Request Picker task

components/offline_pages/background/request_picker.cc

Index: components/offline_pages/background/request_picker.cc
diff --git a/components/offline_pages/background/request_picker.cc b/components/offline_pages/background/request_picker.cc
deleted file mode 100644
index c1d27838165d837bb70bc28bf3768e63a597441d..0000000000000000000000000000000000000000
--- a/components/offline_pages/background/request_picker.cc
+++ /dev/null
@@ -1,276 +0,0 @@
-// 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_picker.h"
-
-#include "base/bind.h"
-#include "base/logging.h"
-#include "components/offline_pages/background/save_page_request.h"
-
-namespace {
-template <typename T>
-int signum(T t) {
-  return (T(0) < t) - (t < T(0));
-}
-
-#define CALL_MEMBER_FUNCTION(object, ptrToMember) ((object)->*(ptrToMember))
-}  // namespace
-
-namespace offline_pages {
-
-RequestPicker::RequestPicker(RequestQueue* requestQueue,
-                             OfflinerPolicy* policy,
-                             RequestNotifier* notifier,
-                             RequestCoordinatorEventLogger* event_logger)
-    : queue_(requestQueue),
-      policy_(policy),
-      notifier_(notifier),
-      event_logger_(event_logger),
-      fewer_retries_better_(false),
-      earlier_requests_better_(false),
-      weak_ptr_factory_(this) {}
-
-RequestPicker::~RequestPicker() {}
-
-// Entry point for the async operation to choose the next request.
-void RequestPicker::ChooseNextRequest(
-    RequestCoordinator::RequestPickedCallback picked_callback,
-    RequestCoordinator::RequestNotPickedCallback not_picked_callback,
-    DeviceConditions* device_conditions,
-    const std::set<int64_t>& disabled_requests) {
-  picked_callback_ = picked_callback;
-  not_picked_callback_ = not_picked_callback;
-  fewer_retries_better_ = policy_->ShouldPreferUntriedRequests();
-  earlier_requests_better_ = policy_->ShouldPreferEarlierRequests();
-  current_conditions_.reset(new DeviceConditions(*device_conditions));
-  // Get all requests from queue (there is no filtering mechanism).
-  queue_->GetRequests(base::Bind(&RequestPicker::GetRequestResultCallback,
-                                 weak_ptr_factory_.GetWeakPtr(),
-                                 disabled_requests));
-}
-
-// When we get contents from the queue, use them to pick the next
-// request to operate on (if any).
-void RequestPicker::GetRequestResultCallback(
-    const std::set<int64_t>& disabled_requests,
-    RequestQueue::GetRequestsResult,
-    std::vector<std::unique_ptr<SavePageRequest>> requests) {
-  // If there is nothing to do, return right away.
-  if (requests.size() == 0) {
-    not_picked_callback_.Run(false);
-    return;
-  }
-
-  // Get the expired requests to be removed from the queue, and the valid ones
-  // from which to pick the next request.
-  std::vector<std::unique_ptr<SavePageRequest>> valid_requests;
-  std::vector<std::unique_ptr<SavePageRequest>> expired_requests;
-  SplitRequests(std::move(requests), &valid_requests, &expired_requests);
-  std::vector<int64_t> expired_request_ids;
-  for (const auto& request : expired_requests)
-    expired_request_ids.push_back(request->request_id());
-
-  queue_->RemoveRequests(expired_request_ids,
-                         base::Bind(&RequestPicker::OnRequestExpired,
-                                    weak_ptr_factory_.GetWeakPtr()));
-
-  // Pick the most deserving request for our conditions.
-  const SavePageRequest* picked_request = nullptr;
-
-  RequestCompareFunction comparator = nullptr;
-
-  // Choose which comparison function to use based on policy.
-  if (policy_->RetryCountIsMoreImportantThanRecency())
-    comparator = &RequestPicker::RetryCountFirstCompareFunction;
-  else
-    comparator = &RequestPicker::RecencyFirstCompareFunction;
-
-  // Iterate once through the requests, keeping track of best candidate.
-  bool non_user_requested_tasks_remaining = false;
-  for (unsigned i = 0; i < valid_requests.size(); ++i) {
-    // If the  request is on the disabled list, skip it.
-    auto search = disabled_requests.find(valid_requests[i]->request_id());
-    if (search != disabled_requests.end()) {
-      continue;
-    }
-    if (!valid_requests[i]->user_requested())
-      non_user_requested_tasks_remaining = true;
-    if (!RequestConditionsSatisfied(valid_requests[i].get()))
-      continue;
-    if (IsNewRequestBetter(picked_request, valid_requests[i].get(), comparator))
-      picked_request = valid_requests[i].get();
-  }
-
-  // If we have a best request to try next, get the request coodinator to
-  // start it.  Otherwise return that we have no candidates.
-  if (picked_request != nullptr) {
-    picked_callback_.Run(*picked_request);
-  } else {
-    not_picked_callback_.Run(non_user_requested_tasks_remaining);
-  }
-}
-
-// Filter out requests that don't meet the current conditions.  For instance, if
-// this is a predictive request, and we are not on WiFi, it should be ignored
-// this round.
-bool RequestPicker::RequestConditionsSatisfied(const SavePageRequest* request) {
-  // If the user did not request the page directly, make sure we are connected
-  // to power and have WiFi and sufficient battery remaining before we take this
-  // request.
-
-  if (!current_conditions_->IsPowerConnected() &&
-      policy_->PowerRequired(request->user_requested())) {
-    return false;
-  }
-
-  if (current_conditions_->GetNetConnectionType() !=
-          net::NetworkChangeNotifier::ConnectionType::CONNECTION_WIFI &&
-      policy_->UnmeteredNetworkRequired(request->user_requested())) {
-    return false;
-  }
-
-  if (current_conditions_->GetBatteryPercentage() <
-      policy_->BatteryPercentageRequired(request->user_requested())) {
-    return false;
-  }
-
-  // If we have already started this page the max number of times, it is not
-  // eligible to try again.
-  if (request->started_attempt_count() >= policy_->GetMaxStartedTries())
-    return false;
-
-  // If we have already completed trying this page the max number of times, it
-  // is not eligible to try again.
-  if (request->completed_attempt_count() >= policy_->GetMaxCompletedTries())
-    return false;
-
-  // If the request is paused, do not consider it.
-  if (request->request_state() == SavePageRequest::RequestState::PAUSED)
-    return false;
-
-  // If the request is expired, do not consider it.
-  base::TimeDelta requestAge = base::Time::Now() - request->creation_time();
-  if (requestAge >
-      base::TimeDelta::FromSeconds(
-          policy_->GetRequestExpirationTimeInSeconds()))
-    return false;
-
-  // If this request is not active yet, return false.
-  // TODO(petewil): If the only reason we return nothing to do is that we have
-  // inactive requests, we still want to try again later after their activation
-  // time elapses, we shouldn't take ourselves completely off the scheduler.
-  if (request->activation_time() > base::Time::Now())
-    return false;
-
-  return true;
-}
-
-// Look at policies to decide which requests to prefer.
-bool RequestPicker::IsNewRequestBetter(const SavePageRequest* oldRequest,
-                                       const SavePageRequest* newRequest,
-                                       RequestCompareFunction comparator) {
-
-  // If there is no old request, the new one is better.
-  if (oldRequest == nullptr)
-    return true;
-
-  // User requested pages get priority.
-  if (newRequest->user_requested() && !oldRequest->user_requested())
-    return true;
-
-  // Otherwise, use the comparison function for the current policy, which
-  // returns true if the older request is better.
-  return !(CALL_MEMBER_FUNCTION(this, comparator)(oldRequest, newRequest));
-}
-
-// Compare the results, checking request count before recency.  Returns true if
-// left hand side is better, false otherwise.
-bool RequestPicker::RetryCountFirstCompareFunction(
-    const SavePageRequest* left, const SavePageRequest* right) {
-  // Check the attempt count.
-  int result = CompareRetryCount(left, right);
-
-  if (result != 0)
-    return (result > 0);
-
-  // If we get here, the attempt counts were the same, so check recency.
-  result = CompareCreationTime(left, right);
-
-  return (result > 0);
-}
-
-// Compare the results, checking recency before request count. Returns true if
-// left hand side is better, false otherwise.
-bool RequestPicker::RecencyFirstCompareFunction(
-    const SavePageRequest* left, const SavePageRequest* right) {
-  // Check the recency.
-  int result = CompareCreationTime(left, right);
-
-  if (result != 0)
-    return (result > 0);
-
-  // If we get here, the recency was the same, so check the attempt count.
-  result = CompareRetryCount(left, right);
-
-  return (result > 0);
-}
-
-// Compare left and right side, returning 1 if the left side is better
-// (preferred by policy), 0 if the same, and -1 if the right side is better.
-int RequestPicker::CompareRetryCount(
-    const SavePageRequest* left, const SavePageRequest* right) {
-  // Check the attempt count.
-  int result = signum(left->completed_attempt_count() -
-                      right->completed_attempt_count());
-
-  // Flip the direction of comparison if policy prefers fewer retries.
-  if (fewer_retries_better_)
-    result *= -1;
-
-  return result;
-}
-
-// Compare left and right side, returning 1 if the left side is better
-// (preferred by policy), 0 if the same, and -1 if the right side is better.
-int RequestPicker::CompareCreationTime(
-    const SavePageRequest* left, const SavePageRequest* right) {
-  // Check the recency.
-  base::TimeDelta difference = left->creation_time() - right->creation_time();
-  int result = signum(difference.InMilliseconds());
-
-  // Flip the direction of comparison if policy prefers fewer retries.
-  if (earlier_requests_better_)
-    result *= -1;
-
-  return result;
-}
-
-void RequestPicker::SplitRequests(
-    std::vector<std::unique_ptr<SavePageRequest>> requests,
-    std::vector<std::unique_ptr<SavePageRequest>>* valid_requests,
-    std::vector<std::unique_ptr<SavePageRequest>>* expired_requests) {
-  for (auto& request : requests) {
-    if (base::Time::Now() - request->creation_time() >=
-        base::TimeDelta::FromSeconds(kRequestExpirationTimeInSeconds)) {
-      expired_requests->push_back(std::move(request));
-    } else {
-      valid_requests->push_back(std::move(request));
-    }
-  }
-}
-
-// Callback used after expired requests are deleted from the queue and notifies
-// the coordinator.
-void RequestPicker::OnRequestExpired(
-    std::unique_ptr<UpdateRequestsResult> result) {
-  const RequestCoordinator::BackgroundSavePageResult save_page_result(
-      RequestCoordinator::BackgroundSavePageResult::EXPIRED);
-  for (const auto& request : result->updated_items) {
-    event_logger_->RecordDroppedSavePageRequest(
-        request.client_id().name_space, save_page_result, request.request_id());
-    notifier_->NotifyCompleted(request, save_page_result);
-  }
-}
-
-}  // namespace offline_pages