Add interface versioning. Methods queryVersion and requireVersion.

mojo/public/js/lib/control_message_proxy.js

Index: mojo/public/js/lib/control_message_proxy.js
diff --git a/mojo/public/js/lib/control_message_proxy.js b/mojo/public/js/lib/control_message_proxy.js
new file mode 100644
index 0000000000000000000000000000000000000000..d6c0734fe1af43be0f802a0e37f5c223101214dd
--- /dev/null
+++ b/mojo/public/js/lib/control_message_proxy.js
@@ -0,0 +1,102 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+define("mojo/public/js/lib/control_message_proxy", [
+  "mojo/public/interfaces/bindings/interface_control_messages.mojom",
+  "mojo/public/js/codec",
+  "mojo/public/js/validator",
+], function(controlMessages, codec, validator) {
+
+  var Validator = validator.Validator;
+
+  function sendRunOrClosePipeMessage(receiver, runOrClosePipeMessageParams) {
+    var messageName = controlMessages.kRunOrClosePipeMessageId;
+    var payloadSize = controlMessages.RunOrClosePipeMessageParams.encodedSize;
+    var builder = new codec.MessageBuilder(messageName, payloadSize);
+    builder.encodeStruct(controlMessages.RunOrClosePipeMessageParams,
+                         runOrClosePipeMessageParams);
+    var message = builder.finish();
+    receiver.accept(message);
+  }
+
+  function validateControlResponse(message) {
+    var messageValidator = new Validator(message);
+    var error = messageValidator.validateMessageIsResponse();
+    if (error != validator.validationError.NONE) {
+      throw error;
+    }
+
+    if (message.getName() != controlMessages.kRunMessageId) {
+      throw new Error("Control message name is not kRunMessageId");
+    }
+
+    // Validate payload.
+    error = controlMessages.RunResponseMessageParams.validate(
+        messageValidator, message.getHeaderNumBytes());
+    if (error != validator.validationError.NONE) {
+      throw error;
+    }
+  }
+
+  function acceptRunResponse(message) {
+    validateControlResponse(message);
+
+    var reader = new codec.MessageReader(message);
+    var runResponseMessageParams = reader.decodeStruct(
+        controlMessages.RunResponseMessageParams);
+
+    return Promise.resolve(runResponseMessageParams);
+  }
+
+ /**
+  * Sends the given run message through the receiver.
+  * Accepts the response message from the receiver and decodes the message
+  * struct to RunResponseMessageParams.
+  *
+  * @param  {Router} receiver.
+  * @param  {RunMessageParams} runMessageParams to be sent via a message.
+  * @return {Promise} that resolves to a RunResponseMessageParams.
+  */
+  function sendRunMessage(receiver, runMessageParams) {
+    var messageName = controlMessages.kRunMessageId;
+    var payloadSize = controlMessages.RunMessageParams.encodedSize;
+    // |requestID| is set to 0, but is later properly set by Router.
+    var builder = new codec.MessageWithRequestIDBuilder(messageName,
+        payloadSize, codec.kMessageExpectsResponse, 0);
+    builder.encodeStruct(controlMessages.RunMessageParams, runMessageParams);
+    var message = builder.finish();
+
+    return receiver.acceptAndExpectResponse(message).then(acceptRunResponse);
+  }
+
+  function ControlMessageProxy(receiver) {
+    this.receiver = receiver;
+  }
+
+  ControlMessageProxy.prototype.queryVersion = function() {
+    var runMessageParams = new controlMessages.RunMessageParams();
+    runMessageParams.input = new controlMessages.RunInput();
+    runMessageParams.input.query_version = new controlMessages.QueryVersion();
+
+    return sendRunMessage(this.receiver, runMessageParams).then(function(
+        runResponseMessageParams) {
+      return runResponseMessageParams.output.query_version_result.version;
+    });
+  };
+
+  ControlMessageProxy.prototype.requireVersion = function(version) {
+    var runOrClosePipeMessageParams = new
+        controlMessages.RunOrClosePipeMessageParams();
+    runOrClosePipeMessageParams.input = new
+        controlMessages.RunOrClosePipeInput();
+    runOrClosePipeMessageParams.input.require_version = new
+        controlMessages.RequireVersion({'version': version});
+    sendRunOrClosePipeMessage(this.receiver, runOrClosePipeMessageParams);
+  };
+
+  var exports = {};
+  exports.ControlMessageProxy = ControlMessageProxy;
+
+  return exports;
+});