google开源库glog源码实现分析

Posted 2022-06-09 shixin_0125

#include <vector>
# define GOOGLE_GLOG_DLL_DECL  __declspec(dllexport)
# define GOOGLE_GLOG_DLL_DECL_FOR_UNITTESTS  __declspec(dllimport)

namespace base_logging 

  // LogMessage::LogStream is a std::ostream backed by this streambuf.
  // This class ignores overflow and leaves two bytes at the end of the
  // buffer to allow for a \\n and \\0.
  class GOOGLE_GLOG_DLL_DECL LogStreamBuf : public std::streambuf 
  public:
    // REQUIREMENTS: "len" must be >= 2 to account for the \\n and \\n.
    LogStreamBuf(char *buf, int len) 
      setp(buf, buf + len - 2);
    
    // This effectively ignores overflow.
    virtual int_type overflow(int_type ch) 
      return ch;
    

    // Legacy public ostrstream method.
    size_t pcount() const  return pptr() - pbase(); 
    char* pbase() const  return std::streambuf::pbase(); 
  ;

  // namespace base_logging

class GOOGLE_GLOG_DLL_DECL LogStream : public std::ostream 
#ifdef _MSC_VER
# pragma warning(default: 4275)
#endif
public:
  LogStream(char *buf, int len, int ctr)
    : std::ostream(NULL),
    streambuf_(buf, len),
    ctr_(ctr),
    self_(this) 
    rdbuf(&streambuf_);
  

  int ctr() const  return ctr_; 
  void set_ctr(int ctr)  ctr_ = ctr; 
  LogStream* self() const  return self_; 

  // Legacy std::streambuf methods.
  size_t pcount() const  return streambuf_.pcount(); 
  char* pbase() const  return streambuf_.pbase(); 
  char* str() const  return pbase(); 

private:
  LogStream(const LogStream&);
  LogStream& operator=(const LogStream&);
  base_logging::LogStreamBuf streambuf_;
  int ctr_;  // Counter hack (for the LOG_EVERY_X() macro)
  LogStream *self_;  // Consistency check hack
;

typedef int LogSeverity;

//static Mutex log_mutex;

// Number of messages sent at each severity.  Under log_mutex.
//int64 LogMessage::num_messages_[NUM_SEVERITIES] =  0, 0, 0, 0 ;

// Globally disable log writing (if disk is full)
static bool stop_writing = false;

const char*const LogSeverityNames[NUM_SEVERITIES] = 
  "INFO", "WARNING", "ERROR", "FATAL"
;

// Has the user called SetExitOnDFatal(true)?
static bool exit_on_dfatal = true;

const char* GetLogSeverityName(LogSeverity severity) 
  return LogSeverityNames[severity];


typedef int pid_t;
#include <processthreadsapi.h>
pid_t GetTID() 
  return GetCurrentThreadId();


#include <iomanip>
class GOOGLE_GLOG_DLL_DECL LogSink 
public:
  virtual ~LogSink() 
  virtual void send(LogSeverity severity, const char* full_filename,
    const char* base_filename, int line,
    const struct ::tm* tm_time,
    const char* message, size_t message_len) = 0;
  virtual void WaitTillSent()
  
  static std::string ToString(LogSeverity severity, const char* file, int line,
    const struct ::tm* tm_time,
    const char* message, size_t message_len)
  
    ostringstream stream(string(message, message_len));
    stream.fill(0);

    // FIXME(jrvb): Updating this to use the correct value for usecs
    // requires changing the signature for both this method and
    // LogSink::send().  This change needs to be done in a separate CL
    // so subclasses of LogSink can be updated at the same time.
    int usecs = 0;

    stream << "[" << LogSeverityNames[severity][0]
      << setw(2) << 1 + tm_time->tm_mon
      << setw(2) << tm_time->tm_mday
      <<  
      << setw(2) << tm_time->tm_hour << :
      << setw(2) << tm_time->tm_min << :
      << setw(2) << tm_time->tm_sec << .
      << setw(6) << usecs
      <<  
      << setfill( ) << setw(5) << GetTID() << setfill(0)
      <<  
      << file << : << line << "] ";

    stream << string(message, message_len);
    GLog库

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