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 #define DISABLE_SIGN_COMPARE_WARNINGS
   8
   9 #include "git-compat-util.h"
  10 #include "abspath.h"
  11 #include "color.h"
  12 #include "commit.h"
  13 #include "diff.h"
  14 #include "diffcore.h"
  15 #include "gettext.h"
  16 #include "revision.h"
  17 #include "parse-options.h"
  18 #include "string-list.h"
  19 #include "dir.h"
  20
  21 static int read_directory_contents(const char *path, struct string_list *list)
  22 {
  23         DIR *dir;
  24         struct dirent *e;
  25
  26         if (!(dir = opendir(path)))
  27                 return error("Could not open directory %s", path);
  28
  29         while ((e = readdir_skip_dot_and_dotdot(dir)))
  30                 string_list_insert(list, e->d_name);
  31
  32         closedir(dir);
  33         return 0;
  34 }
  35
  36 /*
  37  * This should be "(standard input)" or something, but it will
  38  * probably expose many more breakages in the way no-index code
  39  * is bolted onto the diff callchain.
  40  */
  41 static const char file_from_standard_input[] = "-";
  42
  43 /*
  44  * For paths given on the command-line we treat "-" as stdin and named
  45  * pipes and symbolic links to named pipes specially.
  46  */
  47 enum special {
  48         SPECIAL_NONE,
  49         SPECIAL_STDIN,
  50         SPECIAL_PIPE,
  51 };
  52
  53 static int get_mode(const char *path, int *mode, enum special *special)
  54 {
  55         struct stat st;
  56
  57         if (!path || !strcmp(path, "/dev/null")) {
  58                 *mode = 0;
  59 #ifdef GIT_WINDOWS_NATIVE
  60         } else if (!strcasecmp(path, "nul")) {
  61                 *mode = 0;
  62 #endif
  63         } else if (path == file_from_standard_input) {
  64                 *mode = create_ce_mode(0666);
  65                 *special = SPECIAL_STDIN;
  66         } else if (lstat(path, &st)) {
  67                 return error("Could not access '%s'", path);
  68         } else {
  69                 *mode = st.st_mode;
  70         }
  71         /*
  72          * For paths on the command-line treat named pipes and symbolic
  73          * links that resolve to a named pipe specially.
  74          */
  75         if (special &&
  76             (S_ISFIFO(*mode) ||
  77              (S_ISLNK(*mode) && !stat(path, &st) && S_ISFIFO(st.st_mode)))) {
  78                 *mode = create_ce_mode(0666);
  79                 *special = SPECIAL_PIPE;
  80         }
  81
  82         return 0;
  83 }
  84
  85 static void populate_common(struct diff_filespec *s, struct strbuf *buf)
  86 {
  87         size_t size = 0;
  88
  89         s->should_munmap = 0;
  90         s->data = strbuf_detach(buf, &size);
  91         s->size = size;
  92         s->should_free = 1;
  93         s->is_stdin = 1;
  94 }
  95
  96 static void populate_from_pipe(struct diff_filespec *s)
  97 {
  98         struct strbuf buf = STRBUF_INIT;
  99         int fd = xopen(s->path, O_RDONLY);
 100
 101         if (strbuf_read(&buf, fd, 0) < 0)
 102                 die_errno("error while reading from '%s'", s->path);
 103         close(fd);
 104         populate_common(s, &buf);
 105 }
 106
 107 static void populate_from_stdin(struct diff_filespec *s)
 108 {
 109         struct strbuf buf = STRBUF_INIT;
 110
 111         if (strbuf_read(&buf, 0, 0) < 0)
 112                 die_errno("error while reading from stdin");
 113         populate_common(s, &buf);
 114 }
 115
 116 static struct diff_filespec *noindex_filespec(const char *name, int mode,
 117                                               enum special special)
 118 {
 119         struct diff_filespec *s;
 120
 121         if (!name)
 122                 name = "/dev/null";
 123         s = alloc_filespec(name);
 124         fill_filespec(s, null_oid(), 0, mode);
 125         if (special == SPECIAL_STDIN)
 126                 populate_from_stdin(s);
 127         else if (special == SPECIAL_PIPE)
 128                 populate_from_pipe(s);
 129         return s;
 130 }
 131
 132 static int queue_diff(struct diff_options *o,
 133                       const char *name1, const char *name2, int recursing)
 134 {
 135         int mode1 = 0, mode2 = 0;
 136         enum special special1 = SPECIAL_NONE, special2 = SPECIAL_NONE;
 137
 138         /* Paths can only be special if we're not recursing. */
 139         if (get_mode(name1, &mode1, recursing ? NULL : &special1) ||
 140             get_mode(name2, &mode2, recursing ? NULL : &special2))
 141                 return -1;
 142
 143         if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2)) {
 144                 struct diff_filespec *d1, *d2;
 145
 146                 if (S_ISDIR(mode1)) {
 147                         /* 2 is file that is created */
 148                         d1 = noindex_filespec(NULL, 0, SPECIAL_NONE);
 149                         d2 = noindex_filespec(name2, mode2, special2);
 150                         name2 = NULL;
 151                         mode2 = 0;
 152                 } else {
 153                         /* 1 is file that is deleted */
 154                         d1 = noindex_filespec(name1, mode1, special1);
 155                         d2 = noindex_filespec(NULL, 0, SPECIAL_NONE);
 156                         name1 = NULL;
 157                         mode1 = 0;
 158                 }
 159                 /* emit that file */
 160                 diff_queue(&diff_queued_diff, d1, d2);
 161
 162                 /* and then let the entire directory be created or deleted */
 163         }
 164
 165         if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
 166                 struct strbuf buffer1 = STRBUF_INIT;
 167                 struct strbuf buffer2 = STRBUF_INIT;
 168                 struct string_list p1 = STRING_LIST_INIT_DUP;
 169                 struct string_list p2 = STRING_LIST_INIT_DUP;
 170                 int i1, i2, ret = 0;
 171                 size_t len1 = 0, len2 = 0;
 172
 173                 if (name1 && read_directory_contents(name1, &p1))
 174                         return -1;
 175                 if (name2 && read_directory_contents(name2, &p2)) {
 176                         string_list_clear(&p1, 0);
 177                         return -1;
 178                 }
 179
 180                 if (name1) {
 181                         strbuf_addstr(&buffer1, name1);
 182                         strbuf_complete(&buffer1, '/');
 183                         len1 = buffer1.len;
 184                 }
 185
 186                 if (name2) {
 187                         strbuf_addstr(&buffer2, name2);
 188                         strbuf_complete(&buffer2, '/');
 189                         len2 = buffer2.len;
 190                 }
 191
 192                 for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
 193                         const char *n1, *n2;
 194                         int comp;
 195
 196                         strbuf_setlen(&buffer1, len1);
 197                         strbuf_setlen(&buffer2, len2);
 198
 199                         if (i1 == p1.nr)
 200                                 comp = 1;
 201                         else if (i2 == p2.nr)
 202                                 comp = -1;
 203                         else
 204                                 comp = strcmp(p1.items[i1].string, p2.items[i2].string);
 205
 206                         if (comp > 0)
 207                                 n1 = NULL;
 208                         else {
 209                                 strbuf_addstr(&buffer1, p1.items[i1++].string);
 210                                 n1 = buffer1.buf;
 211                         }
 212
 213                         if (comp < 0)
 214                                 n2 = NULL;
 215                         else {
 216                                 strbuf_addstr(&buffer2, p2.items[i2++].string);
 217                                 n2 = buffer2.buf;
 218                         }
 219
 220                         ret = queue_diff(o, n1, n2, 1);
 221                 }
 222                 string_list_clear(&p1, 0);
 223                 string_list_clear(&p2, 0);
 224                 strbuf_release(&buffer1);
 225                 strbuf_release(&buffer2);
 226
 227                 return ret;
 228         } else {
 229                 struct diff_filespec *d1, *d2;
 230
 231                 if (o->flags.reverse_diff) {
 232                         SWAP(mode1, mode2);
 233                         SWAP(name1, name2);
 234                         SWAP(special1, special2);
 235                 }
 236
 237                 d1 = noindex_filespec(name1, mode1, special1);
 238                 d2 = noindex_filespec(name2, mode2, special2);
 239                 diff_queue(&diff_queued_diff, d1, d2);
 240                 return 0;
 241         }
 242 }
 243
 244 /* append basename of F to D */
 245 static void append_basename(struct strbuf *path, const char *dir, const char *file)
 246 {
 247         const char *tail = strrchr(file, '/');
 248
 249         strbuf_addstr(path, dir);
 250         while (path->len && path->buf[path->len - 1] == '/')
 251                 path->len--;
 252         strbuf_addch(path, '/');
 253         strbuf_addstr(path, tail ? tail + 1 : file);
 254 }
 255
 256 /*
 257  * DWIM "diff D F" into "diff D/F F" and "diff F D" into "diff F D/F"
 258  * Note that we append the basename of F to D/, so "diff a/b/file D"
 259  * becomes "diff a/b/file D/file", not "diff a/b/file D/a/b/file".
 260  */
 261 static void fixup_paths(const char **path, struct strbuf *replacement)
 262 {
 263         struct stat st;
 264         unsigned int isdir0 = 0, isdir1 = 0;
 265         unsigned int ispipe0 = 0, ispipe1 = 0;
 266
 267         if (path[0] != file_from_standard_input && !stat(path[0], &st)) {
 268                 isdir0 = S_ISDIR(st.st_mode);
 269                 ispipe0 = S_ISFIFO(st.st_mode);
 270         }
 271
 272         if (path[1] != file_from_standard_input && !stat(path[1], &st)) {
 273                 isdir1 = S_ISDIR(st.st_mode);
 274                 ispipe1 = S_ISFIFO(st.st_mode);
 275         }
 276
 277         if ((path[0] == file_from_standard_input && isdir1) ||
 278             (isdir0 && path[1] == file_from_standard_input))
 279                 die(_("cannot compare stdin to a directory"));
 280
 281         if ((isdir0 && ispipe1) || (ispipe0 && isdir1))
 282                 die(_("cannot compare a named pipe to a directory"));
 283
 284         if (isdir0 == isdir1)
 285                 return;
 286         if (isdir0) {
 287                 append_basename(replacement, path[0], path[1]);
 288                 path[0] = replacement->buf;
 289         } else {
 290                 append_basename(replacement, path[1], path[0]);
 291                 path[1] = replacement->buf;
 292         }
 293 }
 294
 295 static const char * const diff_no_index_usage[] = {
 296         N_("git diff --no-index [<options>] <path> <path>"),
 297         NULL
 298 };
 299
 300 int diff_no_index(struct rev_info *revs,
 301                   int implicit_no_index,
 302                   int argc, const char **argv)
 303 {
 304         int i, no_index;
 305         int ret = 1;
 306         const char *paths[2];
 307         char *to_free[ARRAY_SIZE(paths)] = { 0 };
 308         struct strbuf replacement = STRBUF_INIT;
 309         const char *prefix = revs->prefix;
 310         struct option no_index_options[] = {
 311                 OPT_BOOL_F(0, "no-index", &no_index, "",
 312                            PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
 313                 OPT_END(),
 314         };
 315         struct option *options;
 316
 317         options = add_diff_options(no_index_options, &revs->diffopt);
 318         argc = parse_options(argc, argv, revs->prefix, options,
 319                              diff_no_index_usage, 0);
 320         if (argc != 2) {
 321                 if (implicit_no_index)
 322                         warning(_("Not a git repository. Use --no-index to "
 323                                   "compare two paths outside a working tree"));
 324                 usage_with_options(diff_no_index_usage, options);
 325         }
 326         FREE_AND_NULL(options);
 327         for (i = 0; i < 2; i++) {
 328                 const char *p = argv[i];
 329                 if (!strcmp(p, "-"))
 330                         /*
 331                          * stdin should be spelled as "-"; if you have
 332                          * path that is "-", spell it as "./-".
 333                          */
 334                         p = file_from_standard_input;
 335                 else if (prefix)
 336                         p = to_free[i] = prefix_filename(prefix, p);
 337                 paths[i] = p;
 338         }
 339
 340         fixup_paths(paths, &replacement);
 341
 342         revs->diffopt.skip_stat_unmatch = 1;
 343         if (!revs->diffopt.output_format)
 344                 revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 345
 346         revs->diffopt.flags.no_index = 1;
 347
 348         revs->diffopt.flags.relative_name = 1;
 349         revs->diffopt.prefix = prefix;
 350
 351         revs->max_count = -2;
 352         diff_setup_done(&revs->diffopt);
 353
 354         setup_diff_pager(&revs->diffopt);
 355         revs->diffopt.flags.exit_with_status = 1;
 356
 357         if (queue_diff(&revs->diffopt, paths[0], paths[1], 0))
 358                 goto out;
 359         diff_set_mnemonic_prefix(&revs->diffopt, "1/", "2/");
 360         diffcore_std(&revs->diffopt);
 361         diff_flush(&revs->diffopt);
 362
 363         /*
 364          * The return code for --no-index imitates diff(1):
 365          * 0 = no changes, 1 = changes, else error
 366          */
 367         ret = diff_result_code(revs);
 368
 369 out:
 370         for (i = 0; i < ARRAY_SIZE(to_free); i++)
 371                 free(to_free[i]);
 372         strbuf_release(&replacement);
 373         return ret;
 374 }