On Mon, Jan 31, 2022 at 01:18:32PM +0300, Vladimir Homutov wrote:
> On Mon, Jan 31, 2022 at 10:34:06AM +0300, Roman Arutyunyan wrote:
> > # HG changeset patch
> > # User Roman Arutyunyan <arut@nginx.com>
> > # Date 1643611562 -10800
> > # Mon Jan 31 09:46:02 2022 +0300
> > # Branch quic
> > # Node ID 8dcb9908989401d750b14fe5dccf444a5485c23d
> > # Parent 81a3429db8b00ec9fc476d3687d1cd18088f3365
> > QUIC: introduced explicit stream states.
> >
> > This allows to eliminate the usage of stream connection event flags for tracking
> > stream state.
> >
> > diff --git a/src/event/quic/ngx_event_quic.h b/src/event/quic/ngx_event_quic.h
> > --- a/src/event/quic/ngx_event_quic.h
> > +++ b/src/event/quic/ngx_event_quic.h
> > @@ -28,6 +28,26 @@
> > #define NGX_QUIC_STREAM_UNIDIRECTIONAL 0x02
> >
> >
> > +typedef enum {
> > + NGX_QUIC_STREAM_SEND_READY = 0,
> > + NGX_QUIC_STREAM_SEND_SEND,
> > + NGX_QUIC_STREAM_SEND_DATA_SENT,
> > + NGX_QUIC_STREAM_SEND_DATA_RECVD,
> > + NGX_QUIC_STREAM_SEND_RESET_SENT,
> > + NGX_QUIC_STREAM_SEND_RESET_RECVD
> > +} ngx_quic_stream_send_state_e;
> > +
> > +
> > +typedef enum {
> > + NGX_QUIC_STREAM_RECV_RECV = 0,
> > + NGX_QUIC_STREAM_RECV_SIZE_KNOWN,
> > + NGX_QUIC_STREAM_RECV_DATA_RECVD,
> > + NGX_QUIC_STREAM_RECV_DATA_READ,
> > + NGX_QUIC_STREAM_RECV_RESET_RECVD,
> > + NGX_QUIC_STREAM_RECV_RESET_READ
> > +} ngx_quic_stream_recv_state_e;
> > +
> > +
> > typedef struct {
> > ngx_ssl_t *ssl;
> >
> > @@ -66,6 +86,8 @@ struct ngx_quic_stream_s {
> > ngx_chain_t *in;
> > ngx_chain_t *out;
> > ngx_uint_t cancelable; /* unsigned cancelable:1; */
> > + ngx_quic_stream_send_state_e send_state;
> > + ngx_quic_stream_recv_state_e recv_state;
> > };
>
> let's fix this little style incosistency in a separate patch by moving
> all struct stuff to the right.

OK, added a patch for this.

> [..]
>
> > @@ -780,8 +764,23 @@ ngx_quic_stream_recv(ngx_connection_t *c
> >
> > ngx_quic_free_chain(pc, in);
> >
> > - if (qs->in == NULL) {
> > - rev->ready = rev->pending_eof;
> > + if (len == 0) {
>
> this also covers the case when ngx_quic_stream_recv() is called
> with zero-length buffer. Not sure what semantic should be implemented.
>
> man 2 read says:
>
> If count is zero, read() may detect the errors described below. In
> the absence of any errors, or if read() does not check for errors, a
> read() with a count of 0 returns zero and has no other effects.
>
> i.e. if we have data in buffer, but we are called with zero, we should
> not change state probably and handle this case separately.

You're right, now handling this case separately.

> > + rev->ready = 0;
> > +
> > + if (qs->recv_state == NGX_QUIC_STREAM_RECV_SIZE_KNOWN
> > + && qs->recv_offset == qs->final_size)
> > + {
> > + qs->recv_state = NGX_QUIC_STREAM_RECV_DATA_READ;
> > + }
> > +
> > + if (qs->recv_state == NGX_QUIC_STREAM_RECV_DATA_READ) {
> > + rev->eof = 1;
> > + return 0;
> > + }
> > +
> > + ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
> > + "quic stream id:0x%xL recv() not ready", qs->id);
> > + return NGX_AGAIN;
> > }
> >
> > ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
>
>
> side note: while looking at state transitions, i've realized we never send
> STREAM_DATA_BLOCKED and DATA_BLOCKED.
>
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--
Roman Arutyunyan
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