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, int len,
  72                                  const char *stop_at, struct strbuf *out,
  73                                  int decode_plus)
  74 {
  75         const char *q = *query;
  76
  77         while (len) {
  78                 unsigned char c = *q;
  79
  80                 if (!c)
  81                         break;
  82                 if (stop_at && strchr(stop_at, c)) {
  83                         q++;
  84                         len--;
  85                         break;
  86                 }
  87
  88                 if (c == '%') {
  89                         int val = url_decode_char(q + 1);
  90                         if (0 <= val) {
  91                                 strbuf_addch(out, val);
  92                                 q += 3;
  93                                 len -= 3;
  94                                 continue;
  95                         }
  96                 }
  97
  98                 if (decode_plus && c == '+')
  99                         strbuf_addch(out, ' ');
 100                 else
 101                         strbuf_addch(out, c);
 102                 q++;
 103                 len--;
 104         }
 105         *query = q;
 106         return strbuf_detach(out, NULL);
 107 }
 108
 109 char *url_decode(const char *url)
 110 {
 111         return url_decode_mem(url, strlen(url));
 112 }
 113
 114 char *url_decode_mem(const char *url, int len)
 115 {
 116         struct strbuf out = STRBUF_INIT;
 117         const char *colon = memchr(url, ':', len);
 118
 119         /* Skip protocol part if present */
 120         if (colon && url < colon) {
 121                 strbuf_add(&out, url, colon - url);
 122                 len -= colon - url;
 123                 url = colon;
 124         }
 125         return url_decode_internal(&url, len, NULL, &out, 0);
 126 }
 127
 128 char *url_decode_parameter_name(const char **query)
 129 {
 130         struct strbuf out = STRBUF_INIT;
 131         return url_decode_internal(query, -1, "&=", &out, 1);
 132 }
 133
 134 char *url_decode_parameter_value(const char **query)
 135 {
 136         struct strbuf out = STRBUF_INIT;
 137         return url_decode_internal(query, -1, "&", &out, 1);
 138 }
 139
 140 void end_url_with_slash(struct strbuf *buf, const char *url)
 141 {
 142         strbuf_addstr(buf, url);
 143         if (buf->len && buf->buf[buf->len - 1] != '/')
 144                 strbuf_addstr(buf, "/");
 145 }
 146
 147 void str_end_url_with_slash(const char *url, char **dest) {
 148         struct strbuf buf = STRBUF_INIT;
 149         end_url_with_slash(&buf, url);
 150         free(*dest);
 151         *dest = strbuf_detach(&buf, NULL);
 152 }