githubmirror/brackets

src/view/MainViewManager.js
1 778 строк65 KB
nethip
This has the first cut which now opens default preferences file in the left pane and user preferences file brackets.json in the right pane. Also moved the code from PreferencesManager to DebugCommands extension.
10 июл 2015, 19:40
10 июл 2015, 19:409154e74
/*
 * Copyright (c) 2014 Adobe Systems Incorporated. All rights reserved.
 *  
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation 
 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the 
 * Software is furnished to do so, subject to the following conditions:
 *  
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *  
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
 * DEALINGS IN THE SOFTWARE.
 * 
 */

/*jslint vars: true, plusplus: true, devel: true, nomen: true, indent: 4, maxerr: 50 */
/*global define, $ */

/**
 * MainViewManager manages the arrangement of all open panes as well as provides the controller
 * logic behind all views in the MainView (e.g. ensuring that a file doesn't appear in 2 lists)
 *
 * Each pane contains one or more views wich are created by a view factory and inserted into a pane list. 
 * There may be several panes managed by the MainViewManager with each pane containing a list of views.
 * The panes are always visible and the layout is determined by the MainViewManager and the user.
 *
 * Currently we support only 2 panes.
 *
 * All of the WorkingSet APIs take a paneId Argument.  This can be an actual pane Id, ALL_PANES (in most cases) 
 * or ACTIVE_PANE. ALL_PANES may not be supported for some APIs.  See the API for details.
 *
 * This module dispatches several events:
 *
 *    - activePaneChange - When the active pane changes.  There will always be an active pane.
 *          (e, newPaneId:string, oldPaneId:string) 
 *    - currentFileChange -- When the user has switched to another pane, file, document. When the user closes a view
 *      and there are no other views to show the current file will be null.  
 *          (e, newFile:File, newPaneId:string, oldFile:File, oldPaneId:string)
 *    - paneLayoutChange -- When Orientation changes.
 *          (e, orientation:string)
 *    - paneCreate -- When a pane is created
 *          (e, paneId:string)
 *    - paneDestroy -- When a pane is destroyed
 *          (e, paneId:string)
 *      
 *
 *    To listen for working set changes, you must listen to *all* of these events:
 *    - workingSetAdd -- When a file is added to the working set 
 *          (e, fileAdded:File, index:number, paneId:string)
 *    - workingSetAddList -- When multiple files are added to the working set 
 *          (e, fileAdded:Array.<File>, paneId:string)
 *    - workingSetMove - When a File has moved to a different working set
 *          (e, File:FILE, sourcePaneId:string, destinationPaneId:string)
 *    - workingSetRemove -- When a file is removed from the working set 
 *          (e, fileRemoved:File, suppressRedraw:boolean, paneId:string)
 *    - workingSetRemoveList -- When multiple files are removed from the working set 
 *          (e, filesRemoved:Array.<File>, paneId:string)
 *    - workingSetSort -- When a pane's view array is reordered without additions or removals.
 *          (e, paneId:string)
 *    - workingSetUpdate -- When changes happen due to system events such as a file being deleted.
 *                              listeners should discard all working set info and rebuilt it from the pane 
 *                              by calling getWorkingSet()
 *          (e, paneId:string)
 *    - _workingSetDisableAutoSort -- When the working set is reordered by manually dragging a file. 
 *          (e, paneId:string) For Internal Use Only.
 *
 * To listen for events, do something like this: (see EventDispatcher for details on this pattern)
 *    `MainViewManager.on("eventname", handler);`
 */
define(function (require, exports, module) {
    "use strict";
    
    var _                   = require("thirdparty/lodash"),
        EventDispatcher     = require("utils/EventDispatcher"),
        Strings             = require("strings"),
        AppInit             = require("utils/AppInit"),
        CommandManager      = require("command/CommandManager"),
        MainViewFactory     = require("view/MainViewFactory"),
        ViewStateManager    = require("view/ViewStateManager"),
        Commands            = require("command/Commands"),
        Dialogs             = require("widgets/Dialogs"),
        DefaultDialogs      = require("widgets/DefaultDialogs"),
        EditorManager       = require("editor/EditorManager"),
        FileSystemError     = require("filesystem/FileSystemError"),
        DocumentManager     = require("document/DocumentManager"),
        PreferencesManager  = require("preferences/PreferencesManager"),
        ProjectManager      = require("project/ProjectManager"),
        WorkspaceManager    = require("view/WorkspaceManager"),
        AsyncUtils          = require("utils/Async"),
        ViewUtils           = require("utils/ViewUtils"),
        Resizer             = require("utils/Resizer"),
        Pane                = require("view/Pane").Pane;
        
    /** 
     * Preference setting name for the MainView Saved State
     * @const
     * @private
     */
    var PREFS_NAME          = "mainView.state";
    
    /** 
     * Legacy Preference setting name used to migrate old preferences
     * @const
     * @private
     */
    var OLD_PREFS_NAME      = "project.files";
    
    /** 
     * Special paneId shortcut that can be used to specify that
     * all panes should be targeted by the API.  
     * Not all APIs support this constnant. 
     * Check the API documentation before use.
     * @const
     */
    var ALL_PANES           = "ALL_PANES";

    /** 
     * Special paneId shortcut that can be used to specify that
     * the API should target the focused pane only.  
     * All APIs support this shortcut.
     * @const
     */
    var ACTIVE_PANE        = "ACTIVE_PANE";
        
    /** 
     * Internal pane id
     * @const
     * @private
     */
    var FIRST_PANE          = "first-pane";

    /** 
     * Internal pane id
     * @const
     * @private
     */
    var SECOND_PANE         = "second-pane";
    
    /*
     * NOTE: The following commands and constants will change 
     *        when implementing the UX UI Treatment @larz0
     */

    /** 
     * Vertical layout state name
     * @const
     * @private
     */
    var VERTICAL            = "VERTICAL";

    /** 
     * Horizontal layout state name
     * @const
     * @private
     */
    var HORIZONTAL          = "HORIZONTAL";
    
    /**
     * The minimum width or height that a pane can be
     * @const
     * @private
     */
    var MIN_PANE_SIZE      = 75;
    
    /**
     * current orientation (null, VERTICAL or HORIZONTAL)
     * @type {string=} 
     * @private
     */
    var _orientation = null;
    
    /**
     * current pane id. May not be null
     * @type {!string}
     * @private
     */
    var _activePaneId = null;
    
    /**
     * DOM element hosting the Main View.
     * @type {jQuery}
     * @private
     */
    var _$el;
    
    /**
     * Maps paneId to Pane objects
     * @type {Object.<string, Pane>} 
     * @private
     */
    var _panes = {};
    
    
    /**
     * map of pane scroll states
     * @type {Object.map<string, *>} 
     * @private
     */
    var _paneScrollStates = {};
    
    
    /**
     * flag indicating if traversing is currently taking place
     * When True, changes the current pane's MRU list will not be updated. 
     * Useful for next/previous keyboard navigation (until Ctrl is released)
     * or for incremental-search style document preview like Quick Open will eventually have.
     * @type {!boolean}
     * @private
     */
    var _traversingFileList = false;

    /**
     * The global MRU list (for traversing)
     * @type {Array.<file:File, paneId:string>}
     */
    var _mruList = [];
    
    /**
     * localized pane titles 
     * @type {Object.<FIRST_PANE|SECOND_PANE, <VERTICAL.string, HORIZONTAL.string>}}
     *  Localized string for first and second panes in the current orientation.  
     * @see {@link #getPaneTitle} for more information
     * @private
     */
    var _paneTitles  = {};
        
    /*
     * Initialize _paneTitles
     */
    _paneTitles[FIRST_PANE] = {};
    _paneTitles[SECOND_PANE] = {};
    
    _paneTitles[FIRST_PANE][VERTICAL]     = Strings.LEFT;
    _paneTitles[FIRST_PANE][HORIZONTAL]   = Strings.TOP;
    _paneTitles[SECOND_PANE][VERTICAL]    = Strings.RIGHT;
    _paneTitles[SECOND_PANE][HORIZONTAL]  = Strings.BOTTOM;
    
    /**
     * Makes a MRU List Entry
     * @param {!File} File - the file
     * @param {!string} paneId - the paneId
     * @return {{file:File, paneId:string}}
     * @private
     */
    function _makeMRUListEntry(file, paneId) {
        return {file: file, paneId: paneId};
    }

    /**
     * Locates the first  MRU entry of a file
     * @param {!File} File - the file
     * @return {{file:File, paneId:string}}
     * @private
     */
    function _findFileInMRUList(file) {
        return _.findIndex(_mruList, function (record) {
            return (record.file.fullPath === file.fullPath);
        });
    }

    
    /**
     * Retrieves the currently active Pane Id
     * @return {!string} Active Pane's ID.
     */
    function getActivePaneId() {
        return _activePaneId;
    }
    
    /**
     * Resolve paneId to actual pane.
     * @param {?string} paneId - id of the desired pane. May be symbolic or null (to indicate current pane)
     * @return {string} id of the pane in which to open the document
     */
    function _resolvePaneId(paneId) {
        if (!paneId || paneId === ACTIVE_PANE) {
            return getActivePaneId();
        }
        return paneId;
    }
    
    /**
     * Retrieves the Pane object for the given paneId
     * @param {!string} paneId - id of the pane to retrieve
     * @return {?Pane} the Pane object or null if a pane object doesn't exist for the pane
     * @private
     */
    function _getPane(paneId) {
        paneId = _resolvePaneId(paneId);
        
        if (_panes[paneId]) {
            return _panes[paneId];
        }
        
        return null;
    }
    
    /**
     * Focuses the current pane. If the current pane has a current view, then the pane will focus the view.
     */
    function focusActivePane() {
        _getPane(ACTIVE_PANE).focus();
    }
    
    /**
     * Determines if the pane id is a special pane id
     * @param {!string} paneId - the id to test
     * @return {boolean} true if the pane id is a special identifier, false if not
     */
    function _isSpecialPaneId(paneId) {
        return paneId === ACTIVE_PANE || paneId === ALL_PANES;
    }
    
    /**
     * Makes the file the most recent for the pane and the global mru lists
     * @param {!string} paneId - id of the pane to mae th file most recent or ACTIVE_PANE
     * @param {!File} file - File object to make most recent
     * @private
     */
    function _makeFileMostRecent(paneId, file) {
        var index,
            entry,
            pane = _getPane(paneId);

        if (!_traversingFileList) {
            pane.makeViewMostRecent(file);
        
            index = _.findIndex(_mruList, function (record) {
                return (record.file === file && record.paneId === pane.id);
            });

            entry = _makeMRUListEntry(file, pane.id);

            if (index !== -1) {
                _mruList.splice(index, 1);
            }

            if (_findFileInMRUList(file) !== -1) {
                console.log(file.fullPath + " duplicated in mru list");
            }
            
            // add it to the front of the list
            _mruList.unshift(entry);
        }
    }

    /**
     * Makes the Pane's current file the most recent
     * @param {!string} paneId - id of the pane to make the file most recent, or ACTIVE_PANE
     * @param {!File} file - File object to make most recent
     * @private
     */
    function _makePaneMostRecent(paneId) {
        var pane = _getPane(paneId);

        if (pane.getCurrentlyViewedFile()) {
            _makeFileMostRecent(paneId, pane.getCurrentlyViewedFile());
        }
    }
    
    /**
     * Switch active pane to the specified pane id (or ACTIVE_PANE/ALL_PANES, in which case this
     * call does nothing).
     * @param {!string} paneId - the id of the pane to activate
     */
    function setActivePaneId(newPaneId) {
        if (!_isSpecialPaneId(newPaneId) && newPaneId !== _activePaneId) {
            var oldPaneId = _activePaneId,
                oldPane = _getPane(ACTIVE_PANE),
                newPane = _getPane(newPaneId);
            
            if (!newPane) {
                throw new Error("invalid pane id: " + newPaneId);
            }
            
            _activePaneId = newPaneId;
            
            exports.trigger("activePaneChange", newPaneId, oldPaneId);
            exports.trigger("currentFileChange", _getPane(ACTIVE_PANE).getCurrentlyViewedFile(),
                                                            newPaneId,
                                                            oldPane.getCurrentlyViewedFile(),
                                                            oldPaneId);
            
            _makePaneMostRecent(_activePaneId);
            focusActivePane();
        }
    }
    
    /**
     * Retrieves the Pane ID for the specified container
     * @param {!jQuery} $el - the element of the pane to fetch
     * @return {?string} the id of the pane that matches the container or undefined if a pane doesn't exist for that container
     */
    function _getPaneFromElement($el) {
        return _.find(_panes, function (pane) {
            if (pane.$el[0] === $el[0]) {
                return pane;
            }
        });
    }
    
    /**
     * Retrieves the currently viewed file of the specified paneId
     * @param {?string} paneId - the id of the pane in which to retrieve the currently viewed file
     * @return {?File} File object of the currently viewed file, or null if there isn't one or there's no such pane
     */
    function getCurrentlyViewedFile(paneId) {
        var pane = _getPane(paneId);
        return pane ? pane.getCurrentlyViewedFile() : null;
    }
 
    /**
     * Retrieves the currently viewed path of the pane specified by paneId
     * @param {?string} paneId - the id of the pane in which to retrieve the currently viewed path
     * @return {?string} the path of the currently viewed file or null if there isn't one
     */
    function getCurrentlyViewedPath(paneId) {
        var file = getCurrentlyViewedFile(paneId);
        return file ? file.fullPath : null;
    }
    
    /**
     * EditorManager.activeEditorChange handler 
     *   This event is triggered when an visible editor gains focus
     *   Therefore we need to Activate the pane that the active editor belongs to
     * @private
     * @param {!jQuery.Event} e - jQuery Event object
     * @param {Editor=} current - editor being made the current editor
     */
    function _activeEditorChange(e, current) {
        if (current) {
            var $container = current.$el.parent().parent(),
                pane = _getPaneFromElement($container);

            if (pane) {
                // Editor is a full editor
                if (pane.id !== _activePaneId) {
                    // we just need to set the active pane in this case
                    //  it will dispatch the currentFileChange message as well
                    //  as dispatching other events when the active pane changes
                    setActivePaneId(pane.id);
                }
            } else {
                // Editor is an inline editor, find the parent pane
                var parents = $container.parents(".view-pane");
                if (parents.length === 1) {
                    $container = $(parents[0]);
                    pane = _getPaneFromElement($container);
                    if (pane) {
                        if (pane.id !== _activePaneId) {
                            // activate the pane which will put focus in the pane's doc
                            setActivePaneId(pane.id);
                            // reset the focus to the inline editor
                            current.focus();
                        }
                    }
                }
            }
        }
    }
    
    
    /**
     * Iterates over the pane or ALL_PANES and calls the callback function for each.
     * @param {!string} paneId - id of the pane in which to adjust the scroll state, ALL_PANES or ACTIVE_PANE
     * @param {!function(!pane:Pane):boolean} callback - function to callback on to perform work. 
     * The callback will receive a Pane and should return false to stop iterating.
     * @private
     */
    function _forEachPaneOrPanes(paneId, callback) {
        if (paneId === ALL_PANES) {
            _.forEach(_panes, callback);
        } else {
            callback(_getPane(paneId));
        }
    }
    
    /**
     * Caches the specified pane's current scroll state
     * If there was already cached state for the specified pane, it is discarded and overwritten
     * @param {!string} paneId - id of the pane in which to cache the scroll state,
     *                            ALL_PANES or ACTIVE_PANE
     */
    function cacheScrollState(paneId) {
        _forEachPaneOrPanes(paneId, function (pane) {
            _paneScrollStates[pane.id] = pane.getScrollState();
        });
    }

    
    /**
     * Restores the scroll state from cache and applies the heightDelta 
     * The view implementation is responsible for applying or ignoring the heightDelta.
     * This is used primarily when a modal bar opens to keep the editor from scrolling the current 
     * page out of view in order to maintain the appearance. 
     * The state is removed from the cache after calling this function.  
     * @param {!string} paneId - id of the pane in which to adjust the scroll state, 
     *                              ALL_PANES or ACTIVE_PANE
     * @param {!number} heightDelta - delta H to apply to the scroll state
     */
    function restoreAdjustedScrollState(paneId, heightDelta) {
        _forEachPaneOrPanes(paneId, function (pane) {
            pane.restoreAndAdjustScrollState(_paneScrollStates[pane.id], heightDelta);
            delete _paneScrollStates[pane.id];
        });
    }
        
    
    /**
     * Retrieves the WorkingSet for the given paneId not including temporary views
     * @param {!string} paneId - id of the pane in which to get the view list, ALL_PANES or ACTIVE_PANE
     * @return {Array.<File>}
     */
    function getWorkingSet(paneId) {
        var result = [];

        _forEachPaneOrPanes(paneId, function (pane) {
            var viewList = pane.getViewList();
            result = _.union(result, viewList);
        });

        return result;
    }
    
    
    /**
     * Retrieves the list of all open files including temporary views
     * @return {array.<File>} the list of all open files in all open panes
     */
    function getAllOpenFiles() {
        var result = getWorkingSet(ALL_PANES);
        _.forEach(_panes, function (pane) {
            var file = pane.getCurrentlyViewedFile();
            if (file) {
                result = _.union(result, [file]);
            }
        });
        return result;
    }
    
    /**
     * Retrieves the list of all open pane ids
     * @return {array.<string>} the list of all open panes
     */
    function getPaneIdList() {
        return Object.keys(_panes);
    }
    
    /**
     * Retrieves the size of the selected pane's view list
     * @param {!string} paneId - id of the pane in which to get the workingset size.
     *      Can use `ALL_PANES` or `ACTIVE_PANE`
     * @return {!number} the number of items in the specified pane 
     */
    function getWorkingSetSize(paneId) {
        var result = 0;
        _forEachPaneOrPanes(paneId, function (pane) {
            result += pane.getViewListSize();
        });
        return result;
    }
    
    /**
     * Retrieves the title to display in the workingset view
     * @param {!string} paneId - id of the pane in which to get the title
     * @return {?string} title
     */
    function getPaneTitle(paneId) {
        return _paneTitles[paneId][_orientation];
    }
    
    /**
     * Retrieves the number of panes
     * @return {number} 
     */
    function getPaneCount() {
        return Object.keys(_panes).length;
    }
    
    /**
     * Helper to abastract the common working set search functions
     * @param {!string} paneId - id of the pane to search or ALL_PANES to search all panes
     * @param {!string} fullPath - path of the file to locate
     * @param {!string} method - name of the method to use for searching 
     *       "findInViewList", "findInViewListAddedOrder" or "FindInViewListMRUOrder" 
     * 
     * @private
     */
    function _doFindInWorkingSet(paneId, fullPath, method) {
        var result = -1;
        _forEachPaneOrPanes(paneId, function (pane) {
            var index = pane[method].call(pane, fullPath);
            if (index >= 0) {
                result = index;
                return false;
            }
        });
        return result;
    }

    /**
     * Finds all instances of the specified file in all working sets.  
     * If there is a temporary view of the file, it is not part of the result set
     * @param {!string} fullPath - path of the file to find views of
     * @return {Array.<{pane:string, index:number}>} an array of paneId/index records 
     */
    function findInAllWorkingSets(fullPath) {
        var index,
            result = [];
        
        _.forEach(_panes, function (pane) {
            index = pane.findInViewList(fullPath);
            if (index >= 0) {
                result.push({paneId: pane.id, index: index});
            }
        });
        
        return result;
    }
    
    /**
     * Gets the index of the file matching fullPath in the workingset
     * @param {!string} paneId - id of the pane in which to search or ALL_PANES or ACTIVE_PANE
     * @param {!string} fullPath - full path of the file to search for
     * @return {number} index, -1 if not found.
     */
    function findInWorkingSet(paneId, fullPath) {
        return _doFindInWorkingSet(paneId, fullPath, "findInViewList");
    }
    
    /**
     * Gets the index of the file matching fullPath in the added order workingset
     * @param {!string} paneId - id of the pane in which to search or ALL_PANES or ACTIVE_PANE
     * @param {!string} fullPath - full path of the file to search for
     * @return {number} index, -1 if not found.
     */
    function findInWorkingSetByAddedOrder(paneId, fullPath) {
        return _doFindInWorkingSet(paneId, fullPath, "findInViewListAddedOrder");
    }
    
    /**
     * Gets the index of the file matching fullPath in the MRU order workingset
     * @param {!string} paneId - id of the pane in which to search or ALL_PANES or ACTIVE_PANE
     * @param {!string} fullPath - full path of the file to search for
     * @return {number} index, -1 if not found.
     */
    function findInWorkingSetByMRUOrder(paneId, fullPath) {
        return _doFindInWorkingSet(paneId, fullPath, "findInViewListMRUOrder");
    }

    /**
     * @private 
     * Retrieves pane id where the specified file has been opened. Used to ensure that a file
     *  is open in only one pane so this will change once support for multiple views is added
     * The result includes panes with a temporary view of the file not just working set instances
     * @param {!string} fullPath - full path of the file to search for
     * @return {?string} pane id where the file has been opened or null if it wasn't found
     */
    function _getPaneIdForPath(fullPath) {
        // Search all working sets and pull off the first one
        var info = findInAllWorkingSets(fullPath).shift();

        // Look for a view that has not been added to a working set
        if (!info) {
            _.forEach(_panes, function (pane) {
                if (pane.getCurrentlyViewedPath() === fullPath) {
                    info = {paneId: pane.id};
                    return false;
                }
            });
        }
        
        if (!info) {
            return null;
        }

        return info.paneId;
    }
    
    /**
     * Adds the given file to the end of the workingset, if it is not already there.  
     *  This API does not create a view of the file, it just adds it to the working set
     * Views of files in the working set are persisted and are not destroyed until the user 
     *  closes the file using FILE_CLOSE; Views are created using FILE_OPEN and, when opened, are
     *  made the current view. If a File is already opened then the file is just made current
     *  and its view is shown.
     * @param {!string} paneId - The id of the pane in which to add the file object to or ACTIVE_PANE
     * @param {!File} file - The File object to add to the workingset
     * @param {number=} index - Position to add to list (defaults to last); -1 is ignored
     * @param {boolean=} forceRedraw - If true, a workingset change notification is always sent
     *    (useful if suppressRedraw was used with removeView() earlier)
     */
    function addToWorkingSet(paneId, file, index, force) {
        // look for the file to have already been added to another pane
        var pane = _getPane(paneId),
            existingPaneId = _getPaneIdForPath(file.fullPath);

        if (!pane) {
            throw new Error("invalid pane id: " + paneId);
        }

        if (findInWorkingSet(ALL_PANES, file.fullPath) !== -1) {
            return;
        }
        
        // if it's already open in another pane, then just use that pane
        if (existingPaneId && existingPaneId !== pane.id) {
            pane = _getPane(existingPaneId);
        }
        
        var result = pane.reorderItem(file, index, force),
            entry = _makeMRUListEntry(file, pane.id);

        
        // handles the case of save as so that the file remains in the 
        //  the same location in the working set as the file that was renamed
        if (result === pane.ITEM_FOUND_NEEDS_SORT) {
            console.warn("pane.reorderItem returned pane.ITEM_FOUND_NEEDS_SORT which shouldn't happen " + file);
            exports.trigger("workingSetSort", pane.id);
        } else if (result === pane.ITEM_NOT_FOUND) {
            index = pane.addToViewList(file, index);

            if (_findFileInMRUList(file) === -1) {
                // Add to or update the position in MRU
                if (pane.getCurrentlyViewedFile() === file) {
                    _mruList.unshift(entry);
                } else {
                    _mruList.push(entry);
                }
            }

            exports.trigger("workingSetAdd", file, index, pane.id);
        }
    }

    /**
     * Adds the given file list to the end of the workingset.
     * @param {!string} paneId - The id of the pane in which to add the file object to or ACTIVE_PANE
     * @param {!Array.<File>} fileList - Array of files to add to the pane
     */
    function addListToWorkingSet(paneId, fileList) {
        var uniqueFileList,
            pane = _getPane(paneId);

        uniqueFileList = pane.addListToViewList(fileList);
        
        uniqueFileList.forEach(function (file) {
            if (_findFileInMRUList(file) !== -1) {
                console.log(file.fullPath + " duplicated in mru list");
            }
            _mruList.push(_makeMRUListEntry(file, pane.id));
        });
        
        exports.trigger("workingSetAddList", uniqueFileList, pane.id);
        
        //  find all of the files that could be added but were not 
        var unsolvedList = fileList.filter(function (item) {
            // if the file open in another pane, then add it to the list of unsolvedList
            return (pane.findInViewList(item.fullPath) === -1 && _getPaneIdForPath(item.fullPath));
        });

        // Use the pane id of the first one in the list for pane id and recurse
        //  if we add more panes, then this will recurse until all items in the list are satisified
        if (unsolvedList.length) {
            addListToWorkingSet(_getPaneIdForPath(unsolvedList[0].fullPath), unsolvedList);
        }
    }
    
    /**
     * Removes a file from the global MRU list. Future versions of this 
     *  implementation may support the ALL_PANES constant but FOCUS_PANE is not allowed
     * @param {!string} paneId - Must be a valid paneId (not a shortcut e.g. ALL_PANES)
     @ @param {File} file The file object to remove.
     * @private
     */
    function _removeFileFromMRU(paneId, file) {
        var index,
            compare = function (record) {
                return (record.file === file && record.paneId === paneId);
            };
        
        // find and remove all instances
        do {
            index = _.findIndex(_mruList, compare);
            if (index !== -1) {
                _mruList.splice(index, 1);
            }
        } while (index !== -1);
    }
    
    /**
     * Removes a file the specified pane
     * @param {!string} paneId - Must be a valid paneId (not a shortcut e.g. ALL_PANES)
     * @param {!File} file - the File to remove
     * @param {boolean=} suppressRedraw - true to tell listeners not to redraw 
     *          Use the suppressRedraw flag when calling this function along with many changes to prevent flicker
     * @private
     */
    function _removeView(paneId, file, suppressRedraw) {
        var pane = _getPane(paneId);

        if (pane.removeView(file)) {
            _removeFileFromMRU(pane.id, file);
            exports.trigger("workingSetRemove", file, suppressRedraw, pane.id);
        }
    }
    
    /**
     * moves a view from one pane to another
     * @param {!string} sourcePaneId - id of the source pane
     * @param {!string} destinationPaneId - id of the destination pane
     * @param {!File} file - the File to move
     * @param {Number} destinationIndex - the working set index of the file in the destination pane
     * @return {jQuery.Promise} a promise that resolves when the move has completed.
     * @private
     */
    function _moveView(sourcePaneId, destinationPaneId, file, destinationIndex) {
        var result = new $.Deferred(),
            sourcePane = _getPane(sourcePaneId),
            destinationPane = _getPane(destinationPaneId);
        
        sourcePane.moveView(file, destinationPane, destinationIndex)
            .done(function () {
                // update the mru list
                _mruList.every(function (record) {
                    if (record.file === file && record.paneId === sourcePane.id) {
                        record.paneId = destinationPane.id;
                        return false;
                    }
                    return true;
                });
            
                exports.trigger("workingSetMove", file, sourcePane.id, destinationPane.id);
                result.resolve();
            });
        
        return result.promise();
    }
    
    /**
     * DocumentManager.pathDeleted Event handler to remove a file
     * from the MRU list
     * @param {!jQuery.event} e - 
     * @param {!string} fullPath - path of the file to remove
     * @private
     */
    function _removeDeletedFileFromMRU(e, fullPath) {
        var index,
            compare = function (record) {
                return (record.file.fullPath === fullPath);
            };
        
        // find and remove all instances
        do {
            index = _.findIndex(_mruList, compare);
            if (index !== -1) {
                _mruList.splice(index, 1);
            }
        } while (index !== -1);
    }
    
    /**
     * sorts the pane's view list 
     * @param {!string} paneId - id of the pane to sort, ALL_PANES or ACTIVE_PANE
     * @param {sortFunctionCallback} compareFn - callback to determine sort order (called on each item)
     * @see {@link Pane#sortViewList} for more information
     * @see {@link https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/sort|Sort Array - MDN}
     * @private
     */
    function _sortWorkingSet(paneId, compareFn) {
        _forEachPaneOrPanes(paneId, function (pane) {
            pane.sortViewList(compareFn);
            exports.trigger("workingSetSort", pane.id);
        });
    }
    
    /**
     * moves a working set item from one index to another shifting the items
     * after in the working set up and reinserting it at the desired location
     * @param {!string} paneId - id of the pane to sort
     * @param {!number} fromIndex - the index of the item to move
     * @param {!number} toIndex - the index to move to
     * @private
     */
    function _moveWorkingSetItem(paneId, fromIndex, toIndex) {
        var pane = _getPane(paneId);

        pane.moveWorkingSetItem(fromIndex, toIndex);
        exports.trigger("workingSetSort", pane.id);
        exports.trigger("_workingSetDisableAutoSort", pane.id);
    }

    /**
     * Mutually exchanges the files at the indexes passed by parameters.
     * @param {!string} paneId - id of the pane to swap indices or ACTIVE_PANE
     * @param {!number} index1 - the index on the left
     * @param {!number} index2 - the index on the rigth
     * @private
     */
    function _swapWorkingSetListIndexes(paneId, index1, index2) {
        var pane = _getPane(paneId);

        pane.swapViewListIndexes(index1, index2);
        exports.trigger("workingSetSort", pane.id);
        exports.trigger("_workingSetDisableAutoSort", pane.id);
    }
    
    /**
     * Get the next or previous file in the MRU list.
     * @param {!number} direction - Must be 1 or -1 to traverse forward or backward
     * @return {?{file:File, paneId:string}} The File object of the next item in the traversal order or null if there aren't any files to traverse.
     *                                       May return current file if there are no other files to traverse.
     */
    function traverseToNextViewByMRU(direction) {
        var file = getCurrentlyViewedFile(),
            paneId = getActivePaneId(),
            index = _.findIndex(_mruList, function (record) {
                return (record.file === file && record.paneId === paneId);
            });
        
        return ViewUtils.traverseViewArray(_mruList, index, direction);
    }
    
    /**
     * Get the next or previous file in list order.
     * @param {!number} direction - Must be 1 or -1 to traverse forward or backward
     * @return {?{file:File, paneId:string}} The File object of the next item in the traversal order or null if there aren't any files to traverse.
     *                                       May return current file if there are no other files to traverse.
     */
    function traverseToNextViewInListOrder(direction) {
        var file = getCurrentlyViewedFile(),
            curPaneId = getActivePaneId(),
            allFiles = [],
            index;

        getPaneIdList().forEach(function (paneId) {
            var paneFiles = getWorkingSet(paneId).map(function (file) {
                return { file: file, pane: paneId };
            });
            allFiles = allFiles.concat(paneFiles);
        });

        index = _.findIndex(allFiles, function (record) {
            return (record.file === file && record.pane === curPaneId);
        });

        return ViewUtils.traverseViewArray(allFiles, index, direction);
    }

    /**
     * Indicates that traversal has begun. 
     * Can be called any number of times.
     */
    function beginTraversal() {
        _traversingFileList = true;
    }
    
    /**
     * Un-freezes the MRU list after one or more beginTraversal() calls.
     * Whatever file is current is bumped to the front of the MRU list.
     */
    function endTraversal() {
        var pane = _getPane(ACTIVE_PANE);
        
        if (_traversingFileList) {
            _traversingFileList = false;
            
            _makeFileMostRecent(pane.id, pane.getCurrentlyViewedFile());
        }
    }

    /**
     * Synchronizes the pane's sizer element, updates the pane's resizer maxsize value 
     *   and tells the pane to update its layout
     * @param {boolean} forceRefresh - true to force a resize and refresh of the entire view
     * @private
     */
    function _synchronizePaneSize(pane, forceRefresh) {
        var available;
        
        if (_orientation === VERTICAL) {
            available = _$el.innerWidth();
        } else {
            available = _$el.innerHeight();
        }
    
        // Update the pane's sizer element if it has one and update the max size
        Resizer.resyncSizer(pane.$el);
        pane.$el.data("maxsize", available - MIN_PANE_SIZE);
        pane.updateLayout(forceRefresh);
    }
    
    
    /**
     * Event handler for "workspaceUpdateLayout" to update the layout
     * @param {jQuery.Event} event - jQuery event object
     * @param {number} viewAreaHeight - unused
     * @param {boolean} forceRefresh - true to force a resize and refresh of the entire view
     * @private
     */
    function _updateLayout(event, viewAreaHeight, forceRefresh) {
        var available;
        
        if (_orientation === VERTICAL) {
            available = _$el.innerWidth();
        } else {
            available = _$el.innerHeight();
        }
        
        _.forEach(_panes, function (pane) {
            // For VERTICAL orientation, we set the second pane to be width: auto
            //  so that it resizes to fill the available space in the containing div
            // unfortunately, that doesn't work in the HORIZONTAL orientation so we 
            //  must update the height and convert it into a percentage
            if (pane.id === SECOND_PANE && _orientation === HORIZONTAL) {
                var percentage = ((_panes[FIRST_PANE].$el.height() + 1) / available);
                pane.$el.css("height", 100 - (percentage * 100) + "%");
            }

            _synchronizePaneSize(pane, forceRefresh);
        });
    }

    /**
     * Sets up the initial layout so panes are evenly distributed
     * This also sets css properties that aid in the layout when _updateLayout is called
     * @param {boolean} forceRefresh - true to force a resize and refresh of the entire view
     * @private
     */
    function _initialLayout(forceRefresh) {
        var panes = Object.keys(_panes),
            size = 100 / panes.length;
        
        _.forEach(_panes, function (pane) {
            if (pane.id === FIRST_PANE) {
                if (_orientation === VERTICAL) {
                    pane.$el.css({height: "100%",
                                  width: size + "%",
                                  float: "left"
                                 });
                } else {
                    pane.$el.css({ height: size + "%",
                                   width: "100%"
                                 });
                }
            } else {
                if (_orientation === VERTICAL) {
                    pane.$el.css({  height: "100%",
                                    width: "auto",
                                    float: "none"
                                 });
                } else {
                    pane.$el.css({ width: "100%",
                                   height: "50%"
                                 });
                }
            }
            
            _synchronizePaneSize(pane, forceRefresh);
        });
    }
    
    /**
     * Updates the header text for all panes
     */
    function _updatePaneHeaders() {
        _forEachPaneOrPanes(ALL_PANES, function (pane) {
            pane.updateHeaderText();
        });
        
    }
    
    /**
     * Creates a pane for paneId if one doesn't already exist
     * @param {!string} paneId - id of the pane to create
     * @private
     * @return {?Pane} - the pane object of the new pane, or undefined if no pane created
     */
    function _createPaneIfNecessary(paneId) {
        var newPane;
        
        if (!_panes.hasOwnProperty(paneId)) {
            newPane = new Pane(paneId, _$el);
            _panes[paneId] = newPane;
            
            exports.trigger("paneCreate", newPane.id);
            
            newPane.$el.on("click.mainview dragover.mainview", function () {
                setActivePaneId(newPane.id);
            });

            newPane.on("viewListChange.mainview", function () {
                _updatePaneHeaders();
                exports.trigger("workingSetUpdate", newPane.id);
            });
            newPane.on("currentViewChange.mainview", function (e, newView, oldView) {
                _updatePaneHeaders();
                if (_activePaneId === newPane.id) {
                    exports.trigger("currentFileChange",
                                               newView && newView.getFile(),
                                               newPane.id, oldView && oldView.getFile(),
                                               newPane.id);
                }
            });
            newPane.on("viewDestroy.mainView", function (e, view) {
                _removeFileFromMRU(newPane.id, view.getFile());
            });
        }
        
        return newPane;
    }
    
    /**
     * Makes the first pane resizable
     * @private
     */
    function _makeFirstPaneResizable() {
        var firstPane = _panes[FIRST_PANE];
        Resizer.makeResizable(firstPane.$el,
                              _orientation === HORIZONTAL ? Resizer.DIRECTION_VERTICAL : Resizer.DIRECTION_HORIZONTAL,
                              _orientation === HORIZONTAL ? Resizer.POSITION_BOTTOM : Resizer.POSITION_RIGHT,
                              MIN_PANE_SIZE, false, false, false, true, true);
        
        firstPane.$el.on("panelResizeUpdate", function () {
            _updateLayout();
        });
    }
    
    
    /**
     * Creates a split for the specified orientation
     * @private
     * @param {!string} orientation (VERTICAL|HORIZONTAL)
     */
    function _doSplit(orientation) {
        var firstPane, newPane;
        
        if (orientation === _orientation) {
            return;
        }
        
        firstPane = _panes[FIRST_PANE];
        Resizer.removeSizable(firstPane.$el);

        if (_orientation) {
            _$el.removeClass("split-" + _orientation.toLowerCase());
        }
        _$el.addClass("split-" + orientation.toLowerCase());
        
        _orientation = orientation;
        newPane = _createPaneIfNecessary(SECOND_PANE);
        _makeFirstPaneResizable();
        
        // reset the layout to 50/50 split
        // if we changed orientation then
        //  the percentages are reset as well
        _initialLayout();
        
        exports.trigger("paneLayoutChange", _orientation);
        
        // if new pane was created, and original pane is not empty, make new pane the active pane
        if (newPane && getCurrentlyViewedFile(firstPane.id)) {
            setActivePaneId(newPane.id);
        }
    }
    
    /**
     * Edits a document in the specified pane.
     * This function is only used by:
     *  - Unit Tests (which construct Mock Document objects), 
     *  - by File > New  because there is yet to be an established File object 
     *  - by Find In Files which needs to open documents synchronously in some cases
     * Do not use this API it is for internal use only
     * @param {!string} paneId - id of the pane in which to open the document
     * @param {!Document} doc - document to edit
     * @param {{noPaneActivate:boolean=}=} optionsIn - options
     * @private
     */
    function _edit(paneId, doc, optionsIn) {
        var options = optionsIn || {},
            currentPaneId  = _getPaneIdForPath(doc.file.fullPath);
        
        if (currentPaneId) {
            // If the doc is open in another pane then switch to that pane and call open document
            //  which will really just show the view as it has always done we could just 
            //  do pane.showView(doc._masterEditor) in that case but Editor Manager may do some 
            //  state syncing 
            paneId = currentPaneId;
        }
        
        var pane = _getPane(paneId);
        
        // If file is untitled or otherwise not within project tree, add it to
        // working set right now (don't wait for it to become dirty)
        if (doc.isUntitled() || !ProjectManager.isWithinProject(doc.file.fullPath)) {
            addToWorkingSet(paneId, doc.file);
        }
        
        // open document will show the editor if there is one already
        EditorManager.openDocument(doc, pane, options);
        _makeFileMostRecent(paneId, doc.file);

        if (!options.noPaneActivate) {
            setActivePaneId(paneId);
        }
    }
    
    /**
     * Opens a file in the specified pane this can be used to open a file with a custom viewer
     * or a document for editing.  If it's a document for editing, edit is called on the document 
     * @param {!string} paneId - id of the pane in which to open the document
     * @param {!File} file - file to open
     * @param {{noPaneActivate:boolean=}=} optionsIn - options
     * @return {jQuery.Promise}  promise that resolves to a File object or 
     *                           rejects with a File error or string
     */
    function _open(paneId, file, optionsIn) {
        var result = new $.Deferred(),
            options = optionsIn || {};
        
        function doPostOpenActivation() {
            if (!options.noPaneActivate) {
                setActivePaneId(paneId);
            }
        }
        
        if (!file || !_getPane(paneId)) {
            return result.reject("bad argument").promise();
        }

        var currentPaneId = _getPaneIdForPath(file.fullPath);

        if (currentPaneId) {
            // Warn user (only once) when file is already open in another view
            if (!PreferencesManager.getViewState("splitview.multipane-info") &&
                    currentPaneId !== _resolvePaneId(paneId)) {
                PreferencesManager.setViewState("splitview.multipane-info", true);
                
                // File tree also executes single-click code prior to executing double-click
                // code, so delay showing modal dialog to prevent eating second click
                window.setTimeout(function () {
                    Dialogs.showModalDialog(
                        DefaultDialogs.DIALOG_ID_INFO,
                        Strings.SPLITVIEW_INFO_TITLE,
                        Strings.SPLITVIEW_MULTIPANE_WARNING
                    );
                }, 500);
            }

            // If the doc is open in another pane
            //  then switch to that pane and call open document
            //  which will really just show the view as it has always done
            //  we could just do pane.showView(doc._masterEditor) in that
            //  case but Editor Manager may do some state syncing             
            paneId = currentPaneId;
        }
        
        // See if there is already a view for the file
        var pane = _getPane(paneId);

        // See if there is a factory to create a view for this file
        //  we want to do this first because, we don't want our internal 
        //  editor to edit files for which there are suitable viewfactories
        var factory = MainViewFactory.findSuitableFactoryForPath(file.fullPath);

        if (factory) {
            file.exists(function (fileError, fileExists) {
                if (fileExists) {
                    // let the factory open the file and create a view for it
                    factory.openFile(file, pane)
                        .done(function () {
                            // if we opened a file that isn't in the project
                            //  then add the file to the working set
                            if (!ProjectManager.isWithinProject(file.fullPath)) {
                                addToWorkingSet(paneId, file);
                            }
                            doPostOpenActivation();
                            result.resolve(file);
                        })
                        .fail(function (fileError) {
                            result.reject(fileError);
                        });
                } else {
                    result.reject(fileError || FileSystemError.NOT_FOUND);
                }
            });
        } else {
            DocumentManager.getDocumentForPath(file.fullPath)
                .done(function (doc) {
                    _edit(paneId, doc, $.extend({}, options, {
                        noPaneActivate: true
                    }));
                    doPostOpenActivation();
                    result.resolve(doc.file);
                })
                .fail(function (fileError) {
                    result.reject(fileError);
                });
        }

        result.done(function () {
            _makeFileMostRecent(paneId, file);
        });
        
        return result;
    }
    
    /**
     * Merges second pane into first pane and opens the current file
     * @private
     */
    function _mergePanes() {
        if (_panes.hasOwnProperty(SECOND_PANE)) {
            
            var firstPane = _panes[FIRST_PANE],
                secondPane = _panes[SECOND_PANE],
                fileList = secondPane.getViewList(),
                lastViewed = getCurrentlyViewedFile();
            
            Resizer.removeSizable(firstPane.$el);
            firstPane.mergeFrom(secondPane);
        
            exports.trigger("workingSetRemoveList", fileList, secondPane.id);

            setActivePaneId(firstPane.id);
            
            secondPane.$el.off(".mainview");
            secondPane.off(".mainview");

            secondPane.destroy();
            delete _panes[SECOND_PANE];
            exports.trigger("paneDestroy", secondPane.id);
            exports.trigger("workingSetAddList", fileList, firstPane.id);

            _mruList.forEach(function (record) {
                if (record.paneId === secondPane.id) {
                    record.paneId = firstPane.id;
                }
            });
            
            _$el.removeClass("split-" + _orientation.toLowerCase());
            _orientation = null;
            // this will set the remaining pane to 100%
            _initialLayout();
            
            exports.trigger("paneLayoutChange", _orientation);

            // if the current view before the merger was in the pane
            //  that went away then reopen it so that it's now the current view again
            if (lastViewed && getCurrentlyViewedFile() !== lastViewed) {
                exports._open(firstPane.id, lastViewed);
            }
        }
    }

    /**
     * Closes a file in the specified pane or panes
     * @param {!string} paneId - id of the pane in which to open the document
     * @param {!File} file - file to close
     * @param {Object={noOpenNextFile:boolean}} optionsIn - options 
     * This function does not fail if the file is not open
     */
    function _close(paneId, file, optionsIn) {
        var options = optionsIn || {};
        _forEachPaneOrPanes(paneId, function (pane) {
            if (pane.removeView(file, options.noOpenNextFile)) {
                _removeFileFromMRU(pane.id, file);
                exports.trigger("workingSetRemove", file, false, pane.id);
                return false;
            }
        });
    }

    /**
     * Closes a list of file in the specified pane or panes
     * @param {!string} paneId - id of the pane in which to open the document
     * @param {!Array.<File>} fileList - files to close
     * This function does not fail if the file is not open
     */
    function _closeList(paneId, fileList) {
        _forEachPaneOrPanes(paneId, function (pane) {
            var closedList = pane.removeViews(fileList);
            closedList.forEach(function (file) {
                _removeFileFromMRU(pane.id, file);
            });

            exports.trigger("workingSetRemoveList", closedList, pane.id);
        });
    }
    
    /**
     * Closes all files in the specified pane or panes
     * @param {!string} paneId - id of the pane in which to open the document
     * This function does not fail if the file is not open
     */
    function _closeAll(paneId) {
        _forEachPaneOrPanes(paneId, function (pane) {
            var closedList = pane.getViewList();
            closedList.forEach(function (file) {
                _removeFileFromMRU(pane.id, file);
            });

            pane._reset();
            exports.trigger("workingSetRemoveList", closedList, pane.id);
        });
    }

    
    /**
     * Finds which pane a document belongs to
     * @param {!Document} document - the document to locate
     * @return {?Pane} the pane where the document lives or NULL if it isn't in a pane
     * @private
     */
    function _findPaneForDocument(document) {
        // First check for an editor view of the document 
        var pane = _getPaneFromElement($(document._masterEditor.$el.parent().parent()));
        
        if (!pane) {
            // No view of the document, it may be in a working set and not yet opened
            var info = findInAllWorkingSets(document.file.fullPath).shift();
            if (info) {
                pane = _panes[info.paneId];
            }
        }
        
        return pane;
    }
    
    /**
     * Destroys an editor object if a document is no longer referenced
     * @param {!Document} doc - document to destroy
     */
    function _destroyEditorIfNotNeeded(document) {
        if (!(document instanceof DocumentManager.Document)) {
            throw new Error("_destroyEditorIfUnneeded() should be passed a Document");
        }
        if (document._masterEditor) {
            // findPaneForDocument tries to locate the pane in which the document
            //  is either opened or will be opened (in the event that the document is
            //  in a working set but has yet to be opened) and then asks the pane
            //  to destroy the view if it doesn't need it anymore
            var pane = _findPaneForDocument(document);
            
            if (pane) {
                // let the pane deceide if it wants to destroy the view if it's no needed
                pane.destroyViewIfNotNeeded(document._masterEditor);
            } else {
                // in this case, the document isn't referenced at all so just destroy it
                document._masterEditor.destroy();
            }
        }
    }

    
    /**
     * Loads the workingset state
     * @private
     */
    function _loadViewState(e) {
        // file root is appended for each project
        var panes,
            promises = [],
            context = { location : { scope: "user",
                                     layer: "project" } },
            state = PreferencesManager.getViewState(PREFS_NAME, context);

        function convertViewState() {
            var context = { location : { scope: "user",
                                         layer: "project" } },
                files = PreferencesManager.getViewState(OLD_PREFS_NAME, context);

            if (!files) {
                // nothing to convert
                return;
            }

            var result = {
                orientation: null,
                activePaneId: FIRST_PANE,
                panes: {
                    "first-pane": []
                }
            };

            // Add all files to the workingset without verifying that
            // they still exist on disk (for faster project switching)
            files.forEach(function (value) {
                result.panes[FIRST_PANE].push(value);
            });

            return result;
        }
        
        if (!state) {
            // not converted yet
            state = convertViewState();
        }

        // reset
        _mergePanes();
        _mruList = [];
        ViewStateManager.reset();
        
        if (state) {

            panes = Object.keys(state.panes);
            _orientation = (panes.length > 1) ? state.orientation : null;

            _.forEach(state.panes, function (paneState, paneId) {
                _createPaneIfNecessary(paneId);
                promises.push(_panes[paneId].loadState(paneState));
            });

            AsyncUtils.waitForAll(promises).then(function (opensList) {

                // this will set the default layout of 50/50 or 100 
                //  based on the number of panes
                _initialLayout();
                
                // More than 1 pane, then make it resizable
                //  and layout the panes from serialized state
                if (panes.length > 1) {
                    _makeFirstPaneResizable();

                    // If the split state was serialized correctly
                    //  then setup the splits according to was serialized
                    // Avoid a zero and negative split percentages
                    if ($.isNumeric(state.splitPercentage) && state.splitPercentage > 0) {
                        var prop;
                        if (_orientation === VERTICAL) {
                            prop = "width";
                        } else {
                            prop = "height";
                        }

                        _panes[FIRST_PANE].$el.css(prop, state.splitPercentage * 100 + "%");
                        _updateLayout();
                    }
                }
                
                if (_orientation) {
                    _$el.addClass("split-" + _orientation.toLowerCase());
                    exports.trigger("paneLayoutChange", _orientation);
                }

                _.forEach(_panes, function (pane) {
                    var fileList = pane.getViewList();

                    fileList.forEach(function (file) {
                        if (_findFileInMRUList(file) !== -1) {
                            console.log(file.fullPath + " duplicated in mru list");
                        }
                        _mruList.push(_makeMRUListEntry(file, pane.id));
                    });
                    exports.trigger("workingSetAddList", fileList, pane.id);
                });
                
                promises = [];
                
                opensList.forEach(function (openData) {
                    if (openData) {
                        promises.push(CommandManager.execute(Commands.FILE_OPEN, openData));
                    }
                });
                
                // finally set the active pane
                AsyncUtils.waitForAll(promises).then(function () {
                    setActivePaneId(state.activePaneId);
                });
            });
        }
    }
    
    /**
     * Saves the workingset state
     * @private
     */
    function _saveViewState() {
        function _computeSplitPercentage() {
            var available,
                used;

            if (getPaneCount() === 1) {
                // just short-circuit here and
                //  return 100% to avoid any rounding issues
                return 1;
            } else {
                if (_orientation === VERTICAL) {
                    available = _$el.innerWidth();
                    used = _panes[FIRST_PANE].$el.width();
                } else {
                    available = _$el.innerHeight();
                    used = _panes[FIRST_PANE].$el.height();
                }

                return used / available;
            }
        }

        var projectRoot     = ProjectManager.getProjectRoot(),
            context         = { location : { scope: "user",
                                         layer: "project",
                                         layerID: projectRoot.fullPath } },
            
            state = {
                orientation: _orientation,
                activePaneId: getActivePaneId(),
                splitPercentage: _computeSplitPercentage(),
                panes: {
                }
            };
        

        if (!projectRoot) {
            return;
        }
        
        _.forEach(_panes, function (pane) {
            state.panes[pane.id] = pane.saveState();
        });

        PreferencesManager.setViewState(PREFS_NAME, state, context);
    }
    
    /**
     * Initializes the MainViewManager's view state
     * @param {jQuery} $container - the container where the main view will live
     * @private
     */
    function _initialize($container) {
        if (_activePaneId) {
            throw new Error("MainViewManager has already been initialized");
        }

        _$el = $container;
        _createPaneIfNecessary(FIRST_PANE);
        _activePaneId = FIRST_PANE;
        // One-time init so the pane has the "active" appearance   
        _panes[FIRST_PANE]._handleActivePaneChange(undefined, _activePaneId);
        _initialLayout();

        // This ensures that unit tests that use this function 
        //  get an event handler for workspace events and we don't listen
        //  to the event before we've been initialized
        WorkspaceManager.on("workspaceUpdateLayout", _updateLayout);
    }
    
    /** 
     * Changes the layout scheme
     * @param {!number} rows (may be 1 or 2)
     * @param {!number} columns (may be 1 or 2) 
     * @summay Rows or Columns may be 1 or 2 but both cannot be 2. 1x2, 2x1 or 1x1 are the legal values
     */
    function setLayoutScheme(rows, columns) {
        if ((rows < 1) || (rows > 2) || (columns < 1) || (columns > 2) || (columns === 2 && rows === 2)) {
            console.error("setLayoutScheme unsupported layout " + rows + ", " + columns);
            return false;
        }
        
        if (rows === columns) {
            _mergePanes();
        } else if (rows > columns) {
            _doSplit(HORIZONTAL);
        } else {
            _doSplit(VERTICAL);
        }
        return true;
    }
    
    /** 
     * Retrieves the current layout scheme
     * @return {!{rows: number, columns: number>}}
     */
    function getLayoutScheme() {
        var result = {
            rows: 1,
            columns: 1
        };

        if (_orientation === HORIZONTAL) {
            result.rows = 2;
        } else if (_orientation === VERTICAL) {
            result.columns = 2;
        }
        
        return result;
    }
    
    
    /** 
     * Setup a ready event to initialize ourself
     */
    AppInit.htmlReady(function () {
        _initialize($("#editor-holder"));
    });
    
    // Event handlers - not safe to call on() directly, due to circular dependencies
    EventDispatcher.on_duringInit(ProjectManager, "projectOpen",                       _loadViewState);
    EventDispatcher.on_duringInit(ProjectManager, "beforeProjectClose beforeAppClose", _saveViewState);
    EventDispatcher.on_duringInit(EditorManager, "activeEditorChange",                 _activeEditorChange);
    EventDispatcher.on_duringInit(DocumentManager, "pathDeleted",                      _removeDeletedFileFromMRU);
    
    
    EventDispatcher.makeEventDispatcher(exports);
    
    // Unit Test Helpers
    exports._initialize                   = _initialize;
    exports._getPane                      = _getPane;
        
    // Private Helpers
    exports._removeView                   = _removeView;
    exports._moveView                     = _moveView;
    
    // Private API
    exports._sortWorkingSet               = _sortWorkingSet;
    exports._moveWorkingSetItem           = _moveWorkingSetItem;
    exports._swapWorkingSetListIndexes    = _swapWorkingSetListIndexes;
    exports._destroyEditorIfNotNeeded     = _destroyEditorIfNotNeeded;
    exports._edit                         = _edit;
    exports._open                         = _open;
    exports._close                        = _close;
    exports._closeAll                     = _closeAll;
    exports._closeList                    = _closeList;
    exports._getPaneIdForPath             = _getPaneIdForPath;
    
    // WorkingSet Management  
    exports.addToWorkingSet               = addToWorkingSet;
    exports.addListToWorkingSet           = addListToWorkingSet;
    exports.getWorkingSetSize             = getWorkingSetSize;
    exports.getWorkingSet                 = getWorkingSet;
    
    // Pane state
    exports.cacheScrollState              = cacheScrollState;
    exports.restoreAdjustedScrollState    = restoreAdjustedScrollState;

    // Searching
    exports.findInWorkingSet              = findInWorkingSet;
    exports.findInWorkingSetByAddedOrder  = findInWorkingSetByAddedOrder;
    exports.findInWorkingSetByMRUOrder    = findInWorkingSetByMRUOrder;
    exports.findInAllWorkingSets          = findInAllWorkingSets;
    
    // Traversal
    exports.beginTraversal                = beginTraversal;
    exports.endTraversal                  = endTraversal;
    exports.traverseToNextViewByMRU       = traverseToNextViewByMRU;
    exports.traverseToNextViewInListOrder = traverseToNextViewInListOrder;
    
    // PaneView Attributes
    exports.getActivePaneId               = getActivePaneId;
    exports.setActivePaneId               = setActivePaneId;
    exports.getPaneIdList                 = getPaneIdList;
    exports.getPaneTitle                  = getPaneTitle;
    exports.getPaneCount                  = getPaneCount;
    
    exports.getAllOpenFiles               = getAllOpenFiles;
    exports.focusActivePane               = focusActivePane;
    
    // Layout
    exports.setLayoutScheme               = setLayoutScheme;
    exports.getLayoutScheme               = getLayoutScheme;
    
    // Convenience
    exports.getCurrentlyViewedFile        = getCurrentlyViewedFile;
    exports.getCurrentlyViewedPath        = getCurrentlyViewedPath;
    
    // Constants
    exports.ALL_PANES                     = ALL_PANES;
    exports.ACTIVE_PANE                   = ACTIVE_PANE;
});