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1 // Copyright 2014 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_CLOCK_DEVICE_H_ | 5 #ifndef CHROMECAST_PUBLIC_MEDIA_MEDIA_CLOCK_DEVICE_H_ |
6 #define CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_CLOCK_DEVICE_H_ | 6 #define CHROMECAST_PUBLIC_MEDIA_MEDIA_CLOCK_DEVICE_H_ |
7 | 7 |
8 #include <string> | 8 #include <string> |
9 | 9 |
10 #include "base/basictypes.h" | 10 #include "chromecast/public/time_delta.h" |
byungchul
2015/07/27 18:22:23
relative to chromecast/public
halliwell
2015/07/28 02:19:36
TimeDelta removed now anyway.
| |
11 #include "base/macros.h" | |
12 #include "base/threading/non_thread_safe.h" | |
13 #include "base/time/time.h" | |
14 | 11 |
15 namespace chromecast { | 12 namespace chromecast { |
16 namespace media { | 13 namespace media { |
17 | 14 |
18 // MediaClockDevice - | 15 // MediaClockDevice - |
19 // | 16 // |
20 // State machine: | 17 // State machine: |
21 // ------------------- | 18 // ------------------- |
22 // | | | 19 // | | |
23 // v | | 20 // v | |
24 // kUninitialized --> kIdle --------- kRunning | 21 // kUninitialized --> kIdle --------- kRunning |
25 // | 22 // |
26 // {any state} --> kError | 23 // {any state} --> kError |
27 // | 24 // |
28 // Notes: | 25 // Notes: |
29 // - Hardware resources are acquired when transitioning from the | 26 // - Hardware resources are acquired when transitioning from the |
30 // |kUninitialized| state to the |kIdle| state. | 27 // |kUninitialized| state to the |kIdle| state. |
31 // - The initial value of the timeline can only be set in the kIdle state. | 28 // - The initial value of the timeline can only be set in the kIdle state. |
32 // | 29 // |
33 class MediaClockDevice | 30 class MediaClockDevice { |
34 : NON_EXPORTED_BASE(public base::NonThreadSafe) { | |
35 public: | 31 public: |
36 enum State { | 32 enum State { |
37 kStateUninitialized, | 33 kStateUninitialized, |
38 kStateIdle, | 34 kStateIdle, |
39 kStateRunning, | 35 kStateRunning, |
40 kStateError, | 36 kStateError, |
41 }; | 37 }; |
42 | 38 |
43 // Return true if transition from |state1| to |state2| is a valid state | 39 // Return true if transition from |state1| to |state2| is a valid state |
44 // transition. | 40 // transition. |
45 static bool IsValidStateTransition(State state1, State state2); | 41 inline static bool IsValidStateTransition(State state1, State state2) { |
42 if (state2 == state1) | |
43 return true; | |
44 | |
45 // All states can transition to |kStateError|. | |
46 bool is_transition_valid = (state2 == kStateError); | |
47 | |
48 // All the other valid FSM transitions. | |
49 is_transition_valid = | |
50 is_transition_valid || | |
51 (state1 == kStateUninitialized && (state2 == kStateIdle)) || | |
52 (state1 == kStateIdle && | |
53 (state2 == kStateRunning || state2 == kStateUninitialized)) || | |
54 (state1 == kStateRunning && (state2 == kStateIdle)) || | |
55 (state1 == kStateError && (state2 == kStateUninitialized)); | |
56 | |
57 return is_transition_valid; | |
58 } | |
46 | 59 |
47 // Returns string representation of state (for logging) | 60 // Returns string representation of state (for logging) |
48 static std::string StateToString(const State& state); | 61 inline static std::string StateToString(const State& state) { |
62 switch (state) { | |
63 case kStateUninitialized: | |
64 return "Uninitialized"; | |
65 case kStateIdle: | |
66 return "Idle"; | |
67 case kStateRunning: | |
68 return "Running"; | |
69 case kStateError: | |
70 return "Error"; | |
71 default: | |
72 return ""; | |
73 } | |
74 } | |
byungchul
2015/07/27 18:22:23
Why are these 2 files defined here inline? Is it a
halliwell
2015/07/28 02:19:36
Yes, it's allowed. And all vendors call these fun
byungchul
2015/07/28 18:05:43
I think
1) StateToString() is not necessary to be
halliwell
2015/07/28 23:26:06
StateToString now moved out into implementation co
| |
49 | 75 |
50 MediaClockDevice(); | 76 MediaClockDevice() {} |
51 virtual ~MediaClockDevice(); | 77 virtual ~MediaClockDevice() {} |
52 | 78 |
53 // Return the current state of the media clock. | 79 // Return the current state of the media clock. |
54 virtual State GetState() const = 0; | 80 virtual State GetState() const = 0; |
55 | 81 |
56 // Changes the state and performs any necessary transitions. | 82 // Changes the state and performs any necessary transitions. |
57 // Returns true when successful. | 83 // Returns true when successful. |
58 virtual bool SetState(State new_state) = 0; | 84 virtual bool SetState(State new_state) = 0; |
59 | 85 |
60 // Sets the initial value of the timeline. | 86 // Sets the initial value of the timeline. |
61 // Can only be invoked in state kStateIdle. | 87 // Can only be invoked in state kStateIdle. |
62 // Returns true when successful. | 88 // Returns true when successful. |
63 virtual bool ResetTimeline(base::TimeDelta time) = 0; | 89 virtual bool ResetTimeline(TimeDelta time) = 0; |
64 | 90 |
65 // Sets the clock rate. | 91 // Sets the clock rate. |
66 // Setting it to 0 means the clock is not progressing and that the renderer | 92 // Setting it to 0 means the clock is not progressing and that the renderer |
67 // tied to this media clock should pause rendering. | 93 // tied to this media clock should pause rendering. |
68 // Can only be invoked in states kStateIdle or kStateRunning. | 94 // Can only be invoked in states kStateIdle or kStateRunning. |
69 virtual bool SetRate(float rate) = 0; | 95 virtual bool SetRate(float rate) = 0; |
70 | 96 |
71 // Retrieves the media clock time. | 97 // Retrieves the media clock time. |
72 // Can only be invoked in states kStateIdle or kStateRunning. | 98 // Can only be invoked in states kStateIdle or kStateRunning. |
73 virtual base::TimeDelta GetTime() = 0; | 99 virtual TimeDelta GetTime() = 0; |
74 | |
75 private: | |
76 DISALLOW_COPY_AND_ASSIGN(MediaClockDevice); | |
77 }; | 100 }; |
78 | 101 |
79 } // namespace media | 102 } // namespace media |
80 } // namespace chromecast | 103 } // namespace chromecast |
81 | 104 |
82 #endif // CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_CLOCK_DEVICE_H_ | 105 #endif // CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_CLOCK_DEVICE_H_ |
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