text: // 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 <utility>
  
  #include "base/bind.h"
  #include "base/location.h"
  #include "base/threading/thread_task_runner_handle.h"
  #include "components/offline_pages/background/change_requests_state_task.h"
  #include "components/offline_pages/background/mark_attempt_aborted_task.h"
  #include "components/offline_pages/background/mark_attempt_completed_task.h"
  #include "components/offline_pages/background/mark_attempt_started_task.h"
  #include "components/offline_pages/background/pick_request_task.h"
  #include "components/offline_pages/background/pick_request_task_factory.h"
  #include "components/offline_pages/background/remove_requests_task.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,
                       std::vector<std::unique_ptr<SavePageRequest>> requests) {
    GetRequestsResult result =
        success ? GetRequestsResult::SUCCESS : 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, std::move(requests));
  }
  
  // Completes the add request call.
  void AddRequestDone(const RequestQueue::AddRequestCallback& callback,
                      const SavePageRequest& request,
                      ItemActionStatus status) {
    AddRequestResult result;
    switch (status) {
      case ItemActionStatus::SUCCESS:
        result = AddRequestResult::SUCCESS;
        break;
      case ItemActionStatus::ALREADY_EXISTS:
        result = AddRequestResult::ALREADY_EXISTS;
        break;
      case ItemActionStatus::STORE_ERROR:
        result = AddRequestResult::STORE_FAILURE;
        break;
      case ItemActionStatus::NOT_FOUND:
      default:
        NOTREACHED();
        return;
    }
    callback.Run(result, request);
  }
  
  }  // namespace
  
  RequestQueue::RequestQueue(std::unique_ptr<RequestQueueStore> 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_->AddRequest(request, base::Bind(&AddRequestDone, callback, request));
  }
  
  void RequestQueue::RemoveRequests(const std::vector<int64_t>& request_ids,
                                    const UpdateCallback& callback) {
    std::unique_ptr<Task> task(
        new RemoveRequestsTask(store_.get(), request_ids, callback));
    task_queue_.AddTask(std::move(task));
  }
  
  void RequestQueue::ChangeRequestsState(
      const std::vector<int64_t>& request_ids,
      const SavePageRequest::RequestState new_state,
      const RequestQueue::UpdateCallback& callback) {
    std::unique_ptr<Task> task(new ChangeRequestsStateTask(
        store_.get(), request_ids, new_state, callback));
    task_queue_.AddTask(std::move(task));
  }
  
  void RequestQueue::MarkAttemptStarted(int64_t request_id,
                                        const UpdateCallback& callback) {
    std::unique_ptr<Task> task(
        new MarkAttemptStartedTask(store_.get(), request_id, callback));
    task_queue_.AddTask(std::move(task));
  }
  
  void RequestQueue::MarkAttemptAborted(int64_t request_id,
                                        const UpdateCallback& callback) {
    std::unique_ptr<Task> task(
        new MarkAttemptAbortedTask(store_.get(), request_id, callback));
    task_queue_.AddTask(std::move(task));
  }
  
  void RequestQueue::MarkAttemptCompleted(int64_t request_id,
                                          const UpdateCallback& callback) {
    std::unique_ptr<Task> task(
        new MarkAttemptCompletedTask(store_.get(), request_id, callback));
    task_queue_.AddTask(std::move(task));
  }
  
  void RequestQueue::PurgeRequests(const PurgeRequestsCallback& callback) {}
  
  void RequestQueue::PickNextRequest(
      PickRequestTask::RequestPickedCallback picked_callback,
      PickRequestTask::RequestNotPickedCallback not_picked_callback,
      PickRequestTask::RequestCountCallback request_count_callback,
      DeviceConditions& conditions,
      std::set<int64_t>& disabled_requests) {
    // Using the PickerContext, create a picker task.
    std::unique_ptr<Task> task(picker_factory_->CreatePickerTask(
        store_.get(), picked_callback, not_picked_callback,
        request_count_callback, conditions, disabled_requests));
  
    // Queue up the picking task, it will call one of the callbacks when it
    // completes.
    task_queue_.AddTask(std::move(task));
  }
  
  }  // namespace offline_pages
  