aboutsummaryrefslogtreecommitdiffhomepage
path: root/stream/cache_file.c
blob: 94b3f4bda22bdb9def9337c35a57f9734c6467df (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
/*
 * This file is part of mpv.
 *
 * mpv is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * mpv is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with mpv.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <stdio.h>
#include <stdint.h>

#include "osdep/io.h"

#include "common/common.h"
#include "common/msg.h"

#include "options/options.h"

#include "stream.h"

#define BLOCK_SIZE 1024LL
#define BLOCK_ALIGN(p) ((p) & ~(BLOCK_SIZE - 1))

struct priv {
    struct stream *original;
    FILE *cache_file;
    uint8_t *block_bits;    // 1 bit for each BLOCK_SIZE, whether block was read
    int64_t size;           // currently known size
    int64_t max_size;       // max. size for block_bits and cache_file
};

static bool test_bit(struct priv *p, int64_t pos)
{
    if (pos < 0 || pos >= p->size)
        return false;
    size_t block = pos / BLOCK_SIZE;
    return p->block_bits[block / 8] & (1 << (block % 8));
}

static void set_bit(struct priv *p, int64_t pos, bool bit)
{
    if (pos < 0 || pos >= p->size)
        return;
    size_t block = pos / BLOCK_SIZE;
    unsigned int m = (1 << (block % 8));
    p->block_bits[block / 8] = (p->block_bits[block / 8] & ~m) | (bit ? m : 0);
}

static int fill_buffer(stream_t *s, char *buffer, int max_len)
{
    struct priv *p = s->priv;
    if (s->pos < 0)
        return -1;
    if (s->pos >= p->max_size) {
        if (stream_seek(p->original, s->pos) < 1)
            return -1;
        return stream_read(p->original, buffer, max_len);
    }
    // Size of file changes -> invalidate last block
    if (s->pos >= p->size - BLOCK_SIZE) {
        int64_t new_size = -1;
        stream_control(s, STREAM_CTRL_GET_SIZE, &new_size);
        if (p->size >= 0 && new_size != p->size)
            set_bit(p, BLOCK_ALIGN(p->size), 0);
        p->size = MPMIN(p->max_size, new_size);
    }
    int64_t aligned = BLOCK_ALIGN(s->pos);
    if (!test_bit(p, aligned)) {
        char tmp[BLOCK_SIZE];
        stream_seek(p->original, aligned);
        int r = stream_read(p->original, tmp, BLOCK_SIZE);
        if (r < BLOCK_SIZE) {
            if (p->size < 0) {
                MP_WARN(s, "suspected EOF\n");
            } else if (aligned + r < p->size) {
                MP_ERR(s, "unexpected EOF\n");
                return -1;
            }
        }
        if (fseeko(p->cache_file, aligned, SEEK_SET))
            return -1;
        if (fwrite(tmp, r, 1, p->cache_file) != 1)
            return -1;
        set_bit(p, aligned, 1);
    }
    if (fseeko(p->cache_file, s->pos, SEEK_SET))
        return -1;
    // align/limit to blocks
    max_len = MPMIN(max_len, BLOCK_SIZE - (s->pos % BLOCK_SIZE));
    // Limit to max. known file size
    if (p->size >= 0)
        max_len = MPMIN(max_len, p->size - s->pos);
    return fread(buffer, 1, max_len, p->cache_file);
}

static int seek(stream_t *s, int64_t newpos)
{
    return 1;
}

static int control(stream_t *s, int cmd, void *arg)
{
    struct priv *p = s->priv;
    return stream_control(p->original, cmd, arg);
}

static void s_close(stream_t *s)
{
    struct priv *p = s->priv;
    if (p->cache_file)
        fclose(p->cache_file);
    talloc_free(p);
}

// return 1 on success, 0 if disabled, -1 on error
int stream_file_cache_init(stream_t *cache, stream_t *stream,
                           struct mp_cache_opts *opts)
{
    if (!opts->file || !opts->file[0] || opts->file_max < 1)
        return 0;

    if (!stream->seekable) {
        MP_ERR(cache, "can't cache unseekable stream\n");
        return -1;
    }

    bool use_anon_file = strcmp(opts->file, "TMP") == 0;
    FILE *file = use_anon_file ? tmpfile() : fopen(opts->file, "wb+");
    if (!file) {
        MP_ERR(cache, "can't open cache file '%s'\n", opts->file);
        return -1;
    }

    struct priv *p = talloc_zero(NULL, struct priv);

    cache->priv = p;
    p->original = stream;
    p->cache_file = file;
    p->max_size = opts->file_max * 1024LL;

    // file_max can be INT_MAX, so this is at most about 256MB
    p->block_bits = talloc_zero_size(p, (p->max_size / BLOCK_SIZE + 1) / 8 + 1);

    cache->seek = seek;
    cache->fill_buffer = fill_buffer;
    cache->control = control;
    cache->close = s_close;

    return 1;
}