1// Copyright (c) 2012 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_NETWORK_LOCATION_PROVIDER_H_
6#define CONTENT_BROWSER_GEOLOCATION_NETWORK_LOCATION_PROVIDER_H_
7
8#include <list>
9#include <map>
10
11#include "base/basictypes.h"
12#include "base/memory/ref_counted.h"
13#include "base/memory/scoped_ptr.h"
14#include "base/memory/weak_ptr.h"
15#include "base/strings/string16.h"
16#include "base/threading/non_thread_safe.h"
17#include "base/threading/thread.h"
18#include "content/browser/geolocation/location_provider_base.h"
19#include "content/browser/geolocation/network_location_request.h"
20#include "content/browser/geolocation/wifi_data_provider_manager.h"
21#include "content/common/content_export.h"
22#include "content/public/common/geoposition.h"
23
24namespace content {
25class AccessTokenStore;
26
27
28class NetworkLocationProvider
29    : public base::NonThreadSafe,
30      public LocationProviderBase {
31 public:
32  // Cache of recently resolved locations. Public for tests.
33  class CONTENT_EXPORT PositionCache {
34   public:
35    // The maximum size of the cache of positions.
36    static const size_t kMaximumSize;
37
38    PositionCache();
39    ~PositionCache();
40
41    // Caches the current position response for the current set of cell ID and
42    // WiFi data. In the case of the cache exceeding kMaximumSize this will
43    // evict old entries in FIFO orderer of being added.
44    // Returns true on success, false otherwise.
45    bool CachePosition(const WifiData& wifi_data,
46                       const Geoposition& position);
47
48    // Searches for a cached position response for the current set of data.
49    // Returns NULL if the position is not in the cache, or the cached
50    // position if available. Ownership remains with the cache.
51    const Geoposition* FindPosition(const WifiData& wifi_data);
52
53   private:
54    // Makes the key for the map of cached positions, using a set of
55    // data. Returns true if a good key was generated, false otherwise.
56    static bool MakeKey(const WifiData& wifi_data,
57                        base::string16* key);
58
59    // The cache of positions. This is stored as a map keyed on a string that
60    // represents a set of data, and a list to provide
61    // least-recently-added eviction.
62    typedef std::map<base::string16, Geoposition> CacheMap;
63    CacheMap cache_;
64    typedef std::list<CacheMap::iterator> CacheAgeList;
65    CacheAgeList cache_age_list_;  // Oldest first.
66  };
67
68  NetworkLocationProvider(AccessTokenStore* access_token_store,
69                          net::URLRequestContextGetter* context,
70                          const GURL& url,
71                          const base::string16& access_token);
72  virtual ~NetworkLocationProvider();
73
74  // LocationProvider implementation
75  virtual bool StartProvider(bool high_accuracy) OVERRIDE;
76  virtual void StopProvider() OVERRIDE;
77  virtual void GetPosition(Geoposition *position) OVERRIDE;
78  virtual void RequestRefresh() OVERRIDE;
79  virtual void OnPermissionGranted() OVERRIDE;
80
81 private:
82  // Satisfies a position request from cache or network.
83  void RequestPosition();
84
85  // Gets called when new wifi data is available.
86  void OnWifiDataUpdate();
87
88  // Internal helper used by OnWifiDataUpdate.
89  void OnWifiDataUpdated();
90
91  bool IsStarted() const;
92
93  void OnLocationResponse(const Geoposition& position,
94                          bool server_error,
95                          const base::string16& access_token,
96                          const WifiData& wifi_data);
97
98  scoped_refptr<AccessTokenStore> access_token_store_;
99
100  // The wifi data provider, acquired via global factories.
101  WifiDataProviderManager* wifi_data_provider_manager_;
102
103  WifiDataProviderManager::WifiDataUpdateCallback wifi_data_update_callback_;
104
105  // The  wifi data and a flag to indicate if the data set is complete.
106  WifiData wifi_data_;
107  bool is_wifi_data_complete_;
108
109  // The timestamp for the latest wifi data update.
110  base::Time wifi_data_updated_timestamp_;
111
112  // Cached value loaded from the token store or set by a previous server
113  // response, and sent in each subsequent network request.
114  base::string16 access_token_;
115
116  // The current best position estimate.
117  Geoposition position_;
118
119  // Whether permission has been granted for the provider to operate.
120  bool is_permission_granted_;
121
122  bool is_new_data_available_;
123
124  // The network location request object, and the url it uses.
125  scoped_ptr<NetworkLocationRequest> request_;
126
127  // The cache of positions.
128  scoped_ptr<PositionCache> position_cache_;
129
130  base::WeakPtrFactory<NetworkLocationProvider> weak_factory_;
131
132  DISALLOW_COPY_AND_ASSIGN(NetworkLocationProvider);
133};
134
135// Factory functions for the various types of location provider to abstract
136// over the platform-dependent implementations.
137CONTENT_EXPORT LocationProviderBase* NewNetworkLocationProvider(
138    AccessTokenStore* access_token_store,
139    net::URLRequestContextGetter* context,
140    const GURL& url,
141    const base::string16& access_token);
142
143}  // namespace content
144
145#endif  // CONTENT_BROWSER_GEOLOCATION_NETWORK_LOCATION_PROVIDER_H_
146