gecko/netwerk/cache/src/nsCacheEntryDescriptor.h

/* -*- 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 nsCacheEntryDescriptor.h, released
 * February 22, 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, 22-February-2001
 *
 * 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 _nsCacheEntryDescriptor_h_
#define _nsCacheEntryDescriptor_h_

#include "nsICacheEntryDescriptor.h"
#include "nsCacheEntry.h"
#include "nsIInputStream.h"
#include "nsIOutputStream.h"

/******************************************************************************
* nsCacheEntryDescriptor
*******************************************************************************/
class nsCacheEntryDescriptor :
    public PRCList,
    public nsICacheEntryDescriptor
{
public:
    NS_DECL_ISUPPORTS
    NS_DECL_NSICACHEENTRYDESCRIPTOR
    NS_DECL_NSICACHEENTRYINFO
    
    nsCacheEntryDescriptor(nsCacheEntry * entry, nsCacheAccessMode  mode);
    virtual ~nsCacheEntryDescriptor();
    
    /**
     * utility method to attempt changing data size of associated entry
     */
    nsresult  RequestDataSizeChange(PRInt32 deltaSize);
    
    /**
     * methods callbacks for nsCacheService
     */
    nsCacheEntry * CacheEntry(void)      { return mCacheEntry; }
    void           ClearCacheEntry(void) { mCacheEntry = nsnull; }

private:


     /*************************************************************************
      * input stream wrapper class -
      *
      * The input stream wrapper references the descriptor, but the descriptor
      * doesn't need any references to the stream wrapper.
      *************************************************************************/
     class nsInputStreamWrapper : public nsIInputStream {
     private:
         nsCacheEntryDescriptor    * mDescriptor;
         nsCOMPtr<nsIInputStream>    mInput;
         PRUint32                    mStartOffset;
         PRBool                      mInitialized;
     public:
         NS_DECL_ISUPPORTS
         NS_DECL_NSIINPUTSTREAM

         nsInputStreamWrapper(nsCacheEntryDescriptor * desc, PRUint32 off)
             : mDescriptor(desc)
             , mStartOffset(off)
             , mInitialized(PR_FALSE)
         {
             NS_ADDREF(mDescriptor);
         }
         virtual ~nsInputStreamWrapper()
         {
             NS_RELEASE(mDescriptor);
         }

     private:
         nsresult LazyInit();
         nsresult EnsureInit() { return mInitialized ? NS_OK : LazyInit(); }
     };
     friend class nsInputStreamWrapper;


     /*************************************************************************
      * output stream wrapper class -
      *
      * The output stream wrapper references the descriptor, but the descriptor
      * doesn't need any references to the stream wrapper.
      *************************************************************************/
     class nsOutputStreamWrapper : public nsIOutputStream {
     private:
         nsCacheEntryDescriptor *    mDescriptor;
         nsCOMPtr<nsIOutputStream>   mOutput;
         PRUint32                    mStartOffset;
         PRBool                      mInitialized;
     public:
         NS_DECL_ISUPPORTS
         NS_DECL_NSIOUTPUTSTREAM

         nsOutputStreamWrapper(nsCacheEntryDescriptor * desc, PRUint32 off)
             : mDescriptor(desc)
             , mStartOffset(off)
             , mInitialized(PR_FALSE)
         {
             NS_ADDREF(mDescriptor); // owning ref
         }
         virtual ~nsOutputStreamWrapper()
         { 
             // XXX _HACK_ the storage stream needs this!
             Close();
             NS_RELEASE(mDescriptor);
         }

     private:
         nsresult LazyInit();
         nsresult EnsureInit() { return mInitialized ? NS_OK : LazyInit(); }
         nsresult OnWrite(PRUint32 count);
     };
     friend class nsOutputStreamWrapper;

 private:
     /**
      * nsCacheEntryDescriptor data members
      */
     nsCacheEntry          * mCacheEntry; // we are a child of the entry
     nsCacheAccessMode       mAccessGranted;
};


#endif // _nsCacheEntryDescriptor_h_