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
20namespace content {
21
22class 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_
77