utils/benchmark/src/log.h

   1 #ifndef BENCHMARK_LOG_H_
   2 #define BENCHMARK_LOG_H_
   3
   4 #include <iostream>
   5 #include <ostream>
   6
   7 #include "benchmark/benchmark.h"
   8
   9 namespace benchmark {
  10 namespace internal {
  11
  12 typedef std::basic_ostream<char>&(EndLType)(std::basic_ostream<char>&);
  13
  14 class LogType {
  15   friend LogType& GetNullLogInstance();
  16   friend LogType& GetErrorLogInstance();
  17
  18   // FIXME: Add locking to output.
  19   template <class Tp>
  20   friend LogType& operator<<(LogType&, Tp const&);
  21   friend LogType& operator<<(LogType&, EndLType*);
  22
  23  private:
  24   LogType(std::ostream* out) : out_(out) {}
  25   std::ostream* out_;
  26   BENCHMARK_DISALLOW_COPY_AND_ASSIGN(LogType);
  27 };
  28
  29 template <class Tp>
  30 LogType& operator<<(LogType& log, Tp const& value) {
  31   if (log.out_) {
  32     *log.out_ << value;
  33   }
  34   return log;
  35 }
  36
  37 inline LogType& operator<<(LogType& log, EndLType* m) {
  38   if (log.out_) {
  39     *log.out_ << m;
  40   }
  41   return log;
  42 }
  43
  44 inline int& LogLevel() {
  45   static int log_level = 0;
  46   return log_level;
  47 }
  48
  49 inline LogType& GetNullLogInstance() {
  50   static LogType log(nullptr);
  51   return log;
  52 }
  53
  54 inline LogType& GetErrorLogInstance() {
  55   static LogType log(&std::clog);
  56   return log;
  57 }
  58
  59 inline LogType& GetLogInstanceForLevel(int level) {
  60   if (level <= LogLevel()) {
  61     return GetErrorLogInstance();
  62   }
  63   return GetNullLogInstance();
  64 }
  65
  66 }  // end namespace internal
  67 }  // end namespace benchmark
  68
  69 #define VLOG(x)                                                               \
  70   (::benchmark::internal::GetLogInstanceForLevel(x) << "-- LOG(" << x << "):" \
  71                                                                          " ")
  72
  73 #endif