| 1 | /* |
| 2 | * This file is part of FFmpeg. |
| 3 | * |
| 4 | * FFmpeg is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU Lesser General Public |
| 6 | * License as published by the Free Software Foundation; either |
| 7 | * version 2.1 of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * FFmpeg is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | * Lesser General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU Lesser General Public |
| 15 | * License along with FFmpeg; if not, write to the Free Software |
| 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 17 | */ |
| 18 | |
| 19 | #include <stdint.h> |
| 20 | #include <string.h> |
| 21 | |
| 22 | #include "atomic.h" |
| 23 | #include "buffer_internal.h" |
| 24 | #include "common.h" |
| 25 | #include "mem.h" |
| 26 | #include "thread.h" |
| 27 | |
| 28 | AVBufferRef *av_buffer_create(uint8_t *data, int size, |
| 29 | void (*free)(void *opaque, uint8_t *data), |
| 30 | void *opaque, int flags) |
| 31 | { |
| 32 | AVBufferRef *ref = NULL; |
| 33 | AVBuffer *buf = NULL; |
| 34 | |
| 35 | buf = av_mallocz(sizeof(*buf)); |
| 36 | if (!buf) |
| 37 | return NULL; |
| 38 | |
| 39 | buf->data = data; |
| 40 | buf->size = size; |
| 41 | buf->free = free ? free : av_buffer_default_free; |
| 42 | buf->opaque = opaque; |
| 43 | buf->refcount = 1; |
| 44 | |
| 45 | if (flags & AV_BUFFER_FLAG_READONLY) |
| 46 | buf->flags |= BUFFER_FLAG_READONLY; |
| 47 | |
| 48 | ref = av_mallocz(sizeof(*ref)); |
| 49 | if (!ref) { |
| 50 | av_freep(&buf); |
| 51 | return NULL; |
| 52 | } |
| 53 | |
| 54 | ref->buffer = buf; |
| 55 | ref->data = data; |
| 56 | ref->size = size; |
| 57 | |
| 58 | return ref; |
| 59 | } |
| 60 | |
| 61 | void av_buffer_default_free(void *opaque, uint8_t *data) |
| 62 | { |
| 63 | av_free(data); |
| 64 | } |
| 65 | |
| 66 | AVBufferRef *av_buffer_alloc(int size) |
| 67 | { |
| 68 | AVBufferRef *ret = NULL; |
| 69 | uint8_t *data = NULL; |
| 70 | |
| 71 | data = av_malloc(size); |
| 72 | if (!data) |
| 73 | return NULL; |
| 74 | |
| 75 | ret = av_buffer_create(data, size, av_buffer_default_free, NULL, 0); |
| 76 | if (!ret) |
| 77 | av_freep(&data); |
| 78 | |
| 79 | return ret; |
| 80 | } |
| 81 | |
| 82 | AVBufferRef *av_buffer_allocz(int size) |
| 83 | { |
| 84 | AVBufferRef *ret = av_buffer_alloc(size); |
| 85 | if (!ret) |
| 86 | return NULL; |
| 87 | |
| 88 | memset(ret->data, 0, size); |
| 89 | return ret; |
| 90 | } |
| 91 | |
| 92 | AVBufferRef *av_buffer_ref(AVBufferRef *buf) |
| 93 | { |
| 94 | AVBufferRef *ret = av_mallocz(sizeof(*ret)); |
| 95 | |
| 96 | if (!ret) |
| 97 | return NULL; |
| 98 | |
| 99 | *ret = *buf; |
| 100 | |
| 101 | avpriv_atomic_int_add_and_fetch(&buf->buffer->refcount, 1); |
| 102 | |
| 103 | return ret; |
| 104 | } |
| 105 | |
| 106 | void av_buffer_unref(AVBufferRef **buf) |
| 107 | { |
| 108 | AVBuffer *b; |
| 109 | |
| 110 | if (!buf || !*buf) |
| 111 | return; |
| 112 | b = (*buf)->buffer; |
| 113 | av_freep(buf); |
| 114 | |
| 115 | if (!avpriv_atomic_int_add_and_fetch(&b->refcount, -1)) { |
| 116 | b->free(b->opaque, b->data); |
| 117 | av_freep(&b); |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | int av_buffer_is_writable(const AVBufferRef *buf) |
| 122 | { |
| 123 | if (buf->buffer->flags & AV_BUFFER_FLAG_READONLY) |
| 124 | return 0; |
| 125 | |
| 126 | return avpriv_atomic_int_get(&buf->buffer->refcount) == 1; |
| 127 | } |
| 128 | |
| 129 | void *av_buffer_get_opaque(const AVBufferRef *buf) |
| 130 | { |
| 131 | return buf->buffer->opaque; |
| 132 | } |
| 133 | |
| 134 | int av_buffer_get_ref_count(const AVBufferRef *buf) |
| 135 | { |
| 136 | return buf->buffer->refcount; |
| 137 | } |
| 138 | |
| 139 | int av_buffer_make_writable(AVBufferRef **pbuf) |
| 140 | { |
| 141 | AVBufferRef *newbuf, *buf = *pbuf; |
| 142 | |
| 143 | if (av_buffer_is_writable(buf)) |
| 144 | return 0; |
| 145 | |
| 146 | newbuf = av_buffer_alloc(buf->size); |
| 147 | if (!newbuf) |
| 148 | return AVERROR(ENOMEM); |
| 149 | |
| 150 | memcpy(newbuf->data, buf->data, buf->size); |
| 151 | av_buffer_unref(pbuf); |
| 152 | *pbuf = newbuf; |
| 153 | |
| 154 | return 0; |
| 155 | } |
| 156 | |
| 157 | int av_buffer_realloc(AVBufferRef **pbuf, int size) |
| 158 | { |
| 159 | AVBufferRef *buf = *pbuf; |
| 160 | uint8_t *tmp; |
| 161 | |
| 162 | if (!buf) { |
| 163 | /* allocate a new buffer with av_realloc(), so it will be reallocatable |
| 164 | * later */ |
| 165 | uint8_t *data = av_realloc(NULL, size); |
| 166 | if (!data) |
| 167 | return AVERROR(ENOMEM); |
| 168 | |
| 169 | buf = av_buffer_create(data, size, av_buffer_default_free, NULL, 0); |
| 170 | if (!buf) { |
| 171 | av_freep(&data); |
| 172 | return AVERROR(ENOMEM); |
| 173 | } |
| 174 | |
| 175 | buf->buffer->flags |= BUFFER_FLAG_REALLOCATABLE; |
| 176 | *pbuf = buf; |
| 177 | |
| 178 | return 0; |
| 179 | } else if (buf->size == size) |
| 180 | return 0; |
| 181 | |
| 182 | if (!(buf->buffer->flags & BUFFER_FLAG_REALLOCATABLE) || |
| 183 | !av_buffer_is_writable(buf)) { |
| 184 | /* cannot realloc, allocate a new reallocable buffer and copy data */ |
| 185 | AVBufferRef *new = NULL; |
| 186 | |
| 187 | av_buffer_realloc(&new, size); |
| 188 | if (!new) |
| 189 | return AVERROR(ENOMEM); |
| 190 | |
| 191 | memcpy(new->data, buf->data, FFMIN(size, buf->size)); |
| 192 | |
| 193 | av_buffer_unref(pbuf); |
| 194 | *pbuf = new; |
| 195 | return 0; |
| 196 | } |
| 197 | |
| 198 | tmp = av_realloc(buf->buffer->data, size); |
| 199 | if (!tmp) |
| 200 | return AVERROR(ENOMEM); |
| 201 | |
| 202 | buf->buffer->data = buf->data = tmp; |
| 203 | buf->buffer->size = buf->size = size; |
| 204 | return 0; |
| 205 | } |
| 206 | |
| 207 | AVBufferPool *av_buffer_pool_init(int size, AVBufferRef* (*alloc)(int size)) |
| 208 | { |
| 209 | AVBufferPool *pool = av_mallocz(sizeof(*pool)); |
| 210 | if (!pool) |
| 211 | return NULL; |
| 212 | |
| 213 | ff_mutex_init(&pool->mutex, NULL); |
| 214 | |
| 215 | pool->size = size; |
| 216 | pool->alloc = alloc ? alloc : av_buffer_alloc; |
| 217 | |
| 218 | avpriv_atomic_int_set(&pool->refcount, 1); |
| 219 | |
| 220 | return pool; |
| 221 | } |
| 222 | |
| 223 | /* |
| 224 | * This function gets called when the pool has been uninited and |
| 225 | * all the buffers returned to it. |
| 226 | */ |
| 227 | static void buffer_pool_free(AVBufferPool *pool) |
| 228 | { |
| 229 | while (pool->pool) { |
| 230 | BufferPoolEntry *buf = pool->pool; |
| 231 | pool->pool = buf->next; |
| 232 | |
| 233 | buf->free(buf->opaque, buf->data); |
| 234 | av_freep(&buf); |
| 235 | } |
| 236 | ff_mutex_destroy(&pool->mutex); |
| 237 | av_freep(&pool); |
| 238 | } |
| 239 | |
| 240 | void av_buffer_pool_uninit(AVBufferPool **ppool) |
| 241 | { |
| 242 | AVBufferPool *pool; |
| 243 | |
| 244 | if (!ppool || !*ppool) |
| 245 | return; |
| 246 | pool = *ppool; |
| 247 | *ppool = NULL; |
| 248 | |
| 249 | if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1)) |
| 250 | buffer_pool_free(pool); |
| 251 | } |
| 252 | |
| 253 | /* remove the whole buffer list from the pool and return it */ |
| 254 | static BufferPoolEntry *get_pool(AVBufferPool *pool) |
| 255 | { |
| 256 | BufferPoolEntry *cur = *(void * volatile *)&pool->pool, *last = NULL; |
| 257 | |
| 258 | while (cur != last) { |
| 259 | last = cur; |
| 260 | cur = avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, last, NULL); |
| 261 | if (!cur) |
| 262 | return NULL; |
| 263 | } |
| 264 | |
| 265 | return cur; |
| 266 | } |
| 267 | |
| 268 | static void add_to_pool(BufferPoolEntry *buf) |
| 269 | { |
| 270 | AVBufferPool *pool; |
| 271 | BufferPoolEntry *cur, *end = buf; |
| 272 | |
| 273 | if (!buf) |
| 274 | return; |
| 275 | pool = buf->pool; |
| 276 | |
| 277 | while (end->next) |
| 278 | end = end->next; |
| 279 | |
| 280 | while (avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, NULL, buf)) { |
| 281 | /* pool is not empty, retrieve it and append it to our list */ |
| 282 | cur = get_pool(pool); |
| 283 | end->next = cur; |
| 284 | while (end->next) |
| 285 | end = end->next; |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | static void pool_release_buffer(void *opaque, uint8_t *data) |
| 290 | { |
| 291 | BufferPoolEntry *buf = opaque; |
| 292 | AVBufferPool *pool = buf->pool; |
| 293 | |
| 294 | if(CONFIG_MEMORY_POISONING) |
| 295 | memset(buf->data, FF_MEMORY_POISON, pool->size); |
| 296 | |
| 297 | #if USE_ATOMICS |
| 298 | add_to_pool(buf); |
| 299 | #else |
| 300 | ff_mutex_lock(&pool->mutex); |
| 301 | buf->next = pool->pool; |
| 302 | pool->pool = buf; |
| 303 | ff_mutex_unlock(&pool->mutex); |
| 304 | #endif |
| 305 | |
| 306 | if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1)) |
| 307 | buffer_pool_free(pool); |
| 308 | } |
| 309 | |
| 310 | /* allocate a new buffer and override its free() callback so that |
| 311 | * it is returned to the pool on free */ |
| 312 | static AVBufferRef *pool_alloc_buffer(AVBufferPool *pool) |
| 313 | { |
| 314 | BufferPoolEntry *buf; |
| 315 | AVBufferRef *ret; |
| 316 | |
| 317 | ret = pool->alloc(pool->size); |
| 318 | if (!ret) |
| 319 | return NULL; |
| 320 | |
| 321 | buf = av_mallocz(sizeof(*buf)); |
| 322 | if (!buf) { |
| 323 | av_buffer_unref(&ret); |
| 324 | return NULL; |
| 325 | } |
| 326 | |
| 327 | buf->data = ret->buffer->data; |
| 328 | buf->opaque = ret->buffer->opaque; |
| 329 | buf->free = ret->buffer->free; |
| 330 | buf->pool = pool; |
| 331 | |
| 332 | ret->buffer->opaque = buf; |
| 333 | ret->buffer->free = pool_release_buffer; |
| 334 | |
| 335 | #if USE_ATOMICS |
| 336 | avpriv_atomic_int_add_and_fetch(&pool->refcount, 1); |
| 337 | avpriv_atomic_int_add_and_fetch(&pool->nb_allocated, 1); |
| 338 | #endif |
| 339 | |
| 340 | return ret; |
| 341 | } |
| 342 | |
| 343 | AVBufferRef *av_buffer_pool_get(AVBufferPool *pool) |
| 344 | { |
| 345 | AVBufferRef *ret; |
| 346 | BufferPoolEntry *buf; |
| 347 | |
| 348 | #if USE_ATOMICS |
| 349 | /* check whether the pool is empty */ |
| 350 | buf = get_pool(pool); |
| 351 | if (!buf && pool->refcount <= pool->nb_allocated) { |
| 352 | av_log(NULL, AV_LOG_DEBUG, "Pool race dectected, spining to avoid overallocation and eventual OOM\n"); |
| 353 | while (!buf && avpriv_atomic_int_get(&pool->refcount) <= avpriv_atomic_int_get(&pool->nb_allocated)) |
| 354 | buf = get_pool(pool); |
| 355 | } |
| 356 | |
| 357 | if (!buf) |
| 358 | return pool_alloc_buffer(pool); |
| 359 | |
| 360 | /* keep the first entry, return the rest of the list to the pool */ |
| 361 | add_to_pool(buf->next); |
| 362 | buf->next = NULL; |
| 363 | |
| 364 | ret = av_buffer_create(buf->data, pool->size, pool_release_buffer, |
| 365 | buf, 0); |
| 366 | if (!ret) { |
| 367 | add_to_pool(buf); |
| 368 | return NULL; |
| 369 | } |
| 370 | #else |
| 371 | ff_mutex_lock(&pool->mutex); |
| 372 | buf = pool->pool; |
| 373 | if (buf) { |
| 374 | ret = av_buffer_create(buf->data, pool->size, pool_release_buffer, |
| 375 | buf, 0); |
| 376 | if (ret) { |
| 377 | pool->pool = buf->next; |
| 378 | buf->next = NULL; |
| 379 | } |
| 380 | } else { |
| 381 | ret = pool_alloc_buffer(pool); |
| 382 | } |
| 383 | ff_mutex_unlock(&pool->mutex); |
| 384 | #endif |
| 385 | |
| 386 | if (ret) |
| 387 | avpriv_atomic_int_add_and_fetch(&pool->refcount, 1); |
| 388 | |
| 389 | return ret; |
| 390 | } |