Replace DeviceDataProvider with the non-templated WifiDataProvider.

Also replace DeviceDataProvider::ListenerInterface with WifiDataProvider::WifiDataUpdateCallback. I would have preferred to do that as a separate change, but removing the templating revealed a nasty circular dependency that involved this nested class, which made forward declarations impossible. So, all in one go then.

I also deleted device_data_provider_unittest.cc as its purpose was to test for threading failures. These data providers no longer start their own threads, see https://codereview.chromium.org/22866005/

BUG=103713
TBR=jam

Review URL: https://chromiumcodereview.appspot.com/23181009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@219279 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 195 insertions, 0 deletions

diff --git a/content/browser/geolocation/wifi_data_provider.h b/content/browser/geolocation/wifi_data_provider.h
new file mode 100644
index 0000000..7937f28
--- /dev/null
+++ b/content/browser/geolocation/wifi_data_provider.h
@@ -0,0 +1,195 @@
+// 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.
+
+// A wifi data provider provides wifi data from the device that is used by a
+// NetworkLocationProvider to obtain a position fix. We use a singleton
+// instance of the wifi data provider, which is used by multiple
+// NetworkLocationProvider objects.
+//
+// This file provides WifiDataProvider, which provides static methods to
+// access the singleton instance. The singleton instance uses a private
+// implementation to abstract across platforms and also to allow mock providers
+// to be used for testing.
+//
+// This file also provides WifiDataProviderImplBase, a base class which
+// provides common functionality for the private implementations.
+
+#ifndef CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_
+#define CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_
+
+#include <set>
+
+#include "base/basictypes.h"
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/message_loop/message_loop.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_util.h"
+#include "content/browser/geolocation/wifi_data.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+class WifiDataProvider;
+
+// See class WifiDataProvider for the public client API.
+// WifiDataProvider uses containment to hide platform-specific implementation
+// details from common code. This class provides common functionality for these
+// contained implementation classes. This is a modified pimpl pattern.
+class CONTENT_EXPORT WifiDataProviderImplBase
+    : public base::RefCountedThreadSafe<WifiDataProviderImplBase> {
+ public:
+  WifiDataProviderImplBase();
+
+  // Tells the provider to start looking for data. Callbacks will start
+  // receiving notifications after this call.
+  virtual void StartDataProvider() = 0;
+
+  // Tells the provider to stop looking for data. Callbacks will stop
+  // receiving notifications after this call.
+  virtual void StopDataProvider() = 0;
+
+  // Provides whatever data the provider has, which may be nothing. Return
+  // value indicates whether this is all the data the provider could ever
+  // obtain.
+  virtual bool GetData(WifiData* data) = 0;
+
+  // Sets the container of this class, which is of type WifiDataProvider.
+  // This is required to pass as a parameter when calling a callback.
+  void SetContainer(WifiDataProvider* container);
+
+  typedef base::Callback<void(WifiDataProvider*)> WifiDataUpdateCallback;
+
+  void AddCallback(WifiDataUpdateCallback* callback);
+
+  bool RemoveCallback(WifiDataUpdateCallback* callback);
+
+  bool has_callbacks() const;
+
+ protected:
+  friend class base::RefCountedThreadSafe<WifiDataProviderImplBase>;
+  virtual ~WifiDataProviderImplBase();
+
+  typedef std::set<WifiDataUpdateCallback*> CallbackSet;
+
+  // Runs all callbacks via a posted task, so we can unwind callstack here and
+  // avoid client reentrancy.
+  void RunCallbacks();
+
+  bool CalledOnClientThread() const;
+
+  base::MessageLoop* client_loop() const;
+
+ private:
+  void DoRunCallbacks();
+
+  WifiDataProvider* container_;
+
+  // Reference to the client's message loop. All callbacks should happen in this
+  // context.
+  base::MessageLoop* client_loop_;
+
+  CallbackSet callbacks_;
+
+  DISALLOW_COPY_AND_ASSIGN(WifiDataProviderImplBase);
+};
+
+// A wifi data provider
+//
+// We use a singleton instance of this class which is shared by multiple network
+// location providers. These location providers access the instance through the
+// Register and Unregister methods.
+class CONTENT_EXPORT WifiDataProvider {
+ public:
+  // Sets the factory function which will be used by Register to create the
+  // implementation used by the singleton instance. This factory approach is
+  // used both to abstract accross platform-specific implementations and to
+  // inject mock implementations for testing.
+  typedef WifiDataProviderImplBase* (*ImplFactoryFunction)(void);
+  static void SetFactory(ImplFactoryFunction factory_function_in) {
+    factory_function_ = factory_function_in;
+  }
+
+  static void ResetFactory() {
+    factory_function_ = DefaultFactoryFunction;
+  }
+
+  typedef base::Callback<void(WifiDataProvider*)> WifiDataUpdateCallback;
+
+  // Registers a callback, which will be run whenever new data is available.
+  // Instantiates the singleton if necessary, and always returns it.
+  static WifiDataProvider* Register(WifiDataUpdateCallback* callback);
+
+  // Removes a callback. If this is the last callback, deletes the singleton
+  // instance. Return value indicates success.
+  static bool Unregister(WifiDataUpdateCallback* callback) {
+    DCHECK(instance_);
+    DCHECK(instance_->has_callbacks());
+    if (!instance_->RemoveCallback(callback)) {
+      return false;
+    }
+    if (!instance_->has_callbacks()) {
+      // Must stop the data provider (and any implementation threads) before
+      // destroying to avoid any race conditions in access to the provider in
+      // the destructor chain.
+      instance_->StopDataProvider();
+      delete instance_;
+      instance_ = NULL;
+    }
+    return true;
+  }
+
+  // Provides whatever data the provider has, which may be nothing. Return
+  // value indicates whether this is all the data the provider could ever
+  // obtain.
+  bool GetData(WifiData* data) {
+    return impl_->GetData(data);
+  }
+
+ private:
+  // Private constructor and destructor, callers access singleton through
+  // Register and Unregister.
+  WifiDataProvider();
+  virtual ~WifiDataProvider();
+
+  void AddCallback(WifiDataUpdateCallback* callback) {
+    impl_->AddCallback(callback);
+  }
+
+  bool RemoveCallback(WifiDataUpdateCallback* callback) {
+    return impl_->RemoveCallback(callback);
+  }
+
+  bool has_callbacks() const {
+    return impl_->has_callbacks();
+  }
+
+  void StartDataProvider() {
+    impl_->StartDataProvider();
+  }
+
+  void StopDataProvider() {
+    impl_->StopDataProvider();
+  }
+
+  static WifiDataProviderImplBase* DefaultFactoryFunction();
+
+  // The singleton-like instance of this class. (Not 'true' singleton, as it
+  // may go through multiple create/destroy/create cycles per process instance,
+  // e.g. when under test).
+  static WifiDataProvider* instance_;
+
+  // The factory function used to create the singleton instance.
+  static ImplFactoryFunction factory_function_;
+
+  // The internal implementation.
+  scoped_refptr<WifiDataProviderImplBase> impl_;
+
+  DISALLOW_COPY_AND_ASSIGN(WifiDataProvider);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_