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

[Michael Roth <mdroth@linux.vnet.ibm.com>]

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);
>> +}
>