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 static char *diff_arg_forward  = " - '%s'";
  11 static char *diff_arg_reverse  = " '%s' -";
  12
  13 static void prepare_diff_cmd(void)
  14 {
  15         /*
  16          * Default values above are meant to match the
  17          * Linux kernel development style.  Examples of
  18          * alternative styles you can specify via environment
  19          * variables are:
  20          *
  21          * GIT_DIFF_CMD="diff -L '%s' -L '%s'"
  22          * GIT_DIFF_OPTS="-c";
  23          */
  24         diff_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd;
  25         diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
  26 }
  27
  28 /* Help to copy the thing properly quoted for the shell safety.
  29  * any single quote is replaced with '\'', and the caller is
  30  * expected to enclose the result within a single quote pair.
  31  *
  32  * E.g.
  33  *  original     sq_expand     result
  34  *  name     ==> name      ==> 'name'
  35  *  a b      ==> a b       ==> 'a b'
  36  *  a'b      ==> a'\''b    ==> 'a'\''b'
  37  *
  38  * NOTE! The returned memory belongs to this function so
  39  * do not free it.
  40  */
  41 static char *sq_expand(char *src)
  42 {
  43         static char *buf = NULL;
  44         int cnt, c;
  45         char *cp;
  46
  47         /* count bytes needed to store the quoted string. */
  48         for (cnt = 1, cp = src; *cp; cnt++, cp++)
  49                 if (*cp == '\'')
  50                         cnt += 3;
  51
  52         if (! (buf = malloc(cnt)))
  53             return buf;
  54         cp = buf;
  55         while ((c = *src++)) {
  56                 if (c != '\'')
  57                         *cp++ = c;
  58                 else {
  59                         cp = strcpy(cp, "'\\''");
  60                         cp += 4;
  61                 }
  62         }
  63         *cp = 0;
  64         return buf;
  65 }
  66
  67 static void show_differences(char *name, char *label, void *old_contents,
  68                              unsigned long long old_size, int reverse)
  69 {
  70         FILE *f;
  71         char *name_sq = sq_expand(name);
  72         char *label_sq = (name != label) ? sq_expand(label) : name_sq;
  73         char *diff_arg = reverse ? diff_arg_reverse : diff_arg_forward;
  74         int cmd_size = strlen(name_sq) + strlen(label_sq) * 2 +
  75                 strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg);
  76         char *cmd = malloc(cmd_size);
  77         int next_at;
  78
  79         fflush(stdout);
  80         next_at = snprintf(cmd, cmd_size, diff_cmd, label_sq, label_sq);
  81         next_at += snprintf(cmd+next_at, cmd_size-next_at, "%s", diff_opts);
  82         next_at += snprintf(cmd+next_at, cmd_size-next_at, diff_arg, name_sq);
  83         f = popen(cmd, "w");
  84         if (old_size)
  85                 fwrite(old_contents, old_size, 1, f);
  86         pclose(f);
  87         if (label_sq != name_sq)
  88                 free(label_sq);
  89         free(name_sq);
  90         free(cmd);
  91 }
  92
  93 static void show_diff_empty(struct cache_entry *ce, int reverse)
  94 {
  95         char *old;
  96         unsigned long int size;
  97         unsigned char type[20];
  98
  99         old = read_sha1_file(ce->sha1, type, &size);
 100         if (! old) {
 101                 error("unable to read blob object for %s (%s)", ce->name,
 102                       sha1_to_hex(ce->sha1));
 103                 return;
 104         }
 105         show_differences("/dev/null", ce->name, old, size, reverse);
 106 }
 107
 108 static const char *show_diff_usage = "show-diff [-q] [-s] [-z] [paths...]";
 109
 110 static int matches_pathspec(struct cache_entry *ce, char **spec, int cnt)
 111 {
 112         int i;
 113         int namelen = ce_namelen(ce);
 114         for (i = 0; i < cnt; i++) {
 115                 int speclen = strlen(spec[i]);
 116                 if (! strncmp(spec[i], ce->name, speclen) &&
 117                     speclen <= namelen &&
 118                     (ce->name[speclen] == 0 ||
 119                      ce->name[speclen] == '/'))
 120                         return 1;
 121         }
 122         return 0;
 123 }
 124
 125 int main(int argc, char **argv)
 126 {
 127         int silent = 0;
 128         int silent_on_nonexisting_files = 0;
 129         int machine_readable = 0;
 130         int reverse = 0;
 131         int entries = read_cache();
 132         int i;
 133
 134         while (1 < argc && argv[1][0] == '-') {
 135                 if  (!strcmp(argv[1], "-R"))
 136                         reverse = 1;
 137                 else if (!strcmp(argv[1], "-s"))
 138                         silent_on_nonexisting_files = silent = 1;
 139                 else if (!strcmp(argv[1], "-q"))
 140                         silent_on_nonexisting_files = 1;
 141                 else if (!strcmp(argv[1], "-z"))
 142                         machine_readable = 1;
 143                 else
 144                         usage(show_diff_usage);
 145                 argv++; argc--;
 146         }
 147
 148         /* At this point, if argc == 1, then we are doing everything.
 149          * Otherwise argv[1] .. argv[argc-1] have the explicit paths.
 150          */
 151         if (entries < 0) {
 152                 perror("read_cache");
 153                 exit(1);
 154         }
 155         prepare_diff_cmd();
 156         for (i = 0; i < entries; i++) {
 157                 struct stat st;
 158                 struct cache_entry *ce = active_cache[i];
 159                 int changed;
 160                 unsigned long size;
 161                 char type[20];
 162                 void *old;
 163
 164                 if (1 < argc &&
 165                     ! matches_pathspec(ce, argv+1, argc-1))
 166                         continue;
 167
 168                 if (ce_stage(ce)) {
 169                         if (machine_readable)
 170                                 printf("U %s%c", ce->name, 0);
 171                         else
 172                                 printf("%s: Unmerged\n",
 173                                        ce->name);
 174                         while (i < entries &&
 175                                !strcmp(ce->name, active_cache[i]->name))
 176                                 i++;
 177                         i--; /* compensate for loop control increments */
 178                         continue;
 179                 }
 180
 181                 if (stat(ce->name, &st) < 0) {
 182                         if (errno == ENOENT && silent_on_nonexisting_files)
 183                                 continue;
 184                         if (machine_readable)
 185                                 printf("X %s%c", ce->name, 0);
 186                         else {
 187                                 printf("%s: %s\n", ce->name, strerror(errno));
 188                                 if (errno == ENOENT)
 189                                         show_diff_empty(ce, reverse);
 190                         }
 191                         continue;
 192                 }
 193                 changed = cache_match_stat(ce, &st);
 194                 if (!changed)
 195                         continue;
 196                 if (!machine_readable)
 197                         printf("%s: %s\n", ce->name, sha1_to_hex(ce->sha1));
 198                 else {
 199                         printf("%s %s%c", sha1_to_hex(ce->sha1), ce->name, 0);
 200                         continue;
 201                 }
 202                 if (silent)
 203                         continue;
 204
 205                 old = read_sha1_file(ce->sha1, type, &size);
 206                 if (! old)
 207                         error("unable to read blob object for %s (%s)",
 208                               ce->name, sha1_to_hex(ce->sha1));
 209                 else
 210                         show_differences(ce->name, ce->name, old, size,
 211                                          reverse);
 212                 free(old);
 213         }
 214         return 0;
 215 }