git/archive.c
Jeff King bd54cf17a4 archive: handle commits with an empty tree
git-archive relies on get_pathspec to convert its argv into
a list of pathspecs. When get_pathspec is given an empty
argv list, it returns a single pathspec, the empty string,
to indicate that everything matches. When we feed this to
our path_exists function, we typically see that the pathspec
turns up at least one item in the tree, and we are happy.

But when our tree is empty, we erroneously think it is
because the pathspec is too limited, when in fact it is
simply that there is nothing to be found in the tree. This
is a weird corner case, but the correct behavior is almost
certainly to produce an empty archive, not to exit with an
error.

This patch teaches git-archive to create empty archives when
there is no pathspec given (we continue to complain if a
pathspec is given, since it obviously is not matched). It
also confirms that the tar and zip writers produce sane
output in this instance.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-10 22:25:22 -07:00

452 lines
12 KiB
C

#include "cache.h"
#include "commit.h"
#include "tree-walk.h"
#include "attr.h"
#include "archive.h"
#include "parse-options.h"
#include "unpack-trees.h"
static char const * const archive_usage[] = {
N_("git archive [options] <tree-ish> [<path>...]"),
N_("git archive --list"),
N_("git archive --remote <repo> [--exec <cmd>] [options] <tree-ish> [<path>...]"),
N_("git archive --remote <repo> [--exec <cmd>] --list"),
NULL
};
static const struct archiver **archivers;
static int nr_archivers;
static int alloc_archivers;
void register_archiver(struct archiver *ar)
{
ALLOC_GROW(archivers, nr_archivers + 1, alloc_archivers);
archivers[nr_archivers++] = ar;
}
static void format_subst(const struct commit *commit,
const char *src, size_t len,
struct strbuf *buf)
{
char *to_free = NULL;
struct strbuf fmt = STRBUF_INIT;
struct pretty_print_context ctx = {0};
ctx.date_mode = DATE_NORMAL;
ctx.abbrev = DEFAULT_ABBREV;
if (src == buf->buf)
to_free = strbuf_detach(buf, NULL);
for (;;) {
const char *b, *c;
b = memmem(src, len, "$Format:", 8);
if (!b)
break;
c = memchr(b + 8, '$', (src + len) - b - 8);
if (!c)
break;
strbuf_reset(&fmt);
strbuf_add(&fmt, b + 8, c - b - 8);
strbuf_add(buf, src, b - src);
format_commit_message(commit, fmt.buf, buf, &ctx);
len -= c + 1 - src;
src = c + 1;
}
strbuf_add(buf, src, len);
strbuf_release(&fmt);
free(to_free);
}
void *sha1_file_to_archive(const struct archiver_args *args,
const char *path, const unsigned char *sha1,
unsigned int mode, enum object_type *type,
unsigned long *sizep)
{
void *buffer;
const struct commit *commit = args->convert ? args->commit : NULL;
path += args->baselen;
buffer = read_sha1_file(sha1, type, sizep);
if (buffer && S_ISREG(mode)) {
struct strbuf buf = STRBUF_INIT;
size_t size = 0;
strbuf_attach(&buf, buffer, *sizep, *sizep + 1);
convert_to_working_tree(path, buf.buf, buf.len, &buf);
if (commit)
format_subst(commit, buf.buf, buf.len, &buf);
buffer = strbuf_detach(&buf, &size);
*sizep = size;
}
return buffer;
}
static void setup_archive_check(struct git_attr_check *check)
{
static struct git_attr *attr_export_ignore;
static struct git_attr *attr_export_subst;
if (!attr_export_ignore) {
attr_export_ignore = git_attr("export-ignore");
attr_export_subst = git_attr("export-subst");
}
check[0].attr = attr_export_ignore;
check[1].attr = attr_export_subst;
}
struct archiver_context {
struct archiver_args *args;
write_archive_entry_fn_t write_entry;
};
static int write_archive_entry(const unsigned char *sha1, const char *base,
int baselen, const char *filename, unsigned mode, int stage,
void *context)
{
static struct strbuf path = STRBUF_INIT;
struct archiver_context *c = context;
struct archiver_args *args = c->args;
write_archive_entry_fn_t write_entry = c->write_entry;
struct git_attr_check check[2];
const char *path_without_prefix;
int err;
args->convert = 0;
strbuf_reset(&path);
strbuf_grow(&path, PATH_MAX);
strbuf_add(&path, args->base, args->baselen);
strbuf_add(&path, base, baselen);
strbuf_addstr(&path, filename);
if (S_ISDIR(mode) || S_ISGITLINK(mode))
strbuf_addch(&path, '/');
path_without_prefix = path.buf + args->baselen;
setup_archive_check(check);
if (!git_check_attr(path_without_prefix, ARRAY_SIZE(check), check)) {
if (ATTR_TRUE(check[0].value))
return 0;
args->convert = ATTR_TRUE(check[1].value);
}
if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
if (args->verbose)
fprintf(stderr, "%.*s\n", (int)path.len, path.buf);
err = write_entry(args, sha1, path.buf, path.len, mode);
if (err)
return err;
return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
}
if (args->verbose)
fprintf(stderr, "%.*s\n", (int)path.len, path.buf);
return write_entry(args, sha1, path.buf, path.len, mode);
}
int write_archive_entries(struct archiver_args *args,
write_archive_entry_fn_t write_entry)
{
struct archiver_context context;
struct unpack_trees_options opts;
struct tree_desc t;
struct pathspec pathspec;
int err;
if (args->baselen > 0 && args->base[args->baselen - 1] == '/') {
size_t len = args->baselen;
while (len > 1 && args->base[len - 2] == '/')
len--;
if (args->verbose)
fprintf(stderr, "%.*s\n", (int)len, args->base);
err = write_entry(args, args->tree->object.sha1, args->base,
len, 040777);
if (err)
return err;
}
context.args = args;
context.write_entry = write_entry;
/*
* Setup index and instruct attr to read index only
*/
if (!args->worktree_attributes) {
memset(&opts, 0, sizeof(opts));
opts.index_only = 1;
opts.head_idx = -1;
opts.src_index = &the_index;
opts.dst_index = &the_index;
opts.fn = oneway_merge;
init_tree_desc(&t, args->tree->buffer, args->tree->size);
if (unpack_trees(1, &t, &opts))
return -1;
git_attr_set_direction(GIT_ATTR_INDEX, &the_index);
}
init_pathspec(&pathspec, args->pathspec);
err = read_tree_recursive(args->tree, "", 0, 0, &pathspec,
write_archive_entry, &context);
free_pathspec(&pathspec);
if (err == READ_TREE_RECURSIVE)
err = 0;
return err;
}
static const struct archiver *lookup_archiver(const char *name)
{
int i;
if (!name)
return NULL;
for (i = 0; i < nr_archivers; i++) {
if (!strcmp(name, archivers[i]->name))
return archivers[i];
}
return NULL;
}
static int reject_entry(const unsigned char *sha1, const char *base,
int baselen, const char *filename, unsigned mode,
int stage, void *context)
{
return -1;
}
static int path_exists(struct tree *tree, const char *path)
{
const char *paths[] = { path, NULL };
struct pathspec pathspec;
int ret;
init_pathspec(&pathspec, paths);
ret = read_tree_recursive(tree, "", 0, 0, &pathspec, reject_entry, NULL);
free_pathspec(&pathspec);
return ret != 0;
}
static void parse_pathspec_arg(const char **pathspec,
struct archiver_args *ar_args)
{
ar_args->pathspec = pathspec = get_pathspec("", pathspec);
if (pathspec) {
while (*pathspec) {
if (**pathspec && !path_exists(ar_args->tree, *pathspec))
die("path not found: %s", *pathspec);
pathspec++;
}
}
}
static void parse_treeish_arg(const char **argv,
struct archiver_args *ar_args, const char *prefix,
int remote)
{
const char *name = argv[0];
const unsigned char *commit_sha1;
time_t archive_time;
struct tree *tree;
const struct commit *commit;
unsigned char sha1[20];
/* Remotes are only allowed to fetch actual refs */
if (remote) {
char *ref = NULL;
const char *colon = strchr(name, ':');
int refnamelen = colon ? colon - name : strlen(name);
if (!dwim_ref(name, refnamelen, sha1, &ref))
die("no such ref: %.*s", refnamelen, name);
free(ref);
}
if (get_sha1(name, sha1))
die("Not a valid object name");
commit = lookup_commit_reference_gently(sha1, 1);
if (commit) {
commit_sha1 = commit->object.sha1;
archive_time = commit->date;
} else {
commit_sha1 = NULL;
archive_time = time(NULL);
}
tree = parse_tree_indirect(sha1);
if (tree == NULL)
die("not a tree object");
if (prefix) {
unsigned char tree_sha1[20];
unsigned int mode;
int err;
err = get_tree_entry(tree->object.sha1, prefix,
tree_sha1, &mode);
if (err || !S_ISDIR(mode))
die("current working directory is untracked");
tree = parse_tree_indirect(tree_sha1);
}
ar_args->tree = tree;
ar_args->commit_sha1 = commit_sha1;
ar_args->commit = commit;
ar_args->time = archive_time;
}
#define OPT__COMPR(s, v, h, p) \
{ OPTION_SET_INT, (s), NULL, (v), NULL, (h), \
PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, (p) }
#define OPT__COMPR_HIDDEN(s, v, p) \
{ OPTION_SET_INT, (s), NULL, (v), NULL, "", \
PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN, NULL, (p) }
static int parse_archive_args(int argc, const char **argv,
const struct archiver **ar, struct archiver_args *args,
const char *name_hint, int is_remote)
{
const char *format = NULL;
const char *base = NULL;
const char *remote = NULL;
const char *exec = NULL;
const char *output = NULL;
int compression_level = -1;
int verbose = 0;
int i;
int list = 0;
int worktree_attributes = 0;
struct option opts[] = {
OPT_GROUP(""),
OPT_STRING(0, "format", &format, N_("fmt"), N_("archive format")),
OPT_STRING(0, "prefix", &base, N_("prefix"),
N_("prepend prefix to each pathname in the archive")),
OPT_STRING('o', "output", &output, N_("file"),
N_("write the archive to this file")),
OPT_BOOL(0, "worktree-attributes", &worktree_attributes,
N_("read .gitattributes in working directory")),
OPT__VERBOSE(&verbose, N_("report archived files on stderr")),
OPT__COMPR('0', &compression_level, N_("store only"), 0),
OPT__COMPR('1', &compression_level, N_("compress faster"), 1),
OPT__COMPR_HIDDEN('2', &compression_level, 2),
OPT__COMPR_HIDDEN('3', &compression_level, 3),
OPT__COMPR_HIDDEN('4', &compression_level, 4),
OPT__COMPR_HIDDEN('5', &compression_level, 5),
OPT__COMPR_HIDDEN('6', &compression_level, 6),
OPT__COMPR_HIDDEN('7', &compression_level, 7),
OPT__COMPR_HIDDEN('8', &compression_level, 8),
OPT__COMPR('9', &compression_level, N_("compress better"), 9),
OPT_GROUP(""),
OPT_BOOL('l', "list", &list,
N_("list supported archive formats")),
OPT_GROUP(""),
OPT_STRING(0, "remote", &remote, N_("repo"),
N_("retrieve the archive from remote repository <repo>")),
OPT_STRING(0, "exec", &exec, N_("command"),
N_("path to the remote git-upload-archive command")),
OPT_END()
};
argc = parse_options(argc, argv, NULL, opts, archive_usage, 0);
if (remote)
die("Unexpected option --remote");
if (exec)
die("Option --exec can only be used together with --remote");
if (output)
die("Unexpected option --output");
if (!base)
base = "";
if (list) {
for (i = 0; i < nr_archivers; i++)
if (!is_remote || archivers[i]->flags & ARCHIVER_REMOTE)
printf("%s\n", archivers[i]->name);
exit(0);
}
if (!format && name_hint)
format = archive_format_from_filename(name_hint);
if (!format)
format = "tar";
/* We need at least one parameter -- tree-ish */
if (argc < 1)
usage_with_options(archive_usage, opts);
*ar = lookup_archiver(format);
if (!*ar || (is_remote && !((*ar)->flags & ARCHIVER_REMOTE)))
die("Unknown archive format '%s'", format);
args->compression_level = Z_DEFAULT_COMPRESSION;
if (compression_level != -1) {
if ((*ar)->flags & ARCHIVER_WANT_COMPRESSION_LEVELS)
args->compression_level = compression_level;
else {
die("Argument not supported for format '%s': -%d",
format, compression_level);
}
}
args->verbose = verbose;
args->base = base;
args->baselen = strlen(base);
args->worktree_attributes = worktree_attributes;
return argc;
}
int write_archive(int argc, const char **argv, const char *prefix,
int setup_prefix, const char *name_hint, int remote)
{
int nongit = 0;
const struct archiver *ar = NULL;
struct archiver_args args;
if (setup_prefix && prefix == NULL)
prefix = setup_git_directory_gently(&nongit);
git_config(git_default_config, NULL);
init_tar_archiver();
init_zip_archiver();
argc = parse_archive_args(argc, argv, &ar, &args, name_hint, remote);
if (nongit) {
/*
* We know this will die() with an error, so we could just
* die ourselves; but its error message will be more specific
* than what we could write here.
*/
setup_git_directory();
}
parse_treeish_arg(argv, &args, prefix, remote);
parse_pathspec_arg(argv + 1, &args);
return ar->write_archive(ar, &args);
}
static int match_extension(const char *filename, const char *ext)
{
int prefixlen = strlen(filename) - strlen(ext);
/*
* We need 1 character for the '.', and 1 character to ensure that the
* prefix is non-empty (k.e., we don't match .tar.gz with no actual
* filename).
*/
if (prefixlen < 2 || filename[prefixlen-1] != '.')
return 0;
return !strcmp(filename + prefixlen, ext);
}
const char *archive_format_from_filename(const char *filename)
{
int i;
for (i = 0; i < nr_archivers; i++)
if (match_extension(filename, archivers[i]->name))
return archivers[i]->name;
return NULL;
}