third_party/WebKit/Source/core/inspector/InspectorHistory.cpp

/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
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 *
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 * notice, this list of conditions and the following disclaimer.
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 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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#include "core/inspector/InspectorHistory.h"

#include "bindings/core/v8/ExceptionState.h"
#include "bindings/core/v8/ExceptionStatePlaceholder.h"
#include "core/dom/Node.h"

namespace blink {

namespace {

class UndoableStateMark final : public InspectorHistory::Action {
 public:
  UndoableStateMark() : InspectorHistory::Action("[UndoableState]") {}

  bool perform(ExceptionState&) override { return true; }

  bool undo(ExceptionState&) override { return true; }

  bool redo(ExceptionState&) override { return true; }

  bool isUndoableStateMark() override { return true; }
};

}  // namespace

InspectorHistory::Action::Action(const String& name) : m_name(name) {}

InspectorHistory::Action::~Action() {}

DEFINE_TRACE(InspectorHistory::Action) {}

String InspectorHistory::Action::toString() {
  return m_name;
}

bool InspectorHistory::Action::isUndoableStateMark() {
  return false;
}

String InspectorHistory::Action::mergeId() {
  return "";
}

void InspectorHistory::Action::merge(Action*) {}

InspectorHistory::InspectorHistory() : m_afterLastActionIndex(0) {}

bool InspectorHistory::perform(Action* action, ExceptionState& exceptionState) {
  if (!action->perform(exceptionState))
    return false;
  appendPerformedAction(action);
  return true;
}

void InspectorHistory::appendPerformedAction(Action* action) {
  if (!action->mergeId().isEmpty() && m_afterLastActionIndex > 0 &&
      action->mergeId() == m_history[m_afterLastActionIndex - 1]->mergeId()) {
    m_history[m_afterLastActionIndex - 1]->merge(action);
    if (m_history[m_afterLastActionIndex - 1]->isNoop())
      --m_afterLastActionIndex;
    m_history.resize(m_afterLastActionIndex);
  } else {
    m_history.resize(m_afterLastActionIndex);
    m_history.append(action);
    ++m_afterLastActionIndex;
  }
}

void InspectorHistory::markUndoableState() {
  perform(new UndoableStateMark(), IGNORE_EXCEPTION);
}

bool InspectorHistory::undo(ExceptionState& exceptionState) {
  while (m_afterLastActionIndex > 0 &&
         m_history[m_afterLastActionIndex - 1]->isUndoableStateMark())
    --m_afterLastActionIndex;

  while (m_afterLastActionIndex > 0) {
    Action* action = m_history[m_afterLastActionIndex - 1].get();
    if (!action->undo(exceptionState)) {
      reset();
      return false;
    }
    --m_afterLastActionIndex;
    if (action->isUndoableStateMark())
      break;
  }

  return true;
}

bool InspectorHistory::redo(ExceptionState& exceptionState) {
  while (m_afterLastActionIndex < m_history.size() &&
         m_history[m_afterLastActionIndex]->isUndoableStateMark())
    ++m_afterLastActionIndex;

  while (m_afterLastActionIndex < m_history.size()) {
    Action* action = m_history[m_afterLastActionIndex].get();
    if (!action->redo(exceptionState)) {
      reset();
      return false;
    }
    ++m_afterLastActionIndex;
    if (action->isUndoableStateMark())
      break;
  }
  return true;
}

void InspectorHistory::reset() {
  m_afterLastActionIndex = 0;
  m_history.clear();
}

DEFINE_TRACE(InspectorHistory) {
  visitor->trace(m_history);
}

}  // namespace blink