1 /* 2 * Copyright (C) 2006, 2007 Apple, Inc. All rights reserved. 3 * Copyright (C) 2012 Google, Inc. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY 15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR 18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "config.h" 28 #include "UndoStack.h" 29 30 #include "core/dom/ContainerNode.h" 31 #include "core/editing/UndoStep.h" 32 #include "wtf/TemporaryChange.h" 33 34 namespace WebCore { 35 36 // Arbitrary depth limit for the undo stack, to keep it from using 37 // unbounded memory. This is the maximum number of distinct undoable 38 // actions -- unbroken stretches of typed characters are coalesced 39 // into a single action. 40 static const size_t maximumUndoStackDepth = 1000; 41 42 UndoStack::UndoStack() 43 : m_inRedo(false) 44 { 45 } 46 47 UndoStack::~UndoStack() 48 { 49 } 50 51 PassOwnPtr<UndoStack> UndoStack::create() 52 { 53 return adoptPtr(new UndoStack()); 54 } 55 56 void UndoStack::registerUndoStep(PassRefPtr<UndoStep> step) 57 { 58 if (m_undoStack.size() == maximumUndoStackDepth) 59 m_undoStack.removeFirst(); // drop oldest item off the far end 60 if (!m_inRedo) 61 m_redoStack.clear(); 62 m_undoStack.append(step); 63 } 64 65 void UndoStack::registerRedoStep(PassRefPtr<UndoStep> step) 66 { 67 m_redoStack.append(step); 68 } 69 70 void UndoStack::didUnloadFrame(const Frame& frame) 71 { 72 NoEventDispatchAssertion assertNoEventDispatch; 73 filterOutUndoSteps(m_undoStack, frame); 74 filterOutUndoSteps(m_redoStack, frame); 75 } 76 77 void UndoStack::filterOutUndoSteps(UndoStepStack& stack, const Frame& frame) 78 { 79 UndoStepStack newStack; 80 while (!stack.isEmpty()) { 81 UndoStep* step = stack.first().get(); 82 if (!step->belongsTo(frame)) 83 newStack.append(step); 84 stack.removeFirst(); 85 } 86 stack.swap(newStack); 87 } 88 89 bool UndoStack::canUndo() const 90 { 91 return !m_undoStack.isEmpty(); 92 } 93 94 bool UndoStack::canRedo() const 95 { 96 return !m_redoStack.isEmpty(); 97 } 98 99 void UndoStack::undo() 100 { 101 if (canUndo()) { 102 UndoStepStack::iterator back = --m_undoStack.end(); 103 RefPtr<UndoStep> step(*back); 104 m_undoStack.remove(back); 105 step->unapply(); 106 // unapply will call us back to push this command onto the redo stack. 107 } 108 } 109 110 void UndoStack::redo() 111 { 112 if (canRedo()) { 113 UndoStepStack::iterator back = --m_redoStack.end(); 114 RefPtr<UndoStep> step(*back); 115 m_redoStack.remove(back); 116 117 ASSERT(!m_inRedo); 118 TemporaryChange<bool> redoScope(m_inRedo, true); 119 step->reapply(); 120 // reapply will call us back to push this command onto the undo stack. 121 } 122 } 123 124 } // namesace WebCore 125