Cancel prerendering when a request is paused or removed.

components/offline_pages/background/request_coordinator.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/offline_pages/background/request_coordinator.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 94 matching lines @@
                                  weak_ptr_factory_.GetWeakPtr(), callback));
 }
 
 void RequestCoordinator::GetQueuedRequestsCallback(
     const GetRequestsCallback& callback,
     RequestQueue::GetRequestsResult result,
     const std::vector<SavePageRequest>& requests) {
   callback.Run(requests);
 }
 
+void RequestCoordinator::StopPrerendering() {
+  if (offliner_ && is_busy_) {
+    // TODO(dougarnett): Find current request and mark attempt aborted.

[dougarnett, 2016/08/23 20:59:45]

maybe actually DO MarkAttemptAborted now on active_request_ 

+    offliner_->Cancel();
+  }
+
+  // Stopping offliner means it will not call callback.
+  last_offlining_status_ =
+      Offliner::RequestStatus::REQUEST_COORDINATOR_CANCELED;
+
+  if (active_request_) {
+    RecordOfflinerResultUMA(active_request_->client_id(),
+                            last_offlining_status_);
+    active_request_.reset();
+  }
+
+}
+
+bool RequestCoordinator::CancelActiveRequestIfItMatches(
+    const std::vector<int64_t>& request_ids) {
+  // If we have a request in progress and need to cancel it, call the
+  // pre-renderer to cancel.  TODO Make sure we remove any page created by the
+  // prerenderer if it doesn't get the cancel in time.
+  if (active_request_ != nullptr) {
+    if (request_ids.end() != std::find(request_ids.begin(), request_ids.end(),
+                                       active_request_->request_id())) {
+      StopPrerendering();
+      return true;
+    }
+  }
+
+  return false;
+}
+
 void RequestCoordinator::RemoveRequests(
     const std::vector<int64_t>& request_ids) {
+  bool canceled = CancelActiveRequestIfItMatches(request_ids);
   queue_->RemoveRequests(request_ids,
                          base::Bind(&RequestCoordinator::RemoveRequestsCallback,
                                     weak_ptr_factory_.GetWeakPtr()));
+  if (canceled)
+    TryNextRequest();
 }
 
 void RequestCoordinator::PauseRequests(
     const std::vector<int64_t>& request_ids) {
+  bool canceled = CancelActiveRequestIfItMatches(request_ids);
   queue_->ChangeRequestsState(
       request_ids, SavePageRequest::RequestState::PAUSED,
       base::Bind(&RequestCoordinator::UpdateMultipleRequestsCallback,
                  weak_ptr_factory_.GetWeakPtr()));
+
+  if (canceled)
+    TryNextRequest();
 }
 
 void RequestCoordinator::ResumeRequests(
     const std::vector<int64_t>& request_ids) {
   queue_->ChangeRequestsState(
       request_ids, SavePageRequest::RequestState::AVAILABLE,
       base::Bind(&RequestCoordinator::UpdateMultipleRequestsCallback,
                  weak_ptr_factory_.GetWeakPtr()));
   // TODO: Should we also schedule a task, in case there is not one scheduled?
 }
@@ skipping 27 matching lines @@
 }
 
 void RequestCoordinator::RemoveRequestsCallback(
     const RequestQueue::UpdateMultipleRequestResults& results,
     const std::vector<SavePageRequest>& requests) {
   for (SavePageRequest request : requests)
     NotifyCompleted(request, SavePageStatus::REMOVED);
 }
 
 void RequestCoordinator::StopProcessing() {
   is_canceled_ = true;

[dougarnett, 2016/08/23 20:59:45]

if this flag only applies to StopProcessing (and not to CancelActive*), then
maybe should be renamed to is_stopped_ or processing_stopped_ or something. 

[Pete Williamson, 2016/08/23 21:57:00]

Done.

-  if (offliner_ && is_busy_) {
-    // TODO(dougarnett): Find current request and mark attempt aborted.
-    offliner_->Cancel();
-  }
-
-  // Stopping offliner means it will not call callback.
-  last_offlining_status_ =
-      Offliner::RequestStatus::REQUEST_COORDINATOR_CANCELED;
-
-  if (active_request_) {
-    RecordOfflinerResultUMA(active_request_->client_id(),
-                            last_offlining_status_);
-    active_request_.reset();
-  }
+  StopPrerendering();
 
   // Let the scheduler know we are done processing.
   scheduler_callback_.Run(true);
 }
 
 // Returns true if the caller should expect a callback, false otherwise. For
 // instance, this would return false if a request is already in progress.
 bool RequestCoordinator::StartProcessing(
     const DeviceConditions& device_conditions,
     const base::Callback<void(bool)>& callback) {
@@ skipping 57 matching lines @@
 
   GetOffliner();
   if (!offliner_) {
     DVLOG(0) << "Unable to create Offliner. "
              << "Cannot background offline page.";
     return;
   }
 
   DCHECK(!is_busy_);
   is_busy_ = true;
-  active_request_.reset(new SavePageRequest(request));
 
   // Prepare an updated request to attempt.
   SavePageRequest updated_request(request);
   updated_request.MarkAttemptStarted(base::Time::Now());
+  active_request_.reset(new SavePageRequest(updated_request));
 
   // Start the load and save process in the offliner (Async).
   if (offliner_->LoadAndSave(
           updated_request, base::Bind(&RequestCoordinator::OfflinerDoneCallback,
                                       weak_ptr_factory_.GetWeakPtr()))) {
     // Offliner accepted request so update it in the queue.
     queue_->UpdateRequest(updated_request,
                           base::Bind(&RequestCoordinator::UpdateRequestCallback,
                                      weak_ptr_factory_.GetWeakPtr(),
                                      updated_request.client_id()));
@@ skipping 123 matching lines @@
   FOR_EACH_OBSERVER(Observer, observers_, OnChanged(request));
 }
 
 void RequestCoordinator::GetOffliner() {
   if (!offliner_) {
     offliner_ = factory_->GetOffliner(policy_.get());
   }
 }
 
 }  // namespace offline_pages