FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavformat/cache.c
Date: 2022-12-06 04:36:11
Exec Total Coverage
Lines: 117 154 76.0%
Functions: 7 7 100.0%
Branches: 59 106 55.7%

Line Branch Exec Source
1 /*
2 * Input cache protocol.
3 * Copyright (c) 2011,2014 Michael Niedermayer
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 *
21 * Based on file.c by Fabrice Bellard
22 */
23
24 /**
25 * @TODO
26 * support keeping files
27 * support filling with a background thread
28 */
29
30 #include "libavutil/avassert.h"
31 #include "libavutil/avstring.h"
32 #include "libavutil/file_open.h"
33 #include "libavutil/opt.h"
34 #include "libavutil/tree.h"
35 #include "avio.h"
36 #include <fcntl.h>
37 #if HAVE_IO_H
38 #include <io.h>
39 #endif
40 #if HAVE_UNISTD_H
41 #include <unistd.h>
42 #endif
43 #include <sys/stat.h>
44 #include <stdlib.h>
45 #include "os_support.h"
46 #include "url.h"
47
48 typedef struct CacheEntry {
49 int64_t logical_pos;
50 int64_t physical_pos;
51 int size;
52 } CacheEntry;
53
54 typedef struct Context {
55 AVClass *class;
56 int fd;
57 char *filename;
58 struct AVTreeNode *root;
59 int64_t logical_pos;
60 int64_t cache_pos;
61 int64_t inner_pos;
62 int64_t end;
63 int is_true_eof;
64 URLContext *inner;
65 int64_t cache_hit, cache_miss;
66 int read_ahead_limit;
67 } Context;
68
69 33 static int cmp(const void *key, const void *node)
70 {
71 33 return FFDIFFSIGN(*(const int64_t *)key, ((const CacheEntry *) node)->logical_pos);
72 }
73
74 1 static int cache_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
75 {
76 int ret;
77 char *buffername;
78 1 Context *c= h->priv_data;
79
80 1 av_strstart(arg, "cache:", &arg);
81
82 1 c->fd = avpriv_tempfile("ffcache", &buffername, 0, h);
83
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1 if (c->fd < 0){
84 av_log(h, AV_LOG_ERROR, "Failed to create tempfile\n");
85 return c->fd;
86 }
87
88 1 ret = unlink(buffername);
89
90
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1 if (ret >= 0)
91 1 av_freep(&buffername);
92 else
93 c->filename = buffername;
94
95 1 return ffurl_open_whitelist(&c->inner, arg, flags, &h->interrupt_callback,
96 options, h->protocol_whitelist, h->protocol_blacklist, h);
97 }
98
99 8 static int add_entry(URLContext *h, const unsigned char *buf, int size)
100 {
101 8 Context *c= h->priv_data;
102 8 int64_t pos = -1;
103 int ret;
104 8 CacheEntry *entry = NULL, *next[2] = {NULL, NULL};
105 CacheEntry *entry_ret;
106 8 struct AVTreeNode *node = NULL;
107
108 //FIXME avoid lseek
109 8 pos = lseek(c->fd, 0, SEEK_END);
110
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8 if (pos < 0) {
111 ret = AVERROR(errno);
112 av_log(h, AV_LOG_ERROR, "seek in cache failed\n");
113 goto fail;
114 }
115 8 c->cache_pos = pos;
116
117 8 ret = write(c->fd, buf, size);
118
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8 if (ret < 0) {
119 ret = AVERROR(errno);
120 av_log(h, AV_LOG_ERROR, "write in cache failed\n");
121 goto fail;
122 }
123 8 c->cache_pos += ret;
124
125 8 entry = av_tree_find(c->root, &c->logical_pos, cmp, (void**)next);
126
127
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8 if (!entry)
128 8 entry = next[0];
129
130
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8 if (!entry ||
131
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7 entry->logical_pos + entry->size != c->logical_pos ||
132
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7 entry->physical_pos + entry->size != pos
133 ) {
134 1 entry = av_malloc(sizeof(*entry));
135 1 node = av_tree_node_alloc();
136
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1 if (!entry || !node) {
137 ret = AVERROR(ENOMEM);
138 goto fail;
139 }
140 1 entry->logical_pos = c->logical_pos;
141 1 entry->physical_pos = pos;
142 1 entry->size = ret;
143
144 1 entry_ret = av_tree_insert(&c->root, entry, cmp, &node);
145
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1 if (entry_ret && entry_ret != entry) {
146 ret = -1;
147 av_log(h, AV_LOG_ERROR, "av_tree_insert failed\n");
148 goto fail;
149 }
150 } else
151 7 entry->size += ret;
152
153 8 return 0;
154 fail:
155 //we could truncate the file to pos here if pos >=0 but ftruncate isn't available in VS so
156 //for simplicty we just leave the file a bit larger
157 av_free(entry);
158 av_free(node);
159 return ret;
160 }
161
162 27 static int cache_read(URLContext *h, unsigned char *buf, int size)
163 {
164 27 Context *c= h->priv_data;
165 27 CacheEntry *entry, *next[2] = {NULL, NULL};
166 int64_t r;
167
168 27 entry = av_tree_find(c->root, &c->logical_pos, cmp, (void**)next);
169
170
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27 if (!entry)
171 21 entry = next[0];
172
173
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27 if (entry) {
174 26 int64_t in_block_pos = c->logical_pos - entry->logical_pos;
175
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26 av_assert0(entry->logical_pos <= c->logical_pos);
176
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26 if (in_block_pos < entry->size) {
177 18 int64_t physical_target = entry->physical_pos + in_block_pos;
178
179
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18 if (c->cache_pos != physical_target) {
180 13 r = lseek(c->fd, physical_target, SEEK_SET);
181 } else
182 5 r = c->cache_pos;
183
184
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18 if (r >= 0) {
185 18 c->cache_pos = r;
186 18 r = read(c->fd, buf, FFMIN(size, entry->size - in_block_pos));
187 }
188
189
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18 if (r > 0) {
190 18 c->cache_pos += r;
191 18 c->logical_pos += r;
192 18 c->cache_hit ++;
193 18 return r;
194 }
195 }
196 }
197
198 // Cache miss or some kind of fault with the cache
199
200
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9 if (c->logical_pos != c->inner_pos) {
201 r = ffurl_seek(c->inner, c->logical_pos, SEEK_SET);
202 if (r<0) {
203 av_log(h, AV_LOG_ERROR, "Failed to perform internal seek\n");
204 return r;
205 }
206 c->inner_pos = r;
207 }
208
209 9 r = ffurl_read(c->inner, buf, size);
210
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9 if (r == AVERROR_EOF && size>0) {
211 1 c->is_true_eof = 1;
212
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1 av_assert0(c->end >= c->logical_pos);
213 }
214
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9 if (r<=0)
215 1 return r;
216 8 c->inner_pos += r;
217
218 8 c->cache_miss ++;
219
220 8 add_entry(h, buf, r);
221 8 c->logical_pos += r;
222 8 c->end = FFMAX(c->end, c->logical_pos);
223
224 8 return r;
225 }
226
227 27 static int64_t cache_seek(URLContext *h, int64_t pos, int whence)
228 {
229 27 Context *c= h->priv_data;
230 int64_t ret;
231
232
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27 if (whence == AVSEEK_SIZE) {
233 5 pos= ffurl_seek(c->inner, pos, whence);
234
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5 if(pos <= 0){
235 5 pos= ffurl_seek(c->inner, -1, SEEK_END);
236
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5 if (ffurl_seek(c->inner, c->inner_pos, SEEK_SET) < 0)
237 5 av_log(h, AV_LOG_ERROR, "Inner protocol failed to seekback end : %"PRId64"\n", pos);
238 }
239
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5 if (pos > 0)
240 c->is_true_eof = 1;
241 5 c->end = FFMAX(c->end, pos);
242 5 return pos;
243 }
244
245
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22 if (whence == SEEK_CUR) {
246 whence = SEEK_SET;
247 pos += c->logical_pos;
248
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22 } else if (whence == SEEK_END && c->is_true_eof) {
249 4 resolve_eof:
250 5 whence = SEEK_SET;
251 5 pos += c->end;
252 }
253
254
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23 if (whence == SEEK_SET && pos >= 0 && pos < c->end) {
255 //Seems within filesize, assume it will not fail.
256 22 c->logical_pos = pos;
257 22 return pos;
258 }
259
260 //cache miss
261 1 ret= ffurl_seek(c->inner, pos, whence);
262
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1 if ((whence == SEEK_SET && pos >= c->logical_pos ||
263
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1 whence == SEEK_END && pos <= 0) && ret < 0) {
264
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1 if ( (whence == SEEK_SET && c->read_ahead_limit >= pos - c->logical_pos)
265
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1 || c->read_ahead_limit < 0) {
266 uint8_t tmp[32768];
267
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8 while (c->logical_pos < pos || whence == SEEK_END) {
268 8 int size = sizeof(tmp);
269
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8 if (whence == SEEK_SET)
270 size = FFMIN(sizeof(tmp), pos - c->logical_pos);
271 8 ret = cache_read(h, tmp, size);
272
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8 if (ret == AVERROR_EOF && whence == SEEK_END) {
273
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1 av_assert0(c->is_true_eof);
274 1 goto resolve_eof;
275 }
276
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7 if (ret < 0) {
277 return ret;
278 }
279 }
280 return c->logical_pos;
281 }
282 }
283
284 if (ret >= 0) {
285 c->logical_pos = ret;
286 c->end = FFMAX(c->end, ret);
287 }
288
289 return ret;
290 }
291
292 1 static int enu_free(void *opaque, void *elem)
293 {
294 1 av_free(elem);
295 1 return 0;
296 }
297
298 1 static int cache_close(URLContext *h)
299 {
300 1 Context *c= h->priv_data;
301 int ret;
302
303 1 av_log(h, AV_LOG_INFO, "Statistics, cache hits:%"PRId64" cache misses:%"PRId64"\n",
304 c->cache_hit, c->cache_miss);
305
306 1 close(c->fd);
307
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1 if (c->filename) {
308 ret = unlink(c->filename);
309 if (ret < 0)
310 av_log(h, AV_LOG_ERROR, "Could not delete %s.\n", c->filename);
311 av_freep(&c->filename);
312 }
313 1 ffurl_closep(&c->inner);
314 1 av_tree_enumerate(c->root, NULL, NULL, enu_free);
315 1 av_tree_destroy(c->root);
316
317 1 return 0;
318 }
319
320 #define OFFSET(x) offsetof(Context, x)
321 #define D AV_OPT_FLAG_DECODING_PARAM
322
323 static const AVOption options[] = {
324 { "read_ahead_limit", "Amount in bytes that may be read ahead when seeking isn't supported, -1 for unlimited", OFFSET(read_ahead_limit), AV_OPT_TYPE_INT, { .i64 = 65536 }, -1, INT_MAX, D },
325 {NULL},
326 };
327
328 static const AVClass cache_context_class = {
329 .class_name = "cache",
330 .item_name = av_default_item_name,
331 .option = options,
332 .version = LIBAVUTIL_VERSION_INT,
333 };
334
335 const URLProtocol ff_cache_protocol = {
336 .name = "cache",
337 .url_open2 = cache_open,
338 .url_read = cache_read,
339 .url_seek = cache_seek,
340 .url_close = cache_close,
341 .priv_data_size = sizeof(Context),
342 .priv_data_class = &cache_context_class,
343 };
344