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| 1 // Copyright 2015 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_PASSWORD_MANAGER_CORE_BROWSER_AFFILIATION_FETCH_THROTTLER_H_ |
| 6 #define COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_AFFILIATION_FETCH_THROTTLER_H_ |
| 7 |
| 8 #include "base/gtest_prod_util.h" |
| 9 #include "base/macros.h" |
| 10 #include "base/memory/ref_counted.h" |
| 11 #include "base/memory/scoped_ptr.h" |
| 12 #include "base/memory/weak_ptr.h" |
| 13 #include "net/base/backoff_entry.h" |
| 14 #include "net/base/network_change_notifier.h" |
| 15 |
| 16 namespace base { |
| 17 class TickClock; |
| 18 class SingleThreadTaskRunner; |
| 19 } // namespace base |
| 20 |
| 21 namespace password_manager { |
| 22 |
| 23 class AffiliationFetchThrottlerDelegate; |
| 24 |
| 25 // Implements the throttling logic that the AffiliationBackend will use when it |
| 26 // needs to issue requests over the network to fetch affiliation information. |
| 27 // |
| 28 // This class manages only the scheduling of the requests. It is up to the |
| 29 // consumer (the AffiliationBackend) to actually assemble and send the requests, |
| 30 // to report back about their success or failure, and to retry them if desired. |
| 31 // The process goes like this: |
| 32 // 1.) The consumer calls SignalNetworkRequestNeeded(). |
| 33 // 2.) Once appropriate, OnCanSendNetworkRequest() is called on the delegate. |
| 34 // 3.) The consumer sends the request, and waits until it completes. |
| 35 // 4.) The consumer calls InformOfNetworkRequestComplete(). |
| 36 // Note that only a single request at a time is supported. |
| 37 // |
| 38 // If the request fails in Step 3, the consumer should not automatically retry |
| 39 // it. Instead it should always proceed to Step 4, and then -- if retrying the |
| 40 // request is desired -- proceed immediately to Step 1. That is, it should act |
| 41 // as if another request was needed right away. |
| 42 // |
| 43 // Essentially, this class implements exponential backoff in case of network and |
| 44 // server errors with the additional constraint that no requests will be issued |
| 45 // in the first place while there is known to be no network connectivity. This |
| 46 // prevents the exponential backoff delay from growing huge during long offline |
| 47 // periods, so that requests will not be held back for too long after |
| 48 // connectivity is restored. |
| 49 class AffiliationFetchThrottler |
| 50 : public net::NetworkChangeNotifier::ConnectionTypeObserver { |
| 51 public: |
| 52 // Creates an instance that will use |tick_clock| as its tick source, and will |
| 53 // post to |task_runner| to call the |delegate|'s OnSendNetworkRequest(). The |
| 54 // |delegate| should outlive the throttler. |
| 55 AffiliationFetchThrottler( |
| 56 AffiliationFetchThrottlerDelegate* delegate, |
| 57 const scoped_refptr<base::SingleThreadTaskRunner>& task_runner, |
| 58 scoped_ptr<base::TickClock> tick_clock); |
| 59 ~AffiliationFetchThrottler() override; |
| 60 |
| 61 // Signals to the throttling logic that a network request is needed, and that |
| 62 // OnCanSendNetworkRequest() should be called as soon as the request can be |
| 63 // sent. OnCanSendNetworkRequest() will always be called asynchronously. |
| 64 // |
| 65 // Calls to this method will be ignored when a request is already known to be |
| 66 // needed or while a request is in flight. To signal that another request will |
| 67 // be needed right away after the current one, call this method after calling |
| 68 // InformOfNetworkRequestComplete(). |
| 69 void SignalNetworkRequestNeeded(); |
| 70 |
| 71 // Informs the back-off logic that the in-flight network request has been |
| 72 // completed, either with |success| or not. |
| 73 void InformOfNetworkRequestComplete(bool success); |
| 74 |
| 75 private: |
| 76 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, FailedRequests); |
| 77 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, |
| 78 GracePeriodAfterConnectivityIsRestored); |
| 79 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, |
| 80 GracePeriodAfterConnectivityIsRestored2); |
| 81 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, |
| 82 GracePeriodAfterConnectivityIsRestored3); |
| 83 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, |
| 84 ConnectivityLostDuringBackoff); |
| 85 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, |
| 86 ConnectivityLostAndRestoredDuringBackoff); |
| 87 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, FlakyConnectivity); |
| 88 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, |
| 89 ConnectivityLostDuringRequest); |
| 90 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, |
| 91 ConnectivityLostAndRestoredDuringRequest); |
| 92 FRIEND_TEST_ALL_PREFIXES(AffiliationFetchThrottlerTest, |
| 93 ConnectivityLostAndRestoredDuringRequest2); |
| 94 |
| 95 enum State { IDLE, FETCH_NEEDED, FETCH_IN_FLIGHT }; |
| 96 |
| 97 // Exponential backoff parameters in case of network and server errors |
| 98 static const net::BackoffEntry::Policy kBackoffPolicy; |
| 99 |
| 100 // Minimum delay before sending the first request once network connectivity is |
| 101 // restored. The fuzzing factor in |kBackoffParameters.jitter_factor| applies. |
| 102 static const int64_t kGracePeriodAfterReconnectMs; |
| 103 |
| 104 // Ensures that OnBackoffDelayExpiredCallback() is scheduled to be called back |
| 105 // once the |exponential_backoff_| delay expires. |
| 106 void EnsureCallbackIsScheduled(); |
| 107 |
| 108 // Called back when the |exponential_backoff_| delay expires. |
| 109 void OnBackoffDelayExpiredCallback(); |
| 110 |
| 111 // net::NetworkChangeNotifier::ConnectionTypeObserver: |
| 112 void OnConnectionTypeChanged( |
| 113 net::NetworkChangeNotifier::ConnectionType type) override; |
| 114 |
| 115 AffiliationFetchThrottlerDelegate* delegate_; |
| 116 scoped_refptr<base::SingleThreadTaskRunner> task_runner_; |
| 117 State state_; |
| 118 bool has_network_connectivity_; |
| 119 bool is_fetch_scheduled_; |
| 120 scoped_ptr<base::TickClock> tick_clock_; |
| 121 scoped_ptr<net::BackoffEntry> exponential_backoff_; |
| 122 |
| 123 base::WeakPtrFactory<AffiliationFetchThrottler> weak_ptr_factory_; |
| 124 |
| 125 DISALLOW_COPY_AND_ASSIGN(AffiliationFetchThrottler); |
| 126 }; |
| 127 |
| 128 } // namespace password_manager |
| 129 |
| 130 #endif // COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_AFFILIATION_FETCH_THROTTLER_
H_ |
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