[Qemu-devel] Re: [RFC][PATCH v5 04/21] virtagent: transport definitions and job callbacks

[Michael Roth]

On 12/06/2010 04:02 PM, Adam Litke wrote:
> On Fri, 2010-12-03 at 12:03 -0600, Michael Roth wrote:
> > +static void va_http_send_handler(void *opaque)
> > +{
> > +    VAHTState *s =&va_state->send_state;
> > +    enum va_http_status http_status;
> > +    int fd = va_state->fd;
> > +    int ret;
> > +
> > +    TRACE("called, fd: %d", fd);
> > +
> > +    switch (s->state) {
>
> Why is there a VA_SEND_START state when it always falls through to
> VA_SEND_HDR?  Is there any difference between these?

Nope, not at the moment. I'll stick with just _HDR for now, but if we 
ever need to do some initialization or anything before we start 
sending/reading that's what this would be for.

> > +    case VA_SEND_START:
> > +        s->state = VA_SEND_HDR;
> > +    case VA_SEND_HDR:
> > +        do {
> > +            ret = write(fd, s->hdr + s->hdr_pos, s->hdr_len - s->hdr_pos);
> > +            if (ret<= 0) {
> > +                break;
> > +            }
> > +            s->hdr_pos += ret;
> > +        } while (s->hdr_pos<  s->hdr_len);
> > +        if (ret == -1) {
> > +            if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {
> > +                return;
> > +            } else {
> > +                LOG("error writing header: %s", strerror(errno));
> > +                goto out_bad;
> > +            }
> > +        } else if (ret == 0) {
> > +            LOG("connected closed unexpectedly");
> > +            goto out_bad;
> > +        } else {
> > +            s->state = VA_SEND_BODY;
> > +        }
> > +    case VA_SEND_BODY:
> > +        do {
> > +            ret = write(fd, s->content + s->content_pos,
> > +                        s->content_len - s->content_pos);
> > +            if (ret<= 0) {
> > +                break;
> > +            }
> > +            s->content_pos += ret;
> > +        } while (s->content_pos<  s->content_len);
> > +        if (ret == -1) {
> > +            if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {
> > +                return;
> > +            } else {
> > +                LOG("error writing content: %s", strerror(errno));
> > +                goto out_bad;
> > +            }
> > +        } else if (ret == 0) {
> > +            LOG("connected closed unexpectedly");
> > +            goto out_bad;
> > +        } else {
> > +            http_status = VA_HTTP_STATUS_OK;
> > +            goto out;
> > +        }
> > +    default:
> > +        LOG("unknown state");
> > +        goto out_bad;
> > +    }
> > +
> > +out_bad:
> > +    http_status = VA_HTTP_STATUS_ERROR;
> > +out:
> > +    s->send_cb(http_status, s->content, s->content_len);
> > +    qemu_set_fd_handler(fd, va_http_read_handler, NULL, NULL);
> > +}