components/proximity_auth/metrics.cc

   1 // Copyright 2015 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 #include "components/proximity_auth/metrics.h"
   6
   7 #include "base/logging.h"
   8 #include "base/md5.h"
   9 #include "base/metrics/histogram_macros.h"
  10 #include "base/metrics/sparse_histogram.h"
  11 #include "base/sys_byteorder.h"
  12
  13 namespace proximity_auth {
  14 namespace metrics {
  15
  16 namespace {
  17
  18 // Converts the 4-byte prefix of an MD5 hash into a int32 value.
  19 int32 DigestToInt32(const base::MD5Digest& digest) {
  20   // First, copy to a uint32, since byte swapping and endianness conversions
  21   // expect unsigned integers.
  22   uint32 unsigned_value;
  23   DCHECK_GE(arraysize(digest.a), sizeof(unsigned_value));
  24   memcpy(&unsigned_value, digest.a, sizeof(unsigned_value));
  25   unsigned_value = base::ByteSwap(base::HostToNet32(unsigned_value));
  26
  27   // Then copy the resulting bit pattern to an int32 to match the datatype that
  28   // histograms expect.
  29   int32 value;
  30   memcpy(&value, &unsigned_value, sizeof(value));
  31   return value;
  32 }
  33
  34 // Returns a hash of the given |name|, encoded as a 32-bit signed integer.
  35 int32 HashDeviceModelName(const std::string& name) {
  36   base::MD5Digest digest;
  37   base::MD5Sum(name.c_str(), name.size(), &digest);
  38   return DigestToInt32(digest);
  39 }
  40
  41 }  // namespace
  42
  43 const char kUnknownDeviceModel[] = "Unknown";
  44 const int kUnknownProximityValue = 127;
  45
  46 void RecordAuthProximityRollingRssi(int rolling_rssi) {
  47   if (rolling_rssi != kUnknownProximityValue)
  48     rolling_rssi = std::min(50, std::max(-100, rolling_rssi));
  49
  50   UMA_HISTOGRAM_SPARSE_SLOWLY("EasyUnlock.AuthProximity.RollingRssi",
  51                               rolling_rssi);
  52 }
  53
  54 void RecordAuthProximityTransmitPowerDelta(int transmit_power_delta) {
  55   if (transmit_power_delta != kUnknownProximityValue)
  56     transmit_power_delta = std::min(50, std::max(-100, transmit_power_delta));
  57
  58   UMA_HISTOGRAM_SPARSE_SLOWLY("EasyUnlock.AuthProximity.TransmitPowerDelta",
  59                               transmit_power_delta);
  60 }
  61
  62 void RecordAuthProximityTimeSinceLastZeroRssi(
  63     base::TimeDelta time_since_last_zero_rssi) {
  64   UMA_HISTOGRAM_TIMES("EasyUnlock.AuthProximity.TimeSinceLastZeroRssi",
  65                       time_since_last_zero_rssi);
  66 }
  67
  68 void RecordAuthProximityRemoteDeviceModelHash(const std::string& device_model) {
  69   UMA_HISTOGRAM_SPARSE_SLOWLY("EasyUnlock.AuthProximity.RemoteDeviceModelHash",
  70                               HashDeviceModelName(device_model));
  71 }
  72
  73 void RecordRemoteSecuritySettingsState(RemoteSecuritySettingsState state) {
  74   DCHECK(state < RemoteSecuritySettingsState::COUNT);
  75   UMA_HISTOGRAM_ENUMERATION(
  76       "EasyUnlock.RemoteLockScreenState", static_cast<int>(state),
  77       static_cast<int>(RemoteSecuritySettingsState::COUNT));
  78 }
  79
  80 }  // namespace metrics
  81 }  // namespace proximity_auth