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From: Michael Haggerty <mhagger@alum.mit.edu>
To: Junio C Hamano <gitster@pobox.com>
Cc: Nguyễn Thái Ngọc Duy  <pclouds@gmail.com>,
	David Turner <novalis@novalis.org>, Jeff King <peff@peff.net>,
	git@vger.kernel.org, Michael Haggerty <mhagger@alum.mit.edu>
Subject: [PATCH 05/20] refs_verify_refname_available(): use function in more places
Date: Mon, 20 Mar 2017 17:33:10 +0100
Message-ID: <80808305cd86f4fb3b8b06cd78ba8d0a9cbf11a5.1490026594.git.mhagger@alum.mit.edu> (raw)
In-Reply-To: <cover.1490026594.git.mhagger@alum.mit.edu>

Change `lock_raw_ref()` and `lock_ref_sha1_basic()` to use
`refs_verify_refname_available()` instead of
`verify_refname_available_dir()`. This means that those callsites now
check for conflicts with all references rather than just packed refs,
but the performance cost shouldn't be significant (and will be
regained later).

These were the last callers of `verify_refname_available_dir()`, so
also delete that (very complicated) function.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 refs/files-backend.c | 171 ++++-----------------------------------------------
 1 file changed, 11 insertions(+), 160 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 447f2767f3..cad56efb04 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -738,152 +738,6 @@ static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir)
 	return ref_iterator;
 }
 
-struct nonmatching_ref_data {
-	const struct string_list *skip;
-	const char *conflicting_refname;
-};
-
-static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
-{
-	struct nonmatching_ref_data *data = vdata;
-
-	if (data->skip && string_list_has_string(data->skip, entry->name))
-		return 0;
-
-	data->conflicting_refname = entry->name;
-	return 1;
-}
-
-/*
- * Return 0 if a reference named refname could be created without
- * conflicting with the name of an existing reference in dir.
- * See verify_refname_available for more information.
- */
-static int verify_refname_available_dir(const char *refname,
-					const struct string_list *extras,
-					const struct string_list *skip,
-					struct ref_dir *dir,
-					struct strbuf *err)
-{
-	const char *slash;
-	const char *extra_refname;
-	int pos;
-	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 (e.g.,
-		 * "refs/foo"; if there is a reference with that name,
-		 * it is a conflict, *unless* it is in skip.
-		 */
-		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. 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.
-		 */
-		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 (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.
-	 */
-	strbuf_addstr(&dirname, refname + dirname.len);
-	strbuf_addch(&dirname, '/');
-
-	if (dir) {
-		pos = search_ref_dir(dir, dirname.buf, dirname.len);
-
-		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;
-			}
-		}
-	}
-
-	extra_refname = find_descendant_ref(dirname.buf, extras, skip);
-	if (extra_refname)
-		strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
-			    refname, extra_refname);
-	else
-		ret = 0;
-
-cleanup:
-	strbuf_release(&dirname);
-	return ret;
-}
-
 struct packed_ref_cache {
 	struct ref_entry *root;
 
@@ -1563,7 +1417,7 @@ static void unlock_ref(struct ref_lock *lock)
  *
  * If the reference doesn't already exist, verify that refname doesn't
  * have a D/F conflict with any existing references. extras and skip
- * are passed to verify_refname_available_dir() for this check.
+ * are passed to refs_verify_refname_available() for this check.
  *
  * If mustexist is not set and the reference is not found or is
  * broken, lock the reference anyway but clear sha1.
@@ -1578,7 +1432,7 @@ static void unlock_ref(struct ref_lock *lock)
  *
  * but it includes a lot more code to
  * - Deal with possible races with other processes
- * - Avoid calling verify_refname_available_dir() when it can be
+ * - Avoid calling refs_verify_refname_available() when it can be
  *   avoided, namely if we were successfully able to read the ref
  * - Generate informative error messages in the case of failure
  */
@@ -1635,7 +1489,8 @@ static int lock_raw_ref(struct files_ref_store *refs,
 			} else {
 				/*
 				 * The error message set by
-				 * verify_refname_available_dir() is OK.
+				 * refs_verify_refname_available() is
+				 * OK.
 				 */
 				ret = TRANSACTION_NAME_CONFLICT;
 			}
@@ -1759,16 +1614,13 @@ static int lock_raw_ref(struct files_ref_store *refs,
 
 		/*
 		 * If the ref did not exist and we are creating it,
-		 * make sure there is no existing packed ref whose
-		 * name begins with our refname, nor a packed ref
-		 * whose name is a proper prefix of our refname.
+		 * make sure there is no existing ref that conflicts
+		 * with refname:
 		 */
-		if (verify_refname_available_dir(
-				    refname, extras, skip,
-				    get_packed_refs(refs),
-				    err)) {
+		if (refs_verify_refname_available(
+				    &refs->base, refname,
+				    extras, skip, err))
 			goto error_return;
-		}
 	}
 
 	ret = 0;
@@ -2125,9 +1977,8 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	 * our refname.
 	 */
 	if (is_null_oid(&lock->old_oid) &&
-	    verify_refname_available_dir(refname, extras, skip,
-					 get_packed_refs(refs),
-					 err)) {
+	    refs_verify_refname_available(&refs->base, refname,
+					  extras, skip, err)) {
 		last_errno = ENOTDIR;
 		goto error_return;
 	}
-- 
2.11.0


  parent reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-20 16:33 [PATCH 00/20] Separate `ref_cache` into a separate module Michael Haggerty
2017-03-20 16:33 ` [PATCH 01/20] get_ref_dir(): don't call read_loose_refs() for "refs/bisect" Michael Haggerty
2017-03-20 16:33 ` [PATCH 02/20] refs_read_raw_ref(): new function Michael Haggerty
2017-03-20 16:33 ` [PATCH 03/20] refs_ref_iterator_begin(): " Michael Haggerty
2017-03-20 16:33 ` [PATCH 04/20] refs_verify_refname_available(): implement once for all backends Michael Haggerty
2017-03-20 17:42   ` Jeff King
2017-03-20 22:20     ` Michael Haggerty
2017-03-20 16:33 ` Michael Haggerty [this message]
2017-03-20 16:33 ` [PATCH 06/20] Rename `add_ref()` to `add_ref_entry()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 07/20] Rename `find_ref()` to `find_ref_entry()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 08/20] Rename `remove_entry()` to `remove_entry_from_dir()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 09/20] refs: split `ref_cache` code into separate files Michael Haggerty
2017-03-20 17:49   ` Jeff King
2017-03-20 19:47     ` Junio C Hamano
2017-03-20 20:35       ` Stefan Beller
2017-03-20 22:40         ` Junio C Hamano
2017-03-20 16:33 ` [PATCH 10/20] ref-cache: introduce a new type, ref_cache Michael Haggerty
2017-03-20 16:33 ` [PATCH 11/20] refs: record the ref_store in ref_cache, not ref_dir Michael Haggerty
2017-03-20 17:51   ` Jeff King
2017-03-20 22:39     ` Michael Haggerty
2017-03-20 16:33 ` [PATCH 12/20] ref-cache: use a callback function to fill the cache Michael Haggerty
2017-03-20 16:33 ` [PATCH 13/20] refs: handle "refs/bisect/" in `loose_fill_ref_dir()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 14/20] do_for_each_entry_in_dir(): eliminate `offset` argument Michael Haggerty
2017-03-20 16:33 ` [PATCH 15/20] get_loose_ref_dir(): function renamed from get_loose_refs() Michael Haggerty
2017-03-20 16:33 ` [PATCH 16/20] get_loose_ref_cache(): new function Michael Haggerty
2017-03-20 16:33 ` [PATCH 17/20] cache_ref_iterator_begin(): make function smarter Michael Haggerty
2017-03-20 16:33 ` [PATCH 18/20] commit_packed_refs(): use reference iteration Michael Haggerty
2017-03-20 18:05   ` Jeff King
2017-03-22  8:42     ` Michael Haggerty
2017-03-22 13:06       ` Jeff King
2017-03-20 16:33 ` [PATCH 19/20] files_pack_refs(): " Michael Haggerty
2017-03-20 16:33 ` [PATCH 20/20] do_for_each_entry_in_dir(): delete function Michael Haggerty
2017-03-20 17:25 ` [PATCH 00/20] Separate `ref_cache` into a separate module Junio C Hamano
2017-03-20 18:12 ` Jeff King
2017-03-20 18:24 ` Ævar Arnfjörð Bjarmason
2017-03-20 18:30   ` Jeff King
2017-03-20 22:32 ` Junio C Hamano
2017-03-20 22:48   ` Michael Haggerty

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