#ifndef __ThreadSafeLogging_ah__
#define __ThreadSafeLogging_ah__

#include <stdio.h>
#include <pthread.h>

#include "Log.h"

// This example illustrates how to use the aspectof() function
// to implement thread-local aspects with the pthread library
// or others that support thread-local storage in a similiar way.

// The beginning looks quite normal ...
aspect ThreadSafeLogging {

  int _execs;    // thread local function execution counter
  int _indent;   // per thread indentation of the log

  advice execution ("% TestClass::%(...)") : before () {
    _execs++;
    Log::instance ().print (_indent, true, JoinPoint::signature ());
    _indent++;
  }

  advice execution ("% TestClass::%(...)") : after () {
    _indent--;
    Log::instance ().print (_indent, false, JoinPoint::signature ());
  }

public:

  ThreadSafeLogging () : _execs (0), _indent (0) {}

  ~ThreadSafeLogging () {
    printf ("aspect %p counted %d\n", this, _execs);
  }

  // Here comes the magic: aspectof() is called at each joinpoint in
  // order to determine the aspect instrance to be used for the
  // advice invocation.
  // The following definition retrieves a thread-local aspect instance
  // pointer. If it is still NULL, an aspect object is created and assigned.

  static ThreadSafeLogging *aspectof() {
    extern pthread_key_t tls_aspects_key;
    
    ThreadSafeLogging *me =
      (ThreadSafeLogging*)pthread_getspecific (tls_aspects_key);
    if (!me) {
      me = new ThreadSafeLogging;
      pthread_setspecific (tls_aspects_key, me);
      printf ("created aspect instance %p\n", me);
    }
    return me;
  }

  static void init () {
    extern pthread_key_t tls_aspects_key;

    // create a key for thread-local storage
    pthread_key_create(&tls_aspects_key, &ThreadSafeLogging::destructor);
  }

  // We passed this function to pthread_key_create as a destructor function.
  // It is called by the pthread library when the thread terminates.

  static void destructor (void *me) {
    delete (ThreadSafeLogging*)me;
    printf ("destroyed aspect instance %p\n", me);
  }

};

#endif // __ThreadSafeLogging_ah__