Update the request count when a request fails.

components/offline_pages/background/request_queue.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_queue.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/offline_pages/background/request_queue_store.h"
@@ skipping 20 matching lines @@
 void AddRequestDone(const RequestQueue::AddRequestCallback& callback,
                     const SavePageRequest& request,
                     RequestQueueStore::UpdateStatus status) {
   RequestQueue::AddRequestResult result =
       (status == RequestQueueStore::UpdateStatus::UPDATED)
           ? RequestQueue::AddRequestResult::SUCCESS
           : RequestQueue::AddRequestResult::STORE_FAILURE;
   callback.Run(result, request);
 }
 
+// Completes the update request call.
+void UpdateRequestDone(const RequestQueue::UpdateRequestCallback& callback,
+                       RequestQueueStore::UpdateStatus status) {
+  RequestQueue::UpdateRequestResult result =
+      (status == RequestQueueStore::UpdateStatus::UPDATED)
+          ? RequestQueue::UpdateRequestResult::SUCCESS
+          : RequestQueue::UpdateRequestResult::STORE_FAILURE;
+  callback.Run(result);
+}
+
+
 // Completes the remove request call.
 void RemoveRequestDone(const RequestQueue::UpdateRequestCallback& callback,
                        bool success,
                        int deleted_requests_count) {
   DCHECK_EQ(1, deleted_requests_count);
   RequestQueue::UpdateRequestResult result =
       success ? RequestQueue::UpdateRequestResult::SUCCESS
               : RequestQueue::UpdateRequestResult::STORE_FAILURE;
   callback.Run(result);
 }
 }  // namespace
 
 RequestQueue::RequestQueue(std::unique_ptr<RequestQueueStore> store)
-    : store_(std::move(store)) {}
+    : store_(std::move(store)), weak_ptr_factory_(this) {}
 
 RequestQueue::~RequestQueue() {}
 
 void RequestQueue::GetRequests(const GetRequestsCallback& callback) {
   store_->GetRequests(base::Bind(&GetRequestsDone, callback));
 }
 
 void RequestQueue::AddRequest(const SavePageRequest& request,
                               const AddRequestCallback& callback) {
   // TODO(fgorski): check that request makes sense.
   // TODO(fgorski): check that request does not violate policy.
   store_->AddOrUpdateRequest(request,
                              base::Bind(&AddRequestDone, callback, request));
 }
 
-void RequestQueue::UpdateRequest(const SavePageRequest& request,
-                                 const UpdateRequestCallback& callback) {}
+void RequestQueue::UpdateRequest(const SavePageRequest& update_request,
+                                 const UpdateRequestCallback& update_callback) {
+  // We have to pass the update_callback *through* the get callback.  We do this
+  // by currying the update_callback as a parameter to be used when calling
+  // GetForUpdateDone.  The actual request queue store get operation will not
+  // see this bound parameter, but just pass it along.  GetForUpdateDone then
+  // passes it into the AddOrUpdateRequest method, where it ends up calling back
+  // to the request queue client.
+  store_->GetRequests(base::Bind(

[fgorski, 2016/07/22 16:14:58]

This is probably going to be more efficient if we can query for a single request
based on the ID.  Can  you open a bug, and add a TODO here?

[Pete Williamson, 2016/07/22 18:27:00]

TODO added. crbug.com/630657.

+      &RequestQueue::GetForUpdateDone, weak_ptr_factory_.GetWeakPtr(),
+      update_callback, update_request));
+}
+
+// We need a different version of the GetCallback that can take the curried
+// update_callback as a parameter, and call back into the request queue store
+// implementation.  This must be a member function because we need access to
+// the store pointer to call AddOrUpdateRequest.
+void RequestQueue::GetForUpdateDone(
+    const UpdateRequestCallback& update_callback,
+    const SavePageRequest& update_request,
+    bool success,
+    const std::vector<SavePageRequest>& found_requests) {
+  // If the result was not found, return now.
+  if (!success) {

[fgorski, 2016/07/22 16:14:58]

what about the case where found_request does not contain a request with ID
matching that of update_request?

[Pete Williamson, 2016/07/22 18:27:00]

Added case.

+    update_callback.Run(
+        RequestQueue::UpdateRequestResult::REQUEST_DOES_NOT_EXIST);
+    return;
+  }
+
+  // Since the request exists, update it.
+  store_->AddOrUpdateRequest(update_request,
+                             base::Bind(&UpdateRequestDone, update_callback));
+}
 
 void RequestQueue::RemoveRequest(int64_t request_id,
                                  const UpdateRequestCallback& callback) {
   std::vector<int64_t> request_ids{request_id};
   store_->RemoveRequests(request_ids, base::Bind(RemoveRequestDone, callback));
 }
 
 void RequestQueue::PurgeRequests(const PurgeRequestsCallback& callback) {}
 
 }  // namespace offline_pages