lsquic_spi.h revision 10c492f0 
1/* Copyright (c) 2017 - 2018 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
17
18struct stream_prio_iter
19{
20    lsquic_cid_t                    spi_cid;            /* Used for logging */
21    const char                     *spi_name;           /* Used for logging */
22    uint64_t                        spi_set[4];         /* 256 bits */
23    enum stream_flags               spi_onlist_mask;
24    unsigned char                   spi_cur_prio;
25    unsigned char                   spi_prev_prio;
26    struct lsquic_stream           *spi_prev_stream,
27                                   *spi_next_stream;
28    struct lsquic_streams_tailq     spi_streams[256];
29};
30
31
32void
33lsquic_spi_init (struct stream_prio_iter *, struct lsquic_stream *first,
34         struct lsquic_stream *last, uintptr_t next_ptr_offset,
35         unsigned onlist_mask, lsquic_cid_t cid, const char *name);
36
37struct lsquic_stream *
38lsquic_spi_first (struct stream_prio_iter *);
39
40struct lsquic_stream *
41lsquic_spi_next (struct stream_prio_iter *);
42
43void
44lsquic_spi_exhaust_on (struct stream_prio_iter *);
45
46void
47lsquic_spi_drop_non_high (struct stream_prio_iter *);
48
49void
50lsquic_spi_drop_high (struct stream_prio_iter *);
51
52#endif
53