1 files changed, 241 insertions, 0 deletions
diff --git a/toolkit/actors/UAWidgetsChild.jsm b/toolkit/actors/UAWidgetsChild.jsm
new file mode 100644
index 0000000000..7dfa773ed4
--- /dev/null
+++ b/toolkit/actors/UAWidgetsChild.jsm
@@ -0,0 +1,241 @@
+/* vim: set ts=2 sw=2 sts=2 et tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+"use strict";
+
+var EXPORTED_SYMBOLS = ["UAWidgetsChild"];
+
+const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+class UAWidgetsChild extends JSWindowActorChild {
+  constructor() {
+    super();
+
+    this.widgets = new WeakMap();
+    this.prefsCache = new Map();
+    this.observedPrefs = [];
+
+    // Bug 1570744 - JSWindowActorChild's cannot be used as nsIObserver's
+    // directly, so we create a new function here instead to act as our
+    // nsIObserver, which forwards the notification to the observe method.
+    this.observerFunction = (subject, topic, data) => {
+      this.observe(subject, topic, data);
+    };
+  }
+
+  didDestroy() {
+    for (let pref in this.observedPrefs) {
+      Services.prefs.removeObserver(pref, this.observerFunction);
+    }
+  }
+
+  unwrap(obj) {
+    return Cu.isXrayWrapper(obj) ? obj.wrappedJSObject : obj;
+  }
+
+  handleEvent(aEvent) {
+    switch (aEvent.type) {
+      case "UAWidgetSetupOrChange":
+        this.setupOrNotifyWidget(aEvent.target);
+        break;
+      case "UAWidgetTeardown":
+        this.teardownWidget(aEvent.target);
+        break;
+    }
+  }
+
+  setupOrNotifyWidget(aElement) {
+    if (!this.widgets.has(aElement)) {
+      this.setupWidget(aElement);
+      return;
+    }
+
+    let { widget } = this.widgets.get(aElement);
+
+    if (typeof widget.onchange == "function") {
+      if (
+        this.unwrap(aElement.openOrClosedShadowRoot) !=
+        this.unwrap(widget.shadowRoot)
+      ) {
+        Cu.reportError(
+          "Getting a UAWidgetSetupOrChange event without the ShadowRoot. " +
+            "Torn down already?"
+        );
+        return;
+      }
+      try {
+        widget.onchange();
+      } catch (ex) {
+        Cu.reportError(ex);
+      }
+    }
+  }
+
+  setupWidget(aElement) {
+    let uri;
+    let widgetName;
+    // Use prefKeys to optionally send a list of preferences to forward to
+    // the UAWidget. The UAWidget will receive those preferences as key-value
+    // pairs as the second argument to its constructor. Updates to those prefs
+    // can be observed by implementing an optional onPrefChange method for the
+    // UAWidget that receives the changed pref name as the first argument, and
+    // the updated value as the second.
+    let prefKeys = [];
+    switch (aElement.localName) {
+      case "video":
+      case "audio":
+        uri = "chrome://global/content/elements/videocontrols.js";
+        widgetName = "VideoControlsWidget";
+        prefKeys = [
+          "media.videocontrols.picture-in-picture.video-toggle.enabled",
+          "media.videocontrols.picture-in-picture.video-toggle.always-show",
+          "media.videocontrols.picture-in-picture.video-toggle.min-video-secs",
+          "media.videocontrols.picture-in-picture.video-toggle.position",
+          "media.videocontrols.picture-in-picture.video-toggle.has-used",
+          "media.videocontrols.keyboard-tab-to-all-controls",
+        ];
+        break;
+      case "input":
+        uri = "chrome://global/content/elements/datetimebox.js";
+        widgetName = "DateTimeBoxWidget";
+        break;
+      case "embed":
+      case "object":
+        uri = "chrome://global/content/elements/pluginProblem.js";
+        widgetName = "PluginProblemWidget";
+        break;
+      case "marquee":
+        uri = "chrome://global/content/elements/marquee.js";
+        widgetName = "MarqueeWidget";
+        break;
+    }
+
+    if (!uri || !widgetName) {
+      Cu.reportError(
+        "Getting a UAWidgetSetupOrChange event on undefined element."
+      );
+      return;
+    }
+
+    let shadowRoot = aElement.openOrClosedShadowRoot;
+    if (!shadowRoot) {
+      Cu.reportError(
+        "Getting a UAWidgetSetupOrChange event without the Shadow Root. " +
+          "Torn down already?"
+      );
+      return;
+    }
+
+    let isSystemPrincipal = aElement.nodePrincipal.isSystemPrincipal;
+    let sandbox = isSystemPrincipal
+      ? Object.create(null)
+      : Cu.getUAWidgetScope(aElement.nodePrincipal);
+
+    if (!sandbox[widgetName]) {
+      Services.scriptloader.loadSubScript(uri, sandbox);
+    }
+
+    let prefs = Cu.cloneInto(
+      this.getPrefsForUAWidget(widgetName, prefKeys),
+      sandbox
+    );
+
+    let widget = new sandbox[widgetName](shadowRoot, prefs);
+    if (!isSystemPrincipal) {
+      widget = widget.wrappedJSObject;
+    }
+    if (this.unwrap(widget.shadowRoot) != this.unwrap(shadowRoot)) {
+      Cu.reportError("Widgets should expose their shadow root.");
+    }
+    this.widgets.set(aElement, { widget, widgetName });
+    try {
+      widget.onsetup();
+    } catch (ex) {
+      Cu.reportError(ex);
+    }
+  }
+
+  teardownWidget(aElement) {
+    if (!this.widgets.has(aElement)) {
+      return;
+    }
+    let { widget } = this.widgets.get(aElement);
+    if (typeof widget.destructor == "function") {
+      try {
+        widget.destructor();
+      } catch (ex) {
+        Cu.reportError(ex);
+      }
+    }
+    this.widgets.delete(aElement);
+  }
+
+  getPrefsForUAWidget(aWidgetName, aPrefKeys) {
+    let result = this.prefsCache.get(aWidgetName);
+    if (result) {
+      return result;
+    }
+
+    result = {};
+    for (let key of aPrefKeys) {
+      result[key] = this.getPref(key);
+      this.observePref(key);
+    }
+
+    this.prefsCache.set(aWidgetName, result);
+    return result;
+  }
+
+  observePref(prefKey) {
+    Services.prefs.addObserver(prefKey, this.observerFunction);
+    this.observedPrefs.push(prefKey);
+  }
+
+  getPref(prefKey) {
+    switch (Services.prefs.getPrefType(prefKey)) {
+      case Ci.nsIPrefBranch.PREF_BOOL: {
+        return Services.prefs.getBoolPref(prefKey);
+      }
+      case Ci.nsIPrefBranch.PREF_INT: {
+        return Services.prefs.getIntPref(prefKey);
+      }
+      case Ci.nsIPrefBranch.PREF_STRING: {
+        return Services.prefs.getStringPref(prefKey);
+      }
+    }
+
+    return undefined;
+  }
+
+  observe(subject, topic, data) {
+    if (topic == "nsPref:changed") {
+      for (let [widgetName, prefCache] of this.prefsCache) {
+        if (prefCache.hasOwnProperty(data)) {
+          let newValue = this.getPref(data);
+          prefCache[data] = newValue;
+
+          this.notifyWidgetsOnPrefChange(widgetName, data, newValue);
+        }
+      }
+    }
+  }
+
+  notifyWidgetsOnPrefChange(nameOfWidgetToNotify, prefKey, newValue) {
+    let elements = ChromeUtils.nondeterministicGetWeakMapKeys(this.widgets);
+    for (let element of elements) {
+      if (!Cu.isDeadWrapper(element) && element.isConnected) {
+        let { widgetName, widget } = this.widgets.get(element);
+        if (widgetName == nameOfWidgetToNotify) {
+          if (typeof widget.onPrefChange == "function") {
+            try {
+              widget.onPrefChange(prefKey, newValue);
+            } catch (ex) {
+              Cu.reportError(ex);
+            }
+          }
+        }
+      }
+    }
+  }
+}