Decode trace symbols only when trace requested (GCC)

components/common/cpp/include/ftl/exception.hpp

@@ -7,29 +7,29 @@ namespace ftl {
 class Formatter {
 	public:
 	Formatter() {}
-    ~Formatter() {}
+	~Formatter() {}
 
-    template <typename Type>
-    inline Formatter & operator << (const Type & value)
-    {
-        stream_ << value;
-        return *this;
-    }
+	template <typename Type>
+	inline Formatter & operator << (const Type & value)
+	{
+		stream_ << value;
+		return *this;
+	}
 
-    inline std::string str() const         { return stream_.str(); }
-    inline operator std::string () const   { return stream_.str(); }
+	inline std::string str() const         { return stream_.str(); }
+	inline operator std::string () const   { return stream_.str(); }
 
-    enum ConvertToString 
-    {
-        to_str
-    };
-    inline std::string operator >> (ConvertToString) { return stream_.str(); }
+	enum ConvertToString
+	{
+		to_str
+	};
+	inline std::string operator >> (ConvertToString) { return stream_.str(); }
 
 private:
-    std::stringstream stream_;
+	std::stringstream stream_;
 
-    Formatter(const Formatter &);
-    Formatter & operator = (Formatter &);
+	Formatter(const Formatter &);
+	Formatter & operator = (Formatter &);
 };
 
 class exception : public std::exception
@@ -39,22 +39,30 @@ class exception : public std::exception
 	explicit exception(const Formatter &msg);
 	~exception();
 
-	const char * what () const throw () {
+	const char* what() const throw () {
 		processed_ = true;
-    	return msg_.c_str();
-    }
+		return msg_.c_str();
+	}
 
-    const char * trace () const throw () {
-        return trace_.c_str();
-    }
+	std::string trace() const throw () {
+		return decode_backtrace();
+	}
 
 	void ignore() const { processed_ = true; }
 
 	private:
+	std::string decode_backtrace() const;
+
 	std::string msg_;
-    std::string trace_;
 	mutable bool processed_;
+
+#ifdef __GNUC__
+	static const int TRACE_SIZE_MAX_ = 16;
+	void* trace_[TRACE_SIZE_MAX_];
+	int trace_size_;
+#endif
 };
+
 }
 
 #define FTL_Error(A) (ftl::exception(ftl::Formatter() << __FILE__ << ":" << __LINE__ << ": " << A))