components/metrics/serialization/serialization_utils.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_METRICS_SERIALIZATION_SERIALIZATION_UTILS_H_
   6 #define COMPONENTS_METRICS_SERIALIZATION_SERIALIZATION_UTILS_H_
   7
   8 #include <string>
   9
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/memory/scoped_vector.h"
  12
  13 namespace metrics {
  14
  15 class MetricSample;
  16
  17 // Metrics helpers to serialize and deserialize metrics collected by
  18 // ChromeOS.
  19 namespace SerializationUtils {
  20
  21 // Deserializes a sample passed as a string and return a sample.
  22 // The return value will either be a scoped_ptr to a Metric sample (if the
  23 // deserialization was successful) or a NULL scoped_ptr.
  24 scoped_ptr<MetricSample> ParseSample(const std::string& sample);
  25
  26 // Reads all samples from a file and truncate the file when done.
  27 void ReadAndTruncateMetricsFromFile(const std::string& filename,
  28                                     ScopedVector<MetricSample>* metrics);
  29
  30 // Serializes a sample and write it to filename.
  31 // The format for the message is:
  32 //  message_size, serialized_message
  33 // where
  34 //  * message_size is the total length of the message (message_size +
  35 //    serialized_message) on 4 bytes
  36 //  * serialized_message is the serialized version of sample (using ToString)
  37 //
  38 //  NB: the file will never leave the device so message_size will be written
  39 //  with the architecture's endianness.
  40 bool WriteMetricToFile(const MetricSample& sample, const std::string& filename);
  41
  42 // Maximum length of a serialized message
  43 static const int kMessageMaxLength = 1024;
  44
  45 }  // namespace SerializationUtils
  46 }  // namespace metrics
  47
  48 #endif  // COMPONENTS_METRICS_SERIALIZATION_SERIALIZATION_UTILS_H_