                          nsDiskCacheRecord *  record);

    nsDiskCacheBinding *    FindActiveBinding(uint32_t  hashNumber) const;

    void                    RemoveBinding(nsDiskCacheBinding * binding);

    bool                    ActiveBindings();

    size_t                 SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf);

private:

    nsresult                AddBinding(nsDiskCacheBinding * binding);

    // member variables

    static const PLDHashTableOps ops;

    PLDHashTable           table;

    bool                   initialized;

    static const uint32_t kInitialTableLength = 0;

};

#endif /* _nsDiskCacheBinding_h_ */