Date and Time dialog for when the clock isn't synced.

chromeos/dbus/system_clock_client.cc

 // Copyright (c) 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 "chromeos/dbus/system_clock_client.h"
 
 #include "base/bind.h"
+#include "base/callback.h"
 #include "dbus/bus.h"
 #include "dbus/message.h"
 #include "dbus/object_path.h"
 #include "dbus/object_proxy.h"
 #include "third_party/cros_system_api/dbus/service_constants.h"
 
 namespace chromeos {
 
 // The SystemClockClient implementation used in production.
 class SystemClockClientImpl : public SystemClockClient {
  public:
   SystemClockClientImpl()
-      : system_clock_proxy_(NULL), weak_ptr_factory_(this) {}
+      : can_set_time_(false),
+        can_set_time_initialized_(false),
+        system_clock_proxy_(NULL),
+        weak_ptr_factory_(this) {}
 
   virtual ~SystemClockClientImpl() {
   }
 
   virtual void AddObserver(Observer* observer) OVERRIDE {
     observers_.AddObserver(observer);
   }
 
   virtual void RemoveObserver(Observer* observer) OVERRIDE {
     observers_.RemoveObserver(observer);
   }
 
   virtual bool HasObserver(Observer* observer) OVERRIDE {
     return observers_.HasObserver(observer);
   }
 
+  virtual void SetTime(int64 time_in_seconds) OVERRIDE {
+    // Always try to set the time, because |can_set_time_| may be stale.
+    dbus::MethodCall method_call(
+        system_clock::kSystemClockInterface,
+        system_clock::kSystemClockSet);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendInt64(time_in_seconds);
+    system_clock_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        dbus::ObjectProxy::EmptyResponseCallback());
+  }
+
+  virtual bool CanSetTime() OVERRIDE {
+    return can_set_time_;
+  }
+
  protected:
   virtual void Init(dbus::Bus* bus) OVERRIDE {
     system_clock_proxy_ = bus->GetObjectProxy(
         system_clock::kSystemClockServiceName,
         dbus::ObjectPath(system_clock::kSystemClockServicePath));
 
+    // Check whether the system clock can be set.
+    GetCanSet();
+
     // Monitor the D-Bus signal for TimeUpdated changes.
     system_clock_proxy_->ConnectToSignal(
         system_clock::kSystemClockInterface,
         system_clock::kSystemClockUpdated,
         base::Bind(&SystemClockClientImpl::TimeUpdatedReceived,
                    weak_ptr_factory_.GetWeakPtr()),
         base::Bind(&SystemClockClientImpl::TimeUpdatedConnected,
                    weak_ptr_factory_.GetWeakPtr()));
   }
 
  private:
   // Called when a TimeUpdated signal is received.
   void TimeUpdatedReceived(dbus::Signal* signal) {
     VLOG(1) << "TimeUpdated signal received: " << signal->ToString();
     dbus::MessageReader reader(signal);
     FOR_EACH_OBSERVER(Observer, observers_, SystemClockUpdated());
+
+    // Check if the system clock can be changed now.
+    GetCanSet();
   }
 
   // Called when the TimeUpdated signal is initially connected.
   void TimeUpdatedConnected(const std::string& interface_name,
                             const std::string& signal_name,
                             bool success) {
     LOG_IF(ERROR, !success)
         << "Failed to connect to TimeUpdated signal.";
   }
 
+  // Callback for CanSetTime method.
+  void OnGetCanSet(dbus::Response* response) {
+    if (!response) {
+      LOG(WARNING) << "CanSetTime request failed.";
+      return;
+    }
+
+    dbus::MessageReader reader(response);
+    bool can_set_time;
+    if (!reader.PopBool(&can_set_time)) {
+      LOG(ERROR) << "CanSetTime response invalid: " << response->ToString();
+      return;
+    }
+
+    // Nothing to do if the CanSetTime response hasn't changed.
+    if (can_set_time_initialized_ && can_set_time_ == can_set_time)
+      return;
+
+    can_set_time_initialized_ = true;
+    can_set_time_ = can_set_time;
+
+    FOR_EACH_OBSERVER(Observer,
+                      observers_,
+                      SystemClockCanSetTimeChanged(can_set_time));
+  }
+
+  // Check whether the time can be set.
+  void GetCanSet() {
+    dbus::MethodCall method_call(
+        system_clock::kSystemClockInterface,
+        system_clock::kSystemClockCanSet);
+    dbus::MessageWriter writer(&method_call);
+    system_clock_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        base::Bind(&SystemClockClientImpl::OnGetCanSet,
+                   weak_ptr_factory_.GetWeakPtr()));
+  }
+
+  // Whether the time can be set. Value is false until the first
+  // CanSetTime response is received.
+  bool can_set_time_;
+  bool can_set_time_initialized_;
   dbus::ObjectProxy* system_clock_proxy_;
   ObserverList<Observer> observers_;
 
-  // Note: This should remain the last member so it'll be destroyed and
-  // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<SystemClockClientImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemClockClientImpl);
 };
 
+void SystemClockClient::Observer::SystemClockUpdated() {
+}
+
+void
+SystemClockClient::Observer::SystemClockCanSetTimeChanged(bool can_set_time) {

[Daniel Erat, 2014/04/23 16:33:22]

nit: i think it's more common to move the name to the previous line and break at
the opening '('

[michaelpg, 2014/04/24 01:32:23]

Done.

+}
+
 SystemClockClient::SystemClockClient() {
 }
 
 SystemClockClient::~SystemClockClient() {
 }
 
 // static
 SystemClockClient* SystemClockClient::Create() {
   return new SystemClockClientImpl();
 }
 
 }  // namespace chromeos