net/disk_cache/blockfile/webfonts_histogram.cc

   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 #include "net/disk_cache/blockfile/webfonts_histogram.h"
   6
   7 #include "base/strings/string_piece.h"
   8 #include "base/strings/stringprintf.h"
   9 #include "net/disk_cache/blockfile/entry_impl.h"
  10 #include "net/disk_cache/blockfile/histogram_macros.h"
  11
  12 namespace {
  13
  14 enum WebFontDiskCacheEventType {
  15   CACHE_EVENT_MISS,
  16   CACHE_EVENT_HIT,
  17   CACHE_EVENT_EVICTED_ENTRY,
  18   CACHE_EVENT_MAX
  19 };
  20
  21 // Tests if the substring of str that begins at pos starts with substr. If so,
  22 // returns true and advances pos by the length of substr.
  23 bool Consume(const std::string& str, const base::StringPiece& substr,
  24              std::string::size_type* pos) {
  25   if (!str.compare(*pos, substr.length(), substr.data())) {
  26     *pos += substr.length();
  27     return true;
  28   }
  29   return false;
  30 }
  31
  32 const char kRoboto[] = "roboto";
  33 const char kOpenSans[] = "opensans";
  34 const char kOthers[] = "others";
  35
  36 // Check if the given string is a URL for a font resource of Google Fonts.
  37 // If so, returns a label for UMA histogram ("roboto", "opensans" or "others").
  38 const char* HistogramLabel(const std::string& str) {
  39   std::string::size_type pos = 0;
  40   if (Consume(str, "http://", &pos) || Consume(str, "https://", &pos)) {
  41     if (Consume(str, "themes.googleusercontent.com/static/fonts/", &pos) ||
  42         Consume(str, "ssl.gstatic.com/fonts/", &pos) ||
  43         Consume(str, "fonts.gstatic.com/s/", &pos)) {
  44       if (Consume(str, kRoboto, &pos))
  45         return kRoboto;
  46       if (Consume(str, kOpenSans, &pos))
  47         return kOpenSans;
  48       return kOthers;
  49     }
  50   }
  51   return NULL;
  52 }
  53
  54 std::string HistogramName(const char* prefix, const char* label) {
  55   return base::StringPrintf("WebFont.%s_%s", prefix, label);
  56 }
  57
  58 void RecordCacheEvent(WebFontDiskCacheEventType type, const char* label) {
  59   CACHE_HISTOGRAM_ENUMERATION(HistogramName("DiskCacheHit", label),
  60                               type, CACHE_EVENT_MAX);
  61 }
  62
  63 }  // namespace
  64
  65 namespace disk_cache {
  66 namespace web_fonts_histogram {
  67
  68 void RecordCacheMiss(const std::string& key) {
  69   const char* label = HistogramLabel(key);
  70   if (label)
  71     RecordCacheEvent(CACHE_EVENT_MISS, label);
  72 }
  73
  74 void RecordEvictedEntry(const std::string& key) {
  75   const char* label = HistogramLabel(key);
  76   if (label)
  77     RecordCacheEvent(CACHE_EVENT_EVICTED_ENTRY, label);
  78 }
  79
  80 void RecordCacheHit(EntryImpl* entry) {
  81   const char* label = HistogramLabel(entry->GetKey());
  82   if (!label)
  83     return;
  84   EntryStore* info = entry->entry()->Data();
  85   CACHE_HISTOGRAM_COUNTS_10000(HistogramName("DiskCache.ReuseCount.Hit", label),
  86                                info->reuse_count);
  87   CACHE_HISTOGRAM_AGE(HistogramName("DiskCache.EntryAge.Hit", label),
  88                       base::Time::FromInternalValue(info->creation_time));
  89   RecordCacheEvent(CACHE_EVENT_HIT, label);
  90 }
  91
  92 void RecordEviction(EntryImpl* entry) {
  93   const char* label = HistogramLabel(entry->GetKey());
  94   if (!label)
  95     return;
  96   EntryStore* info = entry->entry()->Data();
  97   CACHE_HISTOGRAM_COUNTS_10000(
  98       HistogramName("DiskCache.ReuseCount.Evict", label),
  99       info->reuse_count);
 100   CACHE_HISTOGRAM_AGE(HistogramName("DiskCache.EntryAge.Evict", label),
 101                       base::Time::FromInternalValue(info->creation_time));
 102 }
 103
 104 }  // namespace web_fonts_histogram
 105 }  // namespace disk_cache