sl@0: // Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: // All rights reserved.
sl@0: // This component and the accompanying materials are made available
sl@0: // under the terms of "Eclipse Public License v1.0"
sl@0: // which accompanies this distribution, and is available
sl@0: // at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: //
sl@0: // Initial Contributors:
sl@0: // Nokia Corporation - initial contribution.
sl@0: //
sl@0: // Contributors:
sl@0: //
sl@0: // Description:
sl@0: //
sl@0: 
sl@0: #include "UT_STD.H"
sl@0: 
sl@0: // Class CDbBasicWindowStage
sl@0: 
sl@0: CDbBasicWindowStage::CDbBasicWindowStage(const TDbWindow& aWindow)
sl@0: 	: iWindow(aWindow), iRecords(EWindowArrayGranularity), iPos(-1)
sl@0: 	{
sl@0: 	__ASSERT(aWindow.Size()!=aWindow.ENone);
sl@0: 	}
sl@0: 
sl@0: TBool CDbBasicWindowStage::GetRecord(TDbRecordId& aRecordId)
sl@0: 	{
sl@0: 	if (TUint(iPos)>=TUint(iRecords.Count()))
sl@0: 		return EFalse;
sl@0: 	aRecordId=iRecords[iPos];
sl@0: 	return ETrue;
sl@0: 	}
sl@0: 
sl@0: void CDbBasicWindowStage::Reset()
sl@0: //
sl@0: // Reset the window to initial state
sl@0: //
sl@0: 	{
sl@0: 	CDbDataStage::Reset();
sl@0: 	iRecords.Reset();
sl@0: 	iPos=-1;
sl@0: 	}
sl@0: 
sl@0: TBool CDbBasicWindowStage::EvaluateL(TInt& aWork,TDbRecordId& aRecordId,TBool& aAtRow)
sl@0: //
sl@0: // Do as much work as we can to make the window match the desired shape
sl@0: //
sl@0: 	{
sl@0: 	TBool eval=CDbDataStage::EvaluateL(aWork,aRecordId,aAtRow);
sl@0: 	if (!eval)
sl@0: 		{
sl@0: 		eval=DoEvaluateL(aWork);
sl@0: 		aAtRow=GetRecord(aRecordId);
sl@0: 		}
sl@0: 	return eval;
sl@0: 	}
sl@0: 
sl@0: TInt CDbBasicWindowStage::CountL()
sl@0: //
sl@0: // Window'd views only report the evaluated records
sl@0: //
sl@0: 	{
sl@0: 	return iRecords.Count();
sl@0: 	}
sl@0: 
sl@0: CDbBasicWindowStage::TGoto CDbBasicWindowStage::GotoL(TInt& /*aWork*/,TDbPosition aPosition,TDbRecordId& aRecordId)
sl@0: 	{
sl@0: 	switch (aPosition)
sl@0: 		{
sl@0: 	default:
sl@0: 		__ASSERT(0);
sl@0: 		break;
sl@0: 	case EDbFirst:
sl@0: 		iPos=0;
sl@0: 		break;
sl@0: 	case EDbLast:
sl@0: 		iPos=iRecords.Count()-1;
sl@0: 		break;
sl@0: 	case EDbNext:
sl@0: 		++iPos;
sl@0: 		break;
sl@0: 	case EDbPrevious:
sl@0: 		--iPos;
sl@0: 		break;
sl@0: 		}
sl@0: 	return GetRecord(aRecordId) ? ESuccess : ENoRow;
sl@0: 	}
sl@0: 
sl@0: TInt CDbBasicWindowStage::Find(TDbRecordId aRecordId,TInt& aPos)
sl@0: 	{
sl@0: 	TKeyArrayFix key(0,ECmpTUint32);
sl@0: 	return iRecords.Find(aRecordId,key,aPos);
sl@0: 	}
sl@0: 
sl@0: TBool CDbBasicWindowStage::GotoL(TDbRecordId aRecordId)
sl@0: 	{
sl@0: 	return Find(aRecordId,iPos)==0;
sl@0: 	}
sl@0: 
sl@0: void CDbBasicWindowStage::ReadRowL(TDbRecordId aRecordId)
sl@0: 	{
sl@0: 	TRAPD(r,CDbDataStage::ReadRowL(aRecordId));
sl@0: 	if (r==KErrNotFound)
sl@0: 		{
sl@0: 		TInt pos;
sl@0: 		if (Find(aRecordId,pos)==KErrNone)
sl@0: 			{
sl@0: 			iRecords.Delete(pos);
sl@0: 			if (pos<iPos)
sl@0: 				--iPos;
sl@0: 			}
sl@0: 		}
sl@0: 	__LEAVE_IF_ERROR(r);
sl@0: 	}
sl@0: 
sl@0: TDbRecordId CDbBasicWindowStage::WriteRowL(TWrite aWrite,TSynch aSynch)
sl@0: 	{
sl@0: 	TDbRecordId id=CDbDataStage::WriteRowL(aWrite,ENoSynch);
sl@0: 	if (aWrite==EAppend && iWindow.Size()==iWindow.EUnlimited)
sl@0: 		{
sl@0: 		iRecords.AppendL(id);
sl@0: 		if (aSynch==ESynch)
sl@0: 			iPos=iRecords.Count()-1;	// follow the append
sl@0: 		}
sl@0: 	return id;
sl@0: 	}
sl@0: 
sl@0: CDbBasicWindowStage::TDelete CDbBasicWindowStage::DeleteRowL(TDbRecordId& aRecordId,TSynch)
sl@0: //
sl@0: // Remove the row from the window if it is present
sl@0: //
sl@0: 	{
sl@0: 	CDbDataStage::DeleteRowL(aRecordId,ENoSynch);
sl@0: 	if (GotoL(aRecordId))
sl@0: 		{
sl@0: 		iRecords.Delete(iPos);
sl@0: 		if (GetRecord(aRecordId))
sl@0: 			return EDeletedAtNext;
sl@0: 		}
sl@0: 	return EDeletedAtEnd;
sl@0: 	}
sl@0: 
sl@0: // Class CDbWindowStage
sl@0: 
sl@0: CDbWindowStage::CDbWindowStage(const TDbWindow& aWindow)
sl@0: 	: CDbBasicWindowStage(aWindow), iIterPos(EAtBeginning), iView(EBeginning)
sl@0: 	{}
sl@0: 
sl@0: void CDbWindowStage::Reset()
sl@0: //
sl@0: // Reset the window to initial state
sl@0: //
sl@0: 	{
sl@0: 	CDbBasicWindowStage::Reset();
sl@0: 	iIterPos=EAtBeginning;
sl@0: 	iView=EBeginning;
sl@0: 	}
sl@0: 
sl@0: TInt CDbWindowStage::WhatToEvaluate()
sl@0: //
sl@0: // count of slots to fill, <0 at beginning, >0 at end. 0 none
sl@0: //
sl@0: 	{
sl@0: 	if (iView==EAll)
sl@0: 		return 0;
sl@0: 	if (iWindow.Size()==iWindow.EUnlimited)
sl@0: 		return KMaxTInt;
sl@0: 	TInt space=iWindow.Size()-iRecords.Count();
sl@0: 	TInt lag=iPos-iWindow.PreferredPos();
sl@0: 	switch (iView)
sl@0: 		{
sl@0: 	default:
sl@0: 		__ASSERT(0);
sl@0: 	case EBeginning:
sl@0: 		return space+Max(lag,0);	// fill up and use forward lag if any
sl@0: 	case EEnd:
sl@0: 		return Min(lag,0)-space;	// fill up backwards and use rear lag if any
sl@0: 	case EMiddle:
sl@0: 		if (lag<0 && iIterPos==EAtBeginning)	// use iterator position if we can
sl@0: 			return lag;
sl@0: 		if (space+lag>0)
sl@0: 			return space+lag;
sl@0: 		if (lag<0)
sl@0: 			return lag;
sl@0: 		return 0;
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: TDbPosition CDbWindowStage::ResetIterToBeginningL()
sl@0: 	{
sl@0: 	for (TInt ii=iRecords.Count();--ii>=0;)
sl@0: 		{
sl@0: 		if (CDbDataStage::GotoL(iRecords[0]))
sl@0: 			return EDbPrevious;
sl@0: // has been deleted, try the next one
sl@0: 		iRecords.Delete(0);
sl@0: 		if (iPos>0)
sl@0: 			--iPos;
sl@0: 		}
sl@0: // no records to work with, start at the end
sl@0: 	return EDbLast;
sl@0: 	}
sl@0: 
sl@0: TDbPosition CDbWindowStage::ResetIterToEndL()
sl@0: 	{
sl@0: 	for (TInt ii=iRecords.Count();--ii>=0;)
sl@0: 		{
sl@0: 		if (CDbDataStage::GotoL(iRecords[ii]))
sl@0: 			return EDbNext;
sl@0: // has been deleted, try the next one
sl@0: 		iRecords.Delete(ii);
sl@0: 		if (iPos>ii)
sl@0: 			--iPos;
sl@0: 		}
sl@0: // no records to work with, start at the beginning
sl@0: 	return EDbFirst;
sl@0: 	}
sl@0: 
sl@0: TDbPosition CDbWindowStage::SetIteratorL(TInt anEval)
sl@0: //
sl@0: // Set the iterator for some work and return the first iterator direction
sl@0: //
sl@0: 	{
sl@0: 	switch (iIterPos)
sl@0: 		{
sl@0: 	default:
sl@0: 		__ASSERT(0);
sl@0: 	case EAtBeginning:
sl@0: 		if (anEval<0)
sl@0: 			return EDbPrevious;
sl@0: // turn around iterator to work at end
sl@0: 		iIterPos=EAtEnd;
sl@0: 		return ResetIterToEndL();
sl@0: 	case EAtEnd:
sl@0: 		if (anEval>0)
sl@0: 			return EDbNext;
sl@0: // turn around iterator to work at beginning
sl@0: 		iIterPos=EAtBeginning;
sl@0: 		return ResetIterToBeginningL();
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: void CDbWindowStage::ExtendAtBeginningL(TInt aRecords,TDbPosition aFirst,TInt& aWork)
sl@0: 	{
sl@0: 	TDbRecordId id=iRecords.Count()>0 ? iRecords[0] : KDbNullRecordId;
sl@0: 	while (aRecords>0)
sl@0: 		{
sl@0: 		switch (CDbDataStage::GotoL(aWork,aFirst,id))
sl@0: 			{
sl@0: 		default:
sl@0: 			__ASSERT(0);
sl@0: 		case EExhausted:
sl@0: 			return;
sl@0: 		case ESuccess:
sl@0: 			if (iRecords.Count()==iWindow.Size())
sl@0: 				{	// drop last record
sl@0: 				iRecords.Delete(iRecords.Count()-1);
sl@0: 				if (iView==EEnd)
sl@0: 					iView=EMiddle;
sl@0: 				}
sl@0: 			iRecords.InsertL(0,id);
sl@0: 			++iPos;
sl@0: 			if (aFirst==EDbLast)
sl@0: 				aFirst=EDbPrevious;
sl@0: 			--aRecords;
sl@0: 			break;
sl@0: 		case ENoRow:	// no more data that way
sl@0: 			iView=iView==EEnd ? EAll : EBeginning;
sl@0: 			return;
sl@0: 		case ESynchFailure:	// have to do some work on the iterator now
sl@0: 			aFirst=ResetIterToBeginningL();
sl@0: 			break;
sl@0: 			}
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: void CDbWindowStage::ExtendAtEndL(TInt aRecords,TDbPosition aFirst,TInt& aWork)
sl@0: 	{
sl@0: 	TDbRecordId id=iRecords.Count()>0 ? iRecords[iRecords.Count()-1] : KDbNullRecordId;
sl@0: 	while (aRecords>0)
sl@0: 		{
sl@0: 		switch (CDbDataStage::GotoL(aWork,aFirst,id))
sl@0: 			{
sl@0: 		default:
sl@0: 			__ASSERT(0);
sl@0: 		case EExhausted:
sl@0: 			return;
sl@0: 		case ESuccess:
sl@0: 			if (iRecords.Count()==iWindow.Size())
sl@0: 				{	// drop first record
sl@0: 				iRecords.Delete(0);
sl@0: 				--iPos;
sl@0: 				if (iView==EBeginning)
sl@0: 					iView=EMiddle;
sl@0: 				}
sl@0: 			iRecords.AppendL(id);
sl@0: 			if (aFirst==EDbFirst)
sl@0: 				aFirst=EDbNext;
sl@0: 			--aRecords;
sl@0: 			break;
sl@0: 		case ENoRow:
sl@0: 			iView=iView==EBeginning ? EAll : EEnd;
sl@0: 			return;
sl@0: 		case ESynchFailure:
sl@0: 			aFirst=ResetIterToEndL();
sl@0: 			break;
sl@0: 			}
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: TBool CDbWindowStage::DoEvaluateL(TInt& aWork)
sl@0: //
sl@0: // Do as much work as we can to make the window match the desired shape
sl@0: //
sl@0: 	{
sl@0: 	for (;;)
sl@0: 		{
sl@0: 		TInt eval=WhatToEvaluate();
sl@0: 		if (eval==0)
sl@0: 			return EFalse;
sl@0: 		if (aWork<=0)
sl@0: 			return ETrue;
sl@0: 		TDbPosition dir=SetIteratorL(eval);
sl@0: 		if (eval>0)
sl@0: 			ExtendAtEndL(eval,dir,aWork);
sl@0: 		else
sl@0: 			ExtendAtBeginningL(-eval,dir,aWork);
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: TBool CDbWindowStage::Unevaluated()
sl@0: //
sl@0: // Return whether it is worth Evaluating
sl@0: //
sl@0: 	{
sl@0: 	return WhatToEvaluate()==0 ? CDbDataStage::Unevaluated() : ETrue;
sl@0: 	}