tracer.h

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#ifndef CVMFS_TRACER_H_
#define CVMFS_TRACER_H_ 1

#include <inttypes.h>
#include <pthread.h>
#include <sys/time.h>

#include <cstdio>
#include <string>

#include "shortstring.h"
#include "util/atomic.h"
#include "util/single_copy.h"

class Tracer : SingleCopy {
 public:
  enum TraceEvents {
    kEventOpen = 1,
    kEventOpenDir,
    kEventReadlink,
    kEventLookup,
    kEventStatFs,
    kEventGetAttr,
    kEventListAttr,
    kEventGetXAttr
  };

  Tracer();
  ~Tracer();

  void Activate(const int buffer_size, const int flush_threshold,
                const std::string &trace_file);
  void Spawn();
  void Flush();
  void inline __attribute__((used)) Trace(const int event,
                                          const PathString &path,
                                          const std::string &msg)
  {
    if (active_) DoTrace(event, path, msg);
  }

  bool inline __attribute__((used)) IsActive() {
    return active_;
  }

 private:
  static const int kEventStart = -1;
  static const int kEventStop = -2;
  static const int kEventFlush = -3;

  struct BufferEntry {
    timeval time_stamp;
    int code;
    PathString path;  
    std::string msg;
  };

  static void *MainFlush(void *data);
  void GetTimespecRel(const int64_t ms, timespec *ts);
  int WriteCsvFile(FILE *fp, const std::string &field);
  int32_t DoTrace(const int event,
                  const PathString &path,
                  const std::string &msg);

  bool active_;
  bool spawned_;
  std::string trace_file_;
  int buffer_size_;
  int flush_threshold_;
  BufferEntry *ring_buffer_;
  atomic_int32 *commit_buffer_;
  pthread_t thread_flush_;
  pthread_cond_t sig_flush_;
  pthread_mutex_t sig_flush_mutex_;
  pthread_cond_t sig_continue_trace_;
  pthread_mutex_t sig_continue_trace_mutex_;
  atomic_int32 seq_no_;
  atomic_int32 flushed_;
  atomic_int32 terminate_flush_thread_;
  atomic_int32 flush_immediately_;
};

#endif  // CVMFS_TRACER_H_