url.c

   1 #include "cache.h"
   2 #include "url.h"
   3
   4 int is_urlschemechar(int first_flag, int ch)
   5 {
   6         /*
   7          * The set of valid URL schemes, as per STD66 (RFC3986) is
   8          * '[A-Za-z][A-Za-z0-9+.-]*'. But use sightly looser check
   9          * of '[A-Za-z0-9][A-Za-z0-9+.-]*' because earlier version
  10          * of check used '[A-Za-z0-9]+' so not to break any remote
  11          * helpers.
  12          */
  13         int alphanumeric, special;
  14         alphanumeric = ch > 0 && isalnum(ch);
  15         special = ch == '+' || ch == '-' || ch == '.';
  16         return alphanumeric || (!first_flag && special);
  17 }
  18
  19 int is_url(const char *url)
  20 {
  21         const char *url2, *first_slash;
  22
  23         if (!url)
  24                 return 0;
  25         url2 = url;
  26         first_slash = strchr(url, '/');
  27
  28         /* Input with no slash at all or slash first can't be URL. */
  29         if (!first_slash || first_slash == url)
  30                 return 0;
  31         /* Character before must be : and next must be /. */
  32         if (first_slash[-1] != ':' || first_slash[1] != '/')
  33                 return 0;
  34         /* There must be something before the :// */
  35         if (first_slash == url + 1)
  36                 return 0;
  37         /*
  38          * Check all characters up to first slash - 1. Only alphanum
  39          * is allowed.
  40          */
  41         url2 = url;
  42         while (url2 < first_slash - 1) {
  43                 if (!is_urlschemechar(url2 == url, (unsigned char)*url2))
  44                         return 0;
  45                 url2++;
  46         }
  47
  48         /* Valid enough. */
  49         return 1;
  50 }
  51
  52 static int url_decode_char(const char *q)
  53 {
  54         int i;
  55         unsigned char val = 0;
  56         for (i = 0; i < 2; i++) {
  57                 unsigned char c = *q++;
  58                 val <<= 4;
  59                 if (c >= '0' && c <= '9')
  60                         val += c - '0';
  61                 else if (c >= 'a' && c <= 'f')
  62                         val += c - 'a' + 10;
  63                 else if (c >= 'A' && c <= 'F')
  64                         val += c - 'A' + 10;
  65                 else
  66                         return -1;
  67         }
  68         return val;
  69 }
  70
  71 static char *url_decode_internal(const char **query, const char *stop_at,
  72                                  struct strbuf *out, int decode_plus)
  73 {
  74         const char *q = *query;
  75
  76         do {
  77                 unsigned char c = *q;
  78
  79                 if (!c)
  80                         break;
  81                 if (stop_at && strchr(stop_at, c)) {
  82                         q++;
  83                         break;
  84                 }
  85
  86                 if (c == '%') {
  87                         int val = url_decode_char(q + 1);
  88                         if (0 <= val) {
  89                                 strbuf_addch(out, val);
  90                                 q += 3;
  91                                 continue;
  92                         }
  93                 }
  94
  95                 if (decode_plus && c == '+')
  96                         strbuf_addch(out, ' ');
  97                 else
  98                         strbuf_addch(out, c);
  99                 q++;
 100         } while (1);
 101         *query = q;
 102         return strbuf_detach(out, NULL);
 103 }
 104
 105 char *url_decode(const char *url)
 106 {
 107         struct strbuf out = STRBUF_INIT;
 108         const char *colon = strchr(url, ':');
 109
 110         /* Skip protocol part if present */
 111         if (colon && url < colon) {
 112                 strbuf_add(&out, url, colon - url);
 113                 url = colon;
 114         }
 115         return url_decode_internal(&url, NULL, &out, 0);
 116 }
 117
 118 char *url_decode_parameter_name(const char **query)
 119 {
 120         struct strbuf out = STRBUF_INIT;
 121         return url_decode_internal(query, "&=", &out, 1);
 122 }
 123
 124 char *url_decode_parameter_value(const char **query)
 125 {
 126         struct strbuf out = STRBUF_INIT;
 127         return url_decode_internal(query, "&", &out, 1);
 128 }
 129
 130 void end_url_with_slash(struct strbuf *buf, const char *url)
 131 {
 132         strbuf_addstr(buf, url);
 133         if (buf->len && buf->buf[buf->len - 1] != '/')
 134                 strbuf_addstr(buf, "/");
 135 }
 136
 137 void str_end_url_with_slash(const char *url, char **dest) {
 138         struct strbuf buf = STRBUF_INIT;
 139         end_url_with_slash(&buf, url);
 140         free(*dest);
 141         *dest = strbuf_detach(&buf, NULL);
 142 }