/////////////////////////////////////////////////
// MT3Q1.cpp - Tracer                          //
//                                             //
// Jim Fawcett, CSE687 - Midterm, Spring 2010  //
/////////////////////////////////////////////////

#include <string>
#include <iostream>
#include <sstream>

class tracer : private std::ostringstream  // Made private as ostringstream
{                                          // doesn't provide virtual functions
public:                                    // so won't support polymorphism.
  tracer(const std::string& name) 
  { 
    *this << "\nstarting: " << (name_ = name); 
    log.append(this->std::ostringstream::str());
    this->std::ostringstream::str("");
  }
  ~tracer()
  { 
    *this << "\nending: " << name_;
    log.append(this->std::ostringstream::str());
  }
  template<class T>
  tracer& operator<<(const T& t)
  {
    std::ostringstream& rStr = *this;
    rStr << t;
    log.append(this->std::ostringstream::str());
    this->std::ostringstream::str("");
    return *this;
  }
  std::string& str() { return log; }
private:
  static std::string log;
  std::string name_;
};

std::string tracer::log = "";

std::ostream& operator<<(std::ostream& out, tracer& tr)
{
  out << tr.str().c_str();
  return out;
}

void fun2(const std::string& say)
{
  tracer t("fun2");
  t << "\n  argument = " << say;
}
void fun1()
{
  tracer t("fun1");
  std::string s = "my local string";
  int count = 3;
  t << "\n  " << s << ", my count = " << count;
  fun2("hello cse687");
}

class global  // created this global object so we
{             // see main's exit
public:
  global() : t_("global") {}
  // here's where we show log
  ~global() { std::cout << t_ << "\n\n"; }
private:
  tracer t_;
} glob;

void main()
{
  std::cout << "\n  MT3Q1 - Tracer";
  std::cout << "\n ================";

  tracer t("main");
  fun1();

  // uncomment if you decide not to use global tracer
  // std::cout << t << "\n\n";
}