// Copyright (c) 2007-2009 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:

 // FONT related functions and the font cache

 // 

 //

 #include "wsfont.h"

 CWsFontCache * CWsFontCache::iSelf = NULL;

 TDblQue<CWsFbsFont> * CWsFontCache::iList = NULL;

 CWsFontCache::CWsFontCache()

 	{

 	}

 CWsFontCache::~CWsFontCache()

 	{

 	}

 void CWsFontCache::CreateInstanceL()

 	{

 	// The list MUST exist before creation of the cache since the cache

 	// contains an array of fonts. When the array is created the fonts add themselves

 	// to the list.

 	// The list is ordered from newest to oldest font used.

 	iList = new (ELeave) TDblQue<CWsFbsFont>(_FOFF(CWsFbsFont,iLink));

 	CleanupStack::PushL(iList);

 	iSelf = new (ELeave) CWsFontCache;

 	CleanupStack::Pop(iList);

 	}

 void CWsFontCache::DestroyInstance()

 	{

 	// The cache has to be destroyed first since the fonts are

 	// destroyed when the cache's array if destroyed. The fonts 

 	// remove themselves from the list

 	delete iSelf;

 	iSelf = NULL;

 	delete iList;

 	iList = NULL;

 	}

 void CWsFontCache::ReleaseFont(CWsFbsFont *&aFont)

 	{

 	if (aFont)

 		{

 		WS_ASSERT_DEBUG(aFont->iCount>0, EWsPanicFontCacheCount);

 		// decrease usage count

 		aFont->iCount--;

 		// when the font reaches zero then the font entry can be reused later

 		aFont = NULL;

 		}

 	}

 TBool CWsFontCache::UseFont(CWsFbsFont *&aFont, TInt aHandle)

 	{

 	ReleaseFont(aFont);

 	CWsFbsFont *font = NULL;

 	// The list is ordered from newest to oldest font used.

 	TDblQueIter<CWsFbsFont> iter(*iList);

 	// Search for the font from newest to oldest font

 	while ((font = iter++) != NULL)

 		{

 		// if the font handle already exists use existing font

 		if (font->Handle() == aHandle)

 			{

 			break;

 			}

 		}

 	// Font not found in cache so find an unused entry

 	if (!font)

 		{

 		// Starting search from oldest to newest font unsed

 		iter.SetToLast();

 		while((font = iter--) != NULL)

 			{

 			// if you find an unused font then use that font entry

 			if (font->iCount == 0)

 				{

 				break;

 				}

 			}

 		// if an unused font is not found then all fonts are being used and 

 		// the font can not be created

 		if (!font)

 			{

 			return(ETrue);	// No room in cache

 			}

 		// release and reuse the font entry to create a new font

 		font->Reset();

 		if (font->Duplicate(aHandle) != KErrNone)

 			{

 			return(EFalse);	// Bad handle, (indicated by aFont=NULL)

 			}

 		}

 	// put font at the font of the list as the font is the newest font

 	font->iLink.Deque();

 	iList->AddFirst(*font);

 	// increase usage count

 	font->iCount++;

 	aFont = font;

 	return(EFalse);

 	}

 TDblQue<CWsFbsFont>& CWsFontCache::List()

 	{

 	return *Instance()->iList;

 	}

 CWsFbsFont::CWsFbsFont()

 	{

 	// add itself to the font cache

 	CWsFontCache::List().AddLast(*this);

 	}

 CWsFbsFont::~CWsFbsFont()

 	{

 	// remove itself from the font cache

 	iLink.Deque();

 	WS_ASSERT_DEBUG(iCount==0, EWsPanicFontCacheCount);

 	}