Configuration for download service.

components/download/internal/config.cc

+// Copyright 2017 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/download/internal/config.h"
+
+#include <string>
+
+#include "base/metrics/field_trial_params.h"
+#include "base/strings/string_number_conversions.h"
+#include "components/download/public/features.h"
+
+namespace download {
+
+namespace {
+
+// Default value for max concurrent downloads configuration.
+const int kDefaultMaxConcurrentDownloads = 4;
+
+// Default value for maximum running downloads of the download service.
+const int kDefaultMaxRunningDownloads = 1;
+
+// Default value for maximum scheduled downloads.
+const int kDefaultMaxScheduledDownloads = 15;
+
+// Default value for maximum retry count.
+const int kDefaultMaxRetryCount = 5;
+
+// Default value for file keep alive time in minutes, keep the file alive for
+// 12 hours by default.
+const int kDefaultFileKeepAliveTimeMinutes = 12 * 60;
+
+// Helper routine to get Finch experiment parameter. If no Finch seed was found,
+// use the |default_value|. The |name| should match an experiment
+// parameter in Finch server configuration.
+int GetFinchConfigInt(const std::string& name, int default_value) {
+  std::string finch_value =
+      base::GetFieldTrialParamValueByFeature(kDownloadServiceFeature, name);
+  int result;
+  return base::StringToInt(finch_value, &result) ? result : default_value;
+}
+
+// Helper routine to load Finch configurations.
+void LoadFinchConfigs(Configuration* config) {

[David Trainor- moved to gerrit, 2017/05/05 20:10:52]

Can we do something like make this static and make it erturn a configuration?

[xingliu, 2017/05/05 22:55:03]

Done.

+  config->max_concurrent_downloads = GetFinchConfigInt(
+      kMaxConcurrentDownloadsConfig, kDefaultMaxConcurrentDownloads);
+  config->max_running_downloads = GetFinchConfigInt(
+      kMaxRunningDownloadsConfig, kDefaultMaxRunningDownloads);
+  config->max_scheduled_downloads = GetFinchConfigInt(
+      kMaxScheduledDownloadsConfig, kDefaultMaxScheduledDownloads);
+  config->max_retry_count =
+      GetFinchConfigInt(kMaxRetryCountConfig, kDefaultMaxRetryCount);
+  config->file_keep_alive_time = base::TimeDelta::FromMinutes(GetFinchConfigInt(
+      kFileKeepAliveTimeMinutesConfig, kDefaultFileKeepAliveTimeMinutes));
+}
+
+}  // namespace
+
+Configuration::Configuration() {
+  LoadFinchConfigs(this);
+}
+
+}  // namespace download