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

components/task_scheduler_util/common/variations_util.cc

Index: components/task_scheduler_util/common/variations_util.cc
diff --git a/components/task_scheduler_util/common/variations_util.cc b/components/task_scheduler_util/common/variations_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..bc072a208ce40112fa6b23f4fb761f5edaa56ecd
--- /dev/null
+++ b/components/task_scheduler_util/common/variations_util.cc
@@ -0,0 +1,108 @@
+// 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/common/variations_util.h"
+
+#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/time/time.h"
+
+namespace task_scheduler_util {
+
+namespace {
+
+struct SchedulerVariableWorkerPoolParams {

[gab, 2016/12/12 17:07:21]

s/Variable/Customizable/ ?

[fdoray, 2016/12/12 18:30:06]

Done.

+  base::SchedulerWorkerPoolParams::StandbyThreadPolicy standby_thread_policy;
+  int max_threads = 0;
+  base::TimeDelta detach_period;
+};
+
+// Converts |pool_descriptor| to a SchedulerWorkerPoolVariableParams. Returns a
+// default SchedulerWorkerPoolVariableParams 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 (int)
+// 5. Standby Thread Policy (string)
+// Additional values may appear as necessary and will be ignored.
+SchedulerVariableWorkerPoolParams StringToVariableWorkerPoolParams(
+    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 variables 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)) {
+    SchedulerVariableWorkerPoolParams params;
+    params.max_threads = base::RecommendedMaxNumberOfThreadsInPool(
+        min, max, cores_multiplier, offset);
+    params.detach_period =
+        base::TimeDelta::FromMilliseconds(detach_milliseconds);
+    params.standby_thread_policy = (tokens.size() >= 6 && tokens[5] == "lazy")
+                                       ? StandbyThreadPolicy::LAZY
+                                       : StandbyThreadPolicy::ONE;
+    return params;
+  }
+  DLOG(ERROR) << "Invalid Worker Pool Descriptor: " << pool_descriptor;
+  return SchedulerVariableWorkerPoolParams();
+}
+
+}  // namespace
+
+SchedulerConstantWorkerPoolParams::SchedulerConstantWorkerPoolParams(
+    const char* name,
+    base::ThreadPriority priority_hint)

[gab, 2016/12/12 17:07:21]

name_in, priority_hint_in

(I prefer that for structs as it avoids name resolution confusion for the
reader, e.g. say the variable was used in the body, which one prevails?)

[fdoray, 2016/12/12 18:30:05]

Done.

+    : name(name), priority_hint(priority_hint) {}
+
+std::vector<base::SchedulerWorkerPoolParams> GetWorkerPoolParams(
+    const std::vector<SchedulerConstantWorkerPoolParams>
+        constant_worker_pool_params_vector,
+    const std::map<std::string, std::string>& variation_params) {
+  std::vector<base::SchedulerWorkerPoolParams> worker_pool_params_vector;
+  for (const auto& constant_worker_pool_params :
+       constant_worker_pool_params_vector) {
+    const auto* const worker_pool_name = constant_worker_pool_params.name;

[gab, 2016/12/12 17:07:21]

s/auto/char/

same length so auto merely hinders readability

[fdoray, 2016/12/12 18:30:05]

Done.

+    auto it = variation_params.find(worker_pool_name);
+    if (it == variation_params.end()) {
+      DLOG(ERROR) << "Missing Worker Pool Configuration: " << worker_pool_name;
+      return std::vector<base::SchedulerWorkerPoolParams>();
+    }
+    const auto variable_worker_pool_params =
+        StringToVariableWorkerPoolParams(it->second);
+    if (variable_worker_pool_params.max_threads <= 0 ||
+        variable_worker_pool_params.detach_period <= base::TimeDelta()) {
+      DLOG(ERROR) << "Invalid Worker Pool Configuration: " << worker_pool_name
+                  << " [" << it->second << "]";
+      return std::vector<base::SchedulerWorkerPoolParams>();
+    }
+    worker_pool_params_vector.emplace_back(
+        worker_pool_name, constant_worker_pool_params.priority_hint,
+        variable_worker_pool_params.standby_thread_policy,
+        variable_worker_pool_params.max_threads,
+        variable_worker_pool_params.detach_period);
+  }
+  return worker_pool_params_vector;
+}
+
+}  // namespace task_scheduler_util