michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: module.metadata = {
michael@0:   "stability": "stable",
michael@0:   "engines": {
michael@0:     "Firefox": "*"
michael@0:   }
michael@0: };
michael@0: 
michael@0: const { Ci, Cc } = require("chrome"),
michael@0:     { setTimeout } = require("./timers"),
michael@0:     { emit, off } = require("./event/core"),
michael@0:     { Class, obscure } = require("./core/heritage"),
michael@0:     { EventTarget } = require("./event/target"),
michael@0:     { ns } = require("./core/namespace"),
michael@0:     { when: unload } = require("./system/unload"),
michael@0:     { ignoreWindow } = require('./private-browsing/utils'),
michael@0:     { getTabs, getTabContentWindow, getTabForContentWindow,
michael@0:       getAllTabContentWindows } = require('./tabs/utils'),
michael@0:     winUtils = require("./window/utils"),
michael@0:     events = require("./system/events"),
michael@0:     { iteratorSymbol, forInIterator } = require("./util/iteration");
michael@0: 
michael@0: // The selection types
michael@0: const HTML = 0x01,
michael@0:       TEXT = 0x02,
michael@0:       DOM  = 0x03; // internal use only
michael@0: 
michael@0: // A more developer-friendly message than the caught exception when is not
michael@0: // possible change a selection.
michael@0: const ERR_CANNOT_CHANGE_SELECTION =
michael@0:   "It isn't possible to change the selection, as there isn't currently a selection";
michael@0: 
michael@0: const selections = ns();
michael@0: 
michael@0: const Selection = Class({
michael@0:   /**
michael@0:    * Creates an object from which a selection can be set, get, etc. Each
michael@0:    * object has an associated with a range number. Range numbers are the
michael@0:    * 0-indexed counter of selection ranges as explained at
michael@0:    * https://developer.mozilla.org/en/DOM/Selection.
michael@0:    *
michael@0:    * @param rangeNumber
michael@0:    *        The zero-based range index into the selection
michael@0:    */
michael@0:   initialize: function initialize(rangeNumber) {
michael@0:     // In order to hide the private `rangeNumber` argument from API consumers
michael@0:     // while still enabling Selection getters/setters to access it, we define
michael@0:     // it as non enumerable, non configurable property. While consumers still
michael@0:     // may discover it they won't be able to do any harm which is good enough
michael@0:     // in this case.
michael@0:     Object.defineProperties(this, {
michael@0:       rangeNumber: {
michael@0:         enumerable: false,
michael@0:         configurable: false,
michael@0:         value: rangeNumber
michael@0:       }
michael@0:     });
michael@0:   },
michael@0:   get text() { return getSelection(TEXT, this.rangeNumber); },
michael@0:   set text(value) { setSelection(TEXT, value, this.rangeNumber); },
michael@0:   get html() { return getSelection(HTML, this.rangeNumber); },
michael@0:   set html(value) { setSelection(HTML, value, this.rangeNumber); },
michael@0:   get isContiguous() {
michael@0: 
michael@0:     // If there are multiple non empty ranges, the selection is definitely
michael@0:     // discontiguous. It returns `false` also if there are no valid selection.
michael@0:     let count = 0;
michael@0:     for (let sel in selectionIterator)
michael@0:       if (++count > 1)
michael@0:         break;
michael@0: 
michael@0:     return count === 1;
michael@0:   }
michael@0: });
michael@0: 
michael@0: const selectionListener = {
michael@0:   notifySelectionChanged: function (document, selection, reason) {
michael@0:     if (!["SELECTALL", "KEYPRESS", "MOUSEUP"].some(function(type) reason &
michael@0:       Ci.nsISelectionListener[type + "_REASON"]) || selection.toString() == "")
michael@0:         return;
michael@0: 
michael@0:     this.onSelect();
michael@0:   },
michael@0: 
michael@0:   onSelect: function() {
michael@0:     emit(module.exports, "select");
michael@0:   }
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Defines iterators so that discontiguous selections can be iterated.
michael@0:  * Empty selections are skipped - see `safeGetRange` for further details.
michael@0:  *
michael@0:  * If discontiguous selections are in a text field, only the first one
michael@0:  * is returned because the text field selection APIs doesn't support
michael@0:  * multiple selections.
michael@0:  */
michael@0: function* forOfIterator() {
michael@0:   let selection = getSelection(DOM);
michael@0:   let count = 0;
michael@0: 
michael@0:   if (selection)
michael@0:     count = selection.rangeCount || (getElementWithSelection() ? 1 : 0);
michael@0: 
michael@0:   for (let i = 0; i < count; i++) {
michael@0:     let sel = Selection(i);
michael@0: 
michael@0:     if (sel.text)
michael@0:       yield Selection(i);
michael@0:   }
michael@0: }
michael@0: 
michael@0: const selectionIteratorOptions = {
michael@0:   __iterator__: forInIterator
michael@0: }
michael@0: selectionIteratorOptions[iteratorSymbol] = forOfIterator;
michael@0: const selectionIterator = obscure(selectionIteratorOptions);
michael@0: 
michael@0: /**
michael@0:  * Returns the most recent focused window.
michael@0:  * if private browsing window is most recent and not supported,
michael@0:  * then ignore it and return `null`, because the focused window
michael@0:  * can't be targeted.
michael@0:  */
michael@0: function getFocusedWindow() {
michael@0:   let window = winUtils.getFocusedWindow();
michael@0: 
michael@0:   return ignoreWindow(window) ? null : window;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Returns the focused element in the most recent focused window
michael@0:  * if private browsing window is most recent and not supported,
michael@0:  * then ignore it and return `null`, because the focused element
michael@0:  * can't be targeted.
michael@0:  */
michael@0: function getFocusedElement() {
michael@0:   let element = winUtils.getFocusedElement();
michael@0: 
michael@0:   if (!element || ignoreWindow(element.ownerDocument.defaultView))
michael@0:     return null;
michael@0: 
michael@0:   return element;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Returns the current selection from most recent content window. Depending on
michael@0:  * the specified |type|, the value returned can be a string of text, stringified
michael@0:  * HTML, or a DOM selection object as described at
michael@0:  * https://developer.mozilla.org/en/DOM/Selection.
michael@0:  *
michael@0:  * @param type
michael@0:  *        Specifies the return type of the selection. Valid values are the one
michael@0:  *        of the constants HTML, TEXT, or DOM.
michael@0:  *
michael@0:  * @param rangeNumber
michael@0:  *        Specifies the zero-based range index of the returned selection.
michael@0:  */
michael@0: function getSelection(type, rangeNumber) {
michael@0:   let window, selection;
michael@0:   try {
michael@0:     window = getFocusedWindow();
michael@0:     selection = window.getSelection();
michael@0:   }
michael@0:   catch (e) {
michael@0:     return null;
michael@0:   }
michael@0: 
michael@0:   // Get the selected content as the specified type
michael@0:   if (type == DOM) {
michael@0:     return selection;
michael@0:   }
michael@0:   else if (type == TEXT) {
michael@0:     let range = safeGetRange(selection, rangeNumber);
michael@0: 
michael@0:     if (range)
michael@0:       return range.toString();
michael@0: 
michael@0:     let node = getElementWithSelection();
michael@0: 
michael@0:     if (!node)
michael@0:       return null;
michael@0: 
michael@0:     return node.value.substring(node.selectionStart, node.selectionEnd);
michael@0:   }
michael@0:   else if (type == HTML) {
michael@0:     let range = safeGetRange(selection, rangeNumber);
michael@0:     // Another way, but this includes the xmlns attribute for all elements in
michael@0:     // Gecko 1.9.2+ :
michael@0:     // return Cc["@mozilla.org/xmlextras/xmlserializer;1"].
michael@0:     //   createInstance(Ci.nsIDOMSerializer).serializeToSTring(range.
michael@0:     //     cloneContents());
michael@0:     if (!range)
michael@0:       return null;
michael@0: 
michael@0:     let node = window.document.createElement("span");
michael@0:     node.appendChild(range.cloneContents());
michael@0:     return node.innerHTML;
michael@0:   }
michael@0: 
michael@0:   throw new Error("Type " + type + " is unrecognized.");
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Sets the current selection of the most recent content document by changing
michael@0:  * the existing selected text/HTML range to the specified value.
michael@0:  *
michael@0:  * @param val
michael@0:  *        The value for the new selection
michael@0:  *
michael@0:  * @param rangeNumber
michael@0:  *        The zero-based range index of the selection to be set
michael@0:  *
michael@0:  */
michael@0: function setSelection(type, val, rangeNumber) {
michael@0:   // Make sure we have a window context & that there is a current selection.
michael@0:   // Selection cannot be set unless there is an existing selection.
michael@0:   let window, selection;
michael@0: 
michael@0:   try {
michael@0:     window = getFocusedWindow();
michael@0:     selection = window.getSelection();
michael@0:   }
michael@0:   catch (e) {
michael@0:     throw new Error(ERR_CANNOT_CHANGE_SELECTION);
michael@0:   }
michael@0: 
michael@0:   let range = safeGetRange(selection, rangeNumber);
michael@0: 
michael@0:   if (range) {
michael@0:     let fragment;
michael@0: 
michael@0:     if (type === HTML)
michael@0:       fragment = range.createContextualFragment(val);
michael@0:     else {
michael@0:       fragment = range.createContextualFragment("");
michael@0:       fragment.textContent = val;
michael@0:     }
michael@0: 
michael@0:     range.deleteContents();
michael@0:     range.insertNode(fragment);
michael@0:   }
michael@0:   else {
michael@0:     let node = getElementWithSelection();
michael@0: 
michael@0:     if (!node)
michael@0:       throw new Error(ERR_CANNOT_CHANGE_SELECTION);
michael@0: 
michael@0:     let { value, selectionStart, selectionEnd } = node;
michael@0: 
michael@0:     let newSelectionEnd = selectionStart + val.length;
michael@0: 
michael@0:     node.value = value.substring(0, selectionStart) +
michael@0:                   val +
michael@0:                   value.substring(selectionEnd, value.length);
michael@0: 
michael@0:     node.setSelectionRange(selectionStart, newSelectionEnd);
michael@0:   }
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Returns the specified range in a selection without throwing an exception.
michael@0:  *
michael@0:  * @param selection
michael@0:  *        A selection object as described at
michael@0:  *         https://developer.mozilla.org/en/DOM/Selection
michael@0:  *
michael@0:  * @param [rangeNumber]
michael@0:  *        Specifies the zero-based range index of the returned selection.
michael@0:  *        If it's not provided the function will return the first non empty
michael@0:  *        range, if any.
michael@0:  */
michael@0: function safeGetRange(selection, rangeNumber) {
michael@0:   try {
michael@0:     let { rangeCount } = selection;
michael@0:     let range = null;
michael@0: 
michael@0:     if (typeof rangeNumber === "undefined")
michael@0:       rangeNumber = 0;
michael@0:     else
michael@0:       rangeCount = rangeNumber + 1;
michael@0: 
michael@0:     for (; rangeNumber < rangeCount; rangeNumber++ ) {
michael@0:       range = selection.getRangeAt(rangeNumber);
michael@0: 
michael@0:       if (range && range.toString())
michael@0:         break;
michael@0: 
michael@0:       range = null;
michael@0:     }
michael@0: 
michael@0:     return range;
michael@0:   }
michael@0:   catch (e) {
michael@0:     return null;
michael@0:   }
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Returns a reference of the DOM's active element for the window given, if it
michael@0:  * supports the text field selection API and has a text selected.
michael@0:  *
michael@0:  * Note:
michael@0:  *   we need this method because window.getSelection doesn't return a selection
michael@0:  *   for text selected in a form field (see bug 85686)
michael@0:  */
michael@0: function getElementWithSelection() {
michael@0:   let element = getFocusedElement();
michael@0: 
michael@0:   if (!element)
michael@0:     return null;
michael@0: 
michael@0:   try {
michael@0:     // Accessing selectionStart and selectionEnd on e.g. a button
michael@0:     // results in an exception thrown as per the HTML5 spec.  See
michael@0:     // http://www.whatwg.org/specs/web-apps/current-work/multipage/association-of-controls-and-forms.html#textFieldSelection
michael@0: 
michael@0:     let { value, selectionStart, selectionEnd } = element;
michael@0: 
michael@0:     let hasSelection = typeof value === "string" &&
michael@0:                       !isNaN(selectionStart) &&
michael@0:                       !isNaN(selectionEnd) &&
michael@0:                       selectionStart !== selectionEnd;
michael@0: 
michael@0:     return hasSelection ? element : null;
michael@0:   }
michael@0:   catch (err) {
michael@0:     return null;
michael@0:   }
michael@0: 
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Adds the Selection Listener to the content's window given
michael@0:  */
michael@0: function addSelectionListener(window) {
michael@0:   let selection = window.getSelection();
michael@0: 
michael@0:   // Don't add the selection's listener more than once to the same window,
michael@0:   // if the selection object is the same
michael@0:   if ("selection" in selections(window) && selections(window).selection === selection)
michael@0:     return;
michael@0: 
michael@0:   // We ensure that the current selection is an instance of
michael@0:   // `nsISelectionPrivate` before working on it, in case is `null`.
michael@0:   //
michael@0:   // If it's `null` it's likely too early to add the listener, and we demand
michael@0:   // that operation to `document-shown` - it can easily happens for frames
michael@0:   if (selection instanceof Ci.nsISelectionPrivate)
michael@0:     selection.addSelectionListener(selectionListener);
michael@0: 
michael@0:   // nsISelectionListener implementation seems not fire a notification if
michael@0:   // a selection is in a text field, therefore we need to add a listener to
michael@0:   // window.onselect, that is fired only for text fields.
michael@0:   // For consistency, we add it only when the nsISelectionListener is added.
michael@0:   //
michael@0:   // https://developer.mozilla.org/en/DOM/window.onselect
michael@0:   window.addEventListener("select", selectionListener.onSelect, true);
michael@0: 
michael@0:   selections(window).selection = selection;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Removes the Selection Listener to the content's window given
michael@0:  */
michael@0: function removeSelectionListener(window) {
michael@0:   // Don't remove the selection's listener to a window that wasn't handled.
michael@0:   if (!("selection" in selections(window)))
michael@0:     return;
michael@0: 
michael@0:   let selection = window.getSelection();
michael@0:   let isSameSelection = selection === selections(window).selection;
michael@0: 
michael@0:   // Before remove the listener, we ensure that the current selection is an
michael@0:   // instance of `nsISelectionPrivate` (it could be `null`), and that is still
michael@0:   // the selection we managed for this window (it could be detached).
michael@0:   if (selection instanceof Ci.nsISelectionPrivate && isSameSelection)
michael@0:     selection.removeSelectionListener(selectionListener);
michael@0: 
michael@0:   window.removeEventListener("select", selectionListener.onSelect, true);
michael@0: 
michael@0:   delete selections(window).selection;
michael@0: };
michael@0: 
michael@0: function onContent(event) {
michael@0:   let window = event.subject.defaultView;
michael@0: 
michael@0:   // We are not interested in documents without valid defaultView (e.g. XML)
michael@0:   // that aren't in a tab (e.g. Panel); or in private windows
michael@0:    if (window && getTabForContentWindow(window) && !ignoreWindow(window)) {
michael@0:     addSelectionListener(window);
michael@0:   }
michael@0: }
michael@0: 
michael@0: // Adds Selection listener to new documents
michael@0: // Note that strong reference is needed for documents that are loading slowly or
michael@0: // where the server didn't close the connection (e.g. "comet").
michael@0: events.on("document-element-inserted", onContent, true);
michael@0: 
michael@0: // Adds Selection listeners to existing documents
michael@0: getAllTabContentWindows().forEach(addSelectionListener);
michael@0: 
michael@0: // When a document is not visible anymore the selection object is detached, and
michael@0: // a new selection object is created when it becomes visible again.
michael@0: // That makes the previous selection's listeners added previously totally
michael@0: // useless – the listeners are not notified anymore.
michael@0: // To fix that we're listening for `document-shown` event in order to add
michael@0: // the listeners to the new selection object created.
michael@0: //
michael@0: // See bug 665386 for further details.
michael@0: 
michael@0: function onShown(event) {
michael@0:   let window = event.subject.defaultView;
michael@0: 
michael@0:   // We are not interested in documents without valid defaultView.
michael@0:   // For example XML documents don't have windows and we don't yet support them.
michael@0:   if (!window)
michael@0:     return;
michael@0: 
michael@0:   // We want to handle only the windows where we added selection's listeners
michael@0:   if ("selection" in selections(window)) {
michael@0:     let currentSelection = window.getSelection();
michael@0:     let { selection } = selections(window);
michael@0: 
michael@0:     // If the current selection for the window given is different from the one
michael@0:     // stored in the namespace, we need to add the listeners again, and replace
michael@0:     // the previous selection in our list with the new one.
michael@0:     //
michael@0:     // Notice that we don't have to remove the listeners from the old selection,
michael@0:     // because is detached. An attempt to remove the listener, will raise an
michael@0:     // error (see http://mxr.mozilla.org/mozilla-central/source/layout/generic/nsSelection.cpp#5343 )
michael@0:     //
michael@0:     // We ensure that the current selection is an instance of
michael@0:     // `nsISelectionPrivate` before working on it, in case is `null`.
michael@0:     if (currentSelection instanceof Ci.nsISelectionPrivate &&
michael@0:       currentSelection !== selection) {
michael@0: 
michael@0:       window.addEventListener("select", selectionListener.onSelect, true);
michael@0:       currentSelection.addSelectionListener(selectionListener);
michael@0:       selections(window).selection = currentSelection;
michael@0:     }
michael@0:   }
michael@0: }
michael@0: 
michael@0: events.on("document-shown", onShown, true);
michael@0: 
michael@0: // Removes Selection listeners when the add-on is unloaded
michael@0: unload(function(){
michael@0:   getAllTabContentWindows().forEach(removeSelectionListener);
michael@0: 
michael@0:   events.off("document-element-inserted", onContent);
michael@0:   events.off("document-shown", onShown);
michael@0: 
michael@0:   off(exports);
michael@0: });
michael@0: 
michael@0: const selection = Class({
michael@0:   extends: EventTarget,
michael@0:   implements: [ Selection, selectionIterator ]
michael@0: })();
michael@0: 
michael@0: module.exports = selection;