RAPPOR implementation

chrome/common/metrics/metrics_log_base.cc

 // 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.
 
 #include "chrome/common/metrics/metrics_log_base.h"
 
 #include "base/base64.h"
 #include "base/basictypes.h"
-#include "base/md5.h"
 #include "base/metrics/histogram_base.h"
 #include "base/metrics/histogram_samples.h"
 #include "base/sys_byteorder.h"

[Alexei Svitkine (slow), 2014/02/05 18:07:01]

Is this header needed by this file anymore?

[Steven Holte, 2014/02/05 22:44:37]

Removed, along with a couple other headers that don't seem needed.

 #include "base/sys_info.h"
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/logging_chrome.h"
 #include "chrome/common/metrics/proto/histogram_event.pb.h"
 #include "chrome/common/metrics/proto/system_profile.pb.h"
 #include "chrome/common/metrics/proto/user_action_event.pb.h"
+#include "components/variations/metrics_util.h"
 
 using base::Histogram;
 using base::HistogramBase;
 using base::HistogramSamples;
 using base::SampleCountIterator;
 using base::Time;
 using base::TimeDelta;
 using metrics::HistogramEventProto;
 using metrics::SystemProfileProto;
 using metrics::UserActionEventProto;
 
 namespace {
 
 // Any id less than 16 bytes is considered to be a testing id.
 bool IsTestingID(const std::string& id) {
   return id.size() < 16;
 }
 
-// Converts the 8-byte prefix of an MD5 hash into a uint64 value.
-inline uint64 HashToUInt64(const std::string& hash) {
-  uint64 value;
-  DCHECK_GE(hash.size(), sizeof(value));
-  memcpy(&value, hash.data(), sizeof(value));
-  return base::HostToNet64(value);
-}
-
 SystemProfileProto::Channel AsProtobufChannel(
     chrome::VersionInfo::Channel channel) {
   switch (channel) {
     case chrome::VersionInfo::CHANNEL_UNKNOWN:
       return SystemProfileProto::CHANNEL_UNKNOWN;
     case chrome::VersionInfo::CHANNEL_CANARY:
       return SystemProfileProto::CHANNEL_CANARY;
     case chrome::VersionInfo::CHANNEL_DEV:
       return SystemProfileProto::CHANNEL_DEV;
     case chrome::VersionInfo::CHANNEL_BETA:
@@ skipping 21 matching lines @@
   uma_proto_.mutable_system_profile()->set_build_timestamp(GetBuildTime());
   uma_proto_.mutable_system_profile()->set_app_version(version_string);
   uma_proto_.mutable_system_profile()->set_channel(
       AsProtobufChannel(chrome::VersionInfo::GetChannel()));
 }
 
 MetricsLogBase::~MetricsLogBase() {}
 
 // static
 uint64 MetricsLogBase::Hash(const std::string& value) {
-  // Create an MD5 hash of the given |value|, represented as a byte buffer
-  // encoded as an std::string.
-  base::MD5Context context;
-  base::MD5Init(&context);
-  base::MD5Update(&context, value);
-
-  base::MD5Digest digest;
-  base::MD5Final(&digest, &context);
-
-  std::string hash_str(reinterpret_cast<char*>(digest.a), arraysize(digest.a));
-  uint64 hash = HashToUInt64(hash_str);
+  uint64 hash = metrics::HashMetricName(value);
 
   // The following log is VERY helpful when folks add some named histogram into
   // the code, but forgot to update the descriptive list of histograms.  When
   // that happens, all we get to see (server side) is a hash of the histogram
   // name.  We can then use this logging to find out what histogram name was
   // being hashed to a given MD5 value by just running the version of Chromium
   // in question with --enable-logging.
   DVLOG(1) << "Metrics: Hash numeric [" << value << "]=[" << hash << "]";
 
   return hash;
@@ skipping 65 matching lines @@
   for (int i = 0; i < histogram_proto->bucket_size(); ++i) {
     HistogramEventProto::Bucket* bucket = histogram_proto->mutable_bucket(i);
     if (i + 1 < histogram_proto->bucket_size() &&
         bucket->max() == histogram_proto->bucket(i + 1).min()) {
       bucket->clear_max();
     } else if (bucket->max() == bucket->min() + 1) {
       bucket->clear_min();
     }
   }
 }