Method info

src/brpc/span.h:195–198

Returns a copy instead of a reference for thread safety. Current usage: Only called by Span2Proto() which immediately passes the result to protobuf's set_info(). In this specific scenario, returning a reference would also be safe because set_info() copies the string before the reference could be invalidated by concurrent Annotate() calls. However, returning by value is more robust: it prevents p

    // future code holds the reference longer, and has no performance penalty due to
    // C++11 move semantics (the temporary is moved, not copied, into protobuf).
    std::string info() const { 
        BAIDU_SCOPED_LOCK(_info_spinlock);
        return _info; 
    }
    
private:
    DISALLOW_COPY_AND_ASSIGN(Span);