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/*
* Copyright (C) 2006, 2007 Apple, Inc. All rights reserved.
* Copyright (C) 2012 Google, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "core/editing/commands/UndoStack.h"
#include "core/dom/ContainerNode.h"
#include "core/editing/commands/UndoStep.h"
#include "wtf/AutoReset.h"
namespace blink {
// Arbitrary depth limit for the undo stack, to keep it from using
// unbounded memory. This is the maximum number of distinct undoable
// actions -- unbroken stretches of typed characters are coalesced
// into a single action.
static const size_t maximumUndoStackDepth = 1000;
UndoStack::UndoStack() : m_inRedo(false) {}
UndoStack* UndoStack::create() {
return new UndoStack();
}
void UndoStack::registerUndoStep(UndoStep* step) {
if (m_undoStack.size() == maximumUndoStackDepth)
m_undoStack.removeFirst(); // drop oldest item off the far end
if (!m_inRedo)
m_redoStack.clear();
m_undoStack.append(step);
}
void UndoStack::registerRedoStep(UndoStep* step) {
m_redoStack.append(step);
}
bool UndoStack::canUndo() const {
return !m_undoStack.isEmpty();
}
bool UndoStack::canRedo() const {
return !m_redoStack.isEmpty();
}
void UndoStack::undo() {
if (canUndo()) {
UndoStepStack::iterator back = --m_undoStack.end();
UndoStep* step(back->get());
m_undoStack.remove(back);
step->unapply();
// unapply will call us back to push this command onto the redo stack.
}
}
void UndoStack::redo() {
if (canRedo()) {
UndoStepStack::iterator back = --m_redoStack.end();
UndoStep* step(back->get());
m_redoStack.remove(back);
DCHECK(!m_inRedo);
AutoReset<bool> redoScope(&m_inRedo, true);
step->reapply();
// reapply will call us back to push this command onto the undo stack.
}
}
void UndoStack::clear() {
m_undoStack.clear();
m_redoStack.clear();
}
DEFINE_TRACE(UndoStack) {
visitor->trace(m_undoStack);
visitor->trace(m_redoStack);
}
} // namespace blink
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