*/
#define REF_HAVE_OLD 0x10
+/*
+ * Used as a flag in ref_update::flags when the lockfile needs to be
+ * committed.
+ */
+#define REF_NEEDS_COMMIT 0x20
+
/*
* Try to read one refname component from the front of refname.
* Return the length of the component found, or -1 if the component is
* presence of an empty subdirectory does not block the creation of a
* similarly-named reference. (The fact that reference names with the
* same leading components can conflict *with each other* is a
- * separate issue that is regulated by is_refname_available().)
+ * separate issue that is regulated by verify_refname_available().)
*
* Please note that the name field contains the fully-qualified
* reference (or subdirectory) name. Space could be saved by only
}
}
-static int entry_matches(struct ref_entry *entry, const struct string_list *list)
-{
- return list && string_list_has_string(list, entry->name);
-}
-
struct nonmatching_ref_data {
const struct string_list *skip;
- struct ref_entry *found;
+ const char *conflicting_refname;
};
static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
{
struct nonmatching_ref_data *data = vdata;
- if (entry_matches(entry, data->skip))
+ if (data->skip && string_list_has_string(data->skip, entry->name))
return 0;
- data->found = entry;
+ data->conflicting_refname = entry->name;
return 1;
}
-static void report_refname_conflict(struct ref_entry *entry,
- const char *refname)
-{
- error("'%s' exists; cannot create '%s'", entry->name, refname);
-}
-
/*
- * Return true iff a reference named refname could be created without
- * conflicting with the name of an existing reference in dir. If
- * skip is non-NULL, ignore potential conflicts with refs in skip
- * (e.g., because they are scheduled for deletion in the same
- * operation).
+ * Return 0 if a reference named refname could be created without
+ * conflicting with the name of an existing reference in dir.
+ * Otherwise, return a negative value and write an explanation to err.
+ * If extras is non-NULL, it is a list of additional refnames with
+ * which refname is not allowed to conflict. If skip is non-NULL,
+ * ignore potential conflicts with refs in skip (e.g., because they
+ * are scheduled for deletion in the same operation). Behavior is
+ * undefined if the same name is listed in both extras and skip.
*
* Two reference names conflict if one of them exactly matches the
- * leading components of the other; e.g., "foo/bar" conflicts with
- * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
- * "foo/barbados".
+ * leading components of the other; e.g., "refs/foo/bar" conflicts
+ * with both "refs/foo" and with "refs/foo/bar/baz" but not with
+ * "refs/foo/bar" or "refs/foo/barbados".
*
- * skip must be sorted.
+ * extras and skip must be sorted.
*/
-static int is_refname_available(const char *refname,
- const struct string_list *skip,
- struct ref_dir *dir)
+static int verify_refname_available(const char *refname,
+ const struct string_list *extras,
+ const struct string_list *skip,
+ struct ref_dir *dir,
+ struct strbuf *err)
{
const char *slash;
- size_t len;
int pos;
- char *dirname;
+ struct strbuf dirname = STRBUF_INIT;
+ int ret = -1;
+
+ /*
+ * For the sake of comments in this function, suppose that
+ * refname is "refs/foo/bar".
+ */
+
+ assert(err);
+ strbuf_grow(&dirname, strlen(refname) + 1);
for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
+ /* Expand dirname to the new prefix, not including the trailing slash: */
+ strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
+
/*
- * We are still at a leading dir of the refname; we are
- * looking for a conflict with a leaf entry.
- *
- * If we find one, we still must make sure it is
- * not in "skip".
+ * We are still at a leading dir of the refname (e.g.,
+ * "refs/foo"; if there is a reference with that name,
+ * it is a conflict, *unless* it is in skip.
*/
- pos = search_ref_dir(dir, refname, slash - refname);
- if (pos >= 0) {
- struct ref_entry *entry = dir->entries[pos];
- if (entry_matches(entry, skip))
- return 1;
- report_refname_conflict(entry, refname);
- return 0;
+ if (dir) {
+ pos = search_ref_dir(dir, dirname.buf, dirname.len);
+ if (pos >= 0 &&
+ (!skip || !string_list_has_string(skip, dirname.buf))) {
+ /*
+ * We found a reference whose name is
+ * a proper prefix of refname; e.g.,
+ * "refs/foo", and is not in skip.
+ */
+ strbuf_addf(err, "'%s' exists; cannot create '%s'",
+ dirname.buf, refname);
+ goto cleanup;
+ }
}
+ if (extras && string_list_has_string(extras, dirname.buf) &&
+ (!skip || !string_list_has_string(skip, dirname.buf))) {
+ strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
+ refname, dirname.buf);
+ goto cleanup;
+ }
/*
* Otherwise, we can try to continue our search with
- * the next component; if we come up empty, we know
- * there is nothing under this whole prefix.
+ * the next component. So try to look up the
+ * directory, e.g., "refs/foo/". If we come up empty,
+ * we know there is nothing under this whole prefix,
+ * but even in that case we still have to continue the
+ * search for conflicts with extras.
*/
- pos = search_ref_dir(dir, refname, slash + 1 - refname);
- if (pos < 0)
- return 1;
-
- dir = get_ref_dir(dir->entries[pos]);
+ strbuf_addch(&dirname, '/');
+ if (dir) {
+ pos = search_ref_dir(dir, dirname.buf, dirname.len);
+ if (pos < 0) {
+ /*
+ * There was no directory "refs/foo/",
+ * so there is nothing under this
+ * whole prefix. So there is no need
+ * to continue looking for conflicting
+ * references. But we need to continue
+ * looking for conflicting extras.
+ */
+ dir = NULL;
+ } else {
+ dir = get_ref_dir(dir->entries[pos]);
+ }
+ }
}
/*
- * We are at the leaf of our refname; we want to
- * make sure there are no directories which match it.
+ * We are at the leaf of our refname (e.g., "refs/foo/bar").
+ * There is no point in searching for a reference with that
+ * name, because a refname isn't considered to conflict with
+ * itself. But we still need to check for references whose
+ * names are in the "refs/foo/bar/" namespace, because they
+ * *do* conflict.
*/
- len = strlen(refname);
- dirname = xmallocz(len + 1);
- sprintf(dirname, "%s/", refname);
- pos = search_ref_dir(dir, dirname, len + 1);
- free(dirname);
+ strbuf_addstr(&dirname, refname + dirname.len);
+ strbuf_addch(&dirname, '/');
+
+ if (dir) {
+ pos = search_ref_dir(dir, dirname.buf, dirname.len);
- if (pos >= 0) {
+ if (pos >= 0) {
+ /*
+ * We found a directory named "$refname/"
+ * (e.g., "refs/foo/bar/"). It is a problem
+ * iff it contains any ref that is not in
+ * "skip".
+ */
+ struct nonmatching_ref_data data;
+
+ data.skip = skip;
+ data.conflicting_refname = NULL;
+ dir = get_ref_dir(dir->entries[pos]);
+ sort_ref_dir(dir);
+ if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
+ strbuf_addf(err, "'%s' exists; cannot create '%s'",
+ data.conflicting_refname, refname);
+ goto cleanup;
+ }
+ }
+ }
+
+ if (extras) {
/*
- * We found a directory named "refname". It is a
- * problem iff it contains any ref that is not
- * in "skip".
+ * Check for entries in extras that start with
+ * "$refname/". We do that by looking for the place
+ * where "$refname/" would be inserted in extras. If
+ * there is an entry at that position that starts with
+ * "$refname/" and is not in skip, then we have a
+ * conflict.
*/
- struct ref_entry *entry = dir->entries[pos];
- struct ref_dir *dir = get_ref_dir(entry);
- struct nonmatching_ref_data data;
+ for (pos = string_list_find_insert_index(extras, dirname.buf, 0);
+ pos < extras->nr; pos++) {
+ const char *extra_refname = extras->items[pos].string;
- data.skip = skip;
- sort_ref_dir(dir);
- if (!do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data))
- return 1;
+ if (!starts_with(extra_refname, dirname.buf))
+ break;
- report_refname_conflict(data.found, refname);
- return 0;
+ if (!skip || !string_list_has_string(skip, extra_refname)) {
+ strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
+ refname, extra_refname);
+ goto cleanup;
+ }
+ }
}
- /*
- * There is no point in searching for another leaf
- * node which matches it; such an entry would be the
- * ref we are looking for, not a conflict.
- */
- return 1;
+ /* No conflicts were found */
+ ret = 0;
+
+cleanup:
+ strbuf_release(&dirname);
+ return ret;
}
struct packed_ref_cache {
*/
static struct ref_lock *lock_ref_sha1_basic(const char *refname,
const unsigned char *old_sha1,
+ const struct string_list *extras,
const struct string_list *skip,
- unsigned int flags, int *type_p)
+ unsigned int flags, int *type_p,
+ struct strbuf *err)
{
char *ref_file;
const char *orig_refname = refname;
int resolve_flags = 0;
int attempts_remaining = 3;
+ assert(err);
+
lock = xcalloc(1, sizeof(struct ref_lock));
lock->lock_fd = -1;
ref_file = git_path("%s", orig_refname);
if (remove_empty_directories(ref_file)) {
last_errno = errno;
- error("there are still refs under '%s'", orig_refname);
+
+ if (!verify_refname_available(orig_refname, extras, skip,
+ get_loose_refs(&ref_cache), err))
+ strbuf_addf(err, "there are still refs under '%s'",
+ orig_refname);
+
goto error_return;
}
refname = resolve_ref_unsafe(orig_refname, resolve_flags,
*type_p = type;
if (!refname) {
last_errno = errno;
- error("unable to resolve reference %s: %s",
- orig_refname, strerror(errno));
+ if (last_errno != ENOTDIR ||
+ !verify_refname_available(orig_refname, extras, skip,
+ get_loose_refs(&ref_cache), err))
+ strbuf_addf(err, "unable to resolve reference %s: %s",
+ orig_refname, strerror(last_errno));
+
goto error_return;
}
/*
* our refname.
*/
if (is_null_sha1(lock->old_sha1) &&
- !is_refname_available(refname, skip, get_packed_refs(&ref_cache))) {
+ verify_refname_available(refname, extras, skip,
+ get_packed_refs(&ref_cache), err)) {
last_errno = ENOTDIR;
goto error_return;
}
/* fall through */
default:
last_errno = errno;
- error("unable to create directory for %s", ref_file);
+ strbuf_addf(err, "unable to create directory for %s", ref_file);
goto error_return;
}
*/
goto retry;
else {
- struct strbuf err = STRBUF_INIT;
- unable_to_lock_message(ref_file, errno, &err);
- error("%s", err.buf);
- strbuf_release(&err);
+ unable_to_lock_message(ref_file, errno, err);
goto error_return;
}
}
static int rename_ref_available(const char *oldname, const char *newname)
{
struct string_list skip = STRING_LIST_INIT_NODUP;
+ struct strbuf err = STRBUF_INIT;
int ret;
string_list_insert(&skip, oldname);
- ret = is_refname_available(newname, &skip, get_packed_refs(&ref_cache))
- && is_refname_available(newname, &skip, get_loose_refs(&ref_cache));
+ ret = !verify_refname_available(newname, NULL, &skip,
+ get_packed_refs(&ref_cache), &err)
+ && !verify_refname_available(newname, NULL, &skip,
+ get_loose_refs(&ref_cache), &err);
+ if (!ret)
+ error("%s", err.buf);
+
string_list_clear(&skip, 0);
+ strbuf_release(&err);
return ret;
}
-static int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1,
- const char *logmsg);
+static int write_ref_to_lockfile(struct ref_lock *lock, const unsigned char *sha1);
+static int commit_ref_update(struct ref_lock *lock,
+ const unsigned char *sha1, const char *logmsg);
int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
{
struct stat loginfo;
int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
const char *symref = NULL;
+ struct strbuf err = STRBUF_INIT;
if (log && S_ISLNK(loginfo.st_mode))
return error("reflog for %s is a symlink", oldrefname);
logmoved = log;
- lock = lock_ref_sha1_basic(newrefname, NULL, NULL, 0, NULL);
+ lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
if (!lock) {
- error("unable to lock %s for update", newrefname);
+ error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
+ strbuf_release(&err);
goto rollback;
}
hashcpy(lock->old_sha1, orig_sha1);
- if (write_ref_sha1(lock, orig_sha1, logmsg)) {
+
+ if (write_ref_to_lockfile(lock, orig_sha1) ||
+ commit_ref_update(lock, orig_sha1, logmsg)) {
error("unable to write current sha1 into %s", newrefname);
goto rollback;
}
return 0;
rollback:
- lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, 0, NULL);
+ lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
if (!lock) {
- error("unable to lock %s for rollback", oldrefname);
+ error("unable to lock %s for rollback: %s", oldrefname, err.buf);
+ strbuf_release(&err);
goto rollbacklog;
}
flag = log_all_ref_updates;
log_all_ref_updates = 0;
- if (write_ref_sha1(lock, orig_sha1, NULL))
+ if (write_ref_to_lockfile(lock, orig_sha1) ||
+ commit_ref_update(lock, orig_sha1, NULL))
error("unable to write current sha1 into %s", oldrefname);
log_all_ref_updates = flag;
}
/*
- * Write sha1 into the ref specified by the lock. Make sure that errno
- * is sane on error.
+ * Write sha1 into the open lockfile, then close the lockfile. On
+ * errors, rollback the lockfile and set errno to reflect the problem.
*/
-static int write_ref_sha1(struct ref_lock *lock,
- const unsigned char *sha1, const char *logmsg)
+static int write_ref_to_lockfile(struct ref_lock *lock,
+ const unsigned char *sha1)
{
static char term = '\n';
struct object *o;
errno = save_errno;
return -1;
}
+ return 0;
+}
+
+/*
+ * Commit a change to a loose reference that has already been written
+ * to the loose reference lockfile. Also update the reflogs if
+ * necessary, using the specified lockmsg (which can be NULL).
+ */
+static int commit_ref_update(struct ref_lock *lock,
+ const unsigned char *sha1, const char *logmsg)
+{
clear_loose_ref_cache(&ref_cache);
if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
(strcmp(lock->ref_name, lock->orig_ref_name) &&
return 0;
}
-static int ref_update_compare(const void *r1, const void *r2)
-{
- const struct ref_update * const *u1 = r1;
- const struct ref_update * const *u2 = r2;
- return strcmp((*u1)->refname, (*u2)->refname);
-}
-
-static int ref_update_reject_duplicates(struct ref_update **updates, int n,
+static int ref_update_reject_duplicates(struct string_list *refnames,
struct strbuf *err)
{
- int i;
+ int i, n = refnames->nr;
assert(err);
for (i = 1; i < n; i++)
- if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
+ if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
strbuf_addf(err,
"Multiple updates for ref '%s' not allowed.",
- updates[i]->refname);
+ refnames->items[i].string);
return 1;
}
return 0;
struct ref_update **updates = transaction->updates;
struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
struct string_list_item *ref_to_delete;
+ struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
assert(err);
return 0;
}
- /* Copy, sort, and reject duplicate refs */
- qsort(updates, n, sizeof(*updates), ref_update_compare);
- if (ref_update_reject_duplicates(updates, n, err)) {
+ /* Fail if a refname appears more than once in the transaction: */
+ for (i = 0; i < n; i++)
+ string_list_append(&affected_refnames, updates[i]->refname);
+ string_list_sort(&affected_refnames);
+ if (ref_update_reject_duplicates(&affected_refnames, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
- /* Acquire all locks while verifying old values */
+ /*
+ * Acquire all locks, verify old values if provided, check
+ * that new values are valid, and write new values to the
+ * lockfiles, ready to be activated. Only keep one lockfile
+ * open at a time to avoid running out of file descriptors.
+ */
for (i = 0; i < n; i++) {
struct ref_update *update = updates[i];
- unsigned int flags = update->flags;
- if ((flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
- flags |= REF_DELETING;
+ if ((update->flags & REF_HAVE_NEW) &&
+ is_null_sha1(update->new_sha1))
+ update->flags |= REF_DELETING;
update->lock = lock_ref_sha1_basic(
update->refname,
((update->flags & REF_HAVE_OLD) ?
update->old_sha1 : NULL),
- NULL,
- flags,
- &update->type);
+ &affected_refnames, NULL,
+ update->flags,
+ &update->type,
+ err);
if (!update->lock) {
+ char *reason;
+
ret = (errno == ENOTDIR)
? TRANSACTION_NAME_CONFLICT
: TRANSACTION_GENERIC_ERROR;
- strbuf_addf(err, "Cannot lock the ref '%s'.",
- update->refname);
+ reason = strbuf_detach(err, NULL);
+ strbuf_addf(err, "Cannot lock ref '%s': %s",
+ update->refname, reason);
+ free(reason);
goto cleanup;
}
- }
-
- /* Perform updates first so live commits remain referenced */
- for (i = 0; i < n; i++) {
- struct ref_update *update = updates[i];
- int flags = update->flags;
-
- if ((flags & REF_HAVE_NEW) && !is_null_sha1(update->new_sha1)) {
+ if ((update->flags & REF_HAVE_NEW) &&
+ !(update->flags & REF_DELETING)) {
int overwriting_symref = ((update->type & REF_ISSYMREF) &&
(update->flags & REF_NODEREF));
- if (!overwriting_symref
- && !hashcmp(update->lock->old_sha1, update->new_sha1)) {
+ if (!overwriting_symref &&
+ !hashcmp(update->lock->old_sha1, update->new_sha1)) {
/*
* The reference already has the desired
* value, so we don't need to write it.
*/
- unlock_ref(update->lock);
+ } else if (write_ref_to_lockfile(update->lock,
+ update->new_sha1)) {
+ /*
+ * The lock was freed upon failure of
+ * write_ref_to_lockfile():
+ */
update->lock = NULL;
- } else if (write_ref_sha1(update->lock, update->new_sha1,
- update->msg)) {
- update->lock = NULL; /* freed by write_ref_sha1 */
strbuf_addf(err, "Cannot update the ref '%s'.",
update->refname);
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
} else {
- /* freed by write_ref_sha1(): */
+ update->flags |= REF_NEEDS_COMMIT;
+ }
+ }
+ if (!(update->flags & REF_NEEDS_COMMIT)) {
+ /*
+ * We didn't have to write anything to the lockfile.
+ * Close it to free up the file descriptor:
+ */
+ if (close_ref(update->lock)) {
+ strbuf_addf(err, "Couldn't close %s.lock",
+ update->refname);
+ goto cleanup;
+ }
+ }
+ }
+
+ /* Perform updates first so live commits remain referenced */
+ for (i = 0; i < n; i++) {
+ struct ref_update *update = updates[i];
+
+ if (update->flags & REF_NEEDS_COMMIT) {
+ if (commit_ref_update(update->lock,
+ update->new_sha1, update->msg)) {
+ /* freed by commit_ref_update(): */
+ update->lock = NULL;
+ strbuf_addf(err, "Cannot update the ref '%s'.",
+ update->refname);
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ } else {
+ /* freed by commit_ref_update(): */
update->lock = NULL;
}
}
/* Perform deletes now that updates are safely completed */
for (i = 0; i < n; i++) {
struct ref_update *update = updates[i];
- int flags = update->flags;
- if ((flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1)) {
+ if (update->flags & REF_DELETING) {
if (delete_ref_loose(update->lock, update->type, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
- if (!(flags & REF_ISPRUNING))
+ if (!(update->flags & REF_ISPRUNING))
string_list_append(&refs_to_delete,
update->lock->ref_name);
}
if (updates[i]->lock)
unlock_ref(updates[i]->lock);
string_list_clear(&refs_to_delete, 0);
+ string_list_clear(&affected_refnames, 0);
return ret;
}
char *log_file;
int status = 0;
int type;
+ struct strbuf err = STRBUF_INIT;
memset(&cb, 0, sizeof(cb));
cb.flags = flags;
* reference itself, plus we might need to update the
* reference if --updateref was specified:
*/
- lock = lock_ref_sha1_basic(refname, sha1, NULL, 0, &type);
- if (!lock)
- return error("cannot lock ref '%s'", refname);
+ lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, 0, &type, &err);
+ if (!lock) {
+ error("cannot lock ref '%s': %s", refname, err.buf);
+ strbuf_release(&err);
+ return -1;
+ }
if (!reflog_exists(refname)) {
unlock_ref(lock);
return 0;