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      1 // Copyright (c) 2009 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 // This file contains macros to simplify histogram reporting from the disk
      6 // cache. The main issue is that we want to have separate histograms for each
      7 // type of cache (regular vs. media, etc), without adding the complexity of
      8 // keeping track of a potentially large number of histogram objects that have to
      9 // survive the backend object that created them.
     10 
     11 #ifndef NET_DISK_CACHE_HISTOGRAM_MACROS_H_
     12 #define NET_DISK_CACHE_HISTOGRAM_MACROS_H_
     13 
     14 // HISTOGRAM_HOURS will collect time related data with a granularity of hours
     15 // and normal values of a few months.
     16 #define UMA_HISTOGRAM_HOURS UMA_HISTOGRAM_COUNTS_10000
     17 
     18 // HISTOGRAM_AGE will collect time elapsed since |initial_time|, with a
     19 // granularity of hours and normal values of a few months.
     20 #define UMA_HISTOGRAM_AGE(name, initial_time)\
     21     UMA_HISTOGRAM_COUNTS_10000(name, (Time::Now() - initial_time).InHours())
     22 
     23 // HISTOGRAM_AGE_MS will collect time elapsed since |initial_time|, with the
     24 // normal resolution of the UMA_HISTOGRAM_TIMES.
     25 #define UMA_HISTOGRAM_AGE_MS(name, initial_time)\
     26     UMA_HISTOGRAM_TIMES(name, Time::Now() - initial_time)
     27 
     28 #define UMA_HISTOGRAM_CACHE_ERROR(name, sample) \
     29     UMA_HISTOGRAM_ENUMERATION(name, sample, 50)
     30 
     31 #ifdef NET_DISK_CACHE_BACKEND_IMPL_CC_
     32 #define BACKEND_OBJ this
     33 #else
     34 #define BACKEND_OBJ backend_
     35 #endif
     36 
     37 // Generates a UMA histogram of the given type, generating the proper name for
     38 // it (asking backend_->HistogramName), and adding the provided sample.
     39 // For example, to generate a regualar UMA_HISTOGRAM_COUNTS, this macro would
     40 // be used as:
     41 //  CACHE_UMA(COUNTS, "MyName", 0, 20);
     42 //  CACHE_UMA(COUNTS, "MyExperiment", 530, 55);
     43 // which roughly translates to:
     44 //  UMA_HISTOGRAM_COUNTS("DiskCache.2.MyName", 20);  // "2" is the CacheType.
     45 //  UMA_HISTOGRAM_COUNTS("DiskCache.2.MyExperiment_530", 55);
     46 //
     47 #define CACHE_UMA(type, name, experiment, sample) {\
     48     const std::string my_name = BACKEND_OBJ->HistogramName(name, experiment);\
     49     switch (BACKEND_OBJ->cache_type()) {\
     50       case net::DISK_CACHE:\
     51         UMA_HISTOGRAM_##type(my_name.data(), sample);\
     52         break;\
     53       case net::MEDIA_CACHE:\
     54         UMA_HISTOGRAM_##type(my_name.data(), sample);\
     55         break;\
     56       default:\
     57         NOTREACHED();\
     58         break;\
     59     }\
     60   }
     61 
     62 #endif  // NET_DISK_CACHE_HISTOGRAM_MACROS_H_
     63