show-diff.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7
   8 static char *diff_cmd = "diff -L 'a/%s' -L 'b/%s' ";
   9 static char *diff_opts = "-p -u";
  10
  11 static void prepare_diff_cmd(void)
  12 {
  13         /*
  14          * Default values above are meant to match the
  15          * Linux kernel development style.  Examples of
  16          * alternative styles you can specify via environment
  17          * variables are:
  18          *
  19          * GIT_DIFF_CMD="diff -L '%s' -L '%s'"
  20          * GIT_DIFF_OPTS="-c";
  21          */
  22         diff_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd;
  23         diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
  24 }
  25
  26 /* Help to copy the thing properly quoted for the shell safety.
  27  * any single quote is replaced with '\'', and the caller is
  28  * expected to enclose the result within a single quote pair.
  29  *
  30  * E.g.
  31  *  original     sq_expand     result
  32  *  name     ==> name      ==> 'name'
  33  *  a b      ==> a b       ==> 'a b'
  34  *  a'b      ==> a'\''b    ==> 'a'\''b'
  35  *
  36  * NOTE! The returned memory belongs to this function so
  37  * do not free it.
  38  */
  39 static char *sq_expand(char *src)
  40 {
  41         static char *buf = NULL;
  42         int cnt, c;
  43         char *cp;
  44
  45         /* count bytes needed to store the quoted string. */
  46         for (cnt = 1, cp = src; *cp; cnt++, cp++)
  47                 if (*cp == '\'')
  48                         cnt += 3;
  49
  50         if (! (buf = malloc(cnt)))
  51             return buf;
  52         cp = buf;
  53         while ((c = *src++)) {
  54                 if (c != '\'')
  55                         *cp++ = c;
  56                 else {
  57                         cp = strcpy(cp, "'\\''");
  58                         cp += 4;
  59                 }
  60         }
  61         *cp = 0;
  62         return buf;
  63 }
  64
  65 static void show_differences(char *name, char *label, void *old_contents,
  66                              unsigned long long old_size)
  67 {
  68         static char *diff_arg = " - '%s'";
  69         FILE *f;
  70         char *name_sq = sq_expand(name);
  71         char *label_sq = (name != label) ? sq_expand(label) : name_sq;
  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(label_sq);
  87         free(name_sq);
  88         free(cmd);
  89 }
  90
  91 static void show_diff_empty(struct cache_entry *ce)
  92 {
  93         char *old;
  94         unsigned long int size;
  95         unsigned char type[20];
  96
  97         old = read_sha1_file(ce->sha1, type, &size);
  98         if (! old) {
  99                 error("unable to read blob object for %s (%s)", ce->name,
 100                       sha1_to_hex(ce->sha1));
 101                 return;
 102         }
 103         show_differences("/dev/null", ce->name, old, size);
 104 }
 105
 106 static const char *show_diff_usage = "show-diff [-q] [-s] [-z] [paths...]";
 107
 108 static int matches_pathspec(struct cache_entry *ce, char **spec, int cnt)
 109 {
 110         int i;
 111         int namelen = ce_namelen(ce);
 112         for (i = 0; i < cnt; i++) {
 113                 int speclen = strlen(spec[i]);
 114                 if (! strncmp(spec[i], ce->name, speclen) &&
 115                     speclen <= namelen &&
 116                     (ce->name[speclen] == 0 ||
 117                      ce->name[speclen] == '/'))
 118                         return 1;
 119         }
 120         return 0;
 121 }
 122
 123 int main(int argc, char **argv)
 124 {
 125         int silent = 0;
 126         int silent_on_nonexisting_files = 0;
 127         int machine_readable = 0;
 128         int entries = read_cache();
 129         int i;
 130
 131         while (1 < argc && argv[1][0] == '-') {
 132                 if (!strcmp(argv[1], "-s"))
 133                         silent_on_nonexisting_files = silent = 1;
 134                 else if (!strcmp(argv[1], "-q"))
 135                         silent_on_nonexisting_files = 1;
 136                 else if (!strcmp(argv[1], "-z"))
 137                         machine_readable = 1;
 138                 else
 139                         usage(show_diff_usage);
 140                 argv++; argc--;
 141         }
 142
 143         /* At this point, if argc == 1, then we are doing everything.
 144          * Otherwise argv[1] .. argv[argc-1] have the explicit paths.
 145          */
 146         if (entries < 0) {
 147                 perror("read_cache");
 148                 exit(1);
 149         }
 150         prepare_diff_cmd();
 151         for (i = 0; i < entries; i++) {
 152                 struct stat st;
 153                 struct cache_entry *ce = active_cache[i];
 154                 int changed;
 155                 unsigned long size;
 156                 char type[20];
 157                 void *old;
 158
 159                 if (1 < argc &&
 160                     ! matches_pathspec(ce, argv+1, argc-1))
 161                         continue;
 162
 163                 if (ce_stage(ce)) {
 164                         if (machine_readable)
 165                                 printf("U %s%c", ce->name, 0);
 166                         else
 167                                 printf("%s: Unmerged\n",
 168                                        ce->name);
 169                         while (i < entries &&
 170                                !strcmp(ce->name, active_cache[i]->name))
 171                                 i++;
 172                         i--; /* compensate for loop control increments */
 173                         continue;
 174                 }
 175
 176                 if (stat(ce->name, &st) < 0) {
 177                         if (errno == ENOENT && silent_on_nonexisting_files)
 178                                 continue;
 179                         if (machine_readable)
 180                                 printf("X %s%c", ce->name, 0);
 181                         else {
 182                                 printf("%s: %s\n", ce->name, strerror(errno));
 183                                 if (errno == ENOENT)
 184                                         show_diff_empty(ce);
 185                         }
 186                         continue;
 187                 }
 188                 changed = cache_match_stat(ce, &st);
 189                 if (!changed)
 190                         continue;
 191                 if (!machine_readable)
 192                         printf("%s: %s\n", ce->name, sha1_to_hex(ce->sha1));
 193                 else {
 194                         printf("%s %s%c", sha1_to_hex(ce->sha1), ce->name, 0);
 195                         continue;
 196                 }
 197                 if (silent)
 198                         continue;
 199
 200                 old = read_sha1_file(ce->sha1, type, &size);
 201                 if (! old)
 202                         error("unable to read blob object for %s (%s)",
 203                               ce->name, sha1_to_hex(ce->sha1));
 204                 else
 205                         show_differences(ce->name, ce->name, old, size);
 206                 free(old);
 207         }
 208         return 0;
 209 }