gecko-dev/netwerk/cache/nsDiskCacheBinding.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is nsDiskCacheBinding.h, released
* May 10, 2001.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Gordon Sheridan <gordon@netscape.com>
* Patrick C. Beard <beard@netscape.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef _nsDiskCacheBinding_h_
#define _nsDiskCacheBinding_h_
#include "nspr.h"
#include "pldhash.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 {
public:
NS_DECL_ISUPPORTS
nsDiskCacheBinding(nsCacheEntry* entry, nsDiskCacheRecord * record);
virtual ~nsDiskCacheBinding();
nsresult EnsureStreamIO();
PRBool IsActive() { return mCacheEntry != nsnull;}
// XXX make friends
public:
nsCacheEntry* mCacheEntry; // back pointer to parent nsCacheEntry
nsDiskCacheRecord mRecord;
nsDiskCacheStreamIO* mStreamIO; // strong reference
PRBool mDoomed; // record is not stored in cache map
PRUint8 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();
nsresult Init();
void Reset();
nsDiskCacheBinding * CreateBinding(nsCacheEntry * entry,
nsDiskCacheRecord * record);
nsDiskCacheBinding * FindActiveBinding(PRUint32 hashNumber);
void RemoveBinding(nsDiskCacheBinding * binding);
PRBool ActiveBindings();
private:
nsresult AddBinding(nsDiskCacheBinding * binding);
// member variables
static PLDHashTableOps ops;
PLDHashTable table;
PRBool initialized;
};
#endif /* _nsDiskCacheBinding_h_ */