dbus: Add ObjectProxy::WaitForServiceToBeAvailable()

Split ConnectToNameOwnerChangedSignal() from ConnectToSignalInternal().
Add WaitForServiceToBeAvailable()
Add test.

BUG=141009
TEST=dbus_unittests
R=satorux@chromium.org

Review URL: https://codereview.chromium.org/25488002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226428 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 170 insertions, 14 deletions

diff --git a/dbus/dbus.gyp b/dbus/dbus.gyp
index 847e7d97..7225845 100644
--- a/dbus/dbus.gyp
+++ b/dbus/dbus.gyp
@@ -103,6 +103,7 @@
         'message_unittest.cc',
         'mock_unittest.cc',
         'object_manager_unittest.cc',
+        'object_proxy_unittest.cc',
         'property_unittest.cc',
         'signal_sender_verification_unittest.cc',
         'string_util_unittest.cc',
diff --git a/dbus/object_proxy.cc b/dbus/object_proxy.cc
index f2c4ebd..d506392 100644
--- a/dbus/object_proxy.cc
+++ b/dbus/object_proxy.cc
@@ -192,6 +192,16 @@ void ObjectProxy::SetNameOwnerChangedCallback(
   name_owner_changed_callback_ = callback;
 }
 
+void ObjectProxy::WaitForServiceToBeAvailable(
+    WaitForServiceToBeAvailableCallback callback) {
+  bus_->AssertOnOriginThread();
+
+  wait_for_service_to_be_available_callbacks_.push_back(callback);
+  bus_->GetDBusTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&ObjectProxy::WaitForServiceToBeAvailableInternal, this));
+}
+
 void ObjectProxy::Detach() {
   bus_->AssertOnDBusThread();
 
@@ -364,14 +374,9 @@ void ObjectProxy::OnPendingCallIsCompleteThunk(DBusPendingCall* pending_call,
   delete data;
 }
 
-bool ObjectProxy::ConnectToSignalInternal(const std::string& interface_name,
-                                          const std::string& signal_name,
-                                          SignalCallback signal_callback) {
+bool ObjectProxy::ConnectToNameOwnerChangedSignal() {
   bus_->AssertOnDBusThread();
 
-  const std::string absolute_signal_name =
-      GetAbsoluteSignalName(interface_name, signal_name);
-
   if (!bus_->Connect() || !bus_->SetUpAsyncOperations())
     return false;
 
@@ -384,11 +389,6 @@ bool ObjectProxy::ConnectToSignalInternal(const std::string& interface_name,
       LOG(ERROR) << "Failed to add filter function";
     }
   }
-  // Add a match rule so the signal goes through HandleMessage().
-  const std::string match_rule =
-      base::StringPrintf("type='signal', interface='%s', path='%s'",
-                         interface_name.c_str(),
-                         object_path_.value().c_str());
   // Add a match_rule listening NameOwnerChanged for the well-known name
   // |service_name_|.
   const std::string name_owner_changed_match_rule =
@@ -399,9 +399,6 @@ bool ObjectProxy::ConnectToSignalInternal(const std::string& interface_name,
           service_name_.c_str());
 
   const bool success =
-      AddMatchRuleWithCallback(match_rule,
-                               absolute_signal_name,
-                               signal_callback) &&
       AddMatchRuleWithoutCallback(name_owner_changed_match_rule,
                                   "org.freedesktop.DBus.NameOwnerChanged");
 
@@ -414,6 +411,49 @@ bool ObjectProxy::ConnectToSignalInternal(const std::string& interface_name,
   return success;
 }
 
+bool ObjectProxy::ConnectToSignalInternal(const std::string& interface_name,
+                                          const std::string& signal_name,
+                                          SignalCallback signal_callback) {
+  bus_->AssertOnDBusThread();
+
+  if (!ConnectToNameOwnerChangedSignal())
+    return false;
+
+  const std::string absolute_signal_name =
+      GetAbsoluteSignalName(interface_name, signal_name);
+
+  // Add a match rule so the signal goes through HandleMessage().
+  const std::string match_rule =
+      base::StringPrintf("type='signal', interface='%s', path='%s'",
+                         interface_name.c_str(),
+                         object_path_.value().c_str());
+  return AddMatchRuleWithCallback(match_rule,
+                                  absolute_signal_name,
+                                  signal_callback);
+}
+
+void ObjectProxy::WaitForServiceToBeAvailableInternal() {
+  bus_->AssertOnDBusThread();
+
+  if (!ConnectToNameOwnerChangedSignal()) {  // Failed to connect to the signal.
+    const bool service_is_ready = false;
+    bus_->GetOriginTaskRunner()->PostTask(
+        FROM_HERE,
+        base::Bind(&ObjectProxy::RunWaitForServiceToBeAvailableCallbacks,
+                   this, service_is_ready));
+    return;
+  }
+
+  const bool service_is_available = !service_name_owner_.empty();
+  if (service_is_available) {  // Service is already available.
+    bus_->GetOriginTaskRunner()->PostTask(
+        FROM_HERE,
+        base::Bind(&ObjectProxy::RunWaitForServiceToBeAvailableCallbacks,
+                   this, service_is_available));
+    return;
+  }
+}
+
 DBusHandlerResult ObjectProxy::HandleMessage(
     DBusConnection* connection,
     DBusMessage* raw_message) {
@@ -625,6 +665,14 @@ DBusHandlerResult ObjectProxy::HandleNameOwnerChanged(
           FROM_HERE,
           base::Bind(&ObjectProxy::RunNameOwnerChangedCallback,
                      this, old_owner, new_owner));
+
+      const bool service_is_available = !service_name_owner_.empty();
+      if (service_is_available) {
+        bus_->GetOriginTaskRunner()->PostTask(
+            FROM_HERE,
+            base::Bind(&ObjectProxy::RunWaitForServiceToBeAvailableCallbacks,
+                       this, service_is_available));
+      }
     }
   }
 
@@ -640,4 +688,14 @@ void ObjectProxy::RunNameOwnerChangedCallback(const std::string& old_owner,
     name_owner_changed_callback_.Run(old_owner, new_owner);
 }
 
+void ObjectProxy::RunWaitForServiceToBeAvailableCallbacks(
+    bool service_is_available) {
+  bus_->AssertOnOriginThread();
+
+  std::vector<WaitForServiceToBeAvailableCallback> callbacks;
+  callbacks.swap(wait_for_service_to_be_available_callbacks_);
+  for (size_t i = 0; i < callbacks.size(); ++i)
+    callbacks[i].Run(service_is_available);
+}
+
 }  // namespace dbus
diff --git a/dbus/object_proxy.h b/dbus/object_proxy.h
index e618d5d..b183be2 100644
--- a/dbus/object_proxy.h
+++ b/dbus/object_proxy.h
@@ -77,6 +77,10 @@ class CHROME_DBUS_EXPORT ObjectProxy
       const std::string& old_owner,
       const std::string& new_owner)> NameOwnerChangedCallback;
 
+  // Called when the service becomes available.
+  typedef base::Callback<void(
+      bool service_is_available)> WaitForServiceToBeAvailableCallback;
+
   // Called when the object proxy is connected to the signal.
   // Parameters:
   // - the interface name.
@@ -152,6 +156,10 @@ class CHROME_DBUS_EXPORT ObjectProxy
   // represented by |service_name_|.
   virtual void SetNameOwnerChangedCallback(NameOwnerChangedCallback callback);
 
+  // Runs the callback as soon as the service becomes available.
+  virtual void WaitForServiceToBeAvailable(
+      WaitForServiceToBeAvailableCallback callback);
+
   // Detaches from the remote object. The Bus object will take care of
   // detaching so you don't have to do this manually.
   //
@@ -208,11 +216,17 @@ class CHROME_DBUS_EXPORT ObjectProxy
   static void OnPendingCallIsCompleteThunk(DBusPendingCall* pending_call,
                                            void* user_data);
 
+  // Connects to NameOwnerChanged signal.
+  bool ConnectToNameOwnerChangedSignal();
+
   // Helper function for ConnectToSignal().
   bool ConnectToSignalInternal(const std::string& interface_name,
                                const std::string& signal_name,
                                SignalCallback signal_callback);
 
+  // Helper function for WaitForServiceToBeAvailable().
+  void WaitForServiceToBeAvailableInternal();
+
   // Handles the incoming request messages and dispatches to the signal
   // callbacks.
   DBusHandlerResult HandleMessage(DBusConnection* connection,
@@ -262,6 +276,9 @@ class CHROME_DBUS_EXPORT ObjectProxy
   void RunNameOwnerChangedCallback(const std::string& old_owner,
                                    const std::string& new_owner);
 
+  // Runs |wait_for_service_to_be_available_callbacks_|.
+  void RunWaitForServiceToBeAvailableCallbacks(bool service_is_available);
+
   scoped_refptr<Bus> bus_;
   std::string service_name_;
   ObjectPath object_path_;
@@ -277,6 +294,10 @@ class CHROME_DBUS_EXPORT ObjectProxy
   // The callback called when NameOwnerChanged signal is received.
   NameOwnerChangedCallback name_owner_changed_callback_;
 
+  // Called when the service becomes available.
+  std::vector<WaitForServiceToBeAvailableCallback>
+      wait_for_service_to_be_available_callbacks_;
+
   std::set<std::string> match_rules_;
 
   const bool ignore_service_unknown_errors_;
diff --git a/dbus/object_proxy_unittest.cc b/dbus/object_proxy_unittest.cc
new file mode 100644
index 0000000..1cf667c
--- /dev/null
+++ b/dbus/object_proxy_unittest.cc
@@ -0,0 +1,76 @@
+// Copyright 2013 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.
+
+#include "base/bind.h"
+#include "base/memory/ref_counted.h"
+#include "base/run_loop.h"
+#include "dbus/bus.h"
+#include "dbus/object_proxy.h"
+#include "dbus/test_service.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace dbus {
+namespace {
+
+class ObjectProxyTest : public testing::Test {
+ protected:
+  virtual void SetUp() OVERRIDE {
+    Bus::Options bus_options;
+    bus_options.bus_type = Bus::SESSION;
+    bus_options.connection_type = Bus::PRIVATE;
+    bus_ = new Bus(bus_options);
+
+    object_proxy_ = bus_->GetObjectProxy(
+        "org.chromium.TestService", ObjectPath("/org/chromium/TestObject"));
+  }
+
+  virtual void TearDown() OVERRIDE {
+    bus_->ShutdownAndBlock();
+  }
+
+  base::MessageLoopForIO message_loop_;
+  scoped_refptr<Bus> bus_;
+  ObjectProxy* object_proxy_;
+};
+
+// Used as a WaitForServiceToBeAvailableCallback.
+void OnServiceIsAvailable(scoped_ptr<base::RunLoop>* run_loop,
+                          bool service_is_available) {
+  EXPECT_TRUE(service_is_available);
+  ASSERT_TRUE(*run_loop);
+  (*run_loop)->Quit();
+}
+
+TEST_F(ObjectProxyTest, WaitForServiceToBeAvailable) {
+  scoped_ptr<base::RunLoop> run_loop;
+
+  // Callback is not yet called because the service is not available.
+  object_proxy_->WaitForServiceToBeAvailable(
+      base::Bind(&OnServiceIsAvailable, &run_loop));
+  base::RunLoop().RunUntilIdle();
+
+  // Start the service.
+  TestService::Options options;
+  TestService test_service(options);
+  ASSERT_TRUE(test_service.StartService());
+  ASSERT_TRUE(test_service.WaitUntilServiceIsStarted());
+  ASSERT_TRUE(test_service.has_ownership());
+
+  // Callback is called beacuse the service became available.
+  run_loop.reset(new base::RunLoop);
+  run_loop->Run();
+
+  // Callback is called because the service is already available.
+  run_loop.reset(new base::RunLoop);
+  object_proxy_->WaitForServiceToBeAvailable(
+      base::Bind(&OnServiceIsAvailable, &run_loop));
+  run_loop->Run();
+
+  // Shut down the service.
+  test_service.ShutdownAndBlock();
+  test_service.Stop();
+}
+
+}  // namespace
+}  // namespace dbus