1 files changed, 290 insertions, 0 deletions
diff --git a/dom/browser-element/BrowserElementChildPreload.js b/dom/browser-element/BrowserElementChildPreload.js
new file mode 100644
index 0000000000..1bbcf9ff05
--- /dev/null
+++ b/dom/browser-element/BrowserElementChildPreload.js
@@ -0,0 +1,290 @@
+/* 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";
+
+/* eslint-env mozilla/frame-script */
+
+function debug(msg) {
+  // dump("BrowserElementChildPreload - " + msg + "\n");
+}
+
+debug("loaded");
+
+var BrowserElementIsReady;
+
+var { BrowserElementPromptService } = ChromeUtils.import(
+  "resource://gre/modules/BrowserElementPromptService.jsm"
+);
+
+function sendAsyncMsg(msg, data) {
+  // Ensure that we don't send any messages before BrowserElementChild.js
+  // finishes loading.
+  if (!BrowserElementIsReady) {
+    return;
+  }
+
+  if (!data) {
+    data = {};
+  }
+
+  data.msg_name = msg;
+  sendAsyncMessage("browser-element-api:call", data);
+}
+
+var LISTENED_EVENTS = [
+  // This listens to unload events from our message manager, but /not/ from
+  // the |content| window.  That's because the window's unload event doesn't
+  // bubble, and we're not using a capturing listener.  If we'd used
+  // useCapture == true, we /would/ hear unload events from the window, which
+  // is not what we want!
+  { type: "unload", useCapture: false, wantsUntrusted: false },
+];
+
+/**
+ * The BrowserElementChild implements one half of <iframe mozbrowser>.
+ * (The other half is, unsurprisingly, BrowserElementParent.)
+ *
+ * This script is injected into an <iframe mozbrowser> via
+ * nsIMessageManager::LoadFrameScript().
+ *
+ * Our job here is to listen for events within this frame and bubble them up to
+ * the parent process.
+ */
+
+var global = this;
+
+function BrowserElementChild() {
+  // Maps outer window id --> weak ref to window.  Used by modal dialog code.
+  this._windowIDDict = {};
+
+  this._init();
+}
+
+BrowserElementChild.prototype = {
+  _init() {
+    debug("Starting up.");
+
+    BrowserElementPromptService.mapWindowToBrowserElementChild(content, this);
+
+    this._shuttingDown = false;
+
+    LISTENED_EVENTS.forEach(event => {
+      addEventListener(
+        event.type,
+        this,
+        event.useCapture,
+        event.wantsUntrusted
+      );
+    });
+
+    addMessageListener("browser-element-api:call", this);
+  },
+
+  /**
+   * Shut down the frame's side of the browser API.  This is called when:
+   *   - our BrowserChildGlobal starts to die
+   *   - the content is moved to frame without the browser API
+   * This is not called when the page inside |content| unloads.
+   */
+  destroy() {
+    debug("Destroying");
+    this._shuttingDown = true;
+
+    BrowserElementPromptService.unmapWindowToBrowserElementChild(content);
+
+    LISTENED_EVENTS.forEach(event => {
+      removeEventListener(
+        event.type,
+        this,
+        event.useCapture,
+        event.wantsUntrusted
+      );
+    });
+
+    removeMessageListener("browser-element-api:call", this);
+  },
+
+  handleEvent(event) {
+    switch (event.type) {
+      case "unload":
+        this.destroy(event);
+        break;
+    }
+  },
+
+  receiveMessage(message) {
+    let self = this;
+
+    let mmCalls = {
+      "unblock-modal-prompt": this._recvStopWaiting,
+    };
+
+    if (message.data.msg_name in mmCalls) {
+      return mmCalls[message.data.msg_name].apply(self, arguments);
+    }
+    return undefined;
+  },
+
+  get _windowUtils() {
+    return content.document.defaultView.windowUtils;
+  },
+
+  _tryGetInnerWindowID(win) {
+    try {
+      return win.windowGlobalChild.innerWindowId;
+    } catch (e) {
+      return null;
+    }
+  },
+
+  /**
+   * Show a modal prompt.  Called by BrowserElementPromptService.
+   */
+  showModalPrompt(win, args) {
+    args.windowID = {
+      outer: win.docShell.outerWindowID,
+      inner: this._tryGetInnerWindowID(win),
+    };
+    sendAsyncMsg("showmodalprompt", args);
+
+    let returnValue = this._waitForResult(win);
+
+    if (
+      args.promptType == "prompt" ||
+      args.promptType == "confirm" ||
+      args.promptType == "custom-prompt"
+    ) {
+      return returnValue;
+    }
+    return undefined;
+  },
+
+  /**
+   * Spin in a nested event loop until we receive a unblock-modal-prompt message for
+   * this window.
+   */
+  _waitForResult(win) {
+    debug("_waitForResult(" + win + ")");
+    let utils = win.windowUtils;
+
+    let outerWindowID = win.docShell.outerWindowID;
+    let innerWindowID = this._tryGetInnerWindowID(win);
+    if (innerWindowID === null) {
+      // I have no idea what waiting for a result means when there's no inner
+      // window, so let's just bail.
+      debug("_waitForResult: No inner window. Bailing.");
+      return undefined;
+    }
+
+    this._windowIDDict[outerWindowID] = Cu.getWeakReference(win);
+
+    debug(
+      "Entering modal state (outerWindowID=" +
+        outerWindowID +
+        ", " +
+        "innerWindowID=" +
+        innerWindowID +
+        ")"
+    );
+
+    utils.enterModalState();
+
+    // We'll decrement win.modalDepth when we receive a unblock-modal-prompt message
+    // for the window.
+    if (!win.modalDepth) {
+      win.modalDepth = 0;
+    }
+    win.modalDepth++;
+    let origModalDepth = win.modalDepth;
+
+    debug("Nested event loop - begin");
+    Services.tm.spinEventLoopUntil(
+      "BrowserElementChildPreload.js:_waitForResult",
+      () => {
+        // Bail out of the loop if the inner window changed; that means the
+        // window navigated.  Bail out when we're shutting down because otherwise
+        // we'll leak our window.
+        if (this._tryGetInnerWindowID(win) !== innerWindowID) {
+          debug(
+            "_waitForResult: Inner window ID changed " +
+              "while in nested event loop."
+          );
+          return true;
+        }
+
+        return win.modalDepth !== origModalDepth || this._shuttingDown;
+      }
+    );
+    debug("Nested event loop - finish");
+
+    if (win.modalDepth == 0) {
+      delete this._windowIDDict[outerWindowID];
+    }
+
+    // If we exited the loop because the inner window changed, then bail on the
+    // modal prompt.
+    if (innerWindowID !== this._tryGetInnerWindowID(win)) {
+      throw Components.Exception(
+        "Modal state aborted by navigation",
+        Cr.NS_ERROR_NOT_AVAILABLE
+      );
+    }
+
+    let returnValue = win.modalReturnValue;
+    delete win.modalReturnValue;
+
+    if (!this._shuttingDown) {
+      utils.leaveModalState();
+    }
+
+    debug(
+      "Leaving modal state (outerID=" +
+        outerWindowID +
+        ", " +
+        "innerID=" +
+        innerWindowID +
+        ")"
+    );
+    return returnValue;
+  },
+
+  _recvStopWaiting(msg) {
+    let outerID = msg.json.windowID.outer;
+    let innerID = msg.json.windowID.inner;
+    let returnValue = msg.json.returnValue;
+    debug(
+      "recvStopWaiting(outer=" +
+        outerID +
+        ", inner=" +
+        innerID +
+        ", returnValue=" +
+        returnValue +
+        ")"
+    );
+
+    if (!this._windowIDDict[outerID]) {
+      debug("recvStopWaiting: No record of outer window ID " + outerID);
+      return;
+    }
+
+    let win = this._windowIDDict[outerID].get();
+
+    if (!win) {
+      debug("recvStopWaiting, but window is gone\n");
+      return;
+    }
+
+    if (innerID !== this._tryGetInnerWindowID(win)) {
+      debug("recvStopWaiting, but inner ID has changed\n");
+      return;
+    }
+
+    debug("recvStopWaiting " + win);
+    win.modalReturnValue = returnValue;
+    win.modalDepth--;
+  },
+};
+
+var api = new BrowserElementChild();