lsquic_spi.h revision 7d09751d 
1/* Copyright (c) 2017 - 2020 LiteSpeed Technologies Inc.  See LICENSE. */
2/*
3 * lsquic_spi.h - SPI: Stream Priority Iterator
4 *
5 * SPI purposefully does not support switching stream priorities while
6 * iterator is active, because this puts iteration termination outside
7 * of our control.  One can imagine (admittedly theoretical) scenario
8 * in which the user keeps on switching stream priorities around and
9 * causing an infinite loop.
10 */
11
12#ifndef LSQUIC_SPI
13#define LSQUIC_SPI 1
14
15#include <stdint.h>
16
17enum stream_q_flags;
18
19
20struct stream_prio_iter
21{
22    const struct lsquic_conn       *spi_conn;           /* Used for logging */
23    const char                     *spi_name;           /* Used for logging */
24    uint64_t                        spi_set[4];         /* 256 bits */
25    enum stream_q_flags             spi_onlist_mask;
26    unsigned                        spi_n_added;
27    unsigned char                   spi_cur_prio;
28    unsigned char                   spi_prev_prio;
29    struct lsquic_stream           *spi_prev_stream,
30                                   *spi_next_stream;
31    struct lsquic_streams_tailq     spi_streams[256];
32};
33
34
35void
36lsquic_spi_init (struct stream_prio_iter *, struct lsquic_stream *first,
37         struct lsquic_stream *last, uintptr_t next_ptr_offset,
38         enum stream_q_flags onlist_mask, const struct lsquic_conn *,
39         const char *name,
40         int (*filter)(void *filter_ctx, struct lsquic_stream *),
41         void *filter_ctx);
42
43struct lsquic_stream *
44lsquic_spi_first (struct stream_prio_iter *);
45
46struct lsquic_stream *
47lsquic_spi_next (struct stream_prio_iter *);
48
49void
50lsquic_spi_exhaust_on (struct stream_prio_iter *);
51
52void
53lsquic_spi_drop_non_high (struct stream_prio_iter *);
54
55void
56lsquic_spi_drop_high (struct stream_prio_iter *);
57
58#endif
59