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-rw-r--r--libavformat/cache.c330
1 files changed, 330 insertions, 0 deletions
diff --git a/libavformat/cache.c b/libavformat/cache.c
new file mode 100644
index 0000000000..6aabca2e78
--- /dev/null
+++ b/libavformat/cache.c
@@ -0,0 +1,330 @@
+/*
+ * Input cache protocol.
+ * Copyright (c) 2011,2014 Michael Niedermayer
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Based on file.c by Fabrice Bellard
+ */
+
+/**
+ * @TODO
+ * support keeping files
+ * support filling with a background thread
+ */
+
+#include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/internal.h"
+#include "libavutil/opt.h"
+#include "libavutil/tree.h"
+#include "avformat.h"
+#include <fcntl.h>
+#if HAVE_IO_H
+#include <io.h>
+#endif
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <sys/stat.h>
+#include <stdlib.h>
+#include "os_support.h"
+#include "url.h"
+
+typedef struct CacheEntry {
+ int64_t logical_pos;
+ int64_t physical_pos;
+ int size;
+} CacheEntry;
+
+typedef struct Context {
+ AVClass *class;
+ int fd;
+ struct AVTreeNode *root;
+ int64_t logical_pos;
+ int64_t cache_pos;
+ int64_t inner_pos;
+ int64_t end;
+ int is_true_eof;
+ URLContext *inner;
+ int64_t cache_hit, cache_miss;
+ int read_ahead_limit;
+} Context;
+
+static int cmp(const void *key, const void *node)
+{
+ return FFDIFFSIGN(*(const int64_t *)key, ((const CacheEntry *) node)->logical_pos);
+}
+
+static int cache_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
+{
+ char *buffername;
+ Context *c= h->priv_data;
+
+ av_strstart(arg, "cache:", &arg);
+
+ c->fd = avpriv_tempfile("ffcache", &buffername, 0, h);
+ if (c->fd < 0){
+ av_log(h, AV_LOG_ERROR, "Failed to create tempfile\n");
+ return c->fd;
+ }
+
+ unlink(buffername);
+ av_freep(&buffername);
+
+ return ffurl_open_whitelist(&c->inner, arg, flags, &h->interrupt_callback,
+ options, h->protocol_whitelist, h->protocol_blacklist, h);
+}
+
+static int add_entry(URLContext *h, const unsigned char *buf, int size)
+{
+ Context *c= h->priv_data;
+ int64_t pos = -1;
+ int ret;
+ CacheEntry *entry = NULL, *next[2] = {NULL, NULL};
+ CacheEntry *entry_ret;
+ struct AVTreeNode *node = NULL;
+
+ //FIXME avoid lseek
+ pos = lseek(c->fd, 0, SEEK_END);
+ if (pos < 0) {
+ ret = AVERROR(errno);
+ av_log(h, AV_LOG_ERROR, "seek in cache failed\n");
+ goto fail;
+ }
+ c->cache_pos = pos;
+
+ ret = write(c->fd, buf, size);
+ if (ret < 0) {
+ ret = AVERROR(errno);
+ av_log(h, AV_LOG_ERROR, "write in cache failed\n");
+ goto fail;
+ }
+ c->cache_pos += ret;
+
+ entry = av_tree_find(c->root, &c->logical_pos, cmp, (void**)next);
+
+ if (!entry)
+ entry = next[0];
+
+ if (!entry ||
+ entry->logical_pos + entry->size != c->logical_pos ||
+ entry->physical_pos + entry->size != pos
+ ) {
+ entry = av_malloc(sizeof(*entry));
+ node = av_tree_node_alloc();
+ if (!entry || !node) {
+ ret = AVERROR(ENOMEM);
+ goto fail;
+ }
+ entry->logical_pos = c->logical_pos;
+ entry->physical_pos = pos;
+ entry->size = ret;
+
+ entry_ret = av_tree_insert(&c->root, entry, cmp, &node);
+ if (entry_ret && entry_ret != entry) {
+ ret = -1;
+ av_log(h, AV_LOG_ERROR, "av_tree_insert failed\n");
+ goto fail;
+ }
+ } else
+ entry->size += ret;
+
+ return 0;
+fail:
+ //we could truncate the file to pos here if pos >=0 but ftruncate isn't available in VS so
+ //for simplicty we just leave the file a bit larger
+ av_free(entry);
+ av_free(node);
+ return ret;
+}
+
+static int cache_read(URLContext *h, unsigned char *buf, int size)
+{
+ Context *c= h->priv_data;
+ CacheEntry *entry, *next[2] = {NULL, NULL};
+ int64_t r;
+
+ entry = av_tree_find(c->root, &c->logical_pos, cmp, (void**)next);
+
+ if (!entry)
+ entry = next[0];
+
+ if (entry) {
+ int64_t in_block_pos = c->logical_pos - entry->logical_pos;
+ av_assert0(entry->logical_pos <= c->logical_pos);
+ if (in_block_pos < entry->size) {
+ int64_t physical_target = entry->physical_pos + in_block_pos;
+
+ if (c->cache_pos != physical_target) {
+ r = lseek(c->fd, physical_target, SEEK_SET);
+ } else
+ r = c->cache_pos;
+
+ if (r >= 0) {
+ c->cache_pos = r;
+ r = read(c->fd, buf, FFMIN(size, entry->size - in_block_pos));
+ }
+
+ if (r > 0) {
+ c->cache_pos += r;
+ c->logical_pos += r;
+ c->cache_hit ++;
+ return r;
+ }
+ }
+ }
+
+ // Cache miss or some kind of fault with the cache
+
+ if (c->logical_pos != c->inner_pos) {
+ r = ffurl_seek(c->inner, c->logical_pos, SEEK_SET);
+ if (r<0) {
+ av_log(h, AV_LOG_ERROR, "Failed to perform internal seek\n");
+ return r;
+ }
+ c->inner_pos = r;
+ }
+
+ r = ffurl_read(c->inner, buf, size);
+ if (r == 0 && size>0) {
+ c->is_true_eof = 1;
+ av_assert0(c->end >= c->logical_pos);
+ }
+ if (r<=0)
+ return r;
+ c->inner_pos += r;
+
+ c->cache_miss ++;
+
+ add_entry(h, buf, r);
+ c->logical_pos += r;
+ c->end = FFMAX(c->end, c->logical_pos);
+
+ return r;
+}
+
+static int64_t cache_seek(URLContext *h, int64_t pos, int whence)
+{
+ Context *c= h->priv_data;
+ int64_t ret;
+
+ if (whence == AVSEEK_SIZE) {
+ pos= ffurl_seek(c->inner, pos, whence);
+ if(pos <= 0){
+ pos= ffurl_seek(c->inner, -1, SEEK_END);
+ if (ffurl_seek(c->inner, c->inner_pos, SEEK_SET) < 0)
+ av_log(h, AV_LOG_ERROR, "Inner protocol failed to seekback end : %"PRId64"\n", pos);
+ }
+ if (pos > 0)
+ c->is_true_eof = 1;
+ c->end = FFMAX(c->end, pos);
+ return pos;
+ }
+
+ if (whence == SEEK_CUR) {
+ whence = SEEK_SET;
+ pos += c->logical_pos;
+ } else if (whence == SEEK_END && c->is_true_eof) {
+resolve_eof:
+ whence = SEEK_SET;
+ pos += c->end;
+ }
+
+ if (whence == SEEK_SET && pos >= 0 && pos < c->end) {
+ //Seems within filesize, assume it will not fail.
+ c->logical_pos = pos;
+ return pos;
+ }
+
+ //cache miss
+ ret= ffurl_seek(c->inner, pos, whence);
+ if ((whence == SEEK_SET && pos >= c->logical_pos ||
+ whence == SEEK_END && pos <= 0) && ret < 0) {
+ if ( (whence == SEEK_SET && c->read_ahead_limit >= pos - c->logical_pos)
+ || c->read_ahead_limit < 0) {
+ uint8_t tmp[32768];
+ while (c->logical_pos < pos || whence == SEEK_END) {
+ int size = sizeof(tmp);
+ if (whence == SEEK_SET)
+ size = FFMIN(sizeof(tmp), pos - c->logical_pos);
+ ret = cache_read(h, tmp, size);
+ if (ret == 0 && whence == SEEK_END) {
+ av_assert0(c->is_true_eof);
+ goto resolve_eof;
+ }
+ if (ret < 0) {
+ return ret;
+ }
+ }
+ return c->logical_pos;
+ }
+ }
+
+ if (ret >= 0) {
+ c->logical_pos = ret;
+ c->end = FFMAX(c->end, ret);
+ }
+
+ return ret;
+}
+
+static int enu_free(void *opaque, void *elem)
+{
+ av_free(elem);
+ return 0;
+}
+
+static int cache_close(URLContext *h)
+{
+ Context *c= h->priv_data;
+
+ av_log(h, AV_LOG_INFO, "Statistics, cache hits:%"PRId64" cache misses:%"PRId64"\n",
+ c->cache_hit, c->cache_miss);
+
+ close(c->fd);
+ ffurl_close(c->inner);
+ av_tree_enumerate(c->root, NULL, NULL, enu_free);
+ av_tree_destroy(c->root);
+
+ return 0;
+}
+
+#define OFFSET(x) offsetof(Context, x)
+#define D AV_OPT_FLAG_DECODING_PARAM
+
+static const AVOption options[] = {
+ { "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 },
+ {NULL},
+};
+
+static const AVClass cache_context_class = {
+ .class_name = "Cache",
+ .item_name = av_default_item_name,
+ .option = options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+const URLProtocol ff_cache_protocol = {
+ .name = "cache",
+ .url_open2 = cache_open,
+ .url_read = cache_read,
+ .url_seek = cache_seek,
+ .url_close = cache_close,
+ .priv_data_size = sizeof(Context),
+ .priv_data_class = &cache_context_class,
+};
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