From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Herland Subject: [PATCHv6 05/23] notes.h/c: Allow combine_notes functions to remove notes Date: Tue, 09 Nov 2010 22:49:41 +0100 Message-ID: <1289339399-4733-6-git-send-email-johan@herland.net> References: <1289339399-4733-1-git-send-email-johan@herland.net> Mime-Version: 1.0 Content-Type: TEXT/PLAIN Content-Transfer-Encoding: 7BIT Cc: johan@herland.net, jrnieder@gmail.com, bebarino@gmail.com, avarab@gmail.com, gitster@pobox.com, srabbelier@gmail.com To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Tue Nov 09 22:50:33 2010 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 1PFw5I-0000PX-0b for gcvg-git-2@lo.gmane.org; Tue, 09 Nov 2010 22:50:32 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755450Ab0KIVuX (ORCPT ); Tue, 9 Nov 2010 16:50:23 -0500 Received: from smtp.getmail.no ([84.208.15.66]:61168 "EHLO smtp.getmail.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755300Ab0KIVuR (ORCPT ); Tue, 9 Nov 2010 16:50:17 -0500 Received: from get-mta-scan01.get.basefarm.net ([10.5.16.4]) by get-mta-out02.get.basefarm.net (Sun Java(tm) System Messaging Server 7.0-0.04 64bit (built Jun 20 2008)) with ESMTP id <0LBN005WS0NNCV30@get-mta-out02.get.basefarm.net> for git@vger.kernel.org; Tue, 09 Nov 2010 22:50:11 +0100 (MET) Received: from get-mta-scan01.get.basefarm.net (localhost.localdomain [127.0.0.1]) by localhost (Email Security Appliance) with SMTP id 6A1451799D0F_CD9C213B for ; Tue, 09 Nov 2010 21:50:11 +0000 (GMT) Received: from smtp.getmail.no (unknown [10.5.16.4]) by get-mta-scan01.get.basefarm.net (Sophos Email Appliance) with ESMTP id 130BB1799D03_CD9C213F for ; Tue, 09 Nov 2010 21:50:11 +0000 (GMT) Received: from alpha.herland ([84.215.68.234]) by get-mta-in01.get.basefarm.net (Sun Java(tm) System Messaging Server 7.0-0.04 64bit (built Jun 20 2008)) with ESMTP id <0LBN00HVN0NLS730@get-mta-in01.get.basefarm.net> for git@vger.kernel.org; Tue, 09 Nov 2010 22:50:11 +0100 (MET) X-Mailer: git-send-email 1.7.3.2.173.gab1c9.dirty In-reply-to: <1289339399-4733-1-git-send-email-johan@herland.net> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Allow combine_notes functions to request that a note be removed, by setting the resulting note SHA1 to null_sha1 (0000000...). For consistency, also teach note_tree_insert() to skip insertion of an empty note (a note with entry->val_sha1 equal to null_sha1) when there is no note to combine it with. In general, an empty note (null_sha1) is treated identically to no note at all, but when adding an empty note where there already exists a non-empty note, we allow the combine_notes function to potentially record a new/changed note. Document this behaviour, and clearly specify how combine_notes functions are expected to handle null_sha1 in input. Before this patch, storing null_sha1s in the notes tree were silently allowed, causing an invalid notes tree (referring to blobs with null_sha1) to be produced by write_notes_tree(). Signed-off-by: Johan Herland --- notes.c | 12 +++++++++++- notes.h | 16 +++++++++++++++- 2 files changed, 26 insertions(+), 2 deletions(-) diff --git a/notes.c b/notes.c index bfb3ea5..0c13a36 100644 --- a/notes.c +++ b/notes.c @@ -248,7 +248,10 @@ static void note_tree_insert(struct notes_tree *t, struct int_node *tree, switch (GET_PTR_TYPE(*p)) { case PTR_TYPE_NULL: assert(!*p); - *p = SET_PTR_TYPE(entry, type); + if (is_null_sha1(entry->val_sha1)) + free(entry); + else + *p = SET_PTR_TYPE(entry, type); return; case PTR_TYPE_NOTE: switch (type) { @@ -264,6 +267,9 @@ static void note_tree_insert(struct notes_tree *t, struct int_node *tree, sha1_to_hex(l->val_sha1), sha1_to_hex(entry->val_sha1), sha1_to_hex(l->key_sha1)); + + if (is_null_sha1(l->val_sha1)) + note_tree_remove(t, tree, n, entry); free(entry); return; } @@ -295,6 +301,10 @@ static void note_tree_insert(struct notes_tree *t, struct int_node *tree, /* non-matching leaf_node */ assert(GET_PTR_TYPE(*p) == PTR_TYPE_NOTE || GET_PTR_TYPE(*p) == PTR_TYPE_SUBTREE); + if (is_null_sha1(entry->val_sha1)) { /* skip insertion of empty note */ + free(entry); + return; + } new_node = (struct int_node *) xcalloc(sizeof(struct int_node), 1); note_tree_insert(t, new_node, n + 1, l, GET_PTR_TYPE(*p), combine_notes); diff --git a/notes.h b/notes.h index 20db42f..79ea797 100644 --- a/notes.h +++ b/notes.h @@ -12,7 +12,10 @@ * resulting SHA1 into the first SHA1 argument (cur_sha1). A non-zero return * value indicates failure. * - * The two given SHA1s must both be non-NULL and different from each other. + * The two given SHA1s shall both be non-NULL and different from each other. + * Either of them (but not both) may be == null_sha1, which indicates an + * empty/non-existent note. If the resulting SHA1 (cur_sha1) is == null_sha1, + * the note will be removed from the notes tree. * * The default combine_notes function (you get this when passing NULL) is * combine_notes_concatenate(), which appends the contents of the new note to @@ -90,6 +93,17 @@ void init_notes(struct notes_tree *t, const char *notes_ref, /* * Add the given note object to the given notes_tree structure * + * If there already exists a note for the given object_sha1, the given + * combine_notes function is invoked to break the tie. If not given (i.e. + * combine_notes == NULL), the default combine_notes function for the given + * notes_tree is used. + * + * Passing note_sha1 == null_sha1 indicates the addition of an + * empty/non-existent note. This is a (potentially expensive) no-op unless + * there already exists a note for the given object_sha1, AND combining that + * note with the empty note (using the given combine_notes function) results + * in a new/changed note. + * * IMPORTANT: The changes made by add_note() to the given notes_tree structure * are not persistent until a subsequent call to write_notes_tree() returns * zero. -- 1.7.3.2.173.gab1c9.dirty