src/input/mrl_helpers.h

   1 /*****************************************************************************
   2  * mrl_helpers.h
   3  *****************************************************************************
   4  * Copyright (C) 2016 VLC authors and VideoLAN
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifndef INPUT_MRL_HELPERS_H
  22 #define INPUT_MRL_HELPERS_H
  23
  24 #include <string.h>
  25 #include <stdlib.h>
  26
  27 #include <vlc_common.h>
  28 #include <vlc_memstream.h>
  29 #include <vlc_arrays.h>
  30 #include <vlc_url.h>
  31
  32 /**
  33  * \defgroup mrl_helpers MRL helpers
  34  * \ingroup mrl
  35  *
  36  * Helper functions related to parsing, as well as generating, data
  37  * related to the \link MRL-specification\endlink.
  38  *
  39  * @{
  40  * \file
  41  **/
  42
  43 /**
  44  * Escape a fragment identifier for use within an MRL
  45  *
  46  * The function will generate a string that follows the \link mrl
  47  * MRL-specification\endlink regarding \em fragment-identifiers.
  48  *
  49  * See the \link mrl MRL-specification\endlink for a detailed
  50  * explanation of how `payload` will be escaped.
  51  *
  52  * \param[out] out `*out` will refer to the created string on success,
  53  *                  and an unspecified value on error.
  54  * \param[in] payload the data to escape.
  55  * \return VLC_SUCCESS on success, an error-code on failure.
  56  **/
  57 static inline int
  58 mrl_EscapeFragmentIdentifier( char** out, char const* payload )
  59 {
  60     struct vlc_memstream mstream;
  61
  62 #define RFC3986_SUBDELIMS  "!" "$" "&" "'" "(" ")" \
  63                            "*" "+" "," ";" "="
  64 #define RFC3986_ALPHA      "abcdefghijklmnopqrstuvwxyz" \
  65                            "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
  66 #define RFC3986_DIGIT      "0123456789"
  67 #define RFC3986_UNRESERVED RFC3986_ALPHA RFC3986_DIGIT "-" "." "_" "~"
  68 #define RFC3986_PCHAR      RFC3986_UNRESERVED RFC3986_SUBDELIMS ":" "@"
  69 #define RFC3986_FRAGMENT   RFC3986_PCHAR "/" "?"
  70
  71     if( vlc_memstream_open( &mstream ) )
  72         return VLC_EGENERIC;
  73
  74     for( char const* p = payload; *p; ++p )
  75     {
  76         vlc_memstream_printf( &mstream,
  77             ( strchr( "!?", *p ) == NULL &&
  78               strchr( RFC3986_FRAGMENT, *p ) ? "%c" : "%%%02hhx"), *p );
  79     }
  80
  81 #undef RFC3986_FRAGMENT
  82 #undef RFC3986_PCHAR
  83 #undef RFC3986_UNRESERVEd
  84 #undef RFC3986_DIGIT
  85 #undef RFC3986_ALPHA
  86 #undef RFC3986_SUBDELIMS
  87
  88     if( vlc_memstream_close( &mstream ) )
  89         return VLC_EGENERIC;
  90
  91     *out = mstream.ptr;
  92     return VLC_SUCCESS;
  93 }
  94
  95 /**
  96  * Split an \link mrl_technical_fragment MRL-fragment\endlink into identifiers
  97  *
  98  * Function used to split the fragment-data (also referred to as
  99  * anchor-data) into an array containing each of the files specified.
 100  *
 101  * See the \link mrl MRL-specification\endlink for detailed
 102  * information regarding how `payload` will be interpreted.
 103  *
 104  * \warning On success, the caller has ownership of the contents of *out_items
 105  *          which means that it is responsible for freeing the individual
 106  *          elements, as well as cleaning the array itself.
 107  *
 108  * \param[out] out_items storage for a vlc_array_t that will contain the
 109  *                       parsed identifiers on success.
 110  * \param[out] out_extra `*out_extra` will point to any remaining data (if any)
 111  * \param[in] payload the data to parse
 112  * \return VLC_SUCCESS on success, an error-code on failure
 113  **/
 114 static inline int
 115 mrl_FragmentSplit( vlc_array_t* out_items,
 116                    char const** out_extra,
 117                    char const* payload )
 118 {
 119     char const* extra = NULL;
 120
 121     vlc_array_init( out_items );
 122
 123     while( strncmp( payload, "!/", 2 ) == 0 )
 124     {
 125         payload += 2;
 126
 127         int len = strcspn( payload, "!?" );
 128         char* decoded = strndup( payload, len );
 129
 130         if( unlikely( !decoded ) || !vlc_uri_decode( decoded ) )
 131             goto error;
 132
 133         vlc_array_append( out_items, decoded );
 134         payload += len;
 135     }
 136
 137     if( *payload )
 138     {
 139         if( *payload == '!' )
 140             goto error;
 141
 142         if( *payload == '?' && vlc_array_count( out_items ) )
 143             ++payload;
 144
 145         extra = payload;
 146     }
 147
 148     *out_extra = extra;
 149     return VLC_SUCCESS;
 150
 151 error:
 152     for( size_t i = 0; i < vlc_array_count( out_items ); ++i )
 153         free( vlc_array_item_at_index( out_items, i ) );
 154     vlc_array_clear( out_items );
 155     return VLC_EGENERIC;;
 156 }
 157
 158 /*
 159  * @}
 160  **/
 161
 162 #endif /* include-guard */