From mboxrd@z Thu Jan 1 00:00:00 1970 From: mhagger@alum.mit.edu Subject: [PATCH 26/28] is_refname_available(): query only possibly-conflicting references Date: Fri, 28 Oct 2011 14:28:39 +0200 Message-ID: <1319804921-17545-27-git-send-email-mhagger@alum.mit.edu> References: <1319804921-17545-1-git-send-email-mhagger@alum.mit.edu> Cc: git@vger.kernel.org, Jeff King , Drew Northup , Jakub Narebski , Heiko Voigt , Johan Herland , Julian Phillips , Michael Haggerty To: Junio C Hamano X-From: git-owner@vger.kernel.org Fri Oct 28 14:32:30 2011 Return-path: Envelope-to: gcvg-git-2@lo.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1RJlbp-0005Dk-BE for gcvg-git-2@lo.gmane.org; Fri, 28 Oct 2011 14:32:29 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932484Ab1J1McW (ORCPT ); Fri, 28 Oct 2011 08:32:22 -0400 Received: from mail.berlin.jpk.com ([212.222.128.130]:55991 "EHLO mail.berlin.jpk.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932387Ab1J1McU (ORCPT ); Fri, 28 Oct 2011 08:32:20 -0400 Received: from michael.berlin.jpk.com ([192.168.100.152]) by mail.berlin.jpk.com with esmtp (Exim 4.50) id 1RJlRw-0007Ud-Tu; Fri, 28 Oct 2011 14:22:16 +0200 X-Mailer: git-send-email 1.7.7 In-Reply-To: <1319804921-17545-1-git-send-email-mhagger@alum.mit.edu> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: From: Michael Haggerty Instead of iterating through all of the references, inquire more pointedly about the references that could conflict with the new name. This requires checking for a few individual references, plus iterating through a small subtree of the rest of the references (and usually the subtree iteration ends without having to recurse). A big benefit is that populating the whole loose reference cache (which can be very expensive) can usually be avoided. Signed-off-by: Michael Haggerty --- refs.c | 40 +++++++++++++++++++++++++++++++++------- 1 files changed, 33 insertions(+), 7 deletions(-) diff --git a/refs.c b/refs.c index 88ef9dd..6a7f9c3 100644 --- a/refs.c +++ b/refs.c @@ -658,7 +658,7 @@ static int name_conflict_fn(const char *existingrefname, const unsigned char *sh int flags, void *cb_data) { struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data; - if (data->oldrefname && !strcmp(data->oldrefname, existingrefname)) + if (!strcmp(data->oldrefname, existingrefname)) return 0; if (names_conflict(data->refname, existingrefname)) { data->conflicting_refname = existingrefname; @@ -669,22 +669,48 @@ static int name_conflict_fn(const char *existingrefname, const unsigned char *sh /* * Return true iff a reference named refname could be created without - * conflicting with the name of an existing reference. If oldrefname - * is non-NULL, ignore potential conflicts with oldrefname (e.g., - * because oldrefname is scheduled for deletion in the same + * conflicting with the name of an existing reference in direntry. If + * oldrefname is non-NULL, ignore potential conflicts with oldrefname + * (e.g., because oldrefname is scheduled for deletion in the same * operation). */ static int is_refname_available(const char *refname, const char *oldrefname, struct ref_entry *direntry) { + int prefixlen = strlen(refname); + char *prefix; + char *slash; struct name_conflict_cb data; + + assert(direntry->flag & REF_DIR); + + if (!oldrefname) + oldrefname = ""; /* invalid; cannot match any existing refname */ + + /* Check whether a prefix of refname is an existing reference: */ + prefix = xmalloc(prefixlen + 2); + memcpy(prefix, refname, prefixlen + 1); + for (slash = strchr(prefix, '/'); slash; slash = strchr(slash + 1, '/')) { + *slash = '\0'; + if (strcmp(oldrefname, prefix)) { + struct ref_entry *entry = find_ref(direntry, prefix); + if (entry) { + error("'%s' exists; cannot create '%s'", prefix, refname); + free(prefix); + return 0; + } + } + *slash = '/'; + } + + /* Check whether refname is a proper prefix of an existing reference: */ + prefix[prefixlen++] = '/'; + prefix[prefixlen] = '\0'; data.refname = refname; data.oldrefname = oldrefname; data.conflicting_refname = NULL; - assert(direntry->flag & REF_DIR); - - if (do_for_each_ref_in_dir(direntry, 0, "", name_conflict_fn, + if (do_for_each_ref_in_dir(direntry, 0, prefix, name_conflict_fn, 0, DO_FOR_EACH_INCLUDE_BROKEN, &data)) { error("'%s' exists; cannot create '%s'", -- 1.7.7