Andrew's git - gitweb.git/blob

dcefe983afd8a0c32fd9ba6d1c8abc6cb9bf6736
   1#include "cache.h"
   2#include "diff.h"
   3
   4static char *diff_cmd = "diff -L 'k/%s' -L 'l/%s' ";
   5static char *diff_opts = "-p -u";
   6static char *diff_arg_forward  = " - '%s'";
   7static char *diff_arg_reverse  = " '%s' -";
   8
   9void prepare_diff_cmd(void)
  10{
  11        /*
  12         * Default values above are meant to match the
  13         * Linux kernel development style.  Examples of
  14         * alternative styles you can specify via environment
  15         * variables are:
  16         *
  17         * GIT_DIFF_CMD="diff -L '%s' -L '%s'"
  18         * GIT_DIFF_OPTS="-c";
  19         */
  20        diff_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd;
  21        diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
  22}
  23
  24/* Help to copy the thing properly quoted for the shell safety.
  25 * any single quote is replaced with '\'', and the caller is
  26 * expected to enclose the result within a single quote pair.
  27 *
  28 * E.g.
  29 *  original     sq_expand     result
  30 *  name     ==> name      ==> 'name'
  31 *  a b      ==> a b       ==> 'a b'
  32 *  a'b      ==> a'\''b    ==> 'a'\''b'
  33 */
  34static char *sq_expand(const char *src)
  35{
  36        static char *buf = NULL;
  37        int cnt, c;
  38        const char *cp;
  39        char *bp;
  40
  41        /* count bytes needed to store the quoted string. */ 
  42        for (cnt = 1, cp = src; *cp; cnt++, cp++)
  43                if (*cp == '\'')
  44                        cnt += 3;
  45
  46        if (! (buf = malloc(cnt)))
  47            return buf;
  48        bp = buf;
  49        while ((c = *src++)) {
  50                if (c != '\'')
  51                        *bp++ = c;
  52                else {
  53                        bp = strcpy(bp, "'\\''");
  54                        bp += 4;
  55                }
  56        }
  57        *bp = 0;
  58        return buf;
  59}
  60
  61void show_differences(const char *name, /* filename on the filesystem */
  62                      const char *label, /* diff label to use */
  63                      void *old_contents, /* contents in core */
  64                      unsigned long long old_size, /* size in core */
  65                      int reverse /* 0: diff core file
  66                                     1: diff file core */)
  67{
  68        FILE *f;
  69        char *name_sq = sq_expand(name);
  70        const char *label_sq = (name != label) ? sq_expand(label) : name_sq;
  71        char *diff_arg = reverse ? diff_arg_reverse : diff_arg_forward;
  72        int cmd_size = strlen(name_sq) + strlen(label_sq) * 2 +
  73                strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg);
  74        char *cmd = malloc(cmd_size);
  75        int next_at;
  76
  77        fflush(stdout);
  78        next_at = snprintf(cmd, cmd_size, diff_cmd, label_sq, label_sq);
  79        next_at += snprintf(cmd+next_at, cmd_size-next_at, "%s", diff_opts);
  80        next_at += snprintf(cmd+next_at, cmd_size-next_at, diff_arg, name_sq);
  81        f = popen(cmd, "w");
  82        if (old_size)
  83                fwrite(old_contents, old_size, 1, f);
  84        pclose(f);
  85        if (label_sq != name_sq)
  86                free((void*)label_sq); /* constness */
  87        free(name_sq);
  88        free(cmd);
  89}
  90
  91void show_diff_empty(const unsigned char *sha1,
  92                     const char *name,
  93                     int reverse)
  94{
  95        char *old;
  96        unsigned long int size;
  97        unsigned char type[20];
  98
  99        old = read_sha1_file(sha1, type, &size);
 100        if (! old) {
 101                error("unable to read blob object for %s (%s)", name,
 102                      sha1_to_hex(sha1));
 103                return;
 104        }
 105        show_differences("/dev/null", name, old, size, reverse);
 106}