1 files changed, 69 insertions, 0 deletions
diff --git a/browser/extensions/screenshots/background/communication.js b/browser/extensions/screenshots/background/communication.js
new file mode 100644
index 0000000000..275b8ef7f8
--- /dev/null
+++ b/browser/extensions/screenshots/background/communication.js
@@ -0,0 +1,69 @@
+/* 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/. */
+
+/* globals catcher, log */
+
+"use strict";
+
+this.communication = (function () {
+  const exports = {};
+
+  const registeredFunctions = {};
+
+  exports.onMessage = catcher.watchFunction((req, sender, sendResponse) => {
+    if (!(req.funcName in registeredFunctions)) {
+      log.error(`Received unknown internal message type ${req.funcName}`);
+      sendResponse({ type: "error", name: "Unknown message type" });
+      return;
+    }
+    if (!Array.isArray(req.args)) {
+      log.error("Received message with no .args list");
+      sendResponse({ type: "error", name: "No .args" });
+      return;
+    }
+    const func = registeredFunctions[req.funcName];
+    let result;
+    try {
+      req.args.unshift(sender);
+      result = func.apply(null, req.args);
+    } catch (e) {
+      log.error(`Error in ${req.funcName}:`, e, e.stack);
+      // FIXME: should consider using makeError from catcher here:
+      sendResponse({
+        type: "error",
+        message: e + "",
+        errorCode: e.errorCode,
+        popupMessage: e.popupMessage,
+      });
+      return;
+    }
+    if (result && result.then) {
+      result
+        .then(concreteResult => {
+          sendResponse({ type: "success", value: concreteResult });
+        })
+        .catch(errorResult => {
+          log.error(
+            `Promise error in ${req.funcName}:`,
+            errorResult,
+            errorResult && errorResult.stack
+          );
+          sendResponse({
+            type: "error",
+            message: errorResult + "",
+            errorCode: errorResult.errorCode,
+            popupMessage: errorResult.popupMessage,
+          });
+        });
+      return;
+    }
+    sendResponse({ type: "success", value: result });
+  });
+
+  exports.register = function (name, func) {
+    registeredFunctions[name] = func;
+  };
+
+  return exports;
+})();