chrome/browser/metrics/metrics_log_serializer.h

   1 // Copyright (c) 2012 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 CHROME_BROWSER_METRICS_METRICS_LOG_SERIALIZER_H_
   6 #define CHROME_BROWSER_METRICS_METRICS_LOG_SERIALIZER_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "base/gtest_prod_util.h"
  12 #include "components/metrics/metrics_log_manager.h"
  13
  14 namespace base {
  15 class ListValue;
  16 }
  17
  18 // Serializer for persisting metrics logs to prefs.
  19 class MetricsLogSerializer : public metrics::MetricsLogManager::LogSerializer {
  20  public:
  21   // Used to produce a histogram that keeps track of the status of recalling
  22   // persisted per logs.
  23   enum LogReadStatus {
  24     RECALL_SUCCESS,         // We were able to correctly recall a persisted log.
  25     LIST_EMPTY,             // Attempting to recall from an empty list.
  26     LIST_SIZE_MISSING,      // Failed to recover list size using GetAsInteger().
  27     LIST_SIZE_TOO_SMALL,    // Too few elements in the list (less than 3).
  28     LIST_SIZE_CORRUPTION,   // List size is not as expected.
  29     LOG_STRING_CORRUPTION,  // Failed to recover log string using GetAsString().
  30     CHECKSUM_CORRUPTION,    // Failed to verify checksum.
  31     CHECKSUM_STRING_CORRUPTION,  // Failed to recover checksum string using
  32                                  // GetAsString().
  33     DECODE_FAIL,            // Failed to decode log.
  34     DEPRECATED_XML_PROTO_MISMATCH,  // The XML and protobuf logs have
  35                                     // inconsistent data.
  36     END_RECALL_STATUS       // Number of bins to use to create the histogram.
  37   };
  38
  39   MetricsLogSerializer();
  40   virtual ~MetricsLogSerializer();
  41
  42   // Implementation of metrics::MetricsLogManager::LogSerializer
  43   virtual void SerializeLogs(
  44       const std::vector<metrics::MetricsLogManager::SerializedLog>& logs,
  45       metrics::MetricsLogManager::LogType log_type) OVERRIDE;
  46   virtual void DeserializeLogs(
  47       metrics::MetricsLogManager::LogType log_type,
  48       std::vector<metrics::MetricsLogManager::SerializedLog>* logs) OVERRIDE;
  49
  50  private:
  51   // Encodes the textual log data from |local_list| and writes it to the given
  52   // pref list, along with list size and checksum.  Logs will be stored starting
  53   // with the most recent, and working backward until at least
  54   // |list_length_limit| logs and |byte_limit| bytes of logs have been
  55   // stored. At least one of those two arguments must be non-zero.
  56   static void WriteLogsToPrefList(
  57       const std::vector<metrics::MetricsLogManager::SerializedLog>& local_list,
  58       size_t list_length_limit,
  59       size_t byte_limit,
  60       base::ListValue* list);
  61
  62   // Decodes and verifies the textual log data from |list|, populating
  63   // |local_list| and returning a status code.
  64   static LogReadStatus ReadLogsFromPrefList(
  65       const base::ListValue& list,
  66       std::vector<metrics::MetricsLogManager::SerializedLog>* local_list);
  67
  68   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, EmptyLogList);
  69   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, SingleElementLogList);
  70   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, LongButTinyLogList);
  71   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, LongButSmallLogList);
  72   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, ShortButLargeLogList);
  73   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, LongAndLargeLogList);
  74   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, SmallRecoveredListSize);
  75   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, RemoveSizeFromLogList);
  76   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, CorruptSizeOfLogList);
  77   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, CorruptChecksumOfLogList);
  78
  79   DISALLOW_COPY_AND_ASSIGN(MetricsLogSerializer);
  80 };
  81
  82 #endif  // CHROME_BROWSER_METRICS_METRICS_LOG_SERIALIZER_H_