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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 | |
3 // found in the LICENSE file. | |
4 | |
5 #include "components/offline_pages/background/pick_request_task.h" | |
6 | |
7 #include "base/bind.h" | |
8 #include "base/logging.h" | |
9 #include "base/time/time.h" | |
10 #include "components/offline_pages/background/device_conditions.h" | |
11 #include "components/offline_pages/background/offliner_policy.h" | |
12 #include "components/offline_pages/background/request_coordinator_event_logger.h
" | |
13 #include "components/offline_pages/background/request_notifier.h" | |
14 #include "components/offline_pages/background/request_queue_store.h" | |
15 #include "components/offline_pages/background/save_page_request.h" | |
16 | |
17 namespace { | |
18 template <typename T> | |
19 int signum(T t) { | |
20 return (T(0) < t) - (t < T(0)); | |
21 } | |
22 | |
23 #define CALL_MEMBER_FUNCTION(object, ptrToMember) ((object)->*(ptrToMember)) | |
24 } // namespace | |
25 | |
26 namespace offline_pages { | |
27 | |
28 PickRequestTask::PickRequestTask(RequestQueueStore* store, | |
29 OfflinerPolicy* policy, | |
30 RequestNotifier* notifier, | |
31 RequestCoordinatorEventLogger* event_logger, | |
32 RequestPickedCallback picked_callback, | |
33 RequestNotPickedCallback not_picked_callback, | |
34 DeviceConditions& device_conditions, | |
35 const std::set<int64_t>& disabled_requests) | |
36 : store_(store), | |
37 policy_(policy), | |
38 notifier_(notifier), | |
39 event_logger_(event_logger), | |
40 picked_callback_(picked_callback), | |
41 not_picked_callback_(not_picked_callback), | |
42 disabled_requests_(disabled_requests), | |
43 weak_ptr_factory_(this) { | |
44 device_conditions_.reset(new DeviceConditions(device_conditions)); | |
45 } | |
46 | |
47 PickRequestTask::~PickRequestTask() {} | |
48 | |
49 void PickRequestTask::Run() { | |
50 // Get all the requests from the queue, we will classify them in the callback. | |
51 store_->GetRequests(base::Bind(&PickRequestTask::ChooseAndPrune, | |
52 weak_ptr_factory_.GetWeakPtr())); | |
53 } | |
54 | |
55 void PickRequestTask::ChooseAndPrune( | |
56 bool success, | |
57 std::vector<std::unique_ptr<SavePageRequest>> requests) { | |
58 // If there is nothing to do, return right away. | |
59 if (requests.size() == 0) { | |
60 not_picked_callback_.Run(false); | |
61 TaskComplete(); | |
62 return; | |
63 } | |
64 | |
65 // Get the expired requests to be removed from the queue, and the valid ones | |
66 // from which to pick the next request. | |
67 std::vector<std::unique_ptr<SavePageRequest>> valid_requests; | |
68 std::vector<int64_t> expired_request_ids; | |
69 SplitRequests(std::move(requests), &valid_requests, &expired_request_ids); | |
70 | |
71 // Continue processing by choosing a request. | |
72 ChooseRequestAndCallback(std::move(valid_requests)); | |
73 | |
74 // Continue processing by handling expired requests, if any. | |
75 if (expired_request_ids.size() == 0) { | |
76 TaskComplete(); | |
77 return; | |
78 } | |
79 | |
80 RemoveStaleRequests(std::move(expired_request_ids)); | |
81 } | |
82 | |
83 void PickRequestTask::ChooseRequestAndCallback( | |
84 std::vector<std::unique_ptr<SavePageRequest>> valid_requests) { | |
85 // Pick the most deserving request for our conditions. | |
86 const SavePageRequest* picked_request = nullptr; | |
87 | |
88 RequestCompareFunction comparator = nullptr; | |
89 | |
90 // Choose which comparison function to use based on policy. | |
91 if (policy_->RetryCountIsMoreImportantThanRecency()) | |
92 comparator = &PickRequestTask::RetryCountFirstCompareFunction; | |
93 else | |
94 comparator = &PickRequestTask::RecencyFirstCompareFunction; | |
95 | |
96 // TODO(petewil): Consider replacing this bool with a better named enum. | |
97 bool non_user_requested_tasks_remaining = false; | |
98 | |
99 // Iterate once through the requests, keeping track of best candidate. | |
100 for (unsigned i = 0; i < valid_requests.size(); ++i) { | |
101 // If the request is on the disabled list, skip it. | |
102 auto search = disabled_requests_.find(valid_requests[i]->request_id()); | |
103 if (search != disabled_requests_.end()) | |
104 continue; | |
105 // If there are non-user-requested tasks remaining, we need to make sure | |
106 // that they are scheduled after we run out of user requested tasks. Here we | |
107 // detect if any exist. If we don't find any user-requested tasks, we will | |
108 // inform the "not_picked_callback_" that it needs to schedule a task for | |
109 // non-user-requested items, which have different network and power needs. | |
110 if (!valid_requests[i]->user_requested()) | |
111 non_user_requested_tasks_remaining = true; | |
112 if (!RequestConditionsSatisfied(valid_requests[i].get())) | |
113 continue; | |
114 if (IsNewRequestBetter(picked_request, valid_requests[i].get(), comparator)) | |
115 picked_request = valid_requests[i].get(); | |
116 } | |
117 | |
118 // If we have a best request to try next, get the request coodinator to | |
119 // start it. Otherwise return that we have no candidates. | |
120 if (picked_request != nullptr) | |
121 picked_callback_.Run(*picked_request); | |
122 else | |
123 not_picked_callback_.Run(non_user_requested_tasks_remaining); | |
124 } | |
125 | |
126 // Continue the async part of the processing by deleting the expired requests. | |
127 // TODO(petewil): Does that really need to be done on the task queue? Hard to | |
128 // see how we need to wait for it before starting the next task. OTOH, we'd hate | |
129 // to do a second slow DB operation to get entries a second time, and waiting | |
130 // until this is done will make sure other gets don't see these old entries. | |
131 // Consider moving this to a fresh task type to clean the queue. | |
132 void PickRequestTask::RemoveStaleRequests( | |
133 std::vector<int64_t> stale_request_ids) { | |
134 store_->RemoveRequests(stale_request_ids, | |
135 base::Bind(&PickRequestTask::OnRequestsExpired, | |
136 weak_ptr_factory_.GetWeakPtr())); | |
137 } | |
138 | |
139 void PickRequestTask::OnRequestsExpired( | |
140 std::unique_ptr<UpdateRequestsResult> result) { | |
141 RequestNotifier::BackgroundSavePageResult save_page_result( | |
142 RequestNotifier::BackgroundSavePageResult::EXPIRED); | |
143 for (const auto& request : result->updated_items) { | |
144 event_logger_->RecordDroppedSavePageRequest( | |
145 request.client_id().name_space, save_page_result, request.request_id()); | |
146 notifier_->NotifyCompleted(request, save_page_result); | |
147 } | |
148 | |
149 // The task is now done, return control to the task queue. | |
150 TaskComplete(); | |
151 } | |
152 | |
153 void PickRequestTask::SplitRequests( | |
154 std::vector<std::unique_ptr<SavePageRequest>> requests, | |
155 std::vector<std::unique_ptr<SavePageRequest>>* valid_requests, | |
156 std::vector<int64_t>* expired_request_ids) { | |
157 for (auto& request : requests) { | |
158 if (base::Time::Now() - request->creation_time() >= | |
159 base::TimeDelta::FromSeconds(kRequestExpirationTimeInSeconds)) { | |
160 expired_request_ids->push_back(request->request_id()); | |
161 } else { | |
162 valid_requests->push_back(std::move(request)); | |
163 } | |
164 } | |
165 } | |
166 | |
167 // Filter out requests that don't meet the current conditions. For instance, if | |
168 // this is a predictive request, and we are not on WiFi, it should be ignored | |
169 // this round. | |
170 bool PickRequestTask::RequestConditionsSatisfied( | |
171 const SavePageRequest* request) { | |
172 // If the user did not request the page directly, make sure we are connected | |
173 // to power and have WiFi and sufficient battery remaining before we take this | |
174 // request. | |
175 if (!device_conditions_->IsPowerConnected() && | |
176 policy_->PowerRequired(request->user_requested())) { | |
177 return false; | |
178 } | |
179 | |
180 if (device_conditions_->GetNetConnectionType() != | |
181 net::NetworkChangeNotifier::ConnectionType::CONNECTION_WIFI && | |
182 policy_->UnmeteredNetworkRequired(request->user_requested())) { | |
183 return false; | |
184 } | |
185 | |
186 if (device_conditions_->GetBatteryPercentage() < | |
187 policy_->BatteryPercentageRequired(request->user_requested())) { | |
188 return false; | |
189 } | |
190 | |
191 // If we have already started this page the max number of times, it is not | |
192 // eligible to try again. | |
193 if (request->started_attempt_count() >= policy_->GetMaxStartedTries()) | |
194 return false; | |
195 | |
196 // If we have already completed trying this page the max number of times, it | |
197 // is not eligible to try again. | |
198 if (request->completed_attempt_count() >= policy_->GetMaxCompletedTries()) | |
199 return false; | |
200 | |
201 // If the request is paused, do not consider it. | |
202 if (request->request_state() == SavePageRequest::RequestState::PAUSED) | |
203 return false; | |
204 | |
205 // If the request is expired, do not consider it. | |
206 base::TimeDelta requestAge = base::Time::Now() - request->creation_time(); | |
207 if (requestAge > base::TimeDelta::FromSeconds( | |
208 policy_->GetRequestExpirationTimeInSeconds())) | |
209 return false; | |
210 | |
211 // If this request is not active yet, return false. | |
212 // TODO(petewil): If the only reason we return nothing to do is that we have | |
213 // inactive requests, we still want to try again later after their activation | |
214 // time elapses, we shouldn't take ourselves completely off the scheduler. | |
215 if (request->activation_time() > base::Time::Now()) | |
216 return false; | |
217 | |
218 return true; | |
219 } | |
220 | |
221 // Look at policies to decide which requests to prefer. | |
222 bool PickRequestTask::IsNewRequestBetter(const SavePageRequest* oldRequest, | |
223 const SavePageRequest* newRequest, | |
224 RequestCompareFunction comparator) { | |
225 // If there is no old request, the new one is better. | |
226 if (oldRequest == nullptr) | |
227 return true; | |
228 | |
229 // User requested pages get priority. | |
230 if (newRequest->user_requested() && !oldRequest->user_requested()) | |
231 return true; | |
232 | |
233 // Otherwise, use the comparison function for the current policy, which | |
234 // returns true if the older request is better. | |
235 return !(CALL_MEMBER_FUNCTION(this, comparator)(oldRequest, newRequest)); | |
236 } | |
237 | |
238 // Compare the results, checking request count before recency. Returns true if | |
239 // left hand side is better, false otherwise. | |
240 bool PickRequestTask::RetryCountFirstCompareFunction( | |
241 const SavePageRequest* left, | |
242 const SavePageRequest* right) { | |
243 // Check the attempt count. | |
244 int result = CompareRetryCount(left, right); | |
245 | |
246 if (result != 0) | |
247 return (result > 0); | |
248 | |
249 // If we get here, the attempt counts were the same, so check recency. | |
250 result = CompareCreationTime(left, right); | |
251 | |
252 return (result > 0); | |
253 } | |
254 | |
255 // Compare the results, checking recency before request count. Returns true if | |
256 // left hand side is better, false otherwise. | |
257 bool PickRequestTask::RecencyFirstCompareFunction( | |
258 const SavePageRequest* left, | |
259 const SavePageRequest* right) { | |
260 // Check the recency. | |
261 int result = CompareCreationTime(left, right); | |
262 | |
263 if (result != 0) | |
264 return (result > 0); | |
265 | |
266 // If we get here, the recency was the same, so check the attempt count. | |
267 result = CompareRetryCount(left, right); | |
268 | |
269 return (result > 0); | |
270 } | |
271 | |
272 // Compare left and right side, returning 1 if the left side is better | |
273 // (preferred by policy), 0 if the same, and -1 if the right side is better. | |
274 int PickRequestTask::CompareRetryCount(const SavePageRequest* left, | |
275 const SavePageRequest* right) { | |
276 // Check the attempt count. | |
277 int result = signum(left->completed_attempt_count() - | |
278 right->completed_attempt_count()); | |
279 | |
280 // Flip the direction of comparison if policy prefers fewer retries. | |
281 if (policy_->ShouldPreferUntriedRequests()) | |
282 result *= -1; | |
283 | |
284 return result; | |
285 } | |
286 | |
287 // Compare left and right side, returning 1 if the left side is better | |
288 // (preferred by policy), 0 if the same, and -1 if the right side is better. | |
289 int PickRequestTask::CompareCreationTime(const SavePageRequest* left, | |
290 const SavePageRequest* right) { | |
291 // Check the recency. | |
292 base::TimeDelta difference = left->creation_time() - right->creation_time(); | |
293 int result = signum(difference.InMilliseconds()); | |
294 | |
295 // Flip the direction of comparison if policy prefers fewer retries. | |
296 if (policy_->ShouldPreferEarlierRequests()) | |
297 result *= -1; | |
298 | |
299 return result; | |
300 } | |
301 | |
302 } // namespace offline_pages | |
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