show-diff.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7 #include <ctype.h>
   8
   9 static char *diff_cmd = "diff -L '%s' -u -N  - '%s'";
  10
  11 /* Help to copy the thing properly quoted for the shell safety.
  12  * any single quote is replaced with '\'', and the caller is
  13  * expected to enclose the result within a single quote pair.
  14  *
  15  * E.g.
  16  *  original     sq_expand     result
  17  *  name     ==> name      ==> 'name'
  18  *  a b      ==> a b       ==> 'a b'
  19  *  a'b      ==> a'\''b    ==> 'a'\''b'
  20  *
  21  * NOTE! The returned memory belongs to this function so
  22  * do not free it.
  23  */
  24 static char *sq_expand(char *src)
  25 {
  26         static char *buf = NULL;
  27         static int buf_size = -1;
  28         int cnt, c;
  29         char *cp;
  30
  31         /* count single quote characters */
  32         for (cnt = 0, cp = src; *cp; cnt++, cp++)
  33                 if (*cp == '\'')
  34                         cnt += 3;
  35
  36         if (buf_size < cnt) {
  37                 free(buf);
  38                 buf_size = cnt;
  39                 buf = malloc(cnt);
  40         }
  41
  42         cp = buf;
  43         while ((c = *src++)) {
  44                 if (c != '\'')
  45                         *cp++ = c;
  46                 else {
  47                         cp = strcpy(cp, "'\\''");
  48                         cp += 4;
  49                 }
  50         }
  51         *cp = 0;
  52         return buf;
  53 }
  54
  55 static void show_differences(char *name, void *old_contents,
  56                              unsigned long long old_size)
  57 {
  58         FILE *f;
  59         static char *cmd = NULL;
  60         static int cmd_size = -1;
  61
  62         char *name_sq = sq_expand(name);
  63         int cmd_required_length = strlen(name_sq) * 2 + strlen(diff_cmd);
  64
  65         if (cmd_size < cmd_required_length) {
  66                 free(cmd);
  67                 cmd_size = cmd_required_length;
  68                 cmd = malloc(cmd_required_length);
  69         }
  70         snprintf(cmd, cmd_size, diff_cmd, name_sq, name_sq);
  71         f = popen(cmd, "w");
  72         if (old_size)
  73                 fwrite(old_contents, old_size, 1, f);
  74         pclose(f);
  75 }
  76
  77 static void show_diff_empty(struct cache_entry *ce)
  78 {
  79         char *old;
  80         unsigned long int size;
  81         int lines=0;
  82         unsigned char type[20], *p, *end;
  83
  84         old = read_sha1_file(ce->sha1, type, &size);
  85         if (size > 0) {
  86                 int startline = 1;
  87                 int c = 0;
  88
  89                 printf("--- %s\n", ce->name);
  90                 printf("+++ /dev/null\n");
  91                 p = old;
  92                 end = old + size;
  93                 while (p < end)
  94                         if (*p++ == '\n')
  95                                 lines ++;
  96                 printf("@@ -1,%d +0,0 @@\n", lines);
  97                 p = old;
  98                 while (p < end) {
  99                         c = *p++;
 100                         if (startline) {
 101                                 putchar('-');
 102                                 startline = 0;
 103                         }
 104                         putchar(c);
 105                         if (c == '\n')
 106                                 startline = 1;
 107                 }
 108                 if (c!='\n')
 109                         printf("\n");
 110                 fflush(stdout);
 111         }
 112 }
 113
 114 static const char *show_diff_usage = "show-diff [-s] [-q] [-z] [paths...]";
 115
 116 static int matches_pathspec(struct cache_entry *ce, char **spec, int cnt)
 117 {
 118         int i;
 119         int namelen = ce_namelen(ce);
 120         for (i = 0; i < cnt; i++) {
 121                 int speclen = strlen(spec[i]);
 122                 if (! strncmp(spec[i], ce->name, speclen) &&
 123                     speclen <= namelen &&
 124                     (ce->name[speclen] == 0 ||
 125                      ce->name[speclen] == '/'))
 126                         return 1;
 127         }
 128         return 0;
 129 }
 130
 131 int main(int argc, char **argv)
 132 {
 133         int silent = 0;
 134         int silent_on_nonexisting_files = 0;
 135         int machine_readable = 0;
 136         int entries = read_cache();
 137         int i;
 138
 139         while (1 < argc && argv[1][0] == '-') {
 140                 if (!strcmp(argv[1], "-s"))
 141                         silent_on_nonexisting_files = silent = 1;
 142                 else if (!strcmp(argv[1], "-q"))
 143                         silent_on_nonexisting_files = 1;
 144                 else if (!strcmp(argv[1], "-z")) {
 145                         machine_readable = 1;
 146                 }
 147                 else
 148                         usage(show_diff_usage);
 149                 argv++; argc--;
 150         }
 151
 152         /* At this point, if argc == 1, then we are doing everything.
 153          * Otherwise argv[1] .. argv[argc-1] have the explicit paths.
 154          */
 155         if (entries < 0) {
 156                 perror("read_cache");
 157                 exit(1);
 158         }
 159         for (i = 0; i < entries; i++) {
 160                 struct stat st;
 161                 struct cache_entry *ce = active_cache[i];
 162                 int changed;
 163                 unsigned long size;
 164                 char type[20];
 165                 void *new;
 166
 167                 if (1 <argc &&
 168                     ! matches_pathspec(ce, argv+1, argc-1))
 169                         continue;
 170
 171                 if (stat(ce->name, &st) < 0) {
 172                         if (errno == ENOENT && silent_on_nonexisting_files)
 173                                 continue;
 174                         if (machine_readable)
 175                                 printf("X %s%c", ce->name, 0);
 176                         else {
 177                                 printf("%s: %s\n", ce->name, strerror(errno));
 178                                 if (errno == ENOENT)
 179                                         show_diff_empty(ce);
 180                         }
 181                         continue;
 182                 }
 183                 changed = cache_match_stat(ce, &st);
 184                 if (!changed)
 185                         continue;
 186                 if (!machine_readable)
 187                         printf("%s: %s\n", ce->name, sha1_to_hex(ce->sha1));
 188                 else {
 189                         printf("%s %s%c", sha1_to_hex(ce->sha1), ce->name, 0);
 190                         continue;
 191                 }
 192                 fflush(stdout);
 193                 if (silent)
 194                         continue;
 195
 196                 new = read_sha1_file(ce->sha1, type, &size);
 197                 show_differences(ce->name, new, size);
 198                 free(new);
 199         }
 200         return 0;
 201 }