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: "use strict";
michael@0: 
michael@0: module.metadata = {
michael@0:   "stability": "unstable"
michael@0: };
michael@0: 
michael@0: const { Ci, Cu } = require("chrome");
michael@0: const events = require("../system/events");
michael@0: const core = require("./core");
michael@0: 
michael@0: const assetsURI = require('../self').data.url();
michael@0: const { Services } = Cu.import("resource://gre/modules/Services.jsm");
michael@0: 
michael@0: const hideContentStyle = "data:text/css,:root {visibility: hidden !important;}";
michael@0: const hideSheetUri = Services.io.newURI(hideContentStyle, null, null);
michael@0: 
michael@0: // Taken from Gaia:
michael@0: // https://github.com/andreasgal/gaia/blob/04fde2640a7f40314643016a5a6c98bf3755f5fd/webapi.js#L1470
michael@0: function translateElement(element) {
michael@0:   element = element || document;
michael@0: 
michael@0:   // check all translatable children (= w/ a `data-l10n-id' attribute)
michael@0:   var children = element.querySelectorAll('*[data-l10n-id]');
michael@0:   var elementCount = children.length;
michael@0:   for (var i = 0; i < elementCount; i++) {
michael@0:     var child = children[i];
michael@0: 
michael@0:     // translate the child
michael@0:     var key = child.dataset.l10nId;
michael@0:     var data = core.get(key);
michael@0:     if (data)
michael@0:       child.textContent = data;
michael@0:   }
michael@0: }
michael@0: exports.translateElement = translateElement;
michael@0: 
michael@0: function onDocumentReady2Translate(event) {
michael@0:   let document = event.target;
michael@0:   document.removeEventListener("DOMContentLoaded", onDocumentReady2Translate,
michael@0:                                false);
michael@0: 
michael@0:   translateElement(document);
michael@0: 
michael@0:   try {
michael@0:     // Finally display document when we finished replacing all text content
michael@0:     if (document.defaultView) {
michael@0:       let winUtils = document.defaultView.QueryInterface(Ci.nsIInterfaceRequestor)
michael@0:                                          .getInterface(Ci.nsIDOMWindowUtils);
michael@0:       winUtils.removeSheet(hideSheetUri, winUtils.USER_SHEET);
michael@0:     }
michael@0:   }
michael@0:   catch(e) {
michael@0:     console.exception(e);
michael@0:   }
michael@0: }
michael@0: 
michael@0: function onContentWindow(event) {
michael@0:   let document = event.subject;
michael@0: 
michael@0:   // Accept only HTML documents
michael@0:   if (!(document instanceof Ci.nsIDOMHTMLDocument))
michael@0:     return;
michael@0: 
michael@0:   // Bug 769483: data:URI documents instanciated with nsIDOMParser
michael@0:   // have a null `location` attribute at this time
michael@0:   if (!document.location)
michael@0:     return;
michael@0: 
michael@0:   // Accept only document from this addon
michael@0:   if (document.location.href.indexOf(assetsURI) !== 0)
michael@0:     return;
michael@0: 
michael@0:   try {
michael@0:     // First hide content of the document in order to have content blinking
michael@0:     // between untranslated and translated states
michael@0:     let winUtils = document.defaultView.QueryInterface(Ci.nsIInterfaceRequestor)
michael@0:                                        .getInterface(Ci.nsIDOMWindowUtils);
michael@0:     winUtils.loadSheet(hideSheetUri, winUtils.USER_SHEET);
michael@0:   }
michael@0:   catch(e) {
michael@0:     console.exception(e);
michael@0:   }
michael@0:   // Wait for DOM tree to be built before applying localization
michael@0:   document.addEventListener("DOMContentLoaded", onDocumentReady2Translate,
michael@0:                             false);
michael@0: }
michael@0: 
michael@0: // Listen to creation of content documents in order to translate them as soon
michael@0: // as possible in their loading process
michael@0: const ON_CONTENT = "document-element-inserted";
michael@0: let enabled = false;
michael@0: function enable() {
michael@0:   if (!enabled) {
michael@0:     events.on(ON_CONTENT, onContentWindow);
michael@0:     enabled = true;
michael@0:   }
michael@0: }
michael@0: exports.enable = enable;
michael@0: 
michael@0: function disable() {
michael@0:   if (enabled) {
michael@0:     events.off(ON_CONTENT, onContentWindow);
michael@0:     enabled = false;
michael@0:   }
michael@0: }
michael@0: exports.disable = disable;
michael@0: 
michael@0: require("sdk/system/unload").when(disable);