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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_UNDO_UNDO_MANAGER_H_
#define COMPONENTS_UNDO_UNDO_MANAGER_H_
#include <stddef.h>
#include <memory>
#include "base/macros.h"
#include "base/memory/scoped_vector.h"
#include "base/observer_list.h"
#include "base/strings/string16.h"
class UndoManagerObserver;
class UndoOperation;
// UndoGroup ------------------------------------------------------------------
// UndoGroup represents a user action and stores all the operations that
// make that action. Typically there is only one operation per UndoGroup.
class UndoGroup {
public:
UndoGroup();
~UndoGroup();
void AddOperation(std::unique_ptr<UndoOperation> operation);
const std::vector<UndoOperation*>& undo_operations() {
return operations_.get();
}
void Undo();
// The resource string id describing the undo and redo action.
int get_undo_label_id() const { return undo_label_id_; }
void set_undo_label_id(int label_id) { undo_label_id_ = label_id; }
int get_redo_label_id() const { return redo_label_id_; }
void set_redo_label_id(int label_id) { redo_label_id_ = label_id; }
private:
ScopedVector<UndoOperation> operations_;
// The resource string id describing the undo and redo action.
int undo_label_id_;
int redo_label_id_;
DISALLOW_COPY_AND_ASSIGN(UndoGroup);
};
// UndoManager ----------------------------------------------------------------
// Maintains user actions as a group of operations that store enough info to
// undo and redo those operations.
class UndoManager {
public:
UndoManager();
~UndoManager();
// Perform an undo or redo operation.
void Undo();
void Redo();
size_t undo_count() const { return undo_actions_.size(); }
size_t redo_count() const { return redo_actions_.size(); }
base::string16 GetUndoLabel() const;
base::string16 GetRedoLabel() const;
void AddUndoOperation(std::unique_ptr<UndoOperation> operation);
// Group multiple operations into one undoable action.
void StartGroupingActions();
void EndGroupingActions();
// Suspend undo tracking while processing non-user initiated changes such as
// profile synchonization.
void SuspendUndoTracking();
void ResumeUndoTracking();
bool IsUndoTrakingSuspended() const;
// Returns all UndoOperations that are awaiting Undo or Redo. Note that
// ownership of the UndoOperations is retained by UndoManager.
std::vector<UndoOperation*> GetAllUndoOperations() const;
// Remove all undo and redo operations. Note that grouping of actions and
// suspension of undo tracking states are left unchanged.
void RemoveAllOperations();
// Observers are notified when the internal state of this class changes.
void AddObserver(UndoManagerObserver* observer);
void RemoveObserver(UndoManagerObserver* observer);
private:
void Undo(bool* performing_indicator,
ScopedVector<UndoGroup>* active_undo_group);
bool is_user_action() const { return !performing_undo_ && !performing_redo_; }
// Notifies the observers that the undo manager's state has changed.
void NotifyOnUndoManagerStateChange();
// Handle the addition of |new_undo_group| to the active undo group container.
void AddUndoGroup(UndoGroup* new_undo_group);
// Returns the undo or redo UndoGroup container that should store the next
// change taking into account if an undo or redo is being executed.
ScopedVector<UndoGroup>* GetActiveUndoGroup();
// Containers of user actions ready for an undo or redo treated as a stack.
ScopedVector<UndoGroup> undo_actions_;
ScopedVector<UndoGroup> redo_actions_;
// The observers to notify when internal state changes.
base::ObserverList<UndoManagerObserver> observers_;
// Supports grouping operations into a single undo action.
int group_actions_count_;
// The container that is used when actions are grouped.
std::unique_ptr<UndoGroup> pending_grouped_action_;
// The action that is in the process of being undone.
UndoGroup* undo_in_progress_action_;
// Supports the suspension of undo tracking.
int undo_suspended_count_;
// Set when executing Undo or Redo so that incoming changes are correctly
// processed.
bool performing_undo_;
bool performing_redo_;
DISALLOW_COPY_AND_ASSIGN(UndoManager);
};
#endif // COMPONENTS_UNDO_UNDO_MANAGER_H_
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