Split browser-specific and generic code in components/task_scheduler_util/.

components/task_scheduler_util/variations/browser_variations_util.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/task_scheduler_util/variations/browser_variations_util.h"
-
-#include <map>
-#include <string>
-#include <vector>
-
-#include "base/logging.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_piece.h"
-#include "base/strings/string_split.h"
-#include "base/task_scheduler/initialization_util.h"
-#include "base/task_scheduler/scheduler_worker_pool_params.h"
-#include "base/task_scheduler/switches.h"
-#include "base/task_scheduler/task_traits.h"
-#include "base/threading/sequenced_worker_pool.h"
-#include "base/time/time.h"
-#include "build/build_config.h"
-#include "components/task_scheduler_util/initialization/browser_util.h"
-#include "components/variations/variations_associated_data.h"
-
-namespace task_scheduler_util {
-namespace variations {
-
-namespace {
-
-constexpr char kFieldTrialName[] = "BrowserScheduler";
-
-// Converts |pool_descriptor| to a SingleWorkerPoolConfiguration. Returns a
-// default SingleWorkerPoolConfiguration on failure.
-//
-// |pool_descriptor| is a semi-colon separated value string with the following
-// items:
-// 0. Minimum Thread Count (int)
-// 1. Maximum Thread Count (int)
-// 2. Thread Count Multiplier (double)
-// 3. Thread Count Offset (int)
-// 4. Detach Time in Milliseconds (milliseconds)
-// 5. Standby Thread Policy (string)
-// Additional values may appear as necessary and will be ignored.
-initialization::SingleWorkerPoolConfiguration
-StringToSingleWorkerPoolConfiguration(const base::StringPiece pool_descriptor) {
-  using StandbyThreadPolicy =
-      base::SchedulerWorkerPoolParams::StandbyThreadPolicy;
-  const std::vector<base::StringPiece> tokens = SplitStringPiece(
-      pool_descriptor, ";", base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
-  // Normally, we wouldn't initialize the values below because we don't read
-  // from them before we write to them. However, some compilers (like MSVC)
-  // complain about uninitialized varaibles due to the as_string() call below.
-  int min = 0;
-  int max = 0;
-  double cores_multiplier = 0.0;
-  int offset = 0;
-  int detach_milliseconds = 0;
-  // Checking for a size greater than the expected amount allows us to be
-  // forward compatible if we add more variation values.
-  if (tokens.size() >= 5 && base::StringToInt(tokens[0], &min) &&
-      base::StringToInt(tokens[1], &max) &&
-      base::StringToDouble(tokens[2].as_string(), &cores_multiplier) &&
-      base::StringToInt(tokens[3], &offset) &&
-      base::StringToInt(tokens[4], &detach_milliseconds)) {
-    initialization::SingleWorkerPoolConfiguration config;
-    config.threads = base::RecommendedMaxNumberOfThreadsInPool(
-        min, max, cores_multiplier, offset);
-    config.detach_period =
-        base::TimeDelta::FromMilliseconds(detach_milliseconds);
-    config.standby_thread_policy = (tokens.size() >= 6 && tokens[5] == "lazy")
-                                       ? StandbyThreadPolicy::LAZY
-                                       : StandbyThreadPolicy::ONE;
-    return config;
-  }
-  DLOG(ERROR) << "Invalid Worker Pool Descriptor: " << pool_descriptor;
-  return initialization::SingleWorkerPoolConfiguration();
-}
-
-// Converts a browser-based |variation_params| to
-// std::vector<base::SchedulerWorkerPoolParams>. Returns an empty vector on
-// failure.
-std::vector<base::SchedulerWorkerPoolParams>
-VariationsParamsToSchedulerWorkerPoolParamsVector(
-    const std::map<std::string, std::string>& variation_params) {
-  static const char* const kWorkerPoolNames[] = {
-      "Background", "BackgroundFileIO", "Foreground", "ForegroundFileIO"};
-  static_assert(
-      arraysize(kWorkerPoolNames) == initialization::WORKER_POOL_COUNT,
-      "Mismatched Worker Pool Types and Worker Pool Names");
-  initialization::BrowserWorkerPoolsConfiguration config;
-  initialization::SingleWorkerPoolConfiguration* const all_pools[]{
-      &config.background, &config.background_file_io, &config.foreground,
-      &config.foreground_file_io,
-  };
-  static_assert(arraysize(kWorkerPoolNames) == arraysize(all_pools),
-                "Mismatched Worker Pool Names and All Pools Array");
-  for (size_t i = 0; i < arraysize(kWorkerPoolNames); ++i) {
-    const auto* const worker_pool_name = kWorkerPoolNames[i];
-    const auto pair = variation_params.find(worker_pool_name);
-    if (pair == variation_params.end()) {
-      DLOG(ERROR) << "Missing Worker Pool Configuration: " << worker_pool_name;
-      return std::vector<base::SchedulerWorkerPoolParams>();
-    }
-
-    auto* const pool_config = all_pools[i];
-    *pool_config = StringToSingleWorkerPoolConfiguration(pair->second);
-    if (pool_config->threads <= 0 ||
-        pool_config->detach_period <= base::TimeDelta()) {
-      DLOG(ERROR) << "Invalid Worker Pool Configuration: " << worker_pool_name
-                  << " [" << pair->second << "]";
-      return std::vector<base::SchedulerWorkerPoolParams>();
-    }
-  }
-  return BrowserWorkerPoolConfigurationToSchedulerWorkerPoolParams(config);
-}
-
-}  // namespace
-
-std::vector<base::SchedulerWorkerPoolParams>
-GetBrowserSchedulerWorkerPoolParamsFromVariations() {
-  std::map<std::string, std::string> variation_params;
-  if (!::variations::GetVariationParams(kFieldTrialName, &variation_params))
-    return std::vector<base::SchedulerWorkerPoolParams>();
-
-  return VariationsParamsToSchedulerWorkerPoolParamsVector(variation_params);
-}
-
-void MaybePerformBrowserTaskSchedulerRedirection() {
-  std::map<std::string, std::string> variation_params;
-  ::variations::GetVariationParams(kFieldTrialName, &variation_params);
-
-  // TODO(gab): Remove this when http://crbug.com/622400 concludes.
-  const auto sequenced_worker_pool_param =
-      variation_params.find("RedirectSequencedWorkerPools");
-  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kDisableBrowserTaskScheduler) &&
-      sequenced_worker_pool_param != variation_params.end() &&
-      sequenced_worker_pool_param->second == "true") {
-    base::SequencedWorkerPool::EnableWithRedirectionToTaskSchedulerForProcess();
-  } else {
-    base::SequencedWorkerPool::EnableForProcess();
-  }
-}
-
-}  // variations
-}  // namespace task_scheduler_util