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      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_CHROMEOS_SERIALIZATION_UTILS_H_
      6 #define COMPONENTS_METRICS_CHROMEOS_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_CHROMEOS_SERIALIZATION_UTILS_H_
     49