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mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-12-07 11:13:41 +02:00
FFmpeg/libavformat/url.h
Andreas Rheinhardt 2a68d945cd avformat/avio: Constify data pointees of write callbacks
They are currently non-const for reasons unknown, although
avio_write() accepts a const buffer.

Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2023-09-10 22:55:42 +02:00

430 lines
16 KiB
C

/*
* 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
*/
/**
* @file
* unbuffered private I/O API
*/
#ifndef AVFORMAT_URL_H
#define AVFORMAT_URL_H
#include "avio.h"
#include "libavutil/dict.h"
#include "libavutil/log.h"
#define URL_PROTOCOL_FLAG_NESTED_SCHEME 1 /*< The protocol name can be the first part of a nested protocol scheme */
#define URL_PROTOCOL_FLAG_NETWORK 2 /*< The protocol uses network */
extern const AVClass ffurl_context_class;
typedef struct URLContext {
const AVClass *av_class; /**< information for av_log(). Set by url_open(). */
const struct URLProtocol *prot;
void *priv_data;
char *filename; /**< specified URL */
int flags;
int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
int is_streamed; /**< true if streamed (no seek possible), default = false */
int is_connected;
AVIOInterruptCB interrupt_callback;
int64_t rw_timeout; /**< maximum time to wait for (network) read/write operation completion, in mcs */
const char *protocol_whitelist;
const char *protocol_blacklist;
int min_packet_size; /**< if non zero, the stream is packetized with this min packet size */
} URLContext;
typedef struct URLProtocol {
const char *name;
int (*url_open)( URLContext *h, const char *url, int flags);
/**
* This callback is to be used by protocols which open further nested
* protocols. options are then to be passed to ffurl_open_whitelist()
* or ffurl_connect() for those nested protocols.
*/
int (*url_open2)(URLContext *h, const char *url, int flags, AVDictionary **options);
int (*url_accept)(URLContext *s, URLContext **c);
int (*url_handshake)(URLContext *c);
/**
* Read data from the protocol.
* If data is immediately available (even less than size), EOF is
* reached or an error occurs (including EINTR), return immediately.
* Otherwise:
* In non-blocking mode, return AVERROR(EAGAIN) immediately.
* In blocking mode, wait for data/EOF/error with a short timeout (0.1s),
* and return AVERROR(EAGAIN) on timeout.
* Checking interrupt_callback, looping on EINTR and EAGAIN and until
* enough data has been read is left to the calling function; see
* retry_transfer_wrapper in avio.c.
*/
int (*url_read)( URLContext *h, unsigned char *buf, int size);
int (*url_write)(URLContext *h, const unsigned char *buf, int size);
int64_t (*url_seek)( URLContext *h, int64_t pos, int whence);
int (*url_close)(URLContext *h);
int (*url_read_pause)(URLContext *h, int pause);
int64_t (*url_read_seek)(URLContext *h, int stream_index,
int64_t timestamp, int flags);
int (*url_get_file_handle)(URLContext *h);
int (*url_get_multi_file_handle)(URLContext *h, int **handles,
int *numhandles);
int (*url_get_short_seek)(URLContext *h);
int (*url_shutdown)(URLContext *h, int flags);
const AVClass *priv_data_class;
int priv_data_size;
int flags;
int (*url_check)(URLContext *h, int mask);
int (*url_open_dir)(URLContext *h);
int (*url_read_dir)(URLContext *h, AVIODirEntry **next);
int (*url_close_dir)(URLContext *h);
int (*url_delete)(URLContext *h);
int (*url_move)(URLContext *h_src, URLContext *h_dst);
const char *default_whitelist;
} URLProtocol;
/**
* Create a URLContext for accessing to the resource indicated by
* url, but do not initiate the connection yet.
*
* @param puc pointer to the location where, in case of success, the
* function puts the pointer to the created URLContext
* @param flags flags which control how the resource indicated by url
* is to be opened
* @param int_cb interrupt callback to use for the URLContext, may be
* NULL
* @return >= 0 in case of success, a negative value corresponding to an
* AVERROR code in case of failure
*/
int ffurl_alloc(URLContext **puc, const char *filename, int flags,
const AVIOInterruptCB *int_cb);
/**
* Connect an URLContext that has been allocated by ffurl_alloc
*
* @param options A dictionary filled with options for nested protocols,
* i.e. it will be passed to url_open2() for protocols implementing it.
* This parameter will be destroyed and replaced with a dict containing options
* that were not found. May be NULL.
*/
int ffurl_connect(URLContext *uc, AVDictionary **options);
/**
* Create an URLContext for accessing to the resource indicated by
* url, and open it.
*
* @param puc pointer to the location where, in case of success, the
* function puts the pointer to the created URLContext
* @param flags flags which control how the resource indicated by url
* is to be opened
* @param int_cb interrupt callback to use for the URLContext, may be
* NULL
* @param options A dictionary filled with protocol-private options. On return
* this parameter will be destroyed and replaced with a dict containing options
* that were not found. May be NULL.
* @param parent An enclosing URLContext, whose generic options should
* be applied to this URLContext as well.
* @return >= 0 in case of success, a negative value corresponding to an
* AVERROR code in case of failure
*/
int ffurl_open_whitelist(URLContext **puc, const char *filename, int flags,
const AVIOInterruptCB *int_cb, AVDictionary **options,
const char *whitelist, const char* blacklist,
URLContext *parent);
/**
* Accept an URLContext c on an URLContext s
*
* @param s server context
* @param c client context, must be unallocated.
* @return >= 0 on success, ff_neterrno() on failure.
*/
int ffurl_accept(URLContext *s, URLContext **c);
/**
* Perform one step of the protocol handshake to accept a new client.
* See avio_handshake() for details.
* Implementations should try to return decreasing values.
* If the protocol uses an underlying protocol, the underlying handshake is
* usually the first step, and the return value can be:
* (largest value for this protocol) + (return value from other protocol)
*
* @param c the client context
* @return >= 0 on success or a negative value corresponding
* to an AVERROR code on failure
*/
int ffurl_handshake(URLContext *c);
int ffurl_read2(void *urlcontext, uint8_t *buf, int size);
/**
* Read up to size bytes from the resource accessed by h, and store
* the read bytes in buf.
*
* @return The number of bytes actually read, or a negative value
* corresponding to an AVERROR code in case of error. A value of zero
* indicates that it is not possible to read more from the accessed
* resource (except if the value of the size argument is also zero).
*/
static inline int ffurl_read(URLContext *h, uint8_t *buf, int size)
{
return ffurl_read2(h, buf, size);
}
/**
* Read as many bytes as possible (up to size), calling the
* read function multiple times if necessary.
* This makes special short-read handling in applications
* unnecessary, if the return value is < size then it is
* certain there was either an error or the end of file was reached.
*/
int ffurl_read_complete(URLContext *h, unsigned char *buf, int size);
#if FF_API_AVIO_WRITE_NONCONST
int ffurl_write2(void *urlcontext, uint8_t *buf, int size);
#else
int ffurl_write2(void *urlcontext, const uint8_t *buf, int size);
#endif
/**
* Write size bytes from buf to the resource accessed by h.
*
* @return the number of bytes actually written, or a negative value
* corresponding to an AVERROR code in case of failure
*/
static inline int ffurl_write(URLContext *h, const uint8_t *buf, int size)
{
#if FF_API_AVIO_WRITE_NONCONST
return ffurl_write2(h, (uint8_t*)buf, size);
#else
return ffurl_write2(h, buf, size);
#endif
}
int64_t ffurl_seek2(void *urlcontext, int64_t pos, int whence);
/**
* Change the position that will be used by the next read/write
* operation on the resource accessed by h.
*
* @param pos specifies the new position to set
* @param whence specifies how pos should be interpreted, it must be
* one of SEEK_SET (seek from the beginning), SEEK_CUR (seek from the
* current position), SEEK_END (seek from the end), or AVSEEK_SIZE
* (return the filesize of the requested resource, pos is ignored).
* @return a negative value corresponding to an AVERROR code in case
* of failure, or the resulting file position, measured in bytes from
* the beginning of the file. You can use this feature together with
* SEEK_CUR to read the current file position.
*/
static inline int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)
{
return ffurl_seek2(h, pos, whence);
}
/**
* Close the resource accessed by the URLContext h, and free the
* memory used by it. Also set the URLContext pointer to NULL.
*
* @return a negative value if an error condition occurred, 0
* otherwise
*/
int ffurl_closep(URLContext **h);
int ffurl_close(URLContext *h);
/**
* Return the filesize of the resource accessed by h, AVERROR(ENOSYS)
* if the operation is not supported by h, or another negative value
* corresponding to an AVERROR error code in case of failure.
*/
int64_t ffurl_size(URLContext *h);
/**
* Return the file descriptor associated with this URL. For RTP, this
* will return only the RTP file descriptor, not the RTCP file descriptor.
*
* @return the file descriptor associated with this URL, or <0 on error.
*/
int ffurl_get_file_handle(URLContext *h);
/**
* Return the file descriptors associated with this URL.
*
* @return 0 on success or <0 on error.
*/
int ffurl_get_multi_file_handle(URLContext *h, int **handles, int *numhandles);
/**
* Return the current short seek threshold value for this URL.
*
* @return threshold (>0) on success or <=0 on error.
*/
int ffurl_get_short_seek(void *urlcontext);
/**
* Signal the URLContext that we are done reading or writing the stream.
*
* @param h pointer to the resource
* @param flags flags which control how the resource indicated by url
* is to be shutdown
*
* @return a negative value if an error condition occurred, 0
* otherwise
*/
int ffurl_shutdown(URLContext *h, int flags);
/**
* Check if the user has requested to interrupt a blocking function
* associated with cb.
*/
int ff_check_interrupt(AVIOInterruptCB *cb);
/* udp.c */
int ff_udp_set_remote_url(URLContext *h, const char *uri);
int ff_udp_get_local_port(URLContext *h);
/**
* Assemble a URL string from components. This is the reverse operation
* of av_url_split.
*
* Note, this requires networking to be initialized, so the caller must
* ensure ff_network_init has been called.
*
* @see av_url_split
*
* @param str the buffer to fill with the url
* @param size the size of the str buffer
* @param proto the protocol identifier, if null, the separator
* after the identifier is left out, too
* @param authorization an optional authorization string, may be null.
* An empty string is treated the same as a null string.
* @param hostname the host name string
* @param port the port number, left out from the string if negative
* @param fmt a generic format string for everything to add after the
* host/port, may be null
* @return the number of characters written to the destination buffer
*/
int ff_url_join(char *str, int size, const char *proto,
const char *authorization, const char *hostname,
int port, const char *fmt, ...) av_printf_format(7, 8);
/**
* Convert a relative url into an absolute url, given a base url.
*
* @param buf the buffer where output absolute url is written
* @param size the size of buf
* @param base the base url, may be equal to buf.
* @param rel the new url, which is interpreted relative to base
* @param handle_dos_paths handle DOS paths for file or unspecified protocol
*/
int ff_make_absolute_url2(char *buf, int size, const char *base,
const char *rel, int handle_dos_paths);
/**
* Convert a relative url into an absolute url, given a base url.
*
* Same as ff_make_absolute_url2 with handle_dos_paths being equal to
* HAVE_DOS_PATHS config variable.
*/
int ff_make_absolute_url(char *buf, int size, const char *base,
const char *rel);
/**
* Allocate directory entry with default values.
*
* @return entry or NULL on error
*/
AVIODirEntry *ff_alloc_dir_entry(void);
const AVClass *ff_urlcontext_child_class_iterate(void **iter);
/**
* Construct a list of protocols matching a given whitelist and/or blacklist.
*
* @param whitelist a comma-separated list of allowed protocol names or NULL. If
* this is a non-empty string, only protocols in this list will
* be included.
* @param blacklist a comma-separated list of forbidden protocol names or NULL.
* If this is a non-empty string, all protocols in this list
* will be excluded.
*
* @return a NULL-terminated array of matching protocols. The array must be
* freed by the caller.
*/
const URLProtocol **ffurl_get_protocols(const char *whitelist,
const char *blacklist);
typedef struct URLComponents {
const char *url; /**< whole URL, for reference */
const char *scheme; /**< possibly including lavf-specific options */
const char *authority; /**< "//" if it is a real URL */
const char *userinfo; /**< including final '@' if present */
const char *host;
const char *port; /**< including initial ':' if present */
const char *path;
const char *query; /**< including initial '?' if present */
const char *fragment; /**< including initial '#' if present */
const char *end;
} URLComponents;
#define url_component_end_scheme authority
#define url_component_end_authority userinfo
#define url_component_end_userinfo host
#define url_component_end_host port
#define url_component_end_port path
#define url_component_end_path query
#define url_component_end_query fragment
#define url_component_end_fragment end
#define url_component_end_authority_full path
#define URL_COMPONENT_HAVE(uc, component) \
((uc).url_component_end_##component > (uc).component)
/**
* Parse an URL to find the components.
*
* Each component runs until the start of the next component,
* possibly including a mandatory delimiter.
*
* @param uc structure to fill with pointers to the components.
* @param url URL to parse.
* @param end end of the URL, or NULL to parse to the end of string.
*
* @return >= 0 for success or an AVERROR code, especially if the URL is
* malformed.
*/
int ff_url_decompose(URLComponents *uc, const char *url, const char *end);
/**
* Move or rename a resource.
*
* @note url_src and url_dst should share the same protocol and authority.
*
* @param url_src url to resource to be moved
* @param url_dst new url to resource if the operation succeeded
* @return >=0 on success or negative on error.
*/
int ffurl_move(const char *url_src, const char *url_dst);
/**
* Delete a resource.
*
* @param url resource to be deleted.
* @return >=0 on success or negative on error.
*/
int ffurl_delete(const char *url);
#endif /* AVFORMAT_URL_H */