diff-no-index.c

   1 /*
   2  * "diff --no-index" support
   3  * Copyright (c) 2007 by Johannes Schindelin
   4  * Copyright (c) 2008 by Junio C Hamano
   5  */
   6
   7 #include "git-compat-util.h"
   8 #include "abspath.h"
   9 #include "color.h"
  10 #include "commit.h"
  11 #include "diff.h"
  12 #include "diffcore.h"
  13 #include "gettext.h"
  14 #include "revision.h"
  15 #include "parse-options.h"
  16 #include "string-list.h"
  17 #include "dir.h"
  18
  19 static int read_directory_contents(const char *path, struct string_list *list)
  20 {
  21         DIR *dir;
  22         struct dirent *e;
  23
  24         if (!(dir = opendir(path)))
  25                 return error("Could not open directory %s", path);
  26
  27         while ((e = readdir_skip_dot_and_dotdot(dir)))
  28                 string_list_insert(list, e->d_name);
  29
  30         closedir(dir);
  31         return 0;
  32 }
  33
  34 /*
  35  * This should be "(standard input)" or something, but it will
  36  * probably expose many more breakages in the way no-index code
  37  * is bolted onto the diff callchain.
  38  */
  39 static const char file_from_standard_input[] = "-";
  40
  41 /*
  42  * For paths given on the command-line we treat "-" as stdin and named
  43  * pipes and symbolic links to named pipes specially.
  44  */
  45 enum special {
  46         SPECIAL_NONE,
  47         SPECIAL_STDIN,
  48         SPECIAL_PIPE,
  49 };
  50
  51 static int get_mode(const char *path, int *mode, enum special *special)
  52 {
  53         struct stat st;
  54
  55         if (!path || !strcmp(path, "/dev/null")) {
  56                 *mode = 0;
  57 #ifdef GIT_WINDOWS_NATIVE
  58         } else if (!strcasecmp(path, "nul")) {
  59                 *mode = 0;
  60 #endif
  61         } else if (path == file_from_standard_input) {
  62                 *mode = create_ce_mode(0666);
  63                 *special = SPECIAL_STDIN;
  64         } else if (lstat(path, &st)) {
  65                 return error("Could not access '%s'", path);
  66         } else {
  67                 *mode = st.st_mode;
  68         }
  69         /*
  70          * For paths on the command-line treat named pipes and symbolic
  71          * links that resolve to a named pipe specially.
  72          */
  73         if (special &&
  74             (S_ISFIFO(*mode) ||
  75              (S_ISLNK(*mode) && !stat(path, &st) && S_ISFIFO(st.st_mode)))) {
  76                 *mode = create_ce_mode(0666);
  77                 *special = SPECIAL_PIPE;
  78         }
  79
  80         return 0;
  81 }
  82
  83 static void populate_common(struct diff_filespec *s, struct strbuf *buf)
  84 {
  85         size_t size = 0;
  86
  87         s->should_munmap = 0;
  88         s->data = strbuf_detach(buf, &size);
  89         s->size = size;
  90         s->should_free = 1;
  91         s->is_stdin = 1;
  92 }
  93
  94 static void populate_from_pipe(struct diff_filespec *s)
  95 {
  96         struct strbuf buf = STRBUF_INIT;
  97         int fd = xopen(s->path, O_RDONLY);
  98
  99         if (strbuf_read(&buf, fd, 0) < 0)
 100                 die_errno("error while reading from '%s'", s->path);
 101         close(fd);
 102         populate_common(s, &buf);
 103 }
 104
 105 static void populate_from_stdin(struct diff_filespec *s)
 106 {
 107         struct strbuf buf = STRBUF_INIT;
 108
 109         if (strbuf_read(&buf, 0, 0) < 0)
 110                 die_errno("error while reading from stdin");
 111         populate_common(s, &buf);
 112 }
 113
 114 static struct diff_filespec *noindex_filespec(const char *name, int mode,
 115                                               enum special special)
 116 {
 117         struct diff_filespec *s;
 118
 119         if (!name)
 120                 name = "/dev/null";
 121         s = alloc_filespec(name);
 122         fill_filespec(s, null_oid(), 0, mode);
 123         if (special == SPECIAL_STDIN)
 124                 populate_from_stdin(s);
 125         else if (special == SPECIAL_PIPE)
 126                 populate_from_pipe(s);
 127         return s;
 128 }
 129
 130 static int queue_diff(struct diff_options *o,
 131                       const char *name1, const char *name2, int recursing)
 132 {
 133         int mode1 = 0, mode2 = 0;
 134         enum special special1 = SPECIAL_NONE, special2 = SPECIAL_NONE;
 135
 136         /* Paths can only be special if we're not recursing. */
 137         if (get_mode(name1, &mode1, recursing ? NULL : &special1) ||
 138             get_mode(name2, &mode2, recursing ? NULL : &special2))
 139                 return -1;
 140
 141         if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2)) {
 142                 struct diff_filespec *d1, *d2;
 143
 144                 if (S_ISDIR(mode1)) {
 145                         /* 2 is file that is created */
 146                         d1 = noindex_filespec(NULL, 0, SPECIAL_NONE);
 147                         d2 = noindex_filespec(name2, mode2, special2);
 148                         name2 = NULL;
 149                         mode2 = 0;
 150                 } else {
 151                         /* 1 is file that is deleted */
 152                         d1 = noindex_filespec(name1, mode1, special1);
 153                         d2 = noindex_filespec(NULL, 0, SPECIAL_NONE);
 154                         name1 = NULL;
 155                         mode1 = 0;
 156                 }
 157                 /* emit that file */
 158                 diff_queue(&diff_queued_diff, d1, d2);
 159
 160                 /* and then let the entire directory be created or deleted */
 161         }
 162
 163         if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
 164                 struct strbuf buffer1 = STRBUF_INIT;
 165                 struct strbuf buffer2 = STRBUF_INIT;
 166                 struct string_list p1 = STRING_LIST_INIT_DUP;
 167                 struct string_list p2 = STRING_LIST_INIT_DUP;
 168                 int i1, i2, ret = 0;
 169                 size_t len1 = 0, len2 = 0;
 170
 171                 if (name1 && read_directory_contents(name1, &p1))
 172                         return -1;
 173                 if (name2 && read_directory_contents(name2, &p2)) {
 174                         string_list_clear(&p1, 0);
 175                         return -1;
 176                 }
 177
 178                 if (name1) {
 179                         strbuf_addstr(&buffer1, name1);
 180                         strbuf_complete(&buffer1, '/');
 181                         len1 = buffer1.len;
 182                 }
 183
 184                 if (name2) {
 185                         strbuf_addstr(&buffer2, name2);
 186                         strbuf_complete(&buffer2, '/');
 187                         len2 = buffer2.len;
 188                 }
 189
 190                 for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
 191                         const char *n1, *n2;
 192                         int comp;
 193
 194                         strbuf_setlen(&buffer1, len1);
 195                         strbuf_setlen(&buffer2, len2);
 196
 197                         if (i1 == p1.nr)
 198                                 comp = 1;
 199                         else if (i2 == p2.nr)
 200                                 comp = -1;
 201                         else
 202                                 comp = strcmp(p1.items[i1].string, p2.items[i2].string);
 203
 204                         if (comp > 0)
 205                                 n1 = NULL;
 206                         else {
 207                                 strbuf_addstr(&buffer1, p1.items[i1++].string);
 208                                 n1 = buffer1.buf;
 209                         }
 210
 211                         if (comp < 0)
 212                                 n2 = NULL;
 213                         else {
 214                                 strbuf_addstr(&buffer2, p2.items[i2++].string);
 215                                 n2 = buffer2.buf;
 216                         }
 217
 218                         ret = queue_diff(o, n1, n2, 1);
 219                 }
 220                 string_list_clear(&p1, 0);
 221                 string_list_clear(&p2, 0);
 222                 strbuf_release(&buffer1);
 223                 strbuf_release(&buffer2);
 224
 225                 return ret;
 226         } else {
 227                 struct diff_filespec *d1, *d2;
 228
 229                 if (o->flags.reverse_diff) {
 230                         SWAP(mode1, mode2);
 231                         SWAP(name1, name2);
 232                         SWAP(special1, special2);
 233                 }
 234
 235                 d1 = noindex_filespec(name1, mode1, special1);
 236                 d2 = noindex_filespec(name2, mode2, special2);
 237                 diff_queue(&diff_queued_diff, d1, d2);
 238                 return 0;
 239         }
 240 }
 241
 242 /* append basename of F to D */
 243 static void append_basename(struct strbuf *path, const char *dir, const char *file)
 244 {
 245         const char *tail = strrchr(file, '/');
 246
 247         strbuf_addstr(path, dir);
 248         while (path->len && path->buf[path->len - 1] == '/')
 249                 path->len--;
 250         strbuf_addch(path, '/');
 251         strbuf_addstr(path, tail ? tail + 1 : file);
 252 }
 253
 254 /*
 255  * DWIM "diff D F" into "diff D/F F" and "diff F D" into "diff F D/F"
 256  * Note that we append the basename of F to D/, so "diff a/b/file D"
 257  * becomes "diff a/b/file D/file", not "diff a/b/file D/a/b/file".
 258  */
 259 static void fixup_paths(const char **path, struct strbuf *replacement)
 260 {
 261         struct stat st;
 262         unsigned int isdir0 = 0, isdir1 = 0;
 263         unsigned int ispipe0 = 0, ispipe1 = 0;
 264
 265         if (path[0] != file_from_standard_input && !stat(path[0], &st)) {
 266                 isdir0 = S_ISDIR(st.st_mode);
 267                 ispipe0 = S_ISFIFO(st.st_mode);
 268         }
 269
 270         if (path[1] != file_from_standard_input && !stat(path[1], &st)) {
 271                 isdir1 = S_ISDIR(st.st_mode);
 272                 ispipe1 = S_ISFIFO(st.st_mode);
 273         }
 274
 275         if ((path[0] == file_from_standard_input && isdir1) ||
 276             (isdir0 && path[1] == file_from_standard_input))
 277                 die(_("cannot compare stdin to a directory"));
 278
 279         if ((isdir0 && ispipe1) || (ispipe0 && isdir1))
 280                 die(_("cannot compare a named pipe to a directory"));
 281
 282         if (isdir0 == isdir1)
 283                 return;
 284         if (isdir0) {
 285                 append_basename(replacement, path[0], path[1]);
 286                 path[0] = replacement->buf;
 287         } else {
 288                 append_basename(replacement, path[1], path[0]);
 289                 path[1] = replacement->buf;
 290         }
 291 }
 292
 293 static const char * const diff_no_index_usage[] = {
 294         N_("git diff --no-index [<options>] <path> <path>"),
 295         NULL
 296 };
 297
 298 int diff_no_index(struct rev_info *revs,
 299                   int implicit_no_index,
 300                   int argc, const char **argv)
 301 {
 302         int i, no_index;
 303         int ret = 1;
 304         const char *paths[2];
 305         char *to_free[ARRAY_SIZE(paths)] = { 0 };
 306         struct strbuf replacement = STRBUF_INIT;
 307         const char *prefix = revs->prefix;
 308         struct option no_index_options[] = {
 309                 OPT_BOOL_F(0, "no-index", &no_index, "",
 310                            PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
 311                 OPT_END(),
 312         };
 313         struct option *options;
 314
 315         options = add_diff_options(no_index_options, &revs->diffopt);
 316         argc = parse_options(argc, argv, revs->prefix, options,
 317                              diff_no_index_usage, 0);
 318         if (argc != 2) {
 319                 if (implicit_no_index)
 320                         warning(_("Not a git repository. Use --no-index to "
 321                                   "compare two paths outside a working tree"));
 322                 usage_with_options(diff_no_index_usage, options);
 323         }
 324         FREE_AND_NULL(options);
 325         for (i = 0; i < 2; i++) {
 326                 const char *p = argv[i];
 327                 if (!strcmp(p, "-"))
 328                         /*
 329                          * stdin should be spelled as "-"; if you have
 330                          * path that is "-", spell it as "./-".
 331                          */
 332                         p = file_from_standard_input;
 333                 else if (prefix)
 334                         p = to_free[i] = prefix_filename(prefix, p);
 335                 paths[i] = p;
 336         }
 337
 338         fixup_paths(paths, &replacement);
 339
 340         revs->diffopt.skip_stat_unmatch = 1;
 341         if (!revs->diffopt.output_format)
 342                 revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 343
 344         revs->diffopt.flags.no_index = 1;
 345
 346         revs->diffopt.flags.relative_name = 1;
 347         revs->diffopt.prefix = prefix;
 348
 349         revs->max_count = -2;
 350         diff_setup_done(&revs->diffopt);
 351
 352         setup_diff_pager(&revs->diffopt);
 353         revs->diffopt.flags.exit_with_status = 1;
 354
 355         if (queue_diff(&revs->diffopt, paths[0], paths[1], 0))
 356                 goto out;
 357         diff_set_mnemonic_prefix(&revs->diffopt, "1/", "2/");
 358         diffcore_std(&revs->diffopt);
 359         diff_flush(&revs->diffopt);
 360
 361         /*
 362          * The return code for --no-index imitates diff(1):
 363          * 0 = no changes, 1 = changes, else error
 364          */
 365         ret = diff_result_code(&revs->diffopt);
 366
 367 out:
 368         for (i = 0; i < ARRAY_SIZE(to_free); i++)
 369                 free(to_free[i]);
 370         strbuf_release(&replacement);
 371         return ret;
 372 }