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1 // Copyright 2014 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_DEVICE_SENSORS_DATA_FETCHER_SHARED_MEMORY_BASE_H_ | |
6 #define CONTENT_BROWSER_DEVICE_SENSORS_DATA_FETCHER_SHARED_MEMORY_BASE_H_ | |
7 | |
8 #include <map> | |
9 | |
10 #include "base/memory/scoped_ptr.h" | |
11 #include "base/memory/shared_memory.h" | |
12 #include "base/message_loop/message_loop.h" | |
13 #include "content/browser/device_sensors/inertial_sensor_consts.h" | |
14 #include "content/common/content_export.h" | |
15 | |
16 namespace content { | |
17 | |
18 // Sensor data fetchers should derive from this base class and implement | |
19 // the abstract Start() and Stop() methods. | |
20 // If the fetcher requires polling it should also implement IsPolling() | |
21 // to return true and the Fetch() method which will be called from the | |
22 // polling thread to fetch data at regular intervals. | |
23 class CONTENT_EXPORT DataFetcherSharedMemoryBase { | |
24 public: | |
25 // Starts updating the shared memory buffer with sensor data at | |
26 // regular intervals. Returns true if the relevant sensors could | |
27 // be successfully activated. | |
28 bool StartFetchingDeviceData(ConsumerType consumer_type); | |
29 | |
30 // Stops updating the shared memory buffer. Returns true if the | |
31 // relevant sensors could be successfully deactivated. | |
32 bool StopFetchingDeviceData(ConsumerType consumer_type); | |
33 | |
34 // Should be called before destruction to make sure all active | |
35 // sensors are unregistered. | |
36 virtual void Shutdown(); | |
37 | |
38 // Returns the shared memory handle of the device sensor data | |
39 // duplicated into the given process. This method should only be | |
40 // called after a call to StartFetchingDeviceData method with | |
41 // corresponding |consumer_type| parameter. | |
42 base::SharedMemoryHandle GetSharedMemoryHandleForProcess( | |
43 ConsumerType consumer_type, base::ProcessHandle process); | |
44 | |
45 enum FetcherType { | |
46 // Fetcher runs on the same thread as its creator. | |
47 FETCHER_TYPE_DEFAULT, | |
48 // Fetcher runs on a separate thread calling |Fetch()| at regular intervals. | |
49 FETCHER_TYPE_POLLING_CALLBACK, | |
50 // Fetcher runs on a separate thread, but no callbacks are executed. | |
51 FETCHER_TYPE_SEPARATE_THREAD | |
52 }; | |
53 | |
54 protected: | |
55 class PollingThread; | |
56 | |
57 DataFetcherSharedMemoryBase(); | |
58 virtual ~DataFetcherSharedMemoryBase(); | |
59 | |
60 // Returns the message loop of the polling thread. | |
61 // Returns NULL if there is no polling thread. | |
62 base::MessageLoop* GetPollingMessageLoop() const; | |
63 | |
64 // If IsPolling() is true this method is called from the |polling_thread_| | |
65 // at regular intervals. | |
66 virtual void Fetch(unsigned consumer_bitmask); | |
67 | |
68 // Returns the type of thread this fetcher runs on. | |
69 virtual FetcherType GetType() const; | |
70 | |
71 // Returns the sensor sampling interval. In particular if this fetcher | |
72 // GetType() == FETCHER_TYPE_POLLING_CALLBACK the interval between | |
73 // successive calls to Fetch(). | |
74 virtual base::TimeDelta GetInterval() const; | |
75 | |
76 // Start() method should call InitSharedMemoryBuffer() to get the shared | |
77 // memory pointer. If IsPolling() is true both Start() and Stop() methods | |
78 // are called from the |polling_thread_|. | |
79 virtual bool Start(ConsumerType consumer_type, void* buffer) = 0; | |
80 virtual bool Stop(ConsumerType consumer_type) = 0; | |
81 | |
82 bool IsPollingTimerRunningForTesting() const; | |
83 | |
84 private: | |
85 bool InitAndStartPollingThreadIfNecessary(); | |
86 base::SharedMemory* GetSharedMemory(ConsumerType consumer_type); | |
87 void* GetSharedMemoryBuffer(ConsumerType consumer_type); | |
88 | |
89 unsigned started_consumers_; | |
90 | |
91 scoped_ptr<PollingThread> polling_thread_; | |
92 | |
93 // Owning pointers. Objects in the map are deleted in dtor. | |
94 typedef std::map<ConsumerType, base::SharedMemory*> SharedMemoryMap; | |
95 SharedMemoryMap shared_memory_map_; | |
96 | |
97 DISALLOW_COPY_AND_ASSIGN(DataFetcherSharedMemoryBase); | |
98 }; | |
99 | |
100 } // namespace content | |
101 | |
102 #endif // CONTENT_BROWSER_DEVICE_SENSORS_DATA_FETCHER_SHARED_MEMORY_BASE_H_ | |
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