serial_log.hpp

#if !defined(__SERIAL_LOG_HPP__)
#define __SERIAL_LOG_HPP__

//
// local includes
//
#include "serial_driver.hpp"

struct serial_log : public serial_driver, private noncopyable
{
    static const int DEFAULT_LINE_SIZE = 69;
    static const int MAX_LINE_SIZE     = 256;

  protected:
    int  line_size, prefix_size;
    char buffer[MAX_LINE_SIZE+1], *ptr;
    bool continued;

  public:
    inline serial_log(const int line_size=0, const char *prefix=nullptr)
        : continued(false)
    {
        set_line_size(line_size);
        prefix_size=prefix ? snprintf(buffer, MAX_LINE_SIZE, "%s | ", prefix) : 0;
        if (prefix_size >= MAX_LINE_SIZE) prefix_size=0;
        reset();
    }

    //
    // serial_driver: override name, reset & write
    //
    virtual inline const char *name(void) const
    {
        return L4VMM_DRIVER" LOG serial";
    }

    virtual inline int reset(void)
    {
        cr();
        continued=false;
        return 0;
    }

    virtual inline int write(const uint8_t c)
    {
        switch (c) {
            case '\b': if (ptr - buffer > prefix_size) ptr--; break;
            //
            // linux printk prints \r\n at the end of a line, so skip \r.
            //     do not reset the buffer. otherwise the line is lost.
            //
            case '\r': /* filtered out */     break;
            case '\n': nl(); continued=false; break;
            default:
                *ptr++=c;
                if (ptr - buffer >= line_size) nl(), continued=true;
            break;
        }

        return 0;
    }

    virtual inline void set_line_size(const int line_size=0)
    {
        if (line_size <= 0) this->line_size=DEFAULT_LINE_SIZE;
        else if (line_size > MAX_LINE_SIZE) this->line_size=MAX_LINE_SIZE;
        else this->line_size=line_size;
    }

  protected:
    inline void cr(void)
    {
        ptr=buffer + prefix_size;
    }

    inline void nl(void)
    {
        *ptr=0;
        if (prefix_size >= 2) buffer[prefix_size - 2]=continued ? ':' : '|';
        log::puts(buffer);
        cr();
    }
};

#endif

// ***** end of source ***** //