svgedit/editor/historyrecording.js

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/* eslint-disable no-var */
/* globals svgedit */
/**
* Package: svgedit.history
*
* Licensed under the MIT License
*
* Copyright(c) 2016 Flint O'Brien
*/
// Dependencies:
// 1) history.js
(function () {
'use strict';
if (!svgedit.history) {
svgedit.history = {};
}
var history = svgedit.history;
/**
* History recording service.
*
* A self-contained service interface for recording history. Once injected, no other dependencies
* or globals are required (example: UndoManager, command types, etc.). Easy to mock for unit tests.
* Built on top of history classes in history.js.
*
* There is a simple start/end interface for batch commands.
*
* HistoryRecordingService.NO_HISTORY is a singleton that can be passed in to functions
* that record history. This helps when the caller requires that no history be recorded.
*
* Usage:
* The following will record history: insert, batch, insert.
* ```
* hrService = new svgedit.history.HistoryRecordingService(this.undoMgr);
* hrService.insertElement(elem, text); // add simple command to history.
* hrService.startBatchCommand('create two elements');
* hrService.changeElement(elem, attrs, text); // add to batchCommand
* hrService.changeElement(elem, attrs2, text); // add to batchCommand
* hrService.endBatchCommand(); // add batch command with two change commands to history.
* hrService.insertElement(elem, text); // add simple command to history.
* ```
*
* Note that all functions return this, so commands can be chained, like so:
*
* ```
* hrService
* .startBatchCommand('create two elements')
* .insertElement(elem, text)
* .changeElement(elem, attrs, text)
* .endBatchCommand();
* ```
*
* @param {svgedit.history.UndoManager} undoManager - The undo manager.
* A value of null is valid for cases where no history recording is required.
* See singleton: HistoryRecordingService.NO_HISTORY
*/
var HistoryRecordingService = history.HistoryRecordingService = function (undoManager) {
this.undoManager_ = undoManager;
this.currentBatchCommand_ = null;
this.batchCommandStack_ = [];
};
/**
* @type {svgedit.history.HistoryRecordingService} NO_HISTORY - Singleton that can be passed
* in to functions that record history, but the caller requires that no history be recorded.
*/
HistoryRecordingService.NO_HISTORY = new HistoryRecordingService();
/**
* Start a batch command so multiple commands can recorded as a single history command.
* Requires a corresponding call to endBatchCommand. Start and end commands can be nested.
*
* @param {string} text - Optional string describing the batch command.
* @returns {svgedit.history.HistoryRecordingService}
*/
HistoryRecordingService.prototype.startBatchCommand = function (text) {
if (!this.undoManager_) { return this; }
this.currentBatchCommand_ = new history.BatchCommand(text);
this.batchCommandStack_.push(this.currentBatchCommand_);
return this;
};
/**
* End a batch command and add it to the history or a parent batch command.
* @returns {svgedit.history.HistoryRecordingService}
*/
HistoryRecordingService.prototype.endBatchCommand = function () {
if (!this.undoManager_) { return this; }
if (this.currentBatchCommand_) {
var batchCommand = this.currentBatchCommand_;
this.batchCommandStack_.pop();
var length = this.batchCommandStack_.length;
this.currentBatchCommand_ = length ? this.batchCommandStack_[length - 1] : null;
this.addCommand_(batchCommand);
}
return this;
};
/**
* Add a MoveElementCommand to the history or current batch command
* @param {Element} elem - The DOM element that was moved
* @param {Element} oldNextSibling - The element's next sibling before it was moved
* @param {Element} oldParent - The element's parent before it was moved
* @param {string} [text] - An optional string visible to user related to this change
* @returns {svgedit.history.HistoryRecordingService}
*/
HistoryRecordingService.prototype.moveElement = function (elem, oldNextSibling, oldParent, text) {
if (!this.undoManager_) { return this; }
this.addCommand_(new history.MoveElementCommand(elem, oldNextSibling, oldParent, text));
return this;
};
/**
* Add an InsertElementCommand to the history or current batch command
* @param {Element} elem - The DOM element that was added
* @param {string} [text] - An optional string visible to user related to this change
* @returns {svgedit.history.HistoryRecordingService}
*/
HistoryRecordingService.prototype.insertElement = function (elem, text) {
if (!this.undoManager_) { return this; }
this.addCommand_(new history.InsertElementCommand(elem, text));
return this;
};
/**
* Add a RemoveElementCommand to the history or current batch command
* @param {Element} elem - The DOM element that was removed
* @param {Element} oldNextSibling - The element's next sibling before it was removed
* @param {Element} oldParent - The element's parent before it was removed
* @param {string} [text] - An optional string visible to user related to this change
* @returns {svgedit.history.HistoryRecordingService}
*/
HistoryRecordingService.prototype.removeElement = function (elem, oldNextSibling, oldParent, text) {
if (!this.undoManager_) { return this; }
this.addCommand_(new history.RemoveElementCommand(elem, oldNextSibling, oldParent, text));
return this;
};
/**
* Add a ChangeElementCommand to the history or current batch command
* @param {Element} elem - The DOM element that was changed
* @param {Object} attrs - An object with the attributes to be changed and the values they had *before* the change
* @param {string} [text] - An optional string visible to user related to this change
* @returns {svgedit.history.HistoryRecordingService}
*/
HistoryRecordingService.prototype.changeElement = function (elem, attrs, text) {
if (!this.undoManager_) { return this; }
this.addCommand_(new history.ChangeElementCommand(elem, attrs, text));
return this;
};
/**
* Private function to add a command to the history or current batch command.
* @param cmd
* @returns {svgedit.history.HistoryRecordingService}
* @private
*/
HistoryRecordingService.prototype.addCommand_ = function (cmd) {
if (!this.undoManager_) { return this; }
if (this.currentBatchCommand_) {
this.currentBatchCommand_.addSubCommand(cmd);
} else {
this.undoManager_.addCommandToHistory(cmd);
}
};
}());