content/browser/geolocation/wifi_data_provider.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_
   6 #define CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_
   7
   8 #include <set>
   9
  10 #include "base/basictypes.h"
  11 #include "base/bind.h"
  12 #include "base/callback.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "base/message_loop/message_loop.h"
  15 #include "base/strings/string16.h"
  16 #include "base/strings/string_util.h"
  17 #include "content/browser/geolocation/wifi_data.h"
  18 #include "content/common/content_export.h"
  19
  20 namespace content {
  21
  22 class CONTENT_EXPORT WifiDataProvider
  23     : public base::RefCountedThreadSafe<WifiDataProvider> {
  24  public:
  25   WifiDataProvider();
  26
  27   // Tells the provider to start looking for data. Callbacks will start
  28   // receiving notifications after this call.
  29   virtual void StartDataProvider() = 0;
  30
  31   // Tells the provider to stop looking for data. Callbacks will stop
  32   // receiving notifications after this call.
  33   virtual void StopDataProvider() = 0;
  34
  35   // Provides whatever data the provider has, which may be nothing. Return
  36   // value indicates whether this is all the data the provider could ever
  37   // obtain.
  38   virtual bool GetData(WifiData* data) = 0;
  39
  40   typedef base::Closure WifiDataUpdateCallback;
  41
  42   void AddCallback(WifiDataUpdateCallback* callback);
  43
  44   bool RemoveCallback(WifiDataUpdateCallback* callback);
  45
  46   bool has_callbacks() const;
  47
  48  protected:
  49   friend class base::RefCountedThreadSafe<WifiDataProvider>;
  50   virtual ~WifiDataProvider();
  51
  52   typedef std::set<WifiDataUpdateCallback*> CallbackSet;
  53
  54   // Runs all callbacks via a posted task, so we can unwind callstack here and
  55   // avoid client reentrancy.
  56   void RunCallbacks();
  57
  58   bool CalledOnClientThread() const;
  59
  60   base::MessageLoop* client_loop() const;
  61
  62  private:
  63   void DoRunCallbacks();
  64
  65   // Reference to the client's message loop. All callbacks should happen in this
  66   // context.
  67   base::MessageLoop* client_loop_;
  68
  69   CallbackSet callbacks_;
  70
  71   DISALLOW_COPY_AND_ASSIGN(WifiDataProvider);
  72 };
  73
  74 }  // namespace content
  75
  76 #endif  // CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_