Reland "Add first part of the network_tester functionality"

webrtc/tools/network_tester/config_reader.cc

+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#include "webrtc/tools/network_tester/config_reader.h"
+
+#include <string>
+#include <vector>
+
+namespace webrtc {
+
+ConfigReader::ConfigReader(const std::string& config_file_path)
+    : proto_config_index_(0) {
+  std::ifstream config_stream(config_file_path,
+                              std::ios_base::in | std::ios_base::binary);
+  RTC_DCHECK(config_stream.is_open());
+  RTC_DCHECK(config_stream.good());
+  std::string config_data((std::istreambuf_iterator<char>(config_stream)),
+                          (std::istreambuf_iterator<char>()));
+  if (config_data.size() > 0) {
+    proto_all_configs_.ParseFromString(config_data);
+  }
+}
+
+ConfigReader::~ConfigReader() = default;
+
+rtc::Optional<ConfigReader::Config> ConfigReader::GetNextConfig() {
+#ifdef WEBRTC_NETWORK_TESTER_PROTO
+  if (proto_config_index_ >= proto_all_configs_.configs_size())
+    return rtc::Optional<Config>();
+  auto proto_config = proto_all_configs_.configs(proto_config_index_++);
+  RTC_DCHECK(proto_config.has_packet_send_interval_ms());
+  RTC_DCHECK(proto_config.has_packet_size());
+  RTC_DCHECK(proto_config.has_execution_time_ms());
+  Config config;
+  config.packet_send_interval_ms = proto_config.packet_send_interval_ms();
+  config.packet_size = proto_config.packet_size();
+  config.execution_time_ms = proto_config.execution_time_ms();
+  return rtc::Optional<Config>(config);
+#else
+  return rtc::Optional<Config>();
+#endif  //  WEBRTC_NETWORK_TESTER_PROTO
+}
+
+}  // namespace webrtc