invalidation_service.h revision 46d4c2bc3267f3f028f39e7e311b0f89aba2e4fd 
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 COMPONENTS_INVALIDATION_INVALIDATION_SERVICE_H_
6#define COMPONENTS_INVALIDATION_INVALIDATION_SERVICE_H_
7
8#include "base/callback_forward.h"
9#include "components/keyed_service/core/keyed_service.h"
10#include "sync/internal_api/public/base/invalidator_state.h"
11#include "sync/notifier/invalidation_util.h"
12
13class IdentityProvider;
14
15namespace syncer {
16class InvalidationHandler;
17}  // namespace syncer
18
19namespace invalidation {
20class InvalidationLogger;
21
22// Interface for classes that handle invalidation registrations and send out
23// invalidations to register handlers.
24//
25// Invalidation clients should follow the pattern below:
26//
27// When starting the client:
28//
29//   frontend->RegisterInvalidationHandler(client_handler);
30//
31// When the set of IDs to register changes for the client during its lifetime
32// (i.e., between calls to RegisterInvalidationHandler(client_handler) and
33// UnregisterInvalidationHandler(client_handler):
34//
35//   frontend->UpdateRegisteredInvalidationIds(client_handler, client_ids);
36//
37// When shutting down the client for browser shutdown:
38//
39//   frontend->UnregisterInvalidationHandler(client_handler);
40//
41// Note that there's no call to UpdateRegisteredIds() -- this is because the
42// invalidation API persists registrations across browser restarts.
43//
44// When permanently shutting down the client, e.g. when disabling the related
45// feature:
46//
47//   frontend->UpdateRegisteredInvalidationIds(client_handler, ObjectIdSet());
48//   frontend->UnregisterInvalidationHandler(client_handler);
49//
50// If an invalidation handler cares about the invalidator state, it should also
51// do the following when starting the client:
52//
53//   invalidator_state = frontend->GetInvalidatorState();
54//
55// It can also do the above in OnInvalidatorStateChange(), or it can use the
56// argument to OnInvalidatorStateChange().
57//
58// It is an error to have registered handlers when an
59// InvalidationFrontend is shut down; clients must ensure that they
60// unregister themselves before then. (Depending on the
61// InvalidationFrontend, shutdown may be equivalent to destruction, or
62// a separate function call like Shutdown()).
63//
64// NOTE(akalin): Invalidations that come in during browser shutdown may get
65// dropped.  This won't matter once we have an Acknowledge API, though: see
66// http://crbug.com/78462 and http://crbug.com/124149.
67//
68// This class inherits from ProfileKeyedService to make it possible to correctly
69// cast from various InvalidationService implementations to ProfileKeyedService
70// in InvalidationServiceFactory.
71class InvalidationService : public KeyedService {
72 public:
73  // Starts sending notifications to |handler|.  |handler| must not be NULL,
74  // and it must not already be registered.
75  //
76  // Handler registrations are persisted across restarts of sync.
77  virtual void RegisterInvalidationHandler(
78      syncer::InvalidationHandler* handler) = 0;
79
80  // Updates the set of ObjectIds associated with |handler|.  |handler| must
81  // not be NULL, and must already be registered.  An ID must be registered for
82  // at most one handler.
83  //
84  // Registered IDs are persisted across restarts of sync.
85  virtual void UpdateRegisteredInvalidationIds(
86      syncer::InvalidationHandler* handler,
87      const syncer::ObjectIdSet& ids) = 0;
88
89  // Stops sending notifications to |handler|.  |handler| must not be NULL, and
90  // it must already be registered.  Note that this doesn't unregister the IDs
91  // associated with |handler|.
92  //
93  // Handler registrations are persisted across restarts of sync.
94  virtual void UnregisterInvalidationHandler(
95      syncer::InvalidationHandler* handler) = 0;
96
97  // Returns the current invalidator state.  When called from within
98  // InvalidationHandler::OnInvalidatorStateChange(), this must return
99  // the updated state.
100  virtual syncer::InvalidatorState GetInvalidatorState() const = 0;
101
102  // Returns the ID belonging to this invalidation client.  Can be used to
103  // prevent the receipt of notifications of our own changes.
104  virtual std::string GetInvalidatorClientId() const = 0;
105
106  // Return the logger used to debug invalidations
107  virtual InvalidationLogger* GetInvalidationLogger() = 0;
108
109  // Triggers requests of internal status.
110  virtual void RequestDetailedStatus(
111      base::Callback<void(const base::DictionaryValue&)> post_caller) const = 0;
112
113  // Returns the identity provider.
114  virtual IdentityProvider* GetIdentityProvider() = 0;
115
116 protected:
117  virtual ~InvalidationService() { }
118};
119
120}  // namespace invalidation
121
122#endif  // COMPONENTS_INVALIDATION_INVALIDATION_SERVICE_H_
123