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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 "third_party/blink/renderer/core/editing/commands/undo_stack.h"
#include "base/auto_reset.h"
#include "third_party/blink/renderer/core/dom/container_node.h"
#include "third_party/blink/renderer/core/editing/commands/undo_step.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 kMaximumUndoStackDepth = 1000;
UndoStack::UndoStack() : in_redo_(false) {}
UndoStack* UndoStack::Create() {
return new UndoStack();
}
void UndoStack::RegisterUndoStep(UndoStep* step) {
if (undo_stack_.size())
DCHECK_GE(step->SequenceNumber(), undo_stack_.back()->SequenceNumber());
if (undo_stack_.size() == kMaximumUndoStackDepth)
undo_stack_.pop_front(); // drop oldest item off the far end
if (!in_redo_)
redo_stack_.clear();
undo_stack_.push_back(step);
}
void UndoStack::RegisterRedoStep(UndoStep* step) {
redo_stack_.push_back(step);
}
bool UndoStack::CanUndo() const {
return !undo_stack_.IsEmpty();
}
bool UndoStack::CanRedo() const {
return !redo_stack_.IsEmpty();
}
void UndoStack::Undo() {
if (CanUndo()) {
UndoStepStack::iterator back = --undo_stack_.end();
UndoStep* step(back->Get());
undo_stack_.erase(back);
step->Unapply();
// unapply will call us back to push this command onto the redo stack.
}
}
void UndoStack::Redo() {
if (CanRedo()) {
UndoStepStack::iterator back = --redo_stack_.end();
UndoStep* step(back->Get());
redo_stack_.erase(back);
DCHECK(!in_redo_);
base::AutoReset<bool> redo_scope(&in_redo_, true);
step->Reapply();
// reapply will call us back to push this command onto the undo stack.
}
}
void UndoStack::Clear() {
undo_stack_.clear();
redo_stack_.clear();
}
void UndoStack::Trace(blink::Visitor* visitor) {
visitor->Trace(undo_stack_);
visitor->Trace(redo_stack_);
}
UndoStack::UndoStepRange::UndoStepRange(const UndoStepStack& steps)
: step_stack_(steps) {}
UndoStack::UndoStepRange UndoStack::UndoSteps() const {
return UndoStepRange(undo_stack_);
}
} // namespace blink
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