FFmpeg: libavformat/url.h Source File

FFmpeg
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 int (*url_interrupt_cb)(void);
38 
39 extern const AVClass ffurl_context_class;
40 
41  typedef struct URLContext {
42   const AVClass *av_class; /**< information for av_log(). Set by url_open(). */
43   struct URLProtocol *prot;
44   void *priv_data;
45   char *filename; /**< specified URL */
46   int flags;
47   int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
48   int is_streamed; /**< true if streamed (no seek possible), default = false */
49   int is_connected;
50   AVIOInterruptCB interrupt_callback;
51   int64_t rw_timeout; /**< maximum time to wait for (network) read/write operation completion, in mcs */
52 } URLContext;
53 
54  typedef struct URLProtocol {
55   const char *name;
56   int (*url_open)( URLContext *h, const char *url, int flags);
57  /**
58  * This callback is to be used by protocols which open further nested
59  * protocols. options are then to be passed to ffurl_open()/ffurl_connect()
60  * for those nested protocols.
61  */
62   int (*url_open2)(URLContext *h, const char *url, int flags, AVDictionary **options);
63 
64  /**
65  * Read data from the protocol.
66  * If data is immediately available (even less than size), EOF is
67  * reached or an error occurs (including EINTR), return immediately.
68  * Otherwise:
69  * In non-blocking mode, return AVERROR(EAGAIN) immediately.
70  * In blocking mode, wait for data/EOF/error with a short timeout (0.1s),
71  * and return AVERROR(EAGAIN) on timeout.
72  * Checking interrupt_callback, looping on EINTR and EAGAIN and until
73  * enough data has been read is left to the calling function; see
74  * retry_transfer_wrapper in avio.c.
75  */
76   int (*url_read)( URLContext *h, unsigned char *buf, int size);
77   int (*url_write)(URLContext *h, const unsigned char *buf, int size);
78   int64_t (*url_seek)( URLContext *h, int64_t pos, int whence);
79   int (*url_close)(URLContext *h);
80   struct URLProtocol *next;
81   int (*url_read_pause)(URLContext *h, int pause);
82   int64_t (*url_read_seek)(URLContext *h, int stream_index,
83  int64_t timestamp, int flags);
84   int (*url_get_file_handle)(URLContext *h);
85   int (*url_get_multi_file_handle)(URLContext *h, int **handles,
86  int *numhandles);
87   int (*url_shutdown)(URLContext *h, int flags);
88   int priv_data_size;
89   const AVClass *priv_data_class;
90   int flags;
91   int (*url_check)(URLContext *h, int mask);
92 } URLProtocol;
93 
94 /**
95  * Create a URLContext for accessing to the resource indicated by
96  * url, but do not initiate the connection yet.
97  *
98  * @param puc pointer to the location where, in case of success, the
99  * function puts the pointer to the created URLContext
100  * @param flags flags which control how the resource indicated by url
101  * is to be opened
102  * @param int_cb interrupt callback to use for the URLContext, may be
103  * NULL
104  * @return >= 0 in case of success, a negative value corresponding to an
105  * AVERROR code in case of failure
106  */
107 int ffurl_alloc(URLContext **puc, const char *filename, int flags,
108  const AVIOInterruptCB *int_cb);
109 
110 /**
111  * Connect an URLContext that has been allocated by ffurl_alloc
112  *
113  * @param options A dictionary filled with options for nested protocols,
114  * i.e. it will be passed to url_open2() for protocols implementing it.
115  * This parameter will be destroyed and replaced with a dict containing options
116  * that were not found. May be NULL.
117  */
118 int ffurl_connect(URLContext *uc, AVDictionary **options);
119 
120 /**
121  * Create an URLContext for accessing to the resource indicated by
122  * url, and open it.
123  *
124  * @param puc pointer to the location where, in case of success, the
125  * function puts the pointer to the created URLContext
126  * @param flags flags which control how the resource indicated by url
127  * is to be opened
128  * @param int_cb interrupt callback to use for the URLContext, may be
129  * NULL
130  * @param options A dictionary filled with protocol-private options. On return
131  * this parameter will be destroyed and replaced with a dict containing options
132  * that were not found. May be NULL.
133  * @return >= 0 in case of success, a negative value corresponding to an
134  * AVERROR code in case of failure
135  */
136 int ffurl_open(URLContext **puc, const char *filename, int flags,
137  const AVIOInterruptCB *int_cb, AVDictionary **options);
138 
139 /**
140  * Read up to size bytes from the resource accessed by h, and store
141  * the read bytes in buf.
142  *
143  * @return The number of bytes actually read, or a negative value
144  * corresponding to an AVERROR code in case of error. A value of zero
145  * indicates that it is not possible to read more from the accessed
146  * resource (except if the value of the size argument is also zero).
147  */
148 int ffurl_read(URLContext *h, unsigned char *buf, int size);
149 
150 /**
151  * Read as many bytes as possible (up to size), calling the
152  * read function multiple times if necessary.
153  * This makes special short-read handling in applications
154  * unnecessary, if the return value is < size then it is
155  * certain there was either an error or the end of file was reached.
156  */
157 int ffurl_read_complete(URLContext *h, unsigned char *buf, int size);
158 
159 /**
160  * Write size bytes from buf to the resource accessed by h.
161  *
162  * @return the number of bytes actually written, or a negative value
163  * corresponding to an AVERROR code in case of failure
164  */
165 int ffurl_write(URLContext *h, const unsigned char *buf, int size);
166 
167 /**
168  * Change the position that will be used by the next read/write
169  * operation on the resource accessed by h.
170  *
171  * @param pos specifies the new position to set
172  * @param whence specifies how pos should be interpreted, it must be
173  * one of SEEK_SET (seek from the beginning), SEEK_CUR (seek from the
174  * current position), SEEK_END (seek from the end), or AVSEEK_SIZE
175  * (return the filesize of the requested resource, pos is ignored).
176  * @return a negative value corresponding to an AVERROR code in case
177  * of failure, or the resulting file position, measured in bytes from
178  * the beginning of the file. You can use this feature together with
179  * SEEK_CUR to read the current file position.
180  */
181 int64_t ffurl_seek(URLContext *h, int64_t pos, int whence);
182 
183 /**
184  * Close the resource accessed by the URLContext h, and free the
185  * memory used by it. Also set the URLContext pointer to NULL.
186  *
187  * @return a negative value if an error condition occurred, 0
188  * otherwise
189  */
190 int ffurl_closep(URLContext **h);
191 int ffurl_close(URLContext *h);
192 
193 /**
194  * Return the filesize of the resource accessed by h, AVERROR(ENOSYS)
195  * if the operation is not supported by h, or another negative value
196  * corresponding to an AVERROR error code in case of failure.
197  */
198 int64_t ffurl_size(URLContext *h);
199 
200 /**
201  * Return the file descriptor associated with this URL. For RTP, this
202  * will return only the RTP file descriptor, not the RTCP file descriptor.
203  *
204  * @return the file descriptor associated with this URL, or <0 on error.
205  */
206 int ffurl_get_file_handle(URLContext *h);
207 
208 /**
209  * Return the file descriptors associated with this URL.
210  *
211  * @return 0 on success or <0 on error.
212  */
213 int ffurl_get_multi_file_handle(URLContext *h, int **handles, int *numhandles);
214 
215 /**
216  * Signal the URLContext that we are done reading or writing the stream.
217  *
218  * @param h pointer to the resource
219  * @param flags flags which control how the resource indicated by url
220  * is to be shutdown
221  *
222  * @return a negative value if an error condition occurred, 0
223  * otherwise
224  */
225 int ffurl_shutdown(URLContext *h, int flags);
226 
227 /**
228  * Register the URLProtocol protocol.
229  *
230  * @param size the size of the URLProtocol struct referenced
231  */
232 int ffurl_register_protocol(URLProtocol *protocol, int size);
233 
234 /**
235  * Check if the user has requested to interrup a blocking function
236  * associated with cb.
237  */
238 int ff_check_interrupt(AVIOInterruptCB *cb);
239 
240 /**
241  * Iterate over all available protocols.
242  *
243  * @param prev result of the previous call to this functions or NULL.
244  */
245 URLProtocol *ffurl_protocol_next(URLProtocol *prev);
246 
247 /* udp.c */
248 int ff_udp_set_remote_url(URLContext *h, const char *uri);
249 int ff_udp_get_local_port(URLContext *h);
250 
251 /**
252  * Assemble a URL string from components. This is the reverse operation
253  * of av_url_split.
254  *
255  * Note, this requires networking to be initialized, so the caller must
256  * ensure ff_network_init has been called.
257  *
258  * @see av_url_split
259  *
260  * @param str the buffer to fill with the url
261  * @param size the size of the str buffer
262  * @param proto the protocol identifier, if null, the separator
263  * after the identifier is left out, too
264  * @param authorization an optional authorization string, may be null.
265  * An empty string is treated the same as a null string.
266  * @param hostname the host name string
267  * @param port the port number, left out from the string if negative
268  * @param fmt a generic format string for everything to add after the
269  * host/port, may be null
270  * @return the number of characters written to the destination buffer
271  */
272 int ff_url_join(char *str, int size, const char *proto,
273  const char *authorization, const char *hostname,
274  int port, const char *fmt, ...) av_printf_format(7, 8);
275 
276 /**
277  * Convert a relative url into an absolute url, given a base url.
278  *
279  * @param buf the buffer where output absolute url is written
280  * @param size the size of buf
281  * @param base the base url, may be equal to buf.
282  * @param rel the new url, which is interpreted relative to base
283  */
284 void ff_make_absolute_url(char *buf, int size, const char *base,
285  const char *rel);
286 
287 
288 #endif /* AVFORMAT_URL_H */
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