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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 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 COMPONENTS_OFFLINE_PAGES_SNAPSHOT_CONTROLLER_H_ | 5 #ifndef COMPONENTS_OFFLINE_PAGES_CORE_SNAPSHOT_CONTROLLER_H_ |
6 #define COMPONENTS_OFFLINE_PAGES_SNAPSHOT_CONTROLLER_H_ | 6 #define COMPONENTS_OFFLINE_PAGES_CORE_SNAPSHOT_CONTROLLER_H_ |
7 | 7 |
8 #include "base/memory/ref_counted.h" | 8 #include "base/memory/ref_counted.h" |
9 #include "base/memory/weak_ptr.h" | 9 #include "base/memory/weak_ptr.h" |
10 #include "base/single_thread_task_runner.h" | 10 #include "base/single_thread_task_runner.h" |
11 | 11 |
12 namespace offline_pages { | 12 namespace offline_pages { |
13 | 13 |
14 // Takes various signals and produces StartSnapshot calls following a specific | 14 // Takes various signals and produces StartSnapshot calls following a specific |
15 // policy. Can request snapshots multiple times per 'session'. Session can be | 15 // policy. Can request snapshots multiple times per 'session'. Session can be |
16 // ended and another one started by calling Reset(). | 16 // ended and another one started by calling Reset(). |
17 // Main invariants: | 17 // Main invariants: |
18 // - It never starts overlapping snapshots, Client reports when previous | 18 // - It never starts overlapping snapshots, Client reports when previous |
19 // snapshot is done. | 19 // snapshot is done. |
20 // - The currently worked on (pending) snapshot is always allowed to complete, | 20 // - The currently worked on (pending) snapshot is always allowed to complete, |
21 // the new attempts to start a snapshot are ignored until it does. | 21 // the new attempts to start a snapshot are ignored until it does. |
22 // - Some signals prevent more snapshots to be taken. | 22 // - Some signals prevent more snapshots to be taken. |
23 // OnLoad is currently such signal. | 23 // OnLoad is currently such signal. |
24 // - Once Reset() is called on the SnapshotController, the delayed tasks are | 24 // - Once Reset() is called on the SnapshotController, the delayed tasks are |
25 // reset so no StartSnapshot calls is made 'cross-session'. | 25 // reset so no StartSnapshot calls is made 'cross-session'. |
26 class SnapshotController { | 26 class SnapshotController { |
27 public: | 27 public: |
28 enum class State { | 28 enum class State { |
29 READY, // Listening to input, will start snapshot when needed. | 29 READY, // Listening to input, will start snapshot when needed. |
30 SNAPSHOT_PENDING, // Snapshot is in progress, don't start another. | 30 SNAPSHOT_PENDING, // Snapshot is in progress, don't start another. |
31 STOPPED, // Terminal state, no snapshots until reset. | 31 STOPPED, // Terminal state, no snapshots until reset. |
32 }; | 32 }; |
33 | 33 |
34 // Client of the SnapshotController. | 34 // Client of the SnapshotController. |
35 class Client { | 35 class Client { |
36 public: | 36 public: |
37 // Invoked at a good moment to start a snapshot. May be invoked multiple | 37 // Invoked at a good moment to start a snapshot. May be invoked multiple |
38 // times, but not in overlapping manner - waits until | 38 // times, but not in overlapping manner - waits until |
39 // PreviousSnapshotCompleted() before the next StatrSnapshot(). | 39 // PreviousSnapshotCompleted() before the next StatrSnapshot(). |
40 // Client should overwrite the result of previous snapshot with the new one, | 40 // Client should overwrite the result of previous snapshot with the new one, |
41 // it is assumed that later snapshots are better then previous. | 41 // it is assumed that later snapshots are better then previous. |
42 virtual void StartSnapshot() = 0; | 42 virtual void StartSnapshot() = 0; |
43 | 43 |
44 protected: | 44 protected: |
45 virtual ~Client() {} | 45 virtual ~Client() {} |
(...skipping 41 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
87 size_t delay_after_document_available_ms_; | 87 size_t delay_after_document_available_ms_; |
88 size_t delay_after_document_on_load_completed_ms_; | 88 size_t delay_after_document_on_load_completed_ms_; |
89 | 89 |
90 base::WeakPtrFactory<SnapshotController> weak_ptr_factory_; | 90 base::WeakPtrFactory<SnapshotController> weak_ptr_factory_; |
91 | 91 |
92 DISALLOW_COPY_AND_ASSIGN(SnapshotController); | 92 DISALLOW_COPY_AND_ASSIGN(SnapshotController); |
93 }; | 93 }; |
94 | 94 |
95 } // namespace offline_pages | 95 } // namespace offline_pages |
96 | 96 |
97 #endif // COMPONENTS_OFFLINE_PAGES_SNAPSHOT_CONTROLLER_H_ | 97 #endif // COMPONENTS_OFFLINE_PAGES_CORE_SNAPSHOT_CONTROLLER_H_ |
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