Use a vector of smart pointers for callback return type.

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"
 #include "components/offline_pages/background/save_page_request.h"
 
 namespace offline_pages {
 
 namespace {
 // Completes the get requests call.
 void GetRequestsDone(const RequestQueue::GetRequestsCallback& callback,
                      bool success,
-                     const std::vector<SavePageRequest>& requests) {
+                     std::vector<std::unique_ptr<SavePageRequest>> requests) {
   RequestQueue::GetRequestsResult result =
       success ? RequestQueue::GetRequestsResult::SUCCESS
               : RequestQueue::GetRequestsResult::STORE_FAILURE;
   // TODO(fgorski): Filter out expired requests based on policy.
   // This may trigger the purging if necessary.
   // Also this may be turned into a method on the request queue or add a policy
   // parameter in the process.
-  callback.Run(result, requests);
+  callback.Run(result, std::move(requests));
 }
 
 // Completes the add request call.
 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.
 // TODO(petewil): Move callers to the UpdateMultipleRequestDone callback
 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);
 }
 
 // Handles updating multiple requests at the same time.
 void UpdateMultipleRequestsDone(
     const RequestQueue::UpdateMultipleRequestsCallback& callback,
     const RequestQueue::UpdateMultipleRequestResults& results,
-    const std::vector<SavePageRequest>& requests) {
-  callback.Run(results, requests);
+    std::vector<std::unique_ptr<SavePageRequest>> requests) {
+  callback.Run(results, std::move(requests));
 }
 
 // Completes the remove request call.
 void RemoveRequestsDone(
     const RequestQueue::RemoveRequestsCallback& callback,
     const RequestQueue::UpdateMultipleRequestResults& results,
-    const std::vector<SavePageRequest>& requests) {
-  callback.Run(results, requests);
+    std::vector<std::unique_ptr<SavePageRequest>> requests) {
+  callback.Run(results, std::move(requests));
 }
 
 }  // namespace
 
 RequestQueue::RequestQueue(std::unique_ptr<RequestQueueStore> store)
     : store_(std::move(store)), weak_ptr_factory_(this) {}
 
 RequestQueue::~RequestQueue() {}
 
 void RequestQueue::GetRequests(const GetRequestsCallback& callback) {
@@ skipping 25 matching lines @@
 }
 
 // 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) {
+    std::vector<std::unique_ptr<SavePageRequest>> found_requests) {
   // If the result was not found, return now.
   if (!success) {
     update_callback.Run(
         RequestQueue::UpdateRequestResult::REQUEST_DOES_NOT_EXIST);
     return;
   }
   // If the found result does not contain the request we are looking for, return
   // now.
   bool found = false;
-  std::vector<SavePageRequest>::const_iterator iter;
+  std::vector<std::unique_ptr<SavePageRequest>>::const_iterator iter;
   for (iter = found_requests.begin(); iter != found_requests.end(); ++iter) {
-    if (iter->request_id() == update_request.request_id())
+    if ((*iter)->request_id() == update_request.request_id())
       found = true;
   }
   if (!found) {
     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::RemoveRequests(const std::vector<int64_t>& request_ids,
                                   const RemoveRequestsCallback& callback) {
   store_->RemoveRequests(request_ids, base::Bind(RemoveRequestsDone, callback));
 }
 
 void RequestQueue::ChangeRequestsState(
     const std::vector<int64_t>& request_ids,
     const SavePageRequest::RequestState new_state,
     const UpdateMultipleRequestsCallback& callback) {
   store_->ChangeRequestsState(request_ids, new_state,
                               base::Bind(UpdateMultipleRequestsDone, callback));
 }
 
 void RequestQueue::PurgeRequests(const PurgeRequestsCallback& callback) {}
 
 }  // namespace offline_pages