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 "core/editing/UndoStack.h" 29 30 #include "core/dom/ContainerNode.h" 31 #include "core/editing/UndoStep.h" 32 #include "platform/EventDispatchForbiddenScope.h" 33 #include "wtf/TemporaryChange.h" 34 35 namespace blink { 36 37 // Arbitrary depth limit for the undo stack, to keep it from using 38 // unbounded memory. This is the maximum number of distinct undoable 39 // actions -- unbroken stretches of typed characters are coalesced 40 // into a single action. 41 static const size_t maximumUndoStackDepth = 1000; 42 43 UndoStack::UndoStack() 44 : m_inRedo(false) 45 { 46 } 47 48 DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(UndoStack) 49 50 PassOwnPtrWillBeRawPtr<UndoStack> UndoStack::create() 51 { 52 return adoptPtrWillBeNoop(new UndoStack()); 53 } 54 55 void UndoStack::registerUndoStep(PassRefPtrWillBeRawPtr<UndoStep> step) 56 { 57 if (m_undoStack.size() == maximumUndoStackDepth) 58 m_undoStack.removeFirst(); // drop oldest item off the far end 59 if (!m_inRedo) 60 m_redoStack.clear(); 61 m_undoStack.append(step); 62 } 63 64 void UndoStack::registerRedoStep(PassRefPtrWillBeRawPtr<UndoStep> step) 65 { 66 m_redoStack.append(step); 67 } 68 69 void UndoStack::didUnloadFrame(const LocalFrame& frame) 70 { 71 EventDispatchForbiddenScope assertNoEventDispatch; 72 filterOutUndoSteps(m_undoStack, frame); 73 filterOutUndoSteps(m_redoStack, frame); 74 } 75 76 void UndoStack::filterOutUndoSteps(UndoStepStack& stack, const LocalFrame& frame) 77 { 78 UndoStepStack newStack; 79 while (!stack.isEmpty()) { 80 UndoStep* step = stack.first().get(); 81 if (!step->belongsTo(frame)) 82 newStack.append(step); 83 stack.removeFirst(); 84 } 85 stack.swap(newStack); 86 } 87 88 bool UndoStack::canUndo() const 89 { 90 return !m_undoStack.isEmpty(); 91 } 92 93 bool UndoStack::canRedo() const 94 { 95 return !m_redoStack.isEmpty(); 96 } 97 98 void UndoStack::undo() 99 { 100 if (canUndo()) { 101 UndoStepStack::iterator back = --m_undoStack.end(); 102 RefPtrWillBeRawPtr<UndoStep> step(back->get()); 103 m_undoStack.remove(back); 104 step->unapply(); 105 // unapply will call us back to push this command onto the redo stack. 106 } 107 } 108 109 void UndoStack::redo() 110 { 111 if (canRedo()) { 112 UndoStepStack::iterator back = --m_redoStack.end(); 113 RefPtrWillBeRawPtr<UndoStep> step(back->get()); 114 m_redoStack.remove(back); 115 116 ASSERT(!m_inRedo); 117 TemporaryChange<bool> redoScope(m_inRedo, true); 118 step->reapply(); 119 // reapply will call us back to push this command onto the undo stack. 120 } 121 } 122 123 void UndoStack::trace(Visitor* visitor) 124 { 125 visitor->trace(m_undoStack); 126 visitor->trace(m_redoStack); 127 } 128 129 } // namespace blink 130