Upload UMA data using protocol buffers.

chrome/browser/metrics/metrics_log_serializer.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_METRICS_METRICS_LOG_SERIALIZER_H_
 #define CHROME_BROWSER_METRICS_METRICS_LOG_SERIALIZER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "chrome/common/metrics/metrics_log_manager.h"
 
 namespace base {
 class ListValue;
 }
 
 // Serializer for persisting metrics logs to prefs.
 class MetricsLogSerializer : public MetricsLogManager::LogSerializer {
  public:
-  // Used to produce a historgram that keeps track of the status of recalling
+  // Used to produce a histogram that keeps track of the status of recalling
   // persisted per logs.
   enum LogReadStatus {
     RECALL_SUCCESS,         // We were able to correctly recall a persisted log.
     LIST_EMPTY,             // Attempting to recall from an empty list.
     LIST_SIZE_MISSING,      // Failed to recover list size using GetAsInteger().
     LIST_SIZE_TOO_SMALL,    // Too few elements in the list (less than 3).
     LIST_SIZE_CORRUPTION,   // List size is not as expected.
     LOG_STRING_CORRUPTION,  // Failed to recover log string using GetAsString().
     CHECKSUM_CORRUPTION,    // Failed to verify checksum.
     CHECKSUM_STRING_CORRUPTION,  // Failed to recover checksum string using
-    // GetAsString().
+                                 // GetAsString().
     DECODE_FAIL,            // Failed to decode log.
+    XML_PROTO_MISMATCH,     // The XML and protobuf logs have inconsistent data.
     END_RECALL_STATUS       // Number of bins to use to create the histogram.
   };
 
   MetricsLogSerializer();
   virtual ~MetricsLogSerializer();
 
   // Implementation of MetricsLogManager::LogSerializer
-  virtual void SerializeLogs(const std::vector<std::string>& logs,
-                             MetricsLogManager::LogType log_type) OVERRIDE;
-  virtual void DeserializeLogs(MetricsLogManager::LogType log_type,
-                               std::vector<std::string>* logs) OVERRIDE;
+  virtual void SerializeLogs(
+      const std::vector<std::pair<std::string, std::string> >& logs,

[jar (doing other things), 2012/02/23 01:59:18]

Please add comment about the meaning of pairs of strings.  I *think* it was
pretty clear that the logs used to be serialized as strings.... but maybe that
wasn't clear... and this is less clear.

+      MetricsLogManager::LogType log_type) OVERRIDE;
+  virtual void DeserializeLogs(
+      MetricsLogManager::LogType log_type,
+      std::vector<std::pair<std::string, std::string> >* logs) OVERRIDE;
 
  private:
   // Encodes the textual log data from |local_list| and writes it to the given
   // pref list, along with list size and checksum.
   static void WriteLogsToPrefList(const std::vector<std::string>& local_list,
                                   const size_t kMaxLocalListSize,
                                   base::ListValue* list);
 
   // Decodes and verifies the textual log data from |list|, populating
   // |local_list| and returning a status code.
+  // |is_xml| should be true if this is an XML log and false if this is a

[jar (doing other things), 2012/02/23 01:59:18]

I wasn't able to understand the comment as written.  

I'm not clear what it means to change a prefs value into a string (presumably
for appending to the local_list).

[Ilya Sherman, 2012/02/24 02:10:06]

Is it clearer now, or still confusing?

[jar (doing other things), 2012/02/27 20:35:34]

Much better. Thanks!

On 2012/02/24 02:10:06, Ilya Sherman wrote:

+  // protobuf log; it is used exclusively for logging histograms.
   static LogReadStatus ReadLogsFromPrefList(
       const base::ListValue& list,
+      bool is_xml,
       std::vector<std::string>* local_list);
 
   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, EmptyLogList);
   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, SingleElementLogList);
   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, OverLimitLogList);
   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, SmallRecoveredListSize);
   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, RemoveSizeFromLogList);
   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, CorruptSizeOfLogList);
   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, CorruptChecksumOfLogList);
 
   DISALLOW_COPY_AND_ASSIGN(MetricsLogSerializer);
 };
 
 #endif  // CHROME_BROWSER_METRICS_METRICS_LOG_SERIALIZER_H_