netwerk/cache/src/nsMemoryCacheDevice.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  *
   3  * ***** BEGIN LICENSE BLOCK *****
   4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   5  *
   6  * The contents of this file are subject to the Mozilla Public License Version
   7  * 1.1 (the "License"); you may not use this file except in compliance with
   8  * the License. You may obtain a copy of the License at
   9  * http://www.mozilla.org/MPL/
  10  *
  11  * Software distributed under the License is distributed on an "AS IS" basis,
  12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  13  * for the specific language governing rights and limitations under the
  14  * License.
  15  *
  16  * The Original Code is nsMemoryCacheDevice.h, released
  17  * February 20, 2001.
  18  *
  19  * The Initial Developer of the Original Code is
  20  * Netscape Communications Corporation.
  21  * Portions created by the Initial Developer are Copyright (C) 2001
  22  * the Initial Developer. All Rights Reserved.
  23  *
  24  * Contributor(s):
  25  *   Gordon Sheridan, 20-February-2001
  26  *   Brian Ryner <bryner@brianryner.com>
  27  *
  28  * Alternatively, the contents of this file may be used under the terms of
  29  * either the GNU General Public License Version 2 or later (the "GPL"), or
  30  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  31  * in which case the provisions of the GPL or the LGPL are applicable instead
  32  * of those above. If you wish to allow use of your version of this file only
  33  * under the terms of either the GPL or the LGPL, and not to allow others to
  34  * use your version of this file under the terms of the MPL, indicate your
  35  * decision by deleting the provisions above and replace them with the notice
  36  * and other provisions required by the GPL or the LGPL. If you do not delete
  37  * the provisions above, a recipient may use your version of this file under
  38  * the terms of any one of the MPL, the GPL or the LGPL.
  39  *
  40  * ***** END LICENSE BLOCK ***** */
  41
  42 #ifndef _nsMemoryCacheDevice_h_
  43 #define _nsMemoryCacheDevice_h_
  44
  45 #include "nsCacheDevice.h"
  46 #include "pldhash.h"
  47 #include "nsCacheEntry.h"
  48
  49
  50 class nsMemoryCacheDeviceInfo;
  51
  52 /******************************************************************************
  53  * nsMemoryCacheDevice
  54  ******************************************************************************/
  55 class nsMemoryCacheDevice : public nsCacheDevice
  56 {
  57 public:
  58     nsMemoryCacheDevice();
  59     virtual ~nsMemoryCacheDevice();
  60
  61     virtual nsresult        Init();
  62     virtual nsresult        Shutdown();
  63
  64     virtual const char *    GetDeviceID(void);
  65
  66     virtual nsresult        BindEntry( nsCacheEntry * entry );
  67     virtual nsCacheEntry *  FindEntry( nsCString * key, PRBool *collision );
  68     virtual void            DoomEntry( nsCacheEntry * entry );
  69     virtual nsresult        DeactivateEntry( nsCacheEntry * entry );
  70
  71     virtual nsresult OpenInputStreamForEntry(nsCacheEntry *     entry,
  72                                              nsCacheAccessMode  mode,
  73                                              PRUint32           offset,
  74                                              nsIInputStream **  result);
  75
  76     virtual nsresult OpenOutputStreamForEntry(nsCacheEntry *     entry,
  77                                               nsCacheAccessMode  mode,
  78                                               PRUint32           offset,
  79                                               nsIOutputStream ** result);
  80
  81     virtual nsresult GetFileForEntry( nsCacheEntry *    entry,
  82                                       nsIFile **        result );
  83
  84     virtual nsresult OnDataSizeChange( nsCacheEntry * entry, PRInt32 deltaSize );
  85
  86     virtual nsresult Visit( nsICacheVisitor * visitor );
  87
  88     virtual nsresult EvictEntries(const char * clientID);
  89
  90     void             SetCapacity(PRInt32  capacity);
  91
  92 private:
  93     friend class nsMemoryCacheDeviceInfo;
  94     enum      { DELETE_ENTRY        = PR_TRUE,
  95                 DO_NOT_DELETE_ENTRY = PR_FALSE };
  96
  97     void      AdjustMemoryLimits( PRInt32  softLimit, PRInt32  hardLimit);
  98     void      EvictEntry( nsCacheEntry * entry , PRBool deleteEntry);
  99     void      EvictEntriesIfNecessary();
 100     int       EvictionList(nsCacheEntry * entry, PRInt32  deltaSize);
 101
 102 #ifdef DEBUG
 103     void      CheckEntryCount();
 104 #endif
 105     /*
 106      *  Data members
 107      */
 108     enum {
 109         kQueueCount = 24   // entries > 2^23 (8Mb) start in last queue
 110     };
 111
 112     nsCacheEntryHashTable  mMemCacheEntries;
 113     PRBool                 mInitialized;
 114
 115     PRCList                mEvictionList[kQueueCount];
 116     PRInt32                mEvictionThreshold;
 117
 118     PRInt32                mHardLimit;
 119     PRInt32                mSoftLimit;
 120
 121     PRInt32                mTotalSize;
 122     PRInt32                mInactiveSize;
 123
 124     PRInt32                mEntryCount;
 125     PRInt32                mMaxEntryCount;
 126
 127     // XXX what other stats do we want to keep?
 128 };
 129
 130
 131 /******************************************************************************
 132  * nsMemoryCacheDeviceInfo - used to call nsIVisitor for about:cache
 133  ******************************************************************************/
 134 class nsMemoryCacheDeviceInfo : public nsICacheDeviceInfo {
 135 public:
 136     NS_DECL_ISUPPORTS
 137     NS_DECL_NSICACHEDEVICEINFO
 138
 139     nsMemoryCacheDeviceInfo(nsMemoryCacheDevice* device)
 140         :   mDevice(device)
 141     {
 142     }
 143
 144     virtual ~nsMemoryCacheDeviceInfo() {}
 145
 146 private:
 147     nsMemoryCacheDevice* mDevice;
 148 };
 149
 150
 151 #endif // _nsMemoryCacheDevice_h_