diff -r deec7e509f66 -r ca9a0fc2f082 contentmgmt/contentaccessfwfordrm/engineering/dox/AsyncSendReceive.dox
--- a/contentmgmt/contentaccessfwfordrm/engineering/dox/AsyncSendReceive.dox	Wed Oct 06 11:09:48 2010 +0530
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,76 +0,0 @@
-// Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
-// All rights reserved.
-// This component and the accompanying materials are made available
-// under the terms of the License "Eclipse Public License v1.0"
-// which accompanies this distribution, and is available
-// at the URL "http://www.eclipse.org/legal/epl-v10.html".
-//
-// Initial Contributors:
-// Nokia Corporation - initial contribution.
-//
-// Contributors:
-//
-// Description:
-// An agent plugin may have to service an asynchronous request, for example when
-// <code>ContentAccess::CAgentManager::NotifyStatusChange()</code> is called.
-// If the agent plugin must make an asynchronous SendReceive() call to service the request
-// then it must be careful to ensure that any memory that is passed as an argument
-// in the call is still valid when the agent server that receives the call processes
-// and uses the memory.
-// There are two ways that this can be achieved:
-// <hr>
-// If the agent plugin cannot guarantee that a variable to be passed in the asynchronous
-// SendReceive() call will still be in scope when the agent server comes to access and use
-// it then the agent plugin should store a local heap copy of the data and pass this
-// in the call instead. It is the responsibility of the agent plugin to maintain this heap 
-// memory and delete it when appropriate. Depending on how and when the agent server uses 
-// the memory, it may be safe to delete the memory after the asynchronous call has 
-// been accepted, or not until the asynchronous request has completed.
-// For example, an agent plugin could implement the API <code>ContentAccess::CAgentManager::NotifyStatusChange()</code> 
-// as illustrated below. Note that for this API the agent plugin can make no assumption about the 
-// scope of the descriptor passed to aURI. 
-// void CTestAgentManager::NotifyStatusChange(const TDesC& aURI, TEventMask aMask, TRequestStatus& aStatus)
-// HBufC* uri = aURI.Alloc();
-// if(uri)
-// // store the heap variable in a local array
-// iAsyncDataArray.Append(uri); // takes ownership of uri
-// SendReceive(EManagerNotifyStatusChange, TIpcArgs(uri,aMask),aStatus);		
-// <hr>
-// Alternatively, the agent plugin can use the variables that are in scope at the time of the 
-// asynchronous SendReceive() call if it makes a synchronous SendReceive() call afterwards,
-// within the same function scope, as illustrated below. The synchronous message can 
-// be a 'no operation' in the agent server.
-// void CTestAgentManager::NotifyStatusChange(const TDesC& aURI, TEventMask aMask, TRequestStatus& aStatus)
-// SendReceive(EManagerNotifyStatusChange, TIpcArgs(&aURI,aMask),aStatus);
-// // this call doesn't have to be immediately after the asynchronous call, but within this function
-// SendReceive(ENoOp,TIpcArgs(NULL));
-// The synchronous call causes the message queue to be flushed into the agent server before the thread returns from the 
-// function and unwinds the call stack. The intention is that the agent server will only complete the second (synchronous) 
-// message after receiving and doing initial processing of the first (asynchronous) message, which may include, for 
-// example, reading the uri descriptor. 
-// However, an obvious disadvantage of this pattern is that it incurs a second IPC call, and so may degrade performance.<br>
-// Moreover, there are several caveats which must hold true in order for the pattern to work:
-// 1. The kernel delivers messages in the order that they are sent (this is currently true).<br>
-// 2. The agent server is guaranteed to finish processing the first message before completing the second message.<br>
-// This requires understanding of the agent server implementation.<br>
-// 3. After initial processing of the first (asynchronous) message the agent server does not need to 
-// access the memory supplied in the message again. This requires understanding of the agent server implementation.<br>
-// 4. The synchronous call is a request that has no effect on the state of the agent server - a 'no operation'
-// may or may not be possible.
-// <b> 
-// For these reasons, this pattern should only be used as a last resort - for example, if the agent plugin cannot store member data in its class for compatibility reasons.
-// <b>
-// 
-//
-
-/**
- @page CAFAsyncSendReceive Making an asynchronous SendReceive() call in an agent plugin
- - @ref StoreLocalCopy
- - @ref SyncSendReceive
- @section StoreLocalCopy Storing a local heap copy of transient data
- @code
- @endcode
- @section SyncSendReceive Following the asynchronous call with a synchronous call
- @code
- @endcode
-*/