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' -p -u - '%s'";
   9
  10 /* Help to copy the thing properly quoted for the shell safety.
  11  * any single quote is replaced with '\'', and the caller is
  12  * expected to enclose the result within a single quote pair.
  13  *
  14  * E.g.
  15  *  original     sq_expand     result
  16  *  name     ==> name      ==> 'name'
  17  *  a b      ==> a b       ==> 'a b'
  18  *  a'b      ==> a'\''b    ==> 'a'\''b'
  19  *
  20  * NOTE! The returned memory belongs to this function so
  21  * do not free it.
  22  */
  23 static char *sq_expand(char *src)
  24 {
  25         static char *buf = NULL;
  26         int cnt, c;
  27         char *cp;
  28
  29         /* count bytes needed to store the quoted string. */
  30         for (cnt = 1, cp = src; *cp; cnt++, cp++)
  31                 if (*cp == '\'')
  32                         cnt += 3;
  33
  34         if (! (buf = malloc(cnt)))
  35             return buf;
  36         cp = buf;
  37         while ((c = *src++)) {
  38                 if (c != '\'')
  39                         *cp++ = c;
  40                 else {
  41                         cp = strcpy(cp, "'\\''");
  42                         cp += 4;
  43                 }
  44         }
  45         *cp = 0;
  46         return buf;
  47 }
  48
  49 static void show_differences(char *name, char *label, void *old_contents,
  50                              unsigned long long old_size)
  51 {
  52         FILE *f;
  53         char *name_sq = sq_expand(name);
  54         char *label_sq = (name != label) ? sq_expand(label) : name_sq;
  55         int cmd_size = strlen(name_sq) +
  56                 strlen(label_sq) * 2 + strlen(diff_cmd);
  57         char *cmd = malloc(cmd_size);
  58
  59         fflush(stdout);
  60         snprintf(cmd, cmd_size, diff_cmd, label_sq, label_sq, name_sq);
  61         f = popen(cmd, "w");
  62         if (old_size)
  63                 fwrite(old_contents, old_size, 1, f);
  64         pclose(f);
  65         if (label_sq != name_sq)
  66                 free(label_sq);
  67         free(name_sq);
  68         free(cmd);
  69 }
  70
  71 static void show_diff_empty(struct cache_entry *ce)
  72 {
  73         char *old;
  74         unsigned long int size;
  75         unsigned char type[20];
  76
  77         old = read_sha1_file(ce->sha1, type, &size);
  78         if (! old) {
  79                 error("unable to read blob object for %s (%s)", ce->name,
  80                       sha1_to_hex(ce->sha1));
  81                 return;
  82         }
  83         show_differences("/dev/null", ce->name, old, size);
  84 }
  85
  86 static const char *show_diff_usage = "show-diff [-q] [-s] [-z] [paths...]";
  87
  88 static int matches_pathspec(struct cache_entry *ce, char **spec, int cnt)
  89 {
  90         int i;
  91         int namelen = ce_namelen(ce);
  92         for (i = 0; i < cnt; i++) {
  93                 int speclen = strlen(spec[i]);
  94                 if (! strncmp(spec[i], ce->name, speclen) &&
  95                     speclen <= namelen &&
  96                     (ce->name[speclen] == 0 ||
  97                      ce->name[speclen] == '/'))
  98                         return 1;
  99         }
 100         return 0;
 101 }
 102
 103 int main(int argc, char **argv)
 104 {
 105         int silent = 0;
 106         int silent_on_nonexisting_files = 0;
 107         int machine_readable = 0;
 108         int entries = read_cache();
 109         int i;
 110
 111         while (1 < argc && argv[1][0] == '-') {
 112                 if (!strcmp(argv[1], "-s"))
 113                         silent_on_nonexisting_files = silent = 1;
 114                 else if (!strcmp(argv[1], "-q"))
 115                         silent_on_nonexisting_files = 1;
 116                 else if (!strcmp(argv[1], "-z"))
 117                         machine_readable = 1;
 118                 else
 119                         usage(show_diff_usage);
 120                 argv++; argc--;
 121         }
 122
 123         /* At this point, if argc == 1, then we are doing everything.
 124          * Otherwise argv[1] .. argv[argc-1] have the explicit paths.
 125          */
 126         if (entries < 0) {
 127                 perror("read_cache");
 128                 exit(1);
 129         }
 130         for (i = 0; i < entries; i++) {
 131                 struct stat st;
 132                 struct cache_entry *ce = active_cache[i];
 133                 int changed;
 134                 unsigned long size;
 135                 char type[20];
 136                 void *old;
 137
 138                 if (1 < argc &&
 139                     ! matches_pathspec(ce, argv+1, argc-1))
 140                         continue;
 141
 142                 if (ce_stage(ce)) {
 143                         if (machine_readable)
 144                                 printf("U %s%c", ce->name, 0);
 145                         else
 146                                 printf("%s: Unmerged\n",
 147                                        ce->name);
 148                         while (i < entries &&
 149                                !strcmp(ce->name, active_cache[i]->name))
 150                                 i++;
 151                         i--; /* compensate for loop control increments */
 152                         continue;
 153                 }
 154
 155                 if (stat(ce->name, &st) < 0) {
 156                         if (errno == ENOENT && silent_on_nonexisting_files)
 157                                 continue;
 158                         if (machine_readable)
 159                                 printf("X %s%c", ce->name, 0);
 160                         else {
 161                                 printf("%s: %s\n", ce->name, strerror(errno));
 162                                 if (errno == ENOENT)
 163                                         show_diff_empty(ce);
 164                         }
 165                         continue;
 166                 }
 167                 changed = cache_match_stat(ce, &st);
 168                 if (!changed)
 169                         continue;
 170                 if (!machine_readable)
 171                         printf("%s: %s\n", ce->name, sha1_to_hex(ce->sha1));
 172                 else {
 173                         printf("%s %s%c", sha1_to_hex(ce->sha1), ce->name, 0);
 174                         continue;
 175                 }
 176                 if (silent)
 177                         continue;
 178
 179                 old = read_sha1_file(ce->sha1, type, &size);
 180                 if (! old)
 181                         error("unable to read blob object for %s (%s)",
 182                               ce->name, sha1_to_hex(ce->sha1));
 183                 else
 184                         show_differences(ce->name, ce->name, old, size);
 185                 free(old);
 186         }
 187         return 0;
 188 }