1#ifndef BENCHMARK_LOG_H_
2#define BENCHMARK_LOG_H_
3
4#include <iostream>
5#include <ostream>
6
7#include "benchmark/macros.h"
8
9namespace benchmark {
10namespace internal {
11
12typedef std::basic_ostream<char>&(EndLType)(std::basic_ostream<char>&);
13
14class 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
29template <class Tp>
30LogType& operator<<(LogType& log, Tp const& value) {
31 if (log.out_) {
32 *log.out_ << value;
33 }
34 return log;
35}
36
37inline LogType& operator<<(LogType& log, EndLType* m) {
38 if (log.out_) {
39 *log.out_ << m;
40 }
41 return log;
42}
43
44inline int& LogLevel() {
45 static int log_level = 0;
46 return log_level;
47}
48
49inline LogType& GetNullLogInstance() {
50 static LogType log(nullptr);
51 return log;
52}
53
54inline LogType& GetErrorLogInstance() {
55 static LogType log(&std::clog);
56 return log;
57}
58
59inline 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
74