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