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libavformat/avio.c

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00001 /*
00002  * unbuffered I/O
00003  * Copyright (c) 2001 Fabrice Bellard
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include <unistd.h>
00023 
00024 #include "libavutil/avstring.h"
00025 #include "libavutil/dict.h"
00026 #include "libavutil/opt.h"
00027 #include "os_support.h"
00028 #include "avformat.h"
00029 #if CONFIG_NETWORK
00030 #include "network.h"
00031 #endif
00032 #include "url.h"
00033 
00034 static URLProtocol *first_protocol = NULL;
00035 
00036 URLProtocol *ffurl_protocol_next(URLProtocol *prev)
00037 {
00038     return prev ? prev->next : first_protocol;
00039 }
00040 
00043 static const char *urlcontext_to_name(void *ptr)
00044 {
00045     URLContext *h = (URLContext *)ptr;
00046     if(h->prot) return h->prot->name;
00047     else        return "NULL";
00048 }
00049 
00050 static void *urlcontext_child_next(void *obj, void *prev)
00051 {
00052     URLContext *h = obj;
00053     if (!prev && h->priv_data && h->prot->priv_data_class)
00054         return h->priv_data;
00055     return NULL;
00056 }
00057 
00058 static const AVClass *urlcontext_child_class_next(const AVClass *prev)
00059 {
00060     URLProtocol *p = NULL;
00061 
00062     /* find the protocol that corresponds to prev */
00063     while (prev && (p = ffurl_protocol_next(p)))
00064         if (p->priv_data_class == prev)
00065             break;
00066 
00067     /* find next protocol with priv options */
00068     while (p = ffurl_protocol_next(p))
00069         if (p->priv_data_class)
00070             return p->priv_data_class;
00071     return NULL;
00072 
00073 }
00074 
00075 static const AVOption options[] = {{NULL}};
00076 const AVClass ffurl_context_class = {
00077     .class_name     = "URLContext",
00078     .item_name      = urlcontext_to_name,
00079     .option         = options,
00080     .version        = LIBAVUTIL_VERSION_INT,
00081     .child_next     = urlcontext_child_next,
00082     .child_class_next = urlcontext_child_class_next,
00083 };
00087 #if FF_API_OLD_INTERRUPT_CB
00088 static int default_interrupt_cb(void);
00089 int (*url_interrupt_cb)(void) = default_interrupt_cb;
00090 #endif
00091 
00092 #if FF_API_OLD_AVIO
00093 URLProtocol *av_protocol_next(URLProtocol *p)
00094 {
00095     return ffurl_protocol_next(p);
00096 }
00097 #endif
00098 
00099 const char *avio_enum_protocols(void **opaque, int output)
00100 {
00101     URLProtocol **p = opaque;
00102     *p = ffurl_protocol_next(*p);
00103     if (!*p) return NULL;
00104     if ((output && (*p)->url_write) || (!output && (*p)->url_read))
00105         return (*p)->name;
00106     return avio_enum_protocols(opaque, output);
00107 }
00108 
00109 int ffurl_register_protocol(URLProtocol *protocol, int size)
00110 {
00111     URLProtocol **p;
00112     if (size < sizeof(URLProtocol)) {
00113         URLProtocol* temp = av_mallocz(sizeof(URLProtocol));
00114         memcpy(temp, protocol, size);
00115         protocol = temp;
00116     }
00117     p = &first_protocol;
00118     while (*p != NULL) p = &(*p)->next;
00119     *p = protocol;
00120     protocol->next = NULL;
00121     return 0;
00122 }
00123 
00124 static int url_alloc_for_protocol (URLContext **puc, struct URLProtocol *up,
00125                                    const char *filename, int flags,
00126                                    const AVIOInterruptCB *int_cb)
00127 {
00128     URLContext *uc;
00129     int err;
00130 
00131 #if CONFIG_NETWORK
00132     if (up->flags & URL_PROTOCOL_FLAG_NETWORK && !ff_network_init())
00133         return AVERROR(EIO);
00134 #endif
00135     uc = av_mallocz(sizeof(URLContext) + strlen(filename) + 1);
00136     if (!uc) {
00137         err = AVERROR(ENOMEM);
00138         goto fail;
00139     }
00140     uc->av_class = &ffurl_context_class;
00141     uc->filename = (char *) &uc[1];
00142     strcpy(uc->filename, filename);
00143     uc->prot = up;
00144     uc->flags = flags;
00145     uc->is_streamed = 0; /* default = not streamed */
00146     uc->max_packet_size = 0; /* default: stream file */
00147     if (up->priv_data_size) {
00148         uc->priv_data = av_mallocz(up->priv_data_size);
00149         if (up->priv_data_class) {
00150             *(const AVClass**)uc->priv_data = up->priv_data_class;
00151             av_opt_set_defaults(uc->priv_data);
00152         }
00153     }
00154     if (int_cb)
00155         uc->interrupt_callback = *int_cb;
00156 
00157     *puc = uc;
00158     return 0;
00159  fail:
00160     *puc = NULL;
00161 #if CONFIG_NETWORK
00162     if (up->flags & URL_PROTOCOL_FLAG_NETWORK)
00163         ff_network_close();
00164 #endif
00165     return err;
00166 }
00167 
00168 int ffurl_connect(URLContext* uc, AVDictionary **options)
00169 {
00170     int err =
00171 #if !FF_API_OLD_AVIO
00172         uc->prot->url_open2 ? uc->prot->url_open2(uc, uc->filename, uc->flags, options) :
00173 #endif
00174         uc->prot->url_open(uc, uc->filename, uc->flags);
00175     if (err)
00176         return err;
00177     uc->is_connected = 1;
00178     //We must be careful here as ffurl_seek() could be slow, for example for http
00179     if(   (uc->flags & AVIO_FLAG_WRITE)
00180        || !strcmp(uc->prot->name, "file"))
00181         if(!uc->is_streamed && ffurl_seek(uc, 0, SEEK_SET) < 0)
00182             uc->is_streamed= 1;
00183     return 0;
00184 }
00185 
00186 #if FF_API_OLD_AVIO
00187 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
00188                        const char *filename, int flags)
00189 {
00190     int ret;
00191 
00192     ret = url_alloc_for_protocol(puc, up, filename, flags, NULL);
00193     if (ret)
00194         goto fail;
00195     ret = ffurl_connect(*puc, NULL);
00196     if (!ret)
00197         return 0;
00198  fail:
00199     ffurl_close(*puc);
00200     *puc = NULL;
00201     return ret;
00202 }
00203 int url_alloc(URLContext **puc, const char *filename, int flags)
00204 {
00205     return ffurl_alloc(puc, filename, flags, NULL);
00206 }
00207 int url_connect(URLContext* uc)
00208 {
00209     return ffurl_connect(uc, NULL);
00210 }
00211 int url_open(URLContext **puc, const char *filename, int flags)
00212 {
00213     return ffurl_open(puc, filename, flags, NULL, NULL);
00214 }
00215 int url_read(URLContext *h, unsigned char *buf, int size)
00216 {
00217     return ffurl_read(h, buf, size);
00218 }
00219 int url_read_complete(URLContext *h, unsigned char *buf, int size)
00220 {
00221     return ffurl_read_complete(h, buf, size);
00222 }
00223 int url_write(URLContext *h, const unsigned char *buf, int size)
00224 {
00225     return ffurl_write(h, buf, size);
00226 }
00227 int64_t url_seek(URLContext *h, int64_t pos, int whence)
00228 {
00229     return ffurl_seek(h, pos, whence);
00230 }
00231 int url_close(URLContext *h)
00232 {
00233     return ffurl_close(h);
00234 }
00235 int64_t url_filesize(URLContext *h)
00236 {
00237     return ffurl_size(h);
00238 }
00239 int url_get_file_handle(URLContext *h)
00240 {
00241     return ffurl_get_file_handle(h);
00242 }
00243 int url_get_max_packet_size(URLContext *h)
00244 {
00245     return h->max_packet_size;
00246 }
00247 void url_get_filename(URLContext *h, char *buf, int buf_size)
00248 {
00249     av_strlcpy(buf, h->filename, buf_size);
00250 }
00251 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb)
00252 {
00253     avio_set_interrupt_cb(interrupt_cb);
00254 }
00255 int av_register_protocol2(URLProtocol *protocol, int size)
00256 {
00257     return ffurl_register_protocol(protocol, size);
00258 }
00259 #endif
00260 
00261 #define URL_SCHEME_CHARS                        \
00262     "abcdefghijklmnopqrstuvwxyz"                \
00263     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"                \
00264     "0123456789+-."
00265 
00266 int ffurl_alloc(URLContext **puc, const char *filename, int flags,
00267                 const AVIOInterruptCB *int_cb)
00268 {
00269     URLProtocol *up = NULL;
00270     char proto_str[128], proto_nested[128], *ptr;
00271     size_t proto_len = strspn(filename, URL_SCHEME_CHARS);
00272 
00273     if (filename[proto_len] != ':' || is_dos_path(filename))
00274         strcpy(proto_str, "file");
00275     else
00276         av_strlcpy(proto_str, filename, FFMIN(proto_len+1, sizeof(proto_str)));
00277 
00278     av_strlcpy(proto_nested, proto_str, sizeof(proto_nested));
00279     if ((ptr = strchr(proto_nested, '+')))
00280         *ptr = '\0';
00281 
00282     while (up = ffurl_protocol_next(up)) {
00283         if (!strcmp(proto_str, up->name))
00284             return url_alloc_for_protocol (puc, up, filename, flags, int_cb);
00285         if (up->flags & URL_PROTOCOL_FLAG_NESTED_SCHEME &&
00286             !strcmp(proto_nested, up->name))
00287             return url_alloc_for_protocol (puc, up, filename, flags, int_cb);
00288     }
00289     *puc = NULL;
00290     return AVERROR(ENOENT);
00291 }
00292 
00293 int ffurl_open(URLContext **puc, const char *filename, int flags,
00294                const AVIOInterruptCB *int_cb, AVDictionary **options)
00295 {
00296     int ret = ffurl_alloc(puc, filename, flags, int_cb);
00297     if (ret)
00298         return ret;
00299     if (options && (*puc)->prot->priv_data_class &&
00300         (ret = av_opt_set_dict((*puc)->priv_data, options)) < 0)
00301         goto fail;
00302     ret = ffurl_connect(*puc, options);
00303     if (!ret)
00304         return 0;
00305 fail:
00306     ffurl_close(*puc);
00307     *puc = NULL;
00308     return ret;
00309 }
00310 
00311 static inline int retry_transfer_wrapper(URLContext *h, unsigned char *buf, int size, int size_min,
00312                                          int (*transfer_func)(URLContext *h, unsigned char *buf, int size))
00313 {
00314     int ret, len;
00315     int fast_retries = 5;
00316 
00317     len = 0;
00318     while (len < size_min) {
00319         ret = transfer_func(h, buf+len, size-len);
00320         if (ret == AVERROR(EINTR))
00321             continue;
00322         if (h->flags & AVIO_FLAG_NONBLOCK)
00323             return ret;
00324         if (ret == AVERROR(EAGAIN)) {
00325             ret = 0;
00326             if (fast_retries)
00327                 fast_retries--;
00328             else
00329                 usleep(1000);
00330         } else if (ret < 1)
00331             return ret < 0 ? ret : len;
00332         if (ret)
00333            fast_retries = FFMAX(fast_retries, 2);
00334         len += ret;
00335         if (ff_check_interrupt(&h->interrupt_callback))
00336             return AVERROR_EXIT;
00337     }
00338     return len;
00339 }
00340 
00341 int ffurl_read(URLContext *h, unsigned char *buf, int size)
00342 {
00343     if (!(h->flags & AVIO_FLAG_READ))
00344         return AVERROR(EIO);
00345     return retry_transfer_wrapper(h, buf, size, 1, h->prot->url_read);
00346 }
00347 
00348 int ffurl_read_complete(URLContext *h, unsigned char *buf, int size)
00349 {
00350     if (!(h->flags & AVIO_FLAG_READ))
00351         return AVERROR(EIO);
00352     return retry_transfer_wrapper(h, buf, size, size, h->prot->url_read);
00353 }
00354 
00355 int ffurl_write(URLContext *h, const unsigned char *buf, int size)
00356 {
00357     if (!(h->flags & AVIO_FLAG_WRITE))
00358         return AVERROR(EIO);
00359     /* avoid sending too big packets */
00360     if (h->max_packet_size && size > h->max_packet_size)
00361         return AVERROR(EIO);
00362 
00363     return retry_transfer_wrapper(h, buf, size, size, h->prot->url_write);
00364 }
00365 
00366 int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)
00367 {
00368     int64_t ret;
00369 
00370     if (!h->prot->url_seek)
00371         return AVERROR(ENOSYS);
00372     ret = h->prot->url_seek(h, pos, whence & ~AVSEEK_FORCE);
00373     return ret;
00374 }
00375 
00376 int ffurl_close(URLContext *h)
00377 {
00378     int ret = 0;
00379     if (!h) return 0; /* can happen when ffurl_open fails */
00380 
00381     if (h->is_connected && h->prot->url_close)
00382         ret = h->prot->url_close(h);
00383 #if CONFIG_NETWORK
00384     if (h->prot->flags & URL_PROTOCOL_FLAG_NETWORK)
00385         ff_network_close();
00386 #endif
00387     if (h->prot->priv_data_size) {
00388         if (h->prot->priv_data_class)
00389             av_opt_free(h->priv_data);
00390         av_free(h->priv_data);
00391     }
00392     av_free(h);
00393     return ret;
00394 }
00395 
00396 #if FF_API_OLD_AVIO
00397 int url_exist(const char *filename)
00398 {
00399     URLContext *h;
00400     if (ffurl_open(&h, filename, AVIO_FLAG_READ, NULL, NULL) < 0)
00401         return 0;
00402     ffurl_close(h);
00403     return 1;
00404 }
00405 #endif
00406 
00407 int avio_check(const char *url, int flags)
00408 {
00409     URLContext *h;
00410     int ret = ffurl_alloc(&h, url, flags, NULL);
00411     if (ret)
00412         return ret;
00413 
00414     if (h->prot->url_check) {
00415         ret = h->prot->url_check(h, flags);
00416     } else {
00417         ret = ffurl_connect(h, NULL);
00418         if (ret >= 0)
00419             ret = flags;
00420     }
00421 
00422     ffurl_close(h);
00423     return ret;
00424 }
00425 
00426 int64_t ffurl_size(URLContext *h)
00427 {
00428     int64_t pos, size;
00429 
00430     size= ffurl_seek(h, 0, AVSEEK_SIZE);
00431     if(size<0){
00432         pos = ffurl_seek(h, 0, SEEK_CUR);
00433         if ((size = ffurl_seek(h, -1, SEEK_END)) < 0)
00434             return size;
00435         size++;
00436         ffurl_seek(h, pos, SEEK_SET);
00437     }
00438     return size;
00439 }
00440 
00441 int ffurl_get_file_handle(URLContext *h)
00442 {
00443     if (!h->prot->url_get_file_handle)
00444         return -1;
00445     return h->prot->url_get_file_handle(h);
00446 }
00447 
00448 #if FF_API_OLD_INTERRUPT_CB
00449 static int default_interrupt_cb(void)
00450 {
00451     return 0;
00452 }
00453 
00454 void avio_set_interrupt_cb(int (*interrupt_cb)(void))
00455 {
00456     if (!interrupt_cb)
00457         interrupt_cb = default_interrupt_cb;
00458     url_interrupt_cb = interrupt_cb;
00459 }
00460 #endif
00461 
00462 int ff_check_interrupt(AVIOInterruptCB *cb)
00463 {
00464     int ret;
00465     if (cb && cb->callback && (ret = cb->callback(cb->opaque)))
00466         return ret;
00467 #if FF_API_OLD_INTERRUPT_CB
00468     return url_interrupt_cb();
00469 #else
00470     return 0;
00471 #endif
00472 }
00473 
00474 #if FF_API_OLD_AVIO
00475 int av_url_read_pause(URLContext *h, int pause)
00476 {
00477     if (!h->prot->url_read_pause)
00478         return AVERROR(ENOSYS);
00479     return h->prot->url_read_pause(h, pause);
00480 }
00481 
00482 int64_t av_url_read_seek(URLContext *h,
00483         int stream_index, int64_t timestamp, int flags)
00484 {
00485     if (!h->prot->url_read_seek)
00486         return AVERROR(ENOSYS);
00487     return h->prot->url_read_seek(h, stream_index, timestamp, flags);
00488 }
00489 #endif
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