root/chrome/browser/extensions/extension_test_message_listener.h

INCLUDED FROM

// Copyright (c) 2012 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.

#ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_TEST_MESSAGE_LISTENER_H_
#define CHROME_BROWSER_EXTENSIONS_EXTENSION_TEST_MESSAGE_LISTENER_H_

#include <string>

#include "base/compiler_specific.h"
#include "base/memory/ref_counted.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"

namespace extensions {
class TestSendMessageFunction;
}

// This class helps us wait for incoming messages sent from javascript via
// chrome.test.sendMessage(). A sample usage would be:
//
//   ExtensionTestMessageListener listener("foo", false);  // won't reply
//   ... do some work
//   ASSERT_TRUE(listener.WaitUntilSatisfied());
//
// It is also possible to have the extension wait for our reply. This is
// useful for coordinating multiple pages/processes and having them wait on
// each other. Example:
//
//   ExtensionTestMessageListener listener1("foo1", true);  // will reply
//   ExtensionTestMessageListener listener2("foo2", true);  // will reply
//   ASSERT_TRUE(listener1.WaitUntilSatisfied());
//   ASSERT_TRUE(listener2.WaitUntilSatisfied());
//   ... do some work
//   listener1.Reply("foo2 is ready");
//   listener2.Reply("foo1 is ready");
//
// Further, we can use this to listen for a success and failure message:
//
//   ExtensionTestMessageListener listener("success", will_reply);
//   listener.set_failure_message("failure");
//   ASSERT_TRUE(listener.WaitUntilSatisfied());
//   if (listener.message() == "success") {
//     HandleSuccess();
//   } else {
//     ASSERT_EQ("failure", listener.message());
//     HandleFailure();
//   }
//
// Or, use it to listen to any arbitrary message:
//
//   ExtensionTestMessageListener listener(will_reply);
//   ASSERT_TRUE(listener.WaitUntilSatisfied());
//   if (listener.message() == "foo")
//     HandleFoo();
//   else if (listener.message() == "bar")
//     HandleBar();
//   else if (listener.message() == "baz")
//     HandleBaz();
//   else
//     NOTREACHED();
//
// You can also use the class to listen for messages from a specified extension:
//
//   ExtensionTestMessageListener listener(will_reply);
//   listener.set_extension_id(extension->id());
//   ASSERT_TRUE(listener.WaitUntilSatisfied());
//   ... do some work.
//
// Finally, you can reset the listener to reuse it.
//
//   ExtensionTestMessageListener listener(true);  // will reply
//   ASSERT_TRUE(listener.WaitUntilSatisfied());
//   while (listener.message() != "end") {
//     Handle(listener.message());
//     listener.Reply("bar");
//     listener.Reset();
//     ASSERT_TRUE(listener.WaitUntilSatisfied());
//   }
//
// Note that when using it in browser tests, you need to make sure it gets
// destructed *before* the browser gets torn down. Two common patterns are to
// either make it a local variable inside your test body, or if it's a member
// variable of a ExtensionBrowserTest subclass, override the
// InProcessBrowserTest::CleanUpOnMainThread() method and clean it up there.
class ExtensionTestMessageListener : public content::NotificationObserver {
 public:
  // We immediately start listening for |expected_message|.
  ExtensionTestMessageListener(const std::string& expected_message,
                               bool will_reply);
  // Construct a message listener which will listen for any message.
  explicit ExtensionTestMessageListener(bool will_reply);

  virtual ~ExtensionTestMessageListener();

  // This returns true immediately if we've already gotten the expected
  // message, or waits until it arrives.
  // Returns false if the wait is interrupted and we still haven't gotten the
  // message, or if the message was equal to |failure_message_|.
  bool WaitUntilSatisfied();

  // Send the given message as a reply. It is only valid to call this after
  // WaitUntilSatisfied has returned true, and if will_reply is true.
  void Reply(const std::string& message);

  // Convenience method that formats int as a string and sends it.
  void Reply(int message);

  // Reset the listener to listen again. No settings (such as messages to
  // listen for) are modified.
  void Reset();

  // Getters and setters.

  bool was_satisfied() const { return satisfied_; }

  void set_failure_message(const std::string& failure_message) {
    failure_message_ = failure_message;
  }

  const std::string& extension_id() const { return extension_id_; }
  void set_extension_id(const std::string& extension_id) {
    extension_id_ = extension_id;
  }

  const std::string& message() const { return message_; }

 private:
  // Implements the content::NotificationObserver interface.
  virtual void Observe(int type,
                       const content::NotificationSource& source,
                       const content::NotificationDetails& details) OVERRIDE;

  content::NotificationRegistrar registrar_;

  // The message we're expecting.
  std::string expected_message_;

  // The last message we received.
  std::string message_;

  // Whether we've seen expected_message_ yet.
  bool satisfied_;

  // If we're waiting, then we want to post a quit task when the expected
  // message arrives.
  bool waiting_;

  // Whether or not we will wait for any message, regardless of contents.
  bool wait_for_any_message_;

  // If true, we expect the calling code to manually send a reply. Otherwise,
  // we send an automatic empty reply to the extension.
  bool will_reply_;

  // Whether or not we have already replied (we can only reply once).
  bool replied_;

  // The extension id that we listen for, or empty.
  std::string extension_id_;

  // The message that signals failure.
  std::string failure_message_;

  // If we received a message that was the failure message.
  bool failed_;

  // The function we need to reply to.
  scoped_refptr<extensions::TestSendMessageFunction> function_;
};

#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_TEST_MESSAGE_LISTENER_H_