Bug 744627 - TokenServerClient should not call callbacks twice; r=rnewman

services/common/tests/unit/test_tokenserverclient.js

@@ -164,3 +164,43 @@ add_test(function test_rich_media_types() {
     server.stop(run_next_test);
   });
 });
+
+add_test(function test_exception_during_callback() {
+  _("Ensure that exceptions thrown during callback handling are handled.");
+
+  let server = httpd_setup({
+    "/foo": function(request, response) {
+      response.setStatusLine(request.httpVersion, 200, "OK");
+      response.setHeader("Content-Type", "application/json");
+
+      let body = JSON.stringify({
+        id:           "id",
+        key:          "key",
+        api_endpoint: "foo",
+        uid:          "uid",
+      });
+      response.bodyOutputStream.write(body, body.length);
+    }
+  });
+
+  let url = TEST_SERVER_URL + "foo";
+  let client = new TokenServerClient();
+  let cb = Async.makeSpinningCallback();
+  let callbackCount = 0;
+
+  client.getTokenFromBrowserIDAssertion(url, "assertion", function(error, r) {
+    do_check_eq(null, error);
+
+    cb();
+
+    callbackCount += 1;
+    throw new Error("I am a bad function!");
+  });
+
+  cb.wait();
+  // This relies on some heavy event loop magic. The error in the main
+  // callback should already have been raised at this point.
+  do_check_eq(callbackCount, 1);
+
+  server.stop(run_next_test);
+});

services/common/tokenserverclient.js

@@ -16,6 +16,7 @@ const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 Cu.import("resource://services-common/log4moz.js");
 Cu.import("resource://services-common/preferences.js");
 Cu.import("resource://services-common/rest.js");
+Cu.import("resource://services-common/utils.js");
 
 const Prefs = new Preferences("services.common.tokenserverclient.");
 
@@ -164,13 +165,32 @@ TokenServerClient.prototype = {
         return;
       }
 
+      let self = this;
+      function callCallback(error, result) {
+        if (!cb) {
+          self._log.warn("Callback already called! Did it throw?");
+          return;
+        }
+
+        try {
+          cb(error, result);
+        } catch (ex) {
+          self._log.warn("Exception when calling user-supplied callback: " +
+                         CommonUtils.exceptionStr(ex));
+        }
+
+        cb = null;
+      }
+
       try {
-        client._processTokenResponse(this.response, cb);
+        client._processTokenResponse(this.response, callCallback);
       } catch (ex) {
+        this._log.warn("Error processing token server response: " +
+                       CommonUtils.exceptionStr(ex));
+
         let error = new TokenServerClientError(ex);
         error.response = this.response;
-        cb(error, null);
-        return;
+        callCallback(error, null);
       }
     });
   },