lsquic_spi.h revision 50aadb33 
1/* Copyright (c) 2017 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 spi_flags {
18    SPI_EXHAUST_PRIO = (1 << 0), /* Exhaust priority level before moving on */
19};
20
21
22struct stream_prio_iter
23{
24    lsquic_cid_t                    spi_cid;            /* Used for logging */
25    const char                     *spi_name;           /* Used for logging */
26    uint64_t                        spi_set[4];         /* 256 bits */
27    enum stream_flags               spi_onlist_mask;
28    enum spi_flags                  spi_flags:8;
29    unsigned char                   spi_cur_prio;
30    unsigned char                   spi_prev_prio;
31    struct lsquic_stream           *spi_prev_stream,
32                                   *spi_next_stream;
33    struct lsquic_streams_tailq     spi_streams[256];
34};
35
36
37void
38lsquic_spi_init_ext (struct stream_prio_iter *, struct lsquic_stream *first,
39         struct lsquic_stream *last, uintptr_t next_ptr_offset,
40         unsigned onlist_mask, int (*filter)(void *, struct lsquic_stream *),
41         void *filter_ctx, lsquic_cid_t cid, const char *name);
42
43#define lsquic_spi_init(spi, first, last, off, mask, cid, name) \
44        lsquic_spi_init_ext(spi, first, last, off, mask, NULL, NULL, cid, name)
45
46#define lsquic_spi_init_simple(spi, first, last, off, mask) \
47        lsquic_spi_init(spi, first, last, off, mask, 0, NULL)
48
49struct lsquic_stream *
50lsquic_spi_first (struct stream_prio_iter *);
51
52struct lsquic_stream *
53lsquic_spi_next (struct stream_prio_iter *);
54
55void
56lsquic_spi_exhaust_on (struct stream_prio_iter *);
57
58#endif
59