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url.h
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1 /*
2  *
3  * This file is part of FFmpeg.
4  *
5  * FFmpeg is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * FFmpeg is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with FFmpeg; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18  */
19 
20 /**
21  * @file
22  * unbuffered private I/O API
23  */
24 
25 #ifndef AVFORMAT_URL_H
26 #define AVFORMAT_URL_H
27 
28 #include "avio.h"
29 #include "libavformat/version.h"
30 
31 #include "libavutil/dict.h"
32 #include "libavutil/log.h"
33 
34 #define URL_PROTOCOL_FLAG_NESTED_SCHEME 1 /*< The protocol name can be the first part of a nested protocol scheme */
35 #define URL_PROTOCOL_FLAG_NETWORK 2 /*< The protocol uses network */
36 
37 extern const AVClass ffurl_context_class;
38 
39 typedef struct URLContext {
40  const AVClass *av_class; /**< information for av_log(). Set by url_open(). */
41  struct URLProtocol *prot;
42  void *priv_data;
43  char *filename; /**< specified URL */
44  int flags;
45  int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
46  int is_streamed; /**< true if streamed (no seek possible), default = false */
49  int64_t rw_timeout; /**< maximum time to wait for (network) read/write operation completion, in mcs */
50 } URLContext;
51 
52 typedef struct URLProtocol {
53  const char *name;
54  int (*url_open)( URLContext *h, const char *url, int flags);
55  /**
56  * This callback is to be used by protocols which open further nested
57  * protocols. options are then to be passed to ffurl_open()/ffurl_connect()
58  * for those nested protocols.
59  */
60  int (*url_open2)(URLContext *h, const char *url, int flags, AVDictionary **options);
61 
62  /**
63  * Read data from the protocol.
64  * If data is immediately available (even less than size), EOF is
65  * reached or an error occurs (including EINTR), return immediately.
66  * Otherwise:
67  * In non-blocking mode, return AVERROR(EAGAIN) immediately.
68  * In blocking mode, wait for data/EOF/error with a short timeout (0.1s),
69  * and return AVERROR(EAGAIN) on timeout.
70  * Checking interrupt_callback, looping on EINTR and EAGAIN and until
71  * enough data has been read is left to the calling function; see
72  * retry_transfer_wrapper in avio.c.
73  */
74  int (*url_read)( URLContext *h, unsigned char *buf, int size);
75  int (*url_write)(URLContext *h, const unsigned char *buf, int size);
76  int64_t (*url_seek)( URLContext *h, int64_t pos, int whence);
77  int (*url_close)(URLContext *h);
78  struct URLProtocol *next;
79  int (*url_read_pause)(URLContext *h, int pause);
80  int64_t (*url_read_seek)(URLContext *h, int stream_index,
81  int64_t timestamp, int flags);
83  int (*url_get_multi_file_handle)(URLContext *h, int **handles,
84  int *numhandles);
85  int (*url_shutdown)(URLContext *h, int flags);
88  int flags;
89  int (*url_check)(URLContext *h, int mask);
93 } URLProtocol;
94 
95 /**
96  * Create a URLContext for accessing to the resource indicated by
97  * url, but do not initiate the connection yet.
98  *
99  * @param puc pointer to the location where, in case of success, the
100  * function puts the pointer to the created URLContext
101  * @param flags flags which control how the resource indicated by url
102  * is to be opened
103  * @param int_cb interrupt callback to use for the URLContext, may be
104  * NULL
105  * @return >= 0 in case of success, a negative value corresponding to an
106  * AVERROR code in case of failure
107  */
108 int ffurl_alloc(URLContext **puc, const char *filename, int flags,
109  const AVIOInterruptCB *int_cb);
110 
111 /**
112  * Connect an URLContext that has been allocated by ffurl_alloc
113  *
114  * @param options A dictionary filled with options for nested protocols,
115  * i.e. it will be passed to url_open2() for protocols implementing it.
116  * This parameter will be destroyed and replaced with a dict containing options
117  * that were not found. May be NULL.
118  */
120 
121 /**
122  * Create an URLContext for accessing to the resource indicated by
123  * url, and open it.
124  *
125  * @param puc pointer to the location where, in case of success, the
126  * function puts the pointer to the created URLContext
127  * @param flags flags which control how the resource indicated by url
128  * is to be opened
129  * @param int_cb interrupt callback to use for the URLContext, may be
130  * NULL
131  * @param options A dictionary filled with protocol-private options. On return
132  * this parameter will be destroyed and replaced with a dict containing options
133  * that were not found. May be NULL.
134  * @return >= 0 in case of success, a negative value corresponding to an
135  * AVERROR code in case of failure
136  */
137 int ffurl_open(URLContext **puc, const char *filename, int flags,
139 
140 /**
141  * Read up to size bytes from the resource accessed by h, and store
142  * the read bytes in buf.
143  *
144  * @return The number of bytes actually read, or a negative value
145  * corresponding to an AVERROR code in case of error. A value of zero
146  * indicates that it is not possible to read more from the accessed
147  * resource (except if the value of the size argument is also zero).
148  */
149 int ffurl_read(URLContext *h, unsigned char *buf, int size);
150 
151 /**
152  * Read as many bytes as possible (up to size), calling the
153  * read function multiple times if necessary.
154  * This makes special short-read handling in applications
155  * unnecessary, if the return value is < size then it is
156  * certain there was either an error or the end of file was reached.
157  */
158 int ffurl_read_complete(URLContext *h, unsigned char *buf, int size);
159 
160 /**
161  * Write size bytes from buf to the resource accessed by h.
162  *
163  * @return the number of bytes actually written, or a negative value
164  * corresponding to an AVERROR code in case of failure
165  */
166 int ffurl_write(URLContext *h, const unsigned char *buf, int size);
167 
168 /**
169  * Change the position that will be used by the next read/write
170  * operation on the resource accessed by h.
171  *
172  * @param pos specifies the new position to set
173  * @param whence specifies how pos should be interpreted, it must be
174  * one of SEEK_SET (seek from the beginning), SEEK_CUR (seek from the
175  * current position), SEEK_END (seek from the end), or AVSEEK_SIZE
176  * (return the filesize of the requested resource, pos is ignored).
177  * @return a negative value corresponding to an AVERROR code in case
178  * of failure, or the resulting file position, measured in bytes from
179  * the beginning of the file. You can use this feature together with
180  * SEEK_CUR to read the current file position.
181  */
182 int64_t ffurl_seek(URLContext *h, int64_t pos, int whence);
183 
184 /**
185  * Close the resource accessed by the URLContext h, and free the
186  * memory used by it. Also set the URLContext pointer to NULL.
187  *
188  * @return a negative value if an error condition occurred, 0
189  * otherwise
190  */
191 int ffurl_closep(URLContext **h);
192 int ffurl_close(URLContext *h);
193 
194 /**
195  * Return the filesize of the resource accessed by h, AVERROR(ENOSYS)
196  * if the operation is not supported by h, or another negative value
197  * corresponding to an AVERROR error code in case of failure.
198  */
199 int64_t ffurl_size(URLContext *h);
200 
201 /**
202  * Return the file descriptor associated with this URL. For RTP, this
203  * will return only the RTP file descriptor, not the RTCP file descriptor.
204  *
205  * @return the file descriptor associated with this URL, or <0 on error.
206  */
208 
209 /**
210  * Return the file descriptors associated with this URL.
211  *
212  * @return 0 on success or <0 on error.
213  */
214 int ffurl_get_multi_file_handle(URLContext *h, int **handles, int *numhandles);
215 
216 /**
217  * Signal the URLContext that we are done reading or writing the stream.
218  *
219  * @param h pointer to the resource
220  * @param flags flags which control how the resource indicated by url
221  * is to be shutdown
222  *
223  * @return a negative value if an error condition occurred, 0
224  * otherwise
225  */
226 int ffurl_shutdown(URLContext *h, int flags);
227 
228 /**
229  * Register the URLProtocol protocol.
230  */
231 int ffurl_register_protocol(URLProtocol *protocol);
232 
233 /**
234  * Check if the user has requested to interrup a blocking function
235  * associated with cb.
236  */
238 
239 /**
240  * Iterate over all available protocols.
241  *
242  * @param prev result of the previous call to this functions or NULL.
243  */
245 
246 /* udp.c */
247 int ff_udp_set_remote_url(URLContext *h, const char *uri);
249 
250 /**
251  * Assemble a URL string from components. This is the reverse operation
252  * of av_url_split.
253  *
254  * Note, this requires networking to be initialized, so the caller must
255  * ensure ff_network_init has been called.
256  *
257  * @see av_url_split
258  *
259  * @param str the buffer to fill with the url
260  * @param size the size of the str buffer
261  * @param proto the protocol identifier, if null, the separator
262  * after the identifier is left out, too
263  * @param authorization an optional authorization string, may be null.
264  * An empty string is treated the same as a null string.
265  * @param hostname the host name string
266  * @param port the port number, left out from the string if negative
267  * @param fmt a generic format string for everything to add after the
268  * host/port, may be null
269  * @return the number of characters written to the destination buffer
270  */
271 int ff_url_join(char *str, int size, const char *proto,
272  const char *authorization, const char *hostname,
273  int port, const char *fmt, ...) av_printf_format(7, 8);
274 
275 /**
276  * Convert a relative url into an absolute url, given a base url.
277  *
278  * @param buf the buffer where output absolute url is written
279  * @param size the size of buf
280  * @param base the base url, may be equal to buf.
281  * @param rel the new url, which is interpreted relative to base
282  */
283 void ff_make_absolute_url(char *buf, int size, const char *base,
284  const char *rel);
285 
286 /**
287  * Allocate directory entry with default values.
288  *
289  * @return entry or NULL on error
290  */
292 
293 
294 #endif /* AVFORMAT_URL_H */