epoc32/include/app/cacheman.h
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:33:34 +0100
branchSymbian3
changeset 4 837f303aceeb
parent 3 e1b950c65cb4
permissions -rw-r--r--
Current Symbian^3 public API header files (from PDK 3.0.h)
This is the epoc32/include tree with the "platform" subtrees removed, and
all but a selected few mbg and rsg files removed.
     1 // Copyright (c) 1999-2009 Nokia Corporation and/or its subsidiary(-ies).
     2 // All rights reserved.
     3 // This component and the accompanying materials are made available
     4 // under the terms of "Eclipse Public License v1.0"
     5 // which accompanies this distribution, and is available
     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".
     7 //
     8 // Initial Contributors:
     9 // Nokia Corporation - initial contribution.
    10 //
    11 // Contributors:
    12 //
    13 // Description:
    14 // CACHEMAN.H
    15 //
    16 /**
    17  * @file 
    18  * @publishedAll
    19  * @released
    20  */
    21 #if !defined (__CACHEMAN_H__)
    22 #define __CACHEMAN_H__
    23 
    24 #include <mentact.h>
    25 #include <msvstd.h>
    26 #include <msvapi.h>
    27 #ifndef SYMBIAN_ENABLE_SPLIT_HEADERS  
    28 #include <cimprunemessage.h>
    29 #include "cimfinder.h"
    30 #endif
    31 
    32 class CImMessageFinder;
    33 class CImMessageCounter;
    34 
    35 struct TImCacheManagerProgress
    36 /** Holds progress of a cache management cleanup operation.
    37 
    38 @see CImCacheManager::ProgressL() 
    39 @publishedAll
    40 @released
    41 */
    42 	{
    43 public:
    44 	/** Total number of messages to process.
    45 	
    46 	Note that, immediately after a CImCacheManager object is started, the progress 
    47 	operation may return 1 for iTotalMessages and 0 for iMessagesProcessed, regardless 
    48 	of the total number of messages. This is because the counter for the iTotalMessages 
    49 	operates asynchronously and may not have counted all of the messages at that 
    50 	time. */
    51 	TInt iTotalMessages;
    52 	/** Number of messages processed so far. */
    53 	TInt iMessagesProcessed;
    54 	};
    55 
    56 class CImCacheManager : public CMsvOperation
    57 /** Provides management of the local cache of messages in remote mailboxes.
    58 
    59 A mailbox that is being used in disconnected mode allows the user access to 
    60 message data by opening the message directly from the remote mailbox. If the 
    61 required message has been downloaded previously, then it will not necessarily 
    62 need to be downloaded again. This functionality is achieved by preserving 
    63 the message data locally, under the remote service entry. The preserved message 
    64 data acts as a cache to allow the user access to the message without the need 
    65 for it to be downloaded every time. 
    66 
    67 The cache management functionality is required to reduce the amount of memory 
    68 that is consumed by the message cache. CImCacheManager provides a mechanism 
    69 for asynchronously traversing a message tree and for removing text and attachment 
    70 data from messages. Deleting more message data will free up more memory but 
    71 there is a higher chance that a user will need to download a message for a 
    72 second time. 
    73 
    74 CImCacheManager is an abstract base class, which can be specialised to implement 
    75 a filter (Filter()) that decides if data for a message shoulded be deleted: 
    76 for example, deletion could be restricted to 'all read messages over a week 
    77 old,' or, 'all read messages, over 20K in size which are also over a day old.' 
    78 @publishedAll
    79 @released
    80 */
    81 	{
    82 public:
    83 	IMPORT_C void StartL(TMsvId aRootEntry, TRequestStatus &aStatus);
    84 	IMPORT_C void StartL(const CMsvEntrySelection& aSelection, TRequestStatus &aStatus);
    85 	IMPORT_C ~CImCacheManager();
    86 	IMPORT_C const TDesC8& ProgressL();
    87 	IMPORT_C void DoCancel();
    88 
    89 protected:
    90 	IMPORT_C void ConstructL();
    91 	IMPORT_C CImCacheManager(CMsvSession& aSession, TRequestStatus& aObserverRequestStatus);
    92 
    93 	IMPORT_C void RunL();
    94 
    95 private:
    96 	// Override this function to filter the currently selected message (iCurrentEntry).
    97 	// Return TRUE if the current entry is to be pruned.
    98 	/** Tests if cache cleanup should be performed on a message entry.
    99 	
   100 	After StartL() has been called, this is called once for each message entry. 
   101 	It should return true if the body text and attachment data belonging to the 
   102 	current message, as held in iCurrentEntry, should be deleted, or false if 
   103 	the message should be left unchanged.
   104 	
   105 	This function must be implemented in any classes derived from CImCacheManager.
   106 	
   107 	@return True to clean the entry, false to leave it unchanged */
   108 	virtual TBool Filter() const = 0;
   109 
   110 	void DoRunL();
   111 
   112 	// Remove the store from the currently selected entry
   113 	inline void PruneMessageL();
   114 	
   115 protected:
   116 	/** Message entry currently being processed. */
   117 	CMsvEntry* iCurrentEntry;
   118 
   119 private:
   120 	CMsvSession& iSession;
   121 	CImMessageFinder* iMessageFinder;
   122 	CImMessageCounter* iMessageCounter;
   123 	CMsvOperation* iDeleteOperation;
   124 
   125 	TImCacheManagerProgress iProgress;
   126 	TRequestStatus* iReport;
   127 
   128 	enum TImcmState
   129 		{
   130 		EImcmLookingForMessage,
   131 		EImcmPruningMessages,
   132 		EImcmCountingMessages,
   133 		EImcmSkippingPrune
   134 		};
   135 
   136 	TMsvId iRootEntry;
   137 	TImcmState iState;
   138 	TPckgBuf<TImCacheManagerProgress> iProgressBuf;
   139 
   140 	CMsvEntrySelection* iMessagesToPrune;
   141 	};
   142 
   143 #endif