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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 CHROME_BROWSER_SYNC_INVALIDATION_FRONTEND_H_ | |
6 #define CHROME_BROWSER_SYNC_INVALIDATION_FRONTEND_H_ | |
7 | |
8 #include "sync/notifier/invalidation_util.h" | |
9 | |
10 namespace syncer { | |
11 class InvalidationHandler; | |
12 } // namespace syncer | |
13 | |
14 // Interface for classes that handle invalidation registrations and send out | |
15 // invalidations to register handlers. | |
16 // | |
17 // Invalidation clients should follow the pattern below: | |
18 // | |
19 // When starting the client: | |
20 // | |
21 // frontend->RegisterInvalidationHandler(client_handler); | |
22 // | |
23 // When the set of IDs to register changes for the client during its lifetime | |
24 // (i.e., between calls to RegisterInvalidationHandler(client_handler) and | |
25 // UnregisterInvalidationHandler(client_handler): | |
26 // | |
27 // frontend->UpdateRegisteredInvalidationIds(client_handler, client_ids); | |
28 // | |
29 // When shutting down the client for browser shutdown: | |
30 // | |
31 // frontend->UnregisterInvalidationHandler(client_handler); | |
32 // | |
33 // Note that there's no call to UpdateRegisteredIds() -- this is because the | |
34 // invalidation API persists registrations across browser restarts. | |
35 // | |
36 // When permanently shutting down the client, e.g. when disabling the related | |
37 // feature: | |
38 // | |
39 // frontend->UpdateRegisteredInvalidationIds(client_handler, ObjectIdSet()); | |
40 // frontend->UnregisterInvalidationHandler(client_handler); | |
41 // | |
42 // If an invalidation handler cares about the invalidator state, it should also | |
43 // do the following when starting the client: | |
44 // | |
45 // invalidator_state = frontend->GetInvalidatorState(); | |
46 // | |
47 // It can also do the above in OnInvalidatorStateChange(), or it can use the | |
48 // argument to OnInvalidatorStateChange(). | |
49 // | |
50 // It is an error to have registered handlers when an | |
51 // InvalidationFrontend is shut down; clients must ensure that they | |
52 // unregister themselves before then. (Depending on the | |
53 // InvalidationFrontend, shutdown may be equivalent to destruction, or | |
54 // a separate function call like Shutdown()). | |
55 // | |
56 // NOTE(akalin): Invalidations that come in during browser shutdown may get | |
57 // dropped. This won't matter once we have an Acknowledge API, though: see | |
58 // http://crbug.com/78462 and http://crbug.com/124149. | |
59 class InvalidationFrontend { | |
60 public: | |
61 // Starts sending notifications to |handler|. |handler| must not be NULL, | |
62 // and it must not already be registered. | |
63 // | |
64 // Handler registrations are persisted across restarts of sync. | |
65 virtual void RegisterInvalidationHandler( | |
66 syncer::InvalidationHandler* handler) = 0; | |
67 | |
68 // Updates the set of ObjectIds associated with |handler|. |handler| must | |
69 // not be NULL, and must already be registered. An ID must be registered for | |
70 // at most one handler. | |
71 // | |
72 // Registered IDs are persisted across restarts of sync. | |
73 virtual void UpdateRegisteredInvalidationIds( | |
74 syncer::InvalidationHandler* handler, | |
75 const syncer::ObjectIdSet& ids) = 0; | |
76 | |
77 // Stops sending notifications to |handler|. |handler| must not be NULL, and | |
78 // it must already be registered. Note that this doesn't unregister the IDs | |
79 // associated with |handler|. | |
80 // | |
81 // Handler registrations are persisted across restarts of sync. | |
82 virtual void UnregisterInvalidationHandler( | |
83 syncer::InvalidationHandler* handler) = 0; | |
84 | |
85 // Sends an acknowledgement that an invalidation for |id| was successfully | |
86 // handled. | |
87 virtual void AcknowledgeInvalidation(const invalidation::ObjectId& id, | |
88 const syncer::AckHandle& ack_handle) = 0; | |
89 | |
90 // Returns the current invalidator state. When called from within | |
91 // InvalidationHandler::OnInvalidatorStateChange(), this must return | |
92 // the updated state. | |
93 virtual syncer::InvalidatorState GetInvalidatorState() const = 0; | |
94 | |
95 protected: | |
96 virtual ~InvalidationFrontend() { } | |
97 }; | |
98 | |
99 #endif // CHROME_BROWSER_SYNC_INVALIDATION_FRONTEND_H_ | |
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