url.con commit Merge branch 'bd/maint-unpack-trees-parawalk-fix' (3919d40)
   1#include "cache.h"
   2
   3int is_urlschemechar(int first_flag, int ch)
   4{
   5        /*
   6         * The set of valid URL schemes, as per STD66 (RFC3986) is
   7         * '[A-Za-z][A-Za-z0-9+.-]*'. But use sightly looser check
   8         * of '[A-Za-z0-9][A-Za-z0-9+.-]*' because earlier version
   9         * of check used '[A-Za-z0-9]+' so not to break any remote
  10         * helpers.
  11         */
  12        int alphanumeric, special;
  13        alphanumeric = ch > 0 && isalnum(ch);
  14        special = ch == '+' || ch == '-' || ch == '.';
  15        return alphanumeric || (!first_flag && special);
  16}
  17
  18int is_url(const char *url)
  19{
  20        const char *url2, *first_slash;
  21
  22        if (!url)
  23                return 0;
  24        url2 = url;
  25        first_slash = strchr(url, '/');
  26
  27        /* Input with no slash at all or slash first can't be URL. */
  28        if (!first_slash || first_slash == url)
  29                return 0;
  30        /* Character before must be : and next must be /. */
  31        if (first_slash[-1] != ':' || first_slash[1] != '/')
  32                return 0;
  33        /* There must be something before the :// */
  34        if (first_slash == url + 1)
  35                return 0;
  36        /*
  37         * Check all characters up to first slash - 1. Only alphanum
  38         * is allowed.
  39         */
  40        url2 = url;
  41        while (url2 < first_slash - 1) {
  42                if (!is_urlschemechar(url2 == url, (unsigned char)*url2))
  43                        return 0;
  44                url2++;
  45        }
  46
  47        /* Valid enough. */
  48        return 1;
  49}
  50
  51static int url_decode_char(const char *q)
  52{
  53        int i;
  54        unsigned char val = 0;
  55        for (i = 0; i < 2; i++) {
  56                unsigned char c = *q++;
  57                val <<= 4;
  58                if (c >= '0' && c <= '9')
  59                        val += c - '0';
  60                else if (c >= 'a' && c <= 'f')
  61                        val += c - 'a' + 10;
  62                else if (c >= 'A' && c <= 'F')
  63                        val += c - 'A' + 10;
  64                else
  65                        return -1;
  66        }
  67        return val;
  68}
  69
  70static char *url_decode_internal(const char **query, const char *stop_at)
  71{
  72        const char *q = *query;
  73        struct strbuf out;
  74
  75        strbuf_init(&out, 16);
  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 (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
 105char *url_decode(const char *url)
 106{
 107        return url_decode_internal(&url, NULL);
 108}
 109
 110char *url_decode_parameter_name(const char **query)
 111{
 112        return url_decode_internal(query, "&=");
 113}
 114
 115char *url_decode_parameter_value(const char **query)
 116{
 117        return url_decode_internal(query, "&");
 118}