date: make DATE_MODE thread-safe
[git.git] / archive.c
bloba6730bebfa07d65d003b5594c63081e6ef7d3e88
1 #include "git-compat-util.h"
2 #include "abspath.h"
3 #include "config.h"
4 #include "convert.h"
5 #include "environment.h"
6 #include "gettext.h"
7 #include "hex.h"
8 #include "object-name.h"
9 #include "path.h"
10 #include "pretty.h"
11 #include "setup.h"
12 #include "refs.h"
13 #include "object-store-ll.h"
14 #include "commit.h"
15 #include "tree.h"
16 #include "tree-walk.h"
17 #include "attr.h"
18 #include "archive.h"
19 #include "parse-options.h"
20 #include "unpack-trees.h"
21 #include "quote.h"
23 static char const * const archive_usage[] = {
24 N_("git archive [<options>] <tree-ish> [<path>...]"),
25 "git archive --list",
26 N_("git archive --remote <repo> [--exec <cmd>] [<options>] <tree-ish> [<path>...]"),
27 N_("git archive --remote <repo> [--exec <cmd>] --list"),
28 NULL
31 static const struct archiver **archivers;
32 static int nr_archivers;
33 static int alloc_archivers;
34 static int remote_allow_unreachable;
36 void register_archiver(struct archiver *ar)
38 ALLOC_GROW(archivers, nr_archivers + 1, alloc_archivers);
39 archivers[nr_archivers++] = ar;
42 void init_archivers(void)
44 init_tar_archiver();
45 init_zip_archiver();
48 static void format_subst(const struct commit *commit,
49 const char *src, size_t len,
50 struct strbuf *buf, struct pretty_print_context *ctx)
52 char *to_free = NULL;
53 struct strbuf fmt = STRBUF_INIT;
55 if (src == buf->buf)
56 to_free = strbuf_detach(buf, NULL);
57 for (;;) {
58 const char *b, *c;
60 b = memmem(src, len, "$Format:", 8);
61 if (!b)
62 break;
63 c = memchr(b + 8, '$', (src + len) - b - 8);
64 if (!c)
65 break;
67 strbuf_reset(&fmt);
68 strbuf_add(&fmt, b + 8, c - b - 8);
70 strbuf_add(buf, src, b - src);
71 repo_format_commit_message(the_repository, commit, fmt.buf,
72 buf, ctx);
73 len -= c + 1 - src;
74 src = c + 1;
76 strbuf_add(buf, src, len);
77 strbuf_release(&fmt);
78 free(to_free);
81 static void *object_file_to_archive(const struct archiver_args *args,
82 const char *path,
83 const struct object_id *oid,
84 unsigned int mode,
85 enum object_type *type,
86 unsigned long *sizep)
88 void *buffer;
89 const struct commit *commit = args->convert ? args->commit : NULL;
90 struct checkout_metadata meta;
92 init_checkout_metadata(&meta, args->refname,
93 args->commit_oid ? args->commit_oid :
94 (args->tree ? &args->tree->object.oid : NULL), oid);
96 path += args->baselen;
97 buffer = repo_read_object_file(the_repository, oid, type, sizep);
98 if (buffer && S_ISREG(mode)) {
99 struct strbuf buf = STRBUF_INIT;
100 size_t size = 0;
102 strbuf_attach(&buf, buffer, *sizep, *sizep + 1);
103 convert_to_working_tree(args->repo->index, path, buf.buf, buf.len, &buf, &meta);
104 if (commit)
105 format_subst(commit, buf.buf, buf.len, &buf, args->pretty_ctx);
106 buffer = strbuf_detach(&buf, &size);
107 *sizep = size;
110 return buffer;
113 struct directory {
114 struct directory *up;
115 struct object_id oid;
116 int baselen, len;
117 unsigned mode;
118 char path[FLEX_ARRAY];
121 struct archiver_context {
122 struct archiver_args *args;
123 write_archive_entry_fn_t write_entry;
124 struct directory *bottom;
127 static const struct attr_check *get_archive_attrs(struct index_state *istate,
128 const char *path)
130 static struct attr_check *check;
131 if (!check)
132 check = attr_check_initl("export-ignore", "export-subst", NULL);
133 git_check_attr(istate, path, check);
134 return check;
137 static int check_attr_export_ignore(const struct attr_check *check)
139 return check && ATTR_TRUE(check->items[0].value);
142 static int check_attr_export_subst(const struct attr_check *check)
144 return check && ATTR_TRUE(check->items[1].value);
147 static int write_archive_entry(const struct object_id *oid, const char *base,
148 int baselen, const char *filename, unsigned mode,
149 void *context)
151 static struct strbuf path = STRBUF_INIT;
152 struct archiver_context *c = context;
153 struct archiver_args *args = c->args;
154 write_archive_entry_fn_t write_entry = c->write_entry;
155 int err;
156 const char *path_without_prefix;
157 unsigned long size;
158 void *buffer;
159 enum object_type type;
161 args->convert = 0;
162 strbuf_reset(&path);
163 strbuf_grow(&path, PATH_MAX);
164 strbuf_add(&path, args->base, args->baselen);
165 strbuf_add(&path, base, baselen);
166 strbuf_addstr(&path, filename);
167 if (S_ISDIR(mode) || S_ISGITLINK(mode))
168 strbuf_addch(&path, '/');
169 path_without_prefix = path.buf + args->baselen;
171 if (!S_ISDIR(mode)) {
172 const struct attr_check *check;
173 check = get_archive_attrs(args->repo->index, path_without_prefix);
174 if (check_attr_export_ignore(check))
175 return 0;
176 args->convert = check_attr_export_subst(check);
179 if (args->prefix) {
180 static struct strbuf new_path = STRBUF_INIT;
181 static struct strbuf buf = STRBUF_INIT;
182 const char *rel;
184 rel = relative_path(path_without_prefix, args->prefix, &buf);
187 * We don't add an entry for the current working
188 * directory when we are at the root; skip it also when
189 * we're in a subdirectory or submodule. Skip entries
190 * higher up as well.
192 if (!strcmp(rel, "./") || starts_with(rel, "../"))
193 return S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0;
195 /* rel can refer to path, so don't edit it in place */
196 strbuf_reset(&new_path);
197 strbuf_add(&new_path, args->base, args->baselen);
198 strbuf_addstr(&new_path, rel);
199 strbuf_swap(&path, &new_path);
202 if (args->verbose)
203 fprintf(stderr, "%.*s\n", (int)path.len, path.buf);
205 if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
206 err = write_entry(args, oid, path.buf, path.len, mode, NULL, 0);
207 if (err)
208 return err;
209 return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
212 /* Stream it? */
213 if (S_ISREG(mode) && !args->convert &&
214 oid_object_info(args->repo, oid, &size) == OBJ_BLOB &&
215 size > big_file_threshold)
216 return write_entry(args, oid, path.buf, path.len, mode, NULL, size);
218 buffer = object_file_to_archive(args, path.buf, oid, mode, &type, &size);
219 if (!buffer)
220 return error(_("cannot read '%s'"), oid_to_hex(oid));
221 err = write_entry(args, oid, path.buf, path.len, mode, buffer, size);
222 free(buffer);
223 return err;
226 static void queue_directory(const struct object_id *oid,
227 struct strbuf *base, const char *filename,
228 unsigned mode, struct archiver_context *c)
230 struct directory *d;
231 size_t len = st_add4(base->len, 1, strlen(filename), 1);
232 d = xmalloc(st_add(sizeof(*d), len));
233 d->up = c->bottom;
234 d->baselen = base->len;
235 d->mode = mode;
236 c->bottom = d;
237 d->len = xsnprintf(d->path, len, "%.*s%s/", (int)base->len, base->buf, filename);
238 oidcpy(&d->oid, oid);
241 static int write_directory(struct archiver_context *c)
243 struct directory *d = c->bottom;
244 int ret;
246 if (!d)
247 return 0;
248 c->bottom = d->up;
249 d->path[d->len - 1] = '\0'; /* no trailing slash */
250 ret =
251 write_directory(c) ||
252 write_archive_entry(&d->oid, d->path, d->baselen,
253 d->path + d->baselen, d->mode,
254 c) != READ_TREE_RECURSIVE;
255 free(d);
256 return ret ? -1 : 0;
259 static int queue_or_write_archive_entry(const struct object_id *oid,
260 struct strbuf *base, const char *filename,
261 unsigned mode, void *context)
263 struct archiver_context *c = context;
265 while (c->bottom &&
266 !(base->len >= c->bottom->len &&
267 !strncmp(base->buf, c->bottom->path, c->bottom->len))) {
268 struct directory *next = c->bottom->up;
269 free(c->bottom);
270 c->bottom = next;
273 if (S_ISDIR(mode)) {
274 size_t baselen = base->len;
275 const struct attr_check *check;
277 /* Borrow base, but restore its original value when done. */
278 strbuf_addstr(base, filename);
279 strbuf_addch(base, '/');
280 check = get_archive_attrs(c->args->repo->index, base->buf);
281 strbuf_setlen(base, baselen);
283 if (check_attr_export_ignore(check))
284 return 0;
285 queue_directory(oid, base, filename, mode, c);
286 return READ_TREE_RECURSIVE;
289 if (write_directory(c))
290 return -1;
291 return write_archive_entry(oid, base->buf, base->len, filename, mode,
292 context);
295 struct extra_file_info {
296 char *base;
297 struct stat stat;
298 void *content;
301 int write_archive_entries(struct archiver_args *args,
302 write_archive_entry_fn_t write_entry)
304 struct archiver_context context;
305 struct unpack_trees_options opts;
306 struct tree_desc t;
307 int err;
308 struct strbuf path_in_archive = STRBUF_INIT;
309 struct strbuf content = STRBUF_INIT;
310 struct object_id fake_oid;
311 int i;
313 oidcpy(&fake_oid, null_oid());
315 if (args->baselen > 0 && args->base[args->baselen - 1] == '/') {
316 size_t len = args->baselen;
318 while (len > 1 && args->base[len - 2] == '/')
319 len--;
320 if (args->verbose)
321 fprintf(stderr, "%.*s\n", (int)len, args->base);
322 err = write_entry(args, &args->tree->object.oid, args->base,
323 len, 040777, NULL, 0);
324 if (err)
325 return err;
328 memset(&context, 0, sizeof(context));
329 context.args = args;
330 context.write_entry = write_entry;
333 * Setup index and instruct attr to read index only
335 if (!args->worktree_attributes) {
336 memset(&opts, 0, sizeof(opts));
337 opts.index_only = 1;
338 opts.head_idx = -1;
339 opts.src_index = args->repo->index;
340 opts.dst_index = args->repo->index;
341 opts.fn = oneway_merge;
342 init_tree_desc(&t, args->tree->buffer, args->tree->size);
343 if (unpack_trees(1, &t, &opts))
344 return -1;
345 git_attr_set_direction(GIT_ATTR_INDEX);
348 err = read_tree(args->repo, args->tree,
349 &args->pathspec,
350 queue_or_write_archive_entry,
351 &context);
352 if (err == READ_TREE_RECURSIVE)
353 err = 0;
354 while (context.bottom) {
355 struct directory *next = context.bottom->up;
356 free(context.bottom);
357 context.bottom = next;
360 for (i = 0; i < args->extra_files.nr; i++) {
361 struct string_list_item *item = args->extra_files.items + i;
362 char *path = item->string;
363 struct extra_file_info *info = item->util;
365 put_be64(fake_oid.hash, i + 1);
367 if (!info->content) {
368 strbuf_reset(&path_in_archive);
369 if (info->base)
370 strbuf_addstr(&path_in_archive, info->base);
371 strbuf_addstr(&path_in_archive, basename(path));
373 strbuf_reset(&content);
374 if (strbuf_read_file(&content, path, info->stat.st_size) < 0)
375 err = error_errno(_("cannot read '%s'"), path);
376 else
377 err = write_entry(args, &fake_oid, path_in_archive.buf,
378 path_in_archive.len,
379 canon_mode(info->stat.st_mode),
380 content.buf, content.len);
381 } else {
382 err = write_entry(args, &fake_oid,
383 path, strlen(path),
384 canon_mode(info->stat.st_mode),
385 info->content, info->stat.st_size);
388 if (err)
389 break;
391 strbuf_release(&path_in_archive);
392 strbuf_release(&content);
394 return err;
397 static const struct archiver *lookup_archiver(const char *name)
399 int i;
401 if (!name)
402 return NULL;
404 for (i = 0; i < nr_archivers; i++) {
405 if (!strcmp(name, archivers[i]->name))
406 return archivers[i];
408 return NULL;
411 struct path_exists_context {
412 struct pathspec pathspec;
413 struct archiver_args *args;
416 static int reject_entry(const struct object_id *oid UNUSED,
417 struct strbuf *base,
418 const char *filename, unsigned mode,
419 void *context)
421 int ret = -1;
422 struct path_exists_context *ctx = context;
424 if (S_ISDIR(mode)) {
425 struct strbuf sb = STRBUF_INIT;
426 strbuf_addbuf(&sb, base);
427 strbuf_addstr(&sb, filename);
428 if (!match_pathspec(ctx->args->repo->index,
429 &ctx->pathspec,
430 sb.buf, sb.len, 0, NULL, 1))
431 ret = READ_TREE_RECURSIVE;
432 strbuf_release(&sb);
434 return ret;
437 static int reject_outside(const struct object_id *oid UNUSED,
438 struct strbuf *base, const char *filename,
439 unsigned mode, void *context)
441 struct archiver_args *args = context;
442 struct strbuf buf = STRBUF_INIT;
443 struct strbuf path = STRBUF_INIT;
444 int ret = 0;
446 if (S_ISDIR(mode))
447 return READ_TREE_RECURSIVE;
449 strbuf_addbuf(&path, base);
450 strbuf_addstr(&path, filename);
451 if (starts_with(relative_path(path.buf, args->prefix, &buf), "../"))
452 ret = -1;
453 strbuf_release(&buf);
454 strbuf_release(&path);
455 return ret;
458 static int path_exists(struct archiver_args *args, const char *path)
460 const char *paths[] = { path, NULL };
461 struct path_exists_context ctx;
462 int ret;
464 ctx.args = args;
465 parse_pathspec(&ctx.pathspec, 0, PATHSPEC_PREFER_CWD,
466 args->prefix, paths);
467 ctx.pathspec.recursive = 1;
468 if (args->prefix && read_tree(args->repo, args->tree, &ctx.pathspec,
469 reject_outside, args))
470 die(_("pathspec '%s' matches files outside the "
471 "current directory"), path);
472 ret = read_tree(args->repo, args->tree,
473 &ctx.pathspec,
474 reject_entry, &ctx);
475 clear_pathspec(&ctx.pathspec);
476 return ret != 0;
479 static void parse_pathspec_arg(const char **pathspec,
480 struct archiver_args *ar_args)
483 * must be consistent with parse_pathspec in path_exists()
484 * Also if pathspec patterns are dependent, we're in big
485 * trouble as we test each one separately
487 parse_pathspec(&ar_args->pathspec, 0, PATHSPEC_PREFER_CWD,
488 ar_args->prefix, pathspec);
489 ar_args->pathspec.recursive = 1;
490 if (pathspec) {
491 while (*pathspec) {
492 if (**pathspec && !path_exists(ar_args, *pathspec))
493 die(_("pathspec '%s' did not match any files"), *pathspec);
494 pathspec++;
499 static void parse_treeish_arg(const char **argv,
500 struct archiver_args *ar_args, int remote)
502 const char *name = argv[0];
503 const struct object_id *commit_oid;
504 time_t archive_time;
505 struct tree *tree;
506 const struct commit *commit;
507 struct object_id oid;
508 char *ref = NULL;
510 /* Remotes are only allowed to fetch actual refs */
511 if (remote && !remote_allow_unreachable) {
512 const char *colon = strchrnul(name, ':');
513 int refnamelen = colon - name;
515 if (!repo_dwim_ref(the_repository, name, refnamelen, &oid, &ref, 0))
516 die(_("no such ref: %.*s"), refnamelen, name);
517 } else {
518 repo_dwim_ref(the_repository, name, strlen(name), &oid, &ref,
522 if (repo_get_oid(the_repository, name, &oid))
523 die(_("not a valid object name: %s"), name);
525 commit = lookup_commit_reference_gently(ar_args->repo, &oid, 1);
526 if (commit) {
527 commit_oid = &commit->object.oid;
528 archive_time = commit->date;
529 } else {
530 commit_oid = NULL;
531 archive_time = time(NULL);
533 if (ar_args->mtime_option)
534 archive_time = approxidate(ar_args->mtime_option);
536 tree = parse_tree_indirect(&oid);
537 if (!tree)
538 die(_("not a tree object: %s"), oid_to_hex(&oid));
540 ar_args->refname = ref;
541 ar_args->tree = tree;
542 ar_args->commit_oid = commit_oid;
543 ar_args->commit = commit;
544 ar_args->time = archive_time;
547 static void extra_file_info_clear(void *util, const char *str UNUSED)
549 struct extra_file_info *info = util;
550 free(info->base);
551 free(info->content);
552 free(info);
555 static int add_file_cb(const struct option *opt, const char *arg, int unset)
557 struct archiver_args *args = opt->value;
558 const char **basep = (const char **)opt->defval;
559 const char *base = *basep;
560 char *path;
561 struct string_list_item *item;
562 struct extra_file_info *info;
564 if (unset) {
565 string_list_clear_func(&args->extra_files,
566 extra_file_info_clear);
567 return 0;
570 if (!arg)
571 return -1;
573 info = xmalloc(sizeof(*info));
574 info->base = xstrdup_or_null(base);
576 if (!strcmp(opt->long_name, "add-file")) {
577 path = prefix_filename(args->prefix, arg);
578 if (stat(path, &info->stat))
579 die(_("File not found: %s"), path);
580 if (!S_ISREG(info->stat.st_mode))
581 die(_("Not a regular file: %s"), path);
582 info->content = NULL; /* read the file later */
583 } else if (!strcmp(opt->long_name, "add-virtual-file")) {
584 struct strbuf buf = STRBUF_INIT;
585 const char *p = arg;
587 if (*p != '"')
588 p = strchr(p, ':');
589 else if (unquote_c_style(&buf, p, &p) < 0)
590 die(_("unclosed quote: '%s'"), arg);
592 if (!p || *p != ':')
593 die(_("missing colon: '%s'"), arg);
595 if (p == arg)
596 die(_("empty file name: '%s'"), arg);
598 path = buf.len ?
599 strbuf_detach(&buf, NULL) : xstrndup(arg, p - arg);
601 if (args->prefix) {
602 char *save = path;
603 path = prefix_filename(args->prefix, path);
604 free(save);
606 memset(&info->stat, 0, sizeof(info->stat));
607 info->stat.st_mode = S_IFREG | 0644;
608 info->content = xstrdup(p + 1);
609 info->stat.st_size = strlen(info->content);
610 } else {
611 BUG("add_file_cb() called for %s", opt->long_name);
613 item = string_list_append_nodup(&args->extra_files, path);
614 item->util = info;
616 return 0;
619 static int number_callback(const struct option *opt, const char *arg, int unset)
621 BUG_ON_OPT_NEG(unset);
622 *(int *)opt->value = strtol(arg, NULL, 10);
623 return 0;
626 static int parse_archive_args(int argc, const char **argv,
627 const struct archiver **ar, struct archiver_args *args,
628 const char *name_hint, int is_remote)
630 const char *format = NULL;
631 const char *base = NULL;
632 const char *remote = NULL;
633 const char *exec = NULL;
634 const char *output = NULL;
635 const char *mtime_option = NULL;
636 int compression_level = -1;
637 int verbose = 0;
638 int i;
639 int list = 0;
640 int worktree_attributes = 0;
641 struct option opts[] = {
642 OPT_GROUP(""),
643 OPT_STRING(0, "format", &format, N_("fmt"), N_("archive format")),
644 OPT_STRING(0, "prefix", &base, N_("prefix"),
645 N_("prepend prefix to each pathname in the archive")),
646 { OPTION_CALLBACK, 0, "add-file", args, N_("file"),
647 N_("add untracked file to archive"), 0, add_file_cb,
648 (intptr_t)&base },
649 { OPTION_CALLBACK, 0, "add-virtual-file", args,
650 N_("path:content"), N_("add untracked file to archive"), 0,
651 add_file_cb, (intptr_t)&base },
652 OPT_STRING('o', "output", &output, N_("file"),
653 N_("write the archive to this file")),
654 OPT_BOOL(0, "worktree-attributes", &worktree_attributes,
655 N_("read .gitattributes in working directory")),
656 OPT__VERBOSE(&verbose, N_("report archived files on stderr")),
657 { OPTION_STRING, 0, "mtime", &mtime_option, N_("time"),
658 N_("set modification time of archive entries"),
659 PARSE_OPT_NONEG },
660 OPT_NUMBER_CALLBACK(&compression_level,
661 N_("set compression level"), number_callback),
662 OPT_GROUP(""),
663 OPT_BOOL('l', "list", &list,
664 N_("list supported archive formats")),
665 OPT_GROUP(""),
666 OPT_STRING(0, "remote", &remote, N_("repo"),
667 N_("retrieve the archive from remote repository <repo>")),
668 OPT_STRING(0, "exec", &exec, N_("command"),
669 N_("path to the remote git-upload-archive command")),
670 OPT_END()
673 argc = parse_options(argc, argv, NULL, opts, archive_usage, 0);
675 if (remote)
676 die(_("Unexpected option --remote"));
677 if (exec)
678 die(_("the option '%s' requires '%s'"), "--exec", "--remote");
679 if (output)
680 die(_("Unexpected option --output"));
681 if (is_remote && args->extra_files.nr)
682 die(_("options '%s' and '%s' cannot be used together"), "--add-file", "--remote");
684 if (!base)
685 base = "";
687 if (list) {
688 if (argc)
689 die(_("extra command line parameter '%s'"), *argv);
690 for (i = 0; i < nr_archivers; i++)
691 if (!is_remote || archivers[i]->flags & ARCHIVER_REMOTE)
692 printf("%s\n", archivers[i]->name);
693 exit(0);
696 if (!format && name_hint)
697 format = archive_format_from_filename(name_hint);
698 if (!format)
699 format = "tar";
701 /* We need at least one parameter -- tree-ish */
702 if (argc < 1)
703 usage_with_options(archive_usage, opts);
704 *ar = lookup_archiver(format);
705 if (!*ar || (is_remote && !((*ar)->flags & ARCHIVER_REMOTE)))
706 die(_("Unknown archive format '%s'"), format);
708 args->compression_level = Z_DEFAULT_COMPRESSION;
709 if (compression_level != -1) {
710 int levels_ok = (*ar)->flags & ARCHIVER_WANT_COMPRESSION_LEVELS;
711 int high_ok = (*ar)->flags & ARCHIVER_HIGH_COMPRESSION_LEVELS;
712 if (levels_ok && (compression_level <= 9 || high_ok))
713 args->compression_level = compression_level;
714 else {
715 die(_("Argument not supported for format '%s': -%d"),
716 format, compression_level);
719 args->verbose = verbose;
720 args->base = base;
721 args->baselen = strlen(base);
722 args->worktree_attributes = worktree_attributes;
723 args->mtime_option = mtime_option;
725 return argc;
728 int write_archive(int argc, const char **argv, const char *prefix,
729 struct repository *repo,
730 const char *name_hint, int remote)
732 const struct archiver *ar = NULL;
733 struct pretty_print_describe_status describe_status = {0};
734 struct pretty_print_context ctx = {0};
735 struct archiver_args args;
736 int rc;
738 git_config_get_bool("uploadarchive.allowunreachable", &remote_allow_unreachable);
739 git_config(git_default_config, NULL);
741 describe_status.max_invocations = 1;
742 ctx.date_mode.type = DATE_NORMAL;
743 ctx.abbrev = DEFAULT_ABBREV;
744 ctx.describe_status = &describe_status;
745 args.pretty_ctx = &ctx;
746 args.repo = repo;
747 args.prefix = prefix;
748 string_list_init_dup(&args.extra_files);
749 argc = parse_archive_args(argc, argv, &ar, &args, name_hint, remote);
750 if (!startup_info->have_repository) {
752 * We know this will die() with an error, so we could just
753 * die ourselves; but its error message will be more specific
754 * than what we could write here.
756 setup_git_directory();
759 parse_treeish_arg(argv, &args, remote);
760 parse_pathspec_arg(argv + 1, &args);
762 rc = ar->write_archive(ar, &args);
764 string_list_clear_func(&args.extra_files, extra_file_info_clear);
765 free(args.refname);
766 clear_pathspec(&args.pathspec);
768 return rc;
771 static int match_extension(const char *filename, const char *ext)
773 int prefixlen = strlen(filename) - strlen(ext);
776 * We need 1 character for the '.', and 1 character to ensure that the
777 * prefix is non-empty (k.e., we don't match .tar.gz with no actual
778 * filename).
780 if (prefixlen < 2 || filename[prefixlen - 1] != '.')
781 return 0;
782 return !strcmp(filename + prefixlen, ext);
785 const char *archive_format_from_filename(const char *filename)
787 int i;
789 for (i = 0; i < nr_archivers; i++)
790 if (match_extension(filename, archivers[i]->name))
791 return archivers[i]->name;
792 return NULL;