1 files changed, 178 insertions, 0 deletions
diff --git a/comm/mail/actors/LinkClickHandlerChild.jsm b/comm/mail/actors/LinkClickHandlerChild.jsm
new file mode 100644
index 0000000000..8ad42a7a23
--- /dev/null
+++ b/comm/mail/actors/LinkClickHandlerChild.jsm
@@ -0,0 +1,178 @@
+/* vim: set ts=2 sw=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";
+
+const EXPORTED_SYMBOLS = [
+  "LinkClickHandlerChild",
+  "StrictLinkClickHandlerChild",
+];
+
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+
+const lazy = {};
+
+XPCOMUtils.defineLazyServiceGetter(
+  lazy,
+  "protocolSvc",
+  "@mozilla.org/uriloader/external-protocol-service;1",
+  "nsIExternalProtocolService"
+);
+
+/**
+ * Extract the href from the link click event.
+ * We look for HTMLAnchorElement, HTMLAreaElement, HTMLLinkElement,
+ * HTMLInputElement.form.action, and nested anchor tags.
+ * If the clicked element was a HTMLInputElement or HTMLButtonElement
+ * we return the form action.
+ *
+ * @returns the url and the text for the link being clicked.
+ */
+function hRefForClickEvent(aEvent) {
+  let target = aEvent.target;
+
+  if (
+    HTMLImageElement.isInstance(target) &&
+    target.hasAttribute("overflowing")
+  ) {
+    // Click on zoomed image.
+    return [null, null];
+  }
+
+  let href = null;
+  if (
+    HTMLAnchorElement.isInstance(target) ||
+    HTMLAreaElement.isInstance(target) ||
+    HTMLLinkElement.isInstance(target)
+  ) {
+    if (target.hasAttribute("href") && !target.download) {
+      href = target.href;
+    }
+  } else {
+    // We may be nested inside of a link node.
+    let linkNode = aEvent.target;
+    while (linkNode && !HTMLAnchorElement.isInstance(linkNode)) {
+      linkNode = linkNode.parentNode;
+    }
+
+    if (linkNode && !linkNode.download) {
+      href = linkNode.href;
+    }
+  }
+  return href;
+}
+
+/**
+ * Listens for click events and, if the click would result in loading a page
+ * on a different base domain from the current page, cancels the click event,
+ * redirecting the URI to an external browser, effectively creating a
+ * single-site browser.
+ *
+ * This actor applies to browsers in the "single-site" message manager group.
+ */
+class LinkClickHandlerChild extends JSWindowActorChild {
+  handleEvent(event) {
+    // Don't handle events that:
+    //   a) are in the parent process (handled by onclick),
+    //   b) aren't trusted,
+    //   c) have already been handled or
+    //   d) aren't left-click.
+    if (
+      this.manager.isInProcess ||
+      !event.isTrusted ||
+      event.defaultPrevented ||
+      event.button
+    ) {
+      return;
+    }
+
+    let eventHRef = hRefForClickEvent(event);
+    if (!eventHRef) {
+      return;
+    }
+
+    let pageURI = Services.io.newURI(this.document.location.href);
+    let eventURI = Services.io.newURI(eventHRef);
+
+    try {
+      if (pageURI.host == eventURI.host) {
+        // Avoid using the eTLD service, and this also works for IP addresses.
+        return;
+      }
+
+      try {
+        if (
+          Services.eTLD.getBaseDomain(eventURI) ==
+          Services.eTLD.getBaseDomain(pageURI)
+        ) {
+          return;
+        }
+      } catch (ex) {
+        if (ex.result != Cr.NS_ERROR_HOST_IS_IP_ADDRESS) {
+          console.error(ex);
+        }
+      }
+    } catch (ex) {
+      // The page or link might be from a host-less URL scheme such as about,
+      // blob, or data. The host is never going to match, carry on.
+    }
+
+    if (
+      !lazy.protocolSvc.isExposedProtocol(eventURI.scheme) ||
+      eventURI.schemeIs("http") ||
+      eventURI.schemeIs("https")
+    ) {
+      event.preventDefault();
+      this.sendAsyncMessage("openLinkExternally", eventHRef);
+    }
+  }
+}
+
+/**
+ * Listens for click events and, if the click would result in loading a
+ * different page from the current page, cancels the click event, redirecting
+ * the URI to an external browser, effectively creating a single-page browser.
+ *
+ * This actor applies to browsers in the "single-page" message manager group.
+ */
+class StrictLinkClickHandlerChild extends JSWindowActorChild {
+  handleEvent(event) {
+    // Don't handle events that:
+    //   a) are in the parent process (handled by onclick),
+    //   b) aren't trusted,
+    //   c) have already been handled or
+    //   d) aren't left-click.
+    if (
+      this.manager.isInProcess ||
+      !event.isTrusted ||
+      event.defaultPrevented ||
+      event.button
+    ) {
+      return;
+    }
+
+    let eventHRef = hRefForClickEvent(event);
+    if (!eventHRef) {
+      return;
+    }
+
+    let pageURI = Services.io.newURI(this.document.location.href);
+    let eventURI = Services.io.newURI(eventHRef);
+    if (eventURI.specIgnoringRef == pageURI.specIgnoringRef) {
+      return;
+    }
+
+    if (
+      !lazy.protocolSvc.isExposedProtocol(eventURI.scheme) ||
+      eventURI.schemeIs("http") ||
+      eventURI.schemeIs("https")
+    ) {
+      event.preventDefault();
+      this.sendAsyncMessage("openLinkExternally", eventHRef);
+    }
+  }
+}