1 files changed, 92 insertions, 0 deletions
diff --git a/toolkit/actors/WebChannelParent.sys.mjs b/toolkit/actors/WebChannelParent.sys.mjs
new file mode 100644
index 0000000000..98b3ad093a
--- /dev/null
+++ b/toolkit/actors/WebChannelParent.sys.mjs
@@ -0,0 +1,92 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* 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/. */
+
+import { WebChannelBroker } from "resource://gre/modules/WebChannel.sys.mjs";
+
+const ERRNO_MISSING_PRINCIPAL = 1;
+const ERRNO_NO_SUCH_CHANNEL = 2;
+
+export class WebChannelParent extends JSWindowActorParent {
+  receiveMessage(msg) {
+    let data = msg.data.contentData;
+    let sendingContext = {
+      browsingContext: this.browsingContext,
+      browser: this.browsingContext.top.embedderElement,
+      eventTarget: msg.data.eventTarget,
+      principal: msg.data.principal,
+    };
+    // data must be a string except for a few legacy origins allowed by browser-content.js.
+    if (typeof data == "string") {
+      try {
+        data = JSON.parse(data);
+      } catch (e) {
+        console.error("Failed to parse WebChannel data as a JSON object");
+        return;
+      }
+    }
+
+    if (data && data.id) {
+      if (!msg.data.principal) {
+        this._sendErrorEventToContent(
+          data.id,
+          sendingContext,
+          ERRNO_MISSING_PRINCIPAL,
+          "Message principal missing"
+        );
+      } else {
+        let validChannelFound = WebChannelBroker.tryToDeliver(
+          data,
+          sendingContext
+        );
+
+        // if no valid origins send an event that there is no such valid channel
+        if (!validChannelFound) {
+          this._sendErrorEventToContent(
+            data.id,
+            sendingContext,
+            ERRNO_NO_SUCH_CHANNEL,
+            "No Such Channel"
+          );
+        }
+      }
+    } else {
+      console.error("WebChannel channel id missing");
+    }
+  }
+
+  /**
+   *
+   * @param id {String}
+   *        The WebChannel id to include in the message
+   * @param sendingContext {Object}
+   *        Message sending context
+   * @param [errorMsg] {String}
+   *        Error message
+   * @private
+   */
+  _sendErrorEventToContent(id, sendingContext, errorNo, errorMsg) {
+    let { eventTarget, principal } = sendingContext;
+
+    errorMsg = errorMsg || "Web Channel Parent error";
+
+    let { currentWindowGlobal = null } = this.browsingContext;
+    if (currentWindowGlobal) {
+      currentWindowGlobal
+        .getActor("WebChannel")
+        .sendAsyncMessage("WebChannelMessageToContent", {
+          id,
+          message: {
+            errno: errorNo,
+            error: errorMsg,
+          },
+          eventTarget,
+          principal,
+        });
+    } else {
+      console.error("Failed to send a WebChannel error. Target invalid.");
+    }
+    console.error(id.toString() + " error message. ", errorMsg);
+  }
+}