textrendering/textformatting/undo/UndoSystemImpl.cpp
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     1 /*
       
     2 * Copyright (c) 2000-2009 Nokia Corporation and/or its subsidiary(-ies).
       
     3 * All rights reserved.
       
     4 * This component and the accompanying materials are made available
       
     5 * under the terms of "Eclipse Public License v1.0"
       
     6 * which accompanies this distribution, and is available
       
     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".
       
     8 *
       
     9 * Initial Contributors:
       
    10 * Nokia Corporation - initial contribution.
       
    11 *
       
    12 * Contributors:
       
    13 *
       
    14 * Description: 
       
    15 *
       
    16 */
       
    17 
       
    18 
       
    19 #include "UndoSystemImpl.h"
       
    20 #include "AssertFileAndLine.h"
       
    21 
       
    22 using namespace UndoSystem;
       
    23 
       
    24 namespace UndoSystemImpl
       
    25 {
       
    26 const TInt KCommandStackGranularity = 10;
       
    27 _LIT(KUndoPanic, "Undo System");
       
    28 }
       
    29 
       
    30 using namespace UndoSystemImpl;
       
    31 
       
    32 
       
    33 void UndoSystem::Panic(TPanicCode aCode)
       
    34 	{
       
    35 	User::Panic(KUndoPanic, aCode);
       
    36 	}
       
    37 
       
    38 /////////////////////
       
    39 //				   //
       
    40 //	CCommandStack  //
       
    41 //				   //
       
    42 /////////////////////
       
    43 
       
    44 CCommandStack::CCommandStack() : iEnd(0), iBookmark(0) {}
       
    45 
       
    46 CCommandStack::~CCommandStack()
       
    47 	{
       
    48 	if (iStack)
       
    49 		{
       
    50 		Reset();
       
    51 		delete iStack;
       
    52 		}
       
    53 	}
       
    54 
       
    55 void CCommandStack::ConstructL()
       
    56 	{
       
    57 	iStack = new(ELeave) CArrayFixSeg<CCommand*>(KCommandStackGranularity);
       
    58 	}
       
    59 
       
    60 CCommandStack* CCommandStack::NewL()
       
    61 	{
       
    62 	CCommandStack* r = new(ELeave) CCommandStack();
       
    63 	CleanupStack::PushL(r);
       
    64 	r->ConstructL();
       
    65 	CleanupStack::Pop(r);
       
    66 	return r;
       
    67 	}
       
    68 
       
    69 TInt CCommandStack::Count() const
       
    70 	{
       
    71 	ASSERT(iEnd <= iStack->Count());
       
    72 	return iEnd;
       
    73 	}
       
    74 
       
    75 void CCommandStack::Reset()
       
    76 	{
       
    77 	PruneTo(0);
       
    78 	iBookmark = -1;
       
    79 	}
       
    80 
       
    81 CCommand* CCommandStack::Top() const
       
    82 	{
       
    83 	ASSERT(0 <= iEnd);
       
    84 	ASSERT(iEnd <= iStack->Count());
       
    85 	return iEnd == 0? 0 : iStack->At(iEnd - 1);
       
    86 	}
       
    87 
       
    88 CCommand* CCommandStack::Pop()
       
    89 	{
       
    90 	ASSERT(iEnd <= iStack->Count());
       
    91 	CCommand* top = Top();
       
    92 	__ASSERT_ALWAYS(top, UndoSystem::Panic(KCommandStackUnderflow));
       
    93 	TInt numSlots = iStack->Count() - iEnd + 1;
       
    94 	ASSERT(numSlots <= iStack->Count());
       
    95 	iStack->Delete(iStack->Count() - numSlots, numSlots);
       
    96 	iEnd = iStack->Count();
       
    97 	if (iEnd < iBookmark)
       
    98 		iBookmark = -1;
       
    99 	return top;
       
   100 	}
       
   101 
       
   102 void CCommandStack::PruneTo(TInt aNumberOfItems)
       
   103 	{
       
   104 	ASSERT(iEnd <= iStack->Count());
       
   105 	iStack->Delete(iEnd, iStack->Count() - iEnd);
       
   106 	iEnd = iStack->Count();
       
   107 	if (aNumberOfItems < iEnd)
       
   108 		{
       
   109 		TInt numberToDestroy = iEnd - aNumberOfItems;
       
   110 		for (TInt i = 0; i != numberToDestroy; ++i)
       
   111 			{
       
   112 			delete iStack->At(i);
       
   113 			}
       
   114 		iStack->Delete(0, numberToDestroy);
       
   115 		iStack->Compress();
       
   116 		iEnd = aNumberOfItems;
       
   117 		iBookmark -= aNumberOfItems;
       
   118 		}
       
   119 	}
       
   120 
       
   121 void CCommandStack::PrepareToPushL(TInt aNumberOfItems)
       
   122 	{
       
   123 	iStack->ResizeL(iEnd + aNumberOfItems);
       
   124 	}
       
   125 
       
   126 void CCommandStack::Push(CCommand* aCommand)
       
   127 	{
       
   128 	ASSERT(aCommand);
       
   129 	__ASSERT_ALWAYS(iEnd < iStack->Count(), UndoSystem::Panic(KCommandStackPushNotPrepared));
       
   130 	iStack->At(iEnd) = aCommand;
       
   131 	++iEnd;
       
   132 	}
       
   133 
       
   134 void CCommandStack::Concatenate(CCommandStack& aStack)
       
   135 	{
       
   136 	TInt thisCount = iEnd;
       
   137 	iEnd += aStack.iEnd;
       
   138 	__ASSERT_DEBUG(iEnd <= iStack->Count(),
       
   139 		UndoSystem::Panic(KCommandStackPushNotPrepared));
       
   140 	for (TInt i = 0; i != aStack.iEnd; ++i, ++thisCount)
       
   141 		iStack->At(thisCount) = (aStack.iStack->At(i));
       
   142 	aStack.iEnd = 0;
       
   143 	aStack.iStack->Reset();
       
   144 	}
       
   145 
       
   146 void CCommandStack::SetBookmark()
       
   147 	{
       
   148 	iBookmark = iEnd;
       
   149 	}
       
   150 
       
   151 TBool CCommandStack::IsAtBookmark() const
       
   152 	{
       
   153 	return iBookmark == iEnd? ETrue : EFalse;
       
   154 	}
       
   155 
       
   156 CSingleCommandStack* CSingleCommandStack::NewL()
       
   157 	{
       
   158 	CSingleCommandStack* r = new(ELeave) CSingleCommandStack;
       
   159 	CleanupStack::PushL(r);
       
   160 	r->iStack.ConstructL();
       
   161 	CleanupStack::Pop(r);
       
   162 	return r;
       
   163 	}
       
   164 
       
   165 ///////////////////////
       
   166 //					 //
       
   167 //	CCommandHistory  //
       
   168 //					 //
       
   169 ///////////////////////
       
   170 
       
   171 CCommandHistory::CCommandHistory()
       
   172 	: iMaxItems(KMaxTInt >> 1)
       
   173 	{
       
   174 	}
       
   175 
       
   176 CCommandHistory::~CCommandHistory()
       
   177 	{
       
   178 	delete iStack;
       
   179 	}
       
   180 
       
   181 void CCommandHistory::ConstructL()
       
   182 	{
       
   183 	iStack = CCommandStack::NewL();
       
   184 	iCurrent = 0;
       
   185 	}
       
   186 
       
   187 CCommandHistory* CCommandHistory::NewL()
       
   188 	{
       
   189 	CCommandHistory* r = new(ELeave) CCommandHistory();
       
   190 	CleanupStack::PushL(r);
       
   191 	r->ConstructL();
       
   192 	CleanupStack::Pop(r);
       
   193 	return r;
       
   194 	}
       
   195 
       
   196 void CCommandHistory::Prune()
       
   197 	{
       
   198 	if (iMaxItems < iStack->Count())
       
   199 		iStack->PruneTo(iMaxItems);
       
   200 	}
       
   201 
       
   202 void CCommandHistory::SetMaxItems(TInt aMaxItems)
       
   203 	{
       
   204 	ASSERT(0 < aMaxItems);
       
   205 	iMaxItems = aMaxItems;
       
   206 	Prune();
       
   207 	}
       
   208 
       
   209 void CCommandHistory::CloseBatch(void* a)
       
   210 	{
       
   211 	CCommandHistory* aThat = reinterpret_cast<CCommandHistory*>(a);
       
   212 	aThat->iCurrent = 0;
       
   213 	if (aThat->iBatchUndoHasBeenWaived)
       
   214 		aThat->Reset();
       
   215 	}
       
   216 
       
   217 void CCommandHistory::DownBatchLevel(void*) {}
       
   218 
       
   219 TBool CCommandHistory::IsWithinBatch() const
       
   220 	{
       
   221 	return iCurrent? ETrue : EFalse;
       
   222 	}
       
   223 
       
   224 void CCommandHistory::BeginBatchLC()
       
   225 	{
       
   226 	if (iCurrent)
       
   227 		{
       
   228 		CleanupStack::PushL(TCleanupItem(DownBatchLevel, this));
       
   229 		}
       
   230 	else
       
   231 		{
       
   232 		iStack->PrepareToPushL(1);
       
   233 		iBatchUndoHasBeenWaived = EFalse;
       
   234 		CleanupStack::PushL(TCleanupItem(CloseBatch, this));
       
   235 		CBatchCommand* batch = CBatchCommand::NewL();
       
   236 		iCurrent = batch;
       
   237 		iStack->Push(batch);
       
   238 		}
       
   239 	}
       
   240 
       
   241 TBool CCommandHistory::UndoHasBeenWaived() const
       
   242 	{
       
   243 	return iCurrent? iBatchUndoHasBeenWaived : EFalse;
       
   244 	}
       
   245 
       
   246 void CCommandHistory::SetUndoWaived()
       
   247 	{
       
   248 	iBatchUndoHasBeenWaived = ETrue;
       
   249 	}
       
   250 
       
   251 void CCommandHistory::Reset()
       
   252 	{
       
   253 	iStack->Reset();
       
   254 	iCurrent = 0;
       
   255 	}
       
   256 
       
   257 void CCommandHistory::PrepareToAddCommandL(CCommand* aCommand)
       
   258 	{
       
   259 	if (iCurrent)
       
   260 		iCurrent->PrepareToPushL(aCommand);
       
   261 	else
       
   262 		iStack->PrepareToPushL(1);
       
   263 	}
       
   264 
       
   265 void CCommandHistory::AddCommand(CCommand* aCommand)
       
   266 	{
       
   267 	if (iCurrent)
       
   268 		iCurrent->Push(aCommand);
       
   269 	else
       
   270 		iStack->Push(aCommand);
       
   271 	if (!iCurrent)
       
   272 		Prune();
       
   273 	}
       
   274 
       
   275 CSingleCommand* CCommandHistory::TopSingleCommand() const
       
   276 	{
       
   277 	CCommand* top = Top();
       
   278 
       
   279 	if (!top)
       
   280 		return 0;
       
   281 
       
   282 	// if the top of the undo stack is an empty batch, then we are starting a new
       
   283 	// batch command and so do not want to combine. Otherwise, if the top is a batch
       
   284 	// with elements, we want to see if we can combine with the top one.
       
   285 	CBatchCommand* batch = top->Batch();
       
   286 	return batch? batch->Top() : top->Single();
       
   287 	}
       
   288 
       
   289 CCommand* CCommandHistory::Top() const
       
   290 	{
       
   291 	return iStack->Top();
       
   292 	}
       
   293 
       
   294 CCommand* CCommandHistory::Pop()
       
   295 	{
       
   296 	ASSERT(!iCurrent);
       
   297 	return iStack->Pop();
       
   298 	}
       
   299 
       
   300 void CCommandHistory::Clean()
       
   301 	{
       
   302 	ASSERT(!iCurrent);
       
   303 	CCommand* command = Top();
       
   304 	if (!command)
       
   305 		return;
       
   306 	CBatchCommand* batch = command->Batch();
       
   307 	if (!batch)
       
   308 		return;
       
   309 	if (batch->IsEmpty())
       
   310 		{
       
   311 		delete Pop();
       
   312 		}
       
   313 	}
       
   314 
       
   315 void CCommandHistory::SetBookmark()
       
   316 	{
       
   317 	iStack->SetBookmark();
       
   318 	}
       
   319 
       
   320 TBool CCommandHistory::IsAtBookmark()
       
   321 	{
       
   322 	return iStack->IsAtBookmark();
       
   323 	}
       
   324