diff -r 453dfc402455 -r 0aa8cc770c8a mtpdataproviders/mtpplaybackcontroldp/mtpplaybackmpximplementation/src/cmtpplaybackcommandchecker.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mtpdataproviders/mtpplaybackcontroldp/mtpplaybackmpximplementation/src/cmtpplaybackcommandchecker.cpp	Tue Aug 31 16:03:15 2010 +0300
@@ -0,0 +1,209 @@
+// Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of "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:
+//
+
+/**
+ @file
+ @internalComponent
+*/
+
+#include "cmtpplaybackcommandchecker.h"
+#include "cmtpplaybackcontrolimpl.h"
+
+// Constants
+__FLOG_STMT(_LIT8(KComponent,"PlaybackCommandChecker");)
+
+// ======== MEMBER FUNCTIONS ========
+
+// ---------------------------------------------------------------------------
+// CMTPPlaybackCommandChecker::NewL
+// ---------------------------------------------------------------------------
+//
+CMTPPlaybackCommandChecker* CMTPPlaybackCommandChecker::NewL(
+            CMTPPlaybackControlImpl& aControlImpl )
+    {
+    CMTPPlaybackCommandChecker* self = new ( ELeave ) 
+                        CMTPPlaybackCommandChecker( aControlImpl );
+    return self;
+    }
+
+// ---------------------------------------------------------------------------
+// CMTPPlaybackCommandChecker::~CMTPPlaybackCommandChecker
+// ---------------------------------------------------------------------------
+//
+CMTPPlaybackCommandChecker::~CMTPPlaybackCommandChecker()
+    {
+    __FLOG(_L8("+CMTPPlaybackCommandChecker::~CMTPPlaybackCommandChecker"));
+    __FLOG(_L8("-CMTPPlaybackCommandChecker::~CMTPPlaybackCommandChecker"));
+    __FLOG_CLOSE;
+    }
+
+// ---------------------------------------------------------------------------
+// CMTPPlaybackCommandChecker::CheckPlaybackCommandContextL
+// ---------------------------------------------------------------------------
+//
+void CMTPPlaybackCommandChecker::CheckPlaybackCommandContextL( TMTPPlaybackCommand aMTPPBCommand )
+    {
+    __FLOG(_L8("+CMTPPlaybackCommandChecker::CheckPlaybackCommandContextL"));
+    
+    MTPPlaybackControlImpl().SetMTPPBCmd( aMTPPBCommand );
+    
+    switch ( aMTPPBCommand )
+        {
+        case EPlaybackCmdInitObject:
+        case EPlaybackCmdGetVolumeSet:
+        case EPlaybackCmdGetVolume:
+        case EPlaybackCmdGetState:
+        case EPlaybackCmdSetVolume:
+            {
+            __FLOG(_L8("no context check for init object command"));
+            }
+            break;
+        case EPlaybackCmdInitIndex:
+        case EPlaybackCmdSkip:
+        case EPlaybackCmdGetIndex:
+            {
+            if ( MTPPlaybackControlImpl().SongCount() < 0 )
+                {
+                User::Leave( KPlaybackErrContextInvalid );
+                }
+            }
+            break;
+        case EPlaybackCmdPlay:
+        case EPlaybackCmdPause:
+        case EPlaybackCmdStop:
+        case EPlaybackCmdSeekForward:
+        case EPlaybackCmdSeekBackward:
+        case EPlaybackCmdGetObject:
+        case EPlaybackCmdSetPosition:
+        case EPlaybackCmdGetPosition:
+            {
+            switch ( MTPPlaybackControlImpl().CurrentState())
+                {
+                case EPbStateNotInitialised:
+                    {
+                    User::Leave( KPlaybackErrContextInvalid );
+                    }
+                default:
+                    break;
+                }
+            }
+            break;
+        default:
+            {
+            __FLOG(_L8("Not support command!"));
+            User::Leave( KPlaybackErrParamInvalid );
+            }
+            break;
+        }
+    
+    __FLOG(_L8("-CMTPPlaybackCommandChecker::CheckPlaybackCommandContextL"));
+    }
+
+// ---------------------------------------------------------------------------
+// CMTPPlaybackCommandChecker::CheckAndUpdatePlaybackParamL
+// ---------------------------------------------------------------------------
+//
+void CMTPPlaybackCommandChecker::CheckAndUpdatePlaybackParamL( CMTPPlaybackCommand& aMTPPPBSourceCmd, 
+                CMTPPbCmdParam** aMTPPPBTargetParam )
+    {
+    __FLOG(_L8("+CMTPPlaybackCommandChecker::CheckAndUpdatePlaybackParamL"));
+    
+    delete *aMTPPPBTargetParam;
+    *aMTPPPBTargetParam = NULL;
+    
+    switch ( aMTPPPBSourceCmd.PlaybackCommand())
+        {
+        case EPlaybackCmdInitObject:
+            {
+            const TMTPPbCategory category = aMTPPPBSourceCmd.ParamL().SuidSetL().Category();
+            TFileName suid = aMTPPPBSourceCmd.ParamL().SuidSetL().Suid();
+            *aMTPPPBTargetParam = CMTPPbCmdParam::NewL( category, suid );
+            }
+            break;
+        case EPlaybackCmdInitIndex:
+            {
+            TUint32 songIndex = aMTPPPBSourceCmd.ParamL().Uint32L();
+            if ( songIndex > ( MTPPlaybackControlImpl().SongCount()-1 ))
+                {
+                User::Leave( KPlaybackErrParamInvalid );
+                }
+            *aMTPPPBTargetParam = CMTPPbCmdParam::NewL( songIndex );
+            }
+            break;
+        case EPlaybackCmdSkip:
+            {
+            TInt32 songIndex = MTPPlaybackControlImpl().SongIndex() + aMTPPPBSourceCmd.ParamL().Int32L();
+            TUint32 songCount = MTPPlaybackControlImpl().SongCount();
+            
+            if ( songIndex < 0 )
+                {
+                songIndex = ( - songIndex ) % songCount;
+                songIndex = ( songCount - songIndex ) % songCount;
+                }
+            else
+                {
+                songIndex = songIndex % songCount;
+                }
+            
+            *aMTPPPBTargetParam = CMTPPbCmdParam::NewL( songIndex);
+            }
+            break;
+        case EPlaybackCmdSetVolume:
+            {
+            TUint32 volume = aMTPPPBSourceCmd.ParamL().Uint32L();
+            if( volume > KPbPlaybackVolumeLevelMax )
+                {
+                User::Leave( KPlaybackErrParamInvalid );
+                }
+            *aMTPPPBTargetParam = CMTPPbCmdParam::NewL( volume );
+            }
+            break;
+        case EPlaybackCmdSetPosition:
+            {
+            TUint32 position= aMTPPPBSourceCmd.ParamL().Uint32L();
+            *aMTPPPBTargetParam = CMTPPbCmdParam::NewL( position );
+            }
+            break;
+        default:
+            {
+            __FLOG(_L8("No param, just cache command"));
+            }
+            break;
+        }
+    
+    __FLOG(_L8("-CMTPPlaybackCommandChecker::CheckAndUpdatePlaybackParamL"));
+    }
+
+// ---------------------------------------------------------------------------
+// CMTPPlaybackCommandChecker::CMTPPlaybackCommandChecker
+// ---------------------------------------------------------------------------
+//
+CMTPPlaybackCommandChecker::CMTPPlaybackCommandChecker( 
+        CMTPPlaybackControlImpl& aControlImpl )
+                : iMTPPlaybackControl( aControlImpl )
+    {
+    __FLOG_OPEN(KMTPSubsystem, KComponent);
+    }
+
+// ---------------------------------------------------------------------------
+// CMTPPlaybackCommandChecker::MTPPlaybackControlImpl
+// ---------------------------------------------------------------------------
+//
+CMTPPlaybackControlImpl& CMTPPlaybackCommandChecker::MTPPlaybackControlImpl()
+    {
+    return iMTPPlaybackControl;
+    }
+
+