Refactors DeviceOrientation to make it more extensible

content/browser/device_orientation/provider_impl.h

 // 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 CONTENT_BROWSER_DEVICE_ORIENTATION_PROVIDER_IMPL_H_
 #define CONTENT_BROWSER_DEVICE_ORIENTATION_PROVIDER_IMPL_H_
 
 #include <set>
 #include <vector>
 
+#include "base/id_map.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time.h"
 #include "content/browser/device_orientation/data_fetcher.h"
-#include "content/browser/device_orientation/orientation.h"
+#include "content/browser/device_orientation/device_data.h"
 #include "content/browser/device_orientation/provider.h"
 #include "content/common/content_export.h"
 
 class MessageLoop;
 
 namespace base {
 class Thread;
 }
 
 namespace device_orientation {
 
 class ProviderImpl : public Provider {
  public:
   typedef DataFetcher* (*DataFetcherFactory)();
 
   // Create a ProviderImpl that uses the NULL-terminated factories array to find
-  // a DataFetcher that can provide orientation data.
+  // a DataFetcher that can provide data.
   CONTENT_EXPORT ProviderImpl(const DataFetcherFactory factories[]);
 
   // From Provider.
   virtual void AddObserver(Observer* observer) OVERRIDE;
   virtual void RemoveObserver(Observer* observer) OVERRIDE;
 
  private:
   virtual ~ProviderImpl();
 
   // Starts or Stops the provider. Called from creator_loop_.
   void Start();
   void Stop();
 
+  // Method for adding a type of observer to poll. Runs on the polling_thread_.

[hans, 2012/07/18 17:21:02]

we're not really polling the observers, though? Maybe something like "Add
another type of data to poll for. Runs on the polling_thread_."

[aousterh, 2012/07/20 11:18:52]

Done. I also renamed the function and member observer_types_.

+  void DoAddObserverType(DeviceData::Type device_data_type);
+  void ScheduleDoAddObserverType(DeviceData::Type device_data_type);
+
   // Method for finding a suitable DataFetcher and starting the polling.
   // Runs on the polling_thread_.
   void DoInitializePollingThread(
-      const std::vector<DataFetcherFactory>& factories);
-  void ScheduleInitializePollingThread();
+      const std::vector<DataFetcherFactory>& factories,
+      DeviceData::Type device_data_type);
+  void ScheduleInitializePollingThread(DeviceData::Type device_data_type);
 
   // Method for polling a DataFetcher. Runs on the polling_thread_.
   void DoPoll();
   void ScheduleDoPoll();
 
-  // Method for notifying observers of an orientation update.
+  // Method for notifying observers of a data update.
   // Runs on the creator_thread_.
-  void DoNotify(const Orientation& orientation);
-  void ScheduleDoNotify(const Orientation& orientation);
-
-  static bool SignificantlyDifferent(const Orientation& orientation1,
-                                     const Orientation& orientation2);
+  void DoNotify(const DeviceData* device_data,
+                DeviceData::Type device_data_type);
+  void ScheduleDoNotify(const DeviceData* device_data,
+                        DeviceData::Type device_data_type);
 
   enum { kDesiredSamplingIntervalMs = 100 };
   base::TimeDelta SamplingInterval() const;
 
   // The Message Loop on which this object was created.
   // Typically the I/O loop, but may be something else during testing.
   MessageLoop* creator_loop_;
 
   // Members below are only to be used from the creator_loop_.
   std::vector<DataFetcherFactory> factories_;
   std::set<Observer*> observers_;
-  Orientation last_notification_;
+  IDMap<DeviceData, IDMapOwnPointer> last_notifications_map_;

[hans, 2012/07/18 17:21:02]

I'm not sure IDMap is the best for this. Could we just use

std::map<DeviceData::Type, scoped_ptr<DeviceData> > instead?

[aousterh, 2012/07/20 11:18:52]

I used IDMap because it's not possible to use std::map with scoped_ptrs, as far
as I can tell. However, now that I made DeviceData RefCounted, this can be a
std::map<DeviceData::Type, scoped_refptr<DeviceData> >. Done.

 
   // When polling_thread_ is running, members below are only to be used
   // from that thread.
   scoped_ptr<DataFetcher> data_fetcher_;
-  Orientation last_orientation_;
+  scoped_ptr<IDMap<DeviceData, IDMapOwnPointer> > last_device_data_map_;

[hans, 2012/07/18 17:21:02]

same here

[aousterh, 2012/07/20 11:18:52]

Done.

   base::WeakPtrFactory<ProviderImpl> weak_factory_;
+  std::set<DeviceData::Type> observer_types_;
 
   // Polling is done on this background thread.
   scoped_ptr<base::Thread> polling_thread_;
 };
 
 }  // namespace device_orientation
 
 #endif  // CONTENT_BROWSER_DEVICE_ORIENTATION_PROVIDER_IMPL_H_