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From: Derrick Stolee <dstolee@microsoft.com>
To: "git@vger.kernel.org" <git@vger.kernel.org>
Cc: "peff@peff.net" <peff@peff.net>,
	"avarab@gmail.com" <avarab@gmail.com>,
	"sbeller@google.com" <sbeller@google.com>,
	"larsxschneider@gmail.com" <larsxschneider@gmail.com>,
	"bmwill@google.com" <bmwill@google.com>,
	Derrick Stolee <dstolee@microsoft.com>
Subject: [PATCH v2 05/10] commit: use generations in paint_down_to_common()
Date: Mon, 9 Apr 2018 16:42:03 +0000	[thread overview]
Message-ID: <20180409164131.37312-6-dstolee@microsoft.com> (raw)
In-Reply-To: <20180409164131.37312-1-dstolee@microsoft.com>

Define compare_commits_by_gen_then_commit_date(), which uses generation
numbers as a primary comparison and commit date to break ties (or as a
comparison when both commits do not have computed generation numbers).

Since the commit-graph file is closed under reachability, we know that
all commits in the file have generation at most GENERATION_NUMBER_MAX
which is less than GENERATION_NUMBER_INFINITY.

This change does not affect the number of commits that are walked during
the execution of paint_down_to_common(), only the order that those
commits are inspected. In the case that commit dates violate topological
order (i.e. a parent is "newer" than a child), the previous code could
walk a commit twice: if a commit is reached with the PARENT1 bit, but
later is re-visited with the PARENT2 bit, then that PARENT2 bit must be
propagated to its parents. Using generation numbers avoids this extra
effort, even if it is somewhat rare.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 commit.c | 19 ++++++++++++++++++-
 commit.h |  1 +
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/commit.c b/commit.c
index 3e39c86abf..95ae7e13a3 100644
--- a/commit.c
+++ b/commit.c
@@ -624,6 +624,23 @@ static int compare_commits_by_author_date(const void *a_, const void *b_,
 	return 0;
 }
 
+int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused)
+{
+	const struct commit *a = a_, *b = b_;
+
+	if (a->generation < b->generation)
+		return 1;
+	else if (a->generation > b->generation)
+		return -1;
+
+	/* newer commits with larger date first */
+	if (a->date < b->date)
+		return 1;
+	else if (a->date > b->date)
+		return -1;
+	return 0;
+}
+
 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 {
 	const struct commit *a = a_, *b = b_;
@@ -773,7 +790,7 @@ static int queue_has_nonstale(struct prio_queue *queue)
 /* all input commits in one and twos[] must have been parsed! */
 static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 {
-	struct prio_queue queue = { compare_commits_by_commit_date };
+	struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
 	struct commit_list *result = NULL;
 	int i;
 
diff --git a/commit.h b/commit.h
index b91df315c5..c440f56bf9 100644
--- a/commit.h
+++ b/commit.h
@@ -332,6 +332,7 @@ extern int remove_signature(struct strbuf *buf);
 extern int check_commit_signature(const struct commit *commit, struct signature_check *sigc);
 
 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused);
+int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused);
 
 LAST_ARG_MUST_BE_NULL
 extern int run_commit_hook(int editor_is_used, const char *index_file, const char *name, ...);
-- 
2.17.0


  parent reply	other threads:[~2018-04-09 16:42 UTC|newest]

Thread overview: 162+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-03 16:51 [PATCH 0/6] Compute and consume generation numbers Derrick Stolee
2018-04-03 16:51 ` [PATCH 1/6] object.c: parse commit in graph first Derrick Stolee
2018-04-03 18:21   ` Jonathan Tan
2018-04-03 18:28     ` Jeff King
2018-04-03 18:32       ` Derrick Stolee
2018-04-03 16:51 ` [PATCH 2/6] commit: add generation number to struct commmit Derrick Stolee
2018-04-03 18:05   ` Brandon Williams
2018-04-03 18:28     ` Jeff King
2018-04-03 18:31       ` Derrick Stolee
2018-04-03 18:32       ` Brandon Williams
2018-04-03 18:44       ` Stefan Beller
2018-04-03 23:17       ` Ramsay Jones
2018-04-03 23:19         ` Jeff King
2018-04-03 18:24   ` Jonathan Tan
2018-04-03 16:51 ` [PATCH 3/6] commit-graph: compute generation numbers Derrick Stolee
2018-04-03 18:30   ` Jonathan Tan
2018-04-03 18:49     ` Stefan Beller
2018-04-03 16:51 ` [PATCH 4/6] commit: use generations in paint_down_to_common() Derrick Stolee
2018-04-03 18:31   ` Stefan Beller
2018-04-03 18:31   ` Jonathan Tan
2018-04-03 16:51 ` [PATCH 5/6] commit.c: use generation to halt paint walk Derrick Stolee
2018-04-03 19:01   ` Jonathan Tan
2018-04-03 16:51 ` [PATCH 6/6] commit-graph.txt: update future work Derrick Stolee
2018-04-03 19:04   ` Jonathan Tan
2018-04-03 16:56 ` [PATCH 0/6] Compute and consume generation numbers Derrick Stolee
2018-04-03 18:03 ` Brandon Williams
2018-04-03 18:29   ` Derrick Stolee
2018-04-03 18:47     ` Jeff King
2018-04-03 19:05       ` Jeff King
2018-04-04 15:45         ` [PATCH 7/6] ref-filter: use generation number for --contains Derrick Stolee
2018-04-04 15:45           ` [PATCH 8/6] commit: use generation numbers for in_merge_bases() Derrick Stolee
2018-04-04 15:48             ` Derrick Stolee
2018-04-04 17:01               ` Brandon Williams
2018-04-04 18:24               ` Jeff King
2018-04-04 18:53                 ` Derrick Stolee
2018-04-04 18:59                   ` Jeff King
2018-04-04 18:22           ` [PATCH 7/6] ref-filter: use generation number for --contains Jeff King
2018-04-04 19:06             ` Derrick Stolee
2018-04-04 19:16               ` Jeff King
2018-04-04 19:22                 ` Derrick Stolee
2018-04-04 19:42                   ` Jeff King
2018-04-04 19:45                     ` Derrick Stolee
2018-04-04 19:46                       ` Jeff King
2018-04-07 17:09     ` [PATCH 0/6] Compute and consume generation numbers Jakub Narebski
2018-04-07 16:55 ` Jakub Narebski
2018-04-08  1:06   ` Derrick Stolee
2018-04-11 19:32     ` Jakub Narebski
2018-04-11 19:58       ` Derrick Stolee
2018-04-14 16:52         ` Jakub Narebski
2018-04-21 20:44           ` Jakub Narebski
2018-04-23 13:54             ` Derrick Stolee
2018-04-09 16:41 ` [PATCH v2 00/10] " Derrick Stolee
2018-04-09 16:41   ` [PATCH v2 01/10] object.c: parse commit in graph first Derrick Stolee
2018-04-09 16:41   ` [PATCH v2 02/10] merge: check config before loading commits Derrick Stolee
2018-04-11  2:12     ` Junio C Hamano
2018-04-11 12:49       ` Derrick Stolee
2018-04-09 16:42   ` [PATCH v2 03/10] commit: add generation number to struct commmit Derrick Stolee
2018-04-09 17:59     ` Stefan Beller
2018-04-11  2:31     ` Junio C Hamano
2018-04-11 12:57       ` Derrick Stolee
2018-04-11 23:28         ` Junio C Hamano
2018-04-09 16:42   ` [PATCH v2 04/10] commit-graph: compute generation numbers Derrick Stolee
2018-04-11  2:51     ` Junio C Hamano
2018-04-11 13:02       ` Derrick Stolee
2018-04-11 18:49         ` Stefan Beller
2018-04-11 19:26         ` Eric Sunshine
2018-04-09 16:42   ` Derrick Stolee [this message]
2018-04-09 16:42   ` [PATCH v2 06/10] commit.c: use generation to halt paint walk Derrick Stolee
2018-04-11  3:02     ` Junio C Hamano
2018-04-11 13:24       ` Derrick Stolee
2018-04-09 16:42   ` [PATCH v2 07/10] commit-graph.txt: update future work Derrick Stolee
2018-04-12  9:12     ` Junio C Hamano
2018-04-12 11:35       ` Derrick Stolee
2018-04-13  9:53         ` Jakub Narebski
2018-04-09 16:42   ` [PATCH v2 08/10] ref-filter: use generation number for --contains Derrick Stolee
2018-04-09 16:42   ` [PATCH v2 09/10] commit: use generation numbers for in_merge_bases() Derrick Stolee
2018-04-09 16:42   ` [PATCH v2 10/10] commit: add short-circuit to paint_down_to_common() Derrick Stolee
2018-04-17 17:00   ` [PATCH v3 0/9] Compute and consume generation numbers Derrick Stolee
2018-04-17 17:00     ` [PATCH v3 1/9] commit: add generation number to struct commmit Derrick Stolee
2018-04-17 17:00     ` [PATCH v3 2/9] commit-graph: compute generation numbers Derrick Stolee
2018-04-17 17:00     ` [PATCH v3 3/9] commit: use generations in paint_down_to_common() Derrick Stolee
2018-04-18 14:31       ` Jakub Narebski
2018-04-18 14:46         ` Derrick Stolee
2018-04-17 17:00     ` [PATCH v3 4/9] commit-graph.txt: update design document Derrick Stolee
2018-04-18 19:47       ` Jakub Narebski
2018-04-17 17:00     ` [PATCH v3 5/9] ref-filter: use generation number for --contains Derrick Stolee
2018-04-18 21:02       ` Jakub Narebski
2018-04-23 14:22         ` Derrick Stolee
2018-04-24 18:56           ` Jakub Narebski
2018-04-25 14:11             ` Derrick Stolee
2018-04-17 17:00     ` [PATCH v3 6/9] commit: use generation numbers for in_merge_bases() Derrick Stolee
2018-04-18 22:15       ` Jakub Narebski
2018-04-23 14:31         ` Derrick Stolee
2018-04-17 17:00     ` [PATCH v3 7/9] commit: add short-circuit to paint_down_to_common() Derrick Stolee
2018-04-18 23:19       ` Jakub Narebski
2018-04-23 14:40         ` Derrick Stolee
2018-04-23 21:38           ` Jakub Narebski
2018-04-24 12:31             ` Derrick Stolee
2018-04-19  8:32       ` Jakub Narebski
2018-04-17 17:00     ` [PATCH v3 8/9] commit-graph: always load commit-graph information Derrick Stolee
2018-04-17 17:50       ` Derrick Stolee
2018-04-19  0:02       ` Jakub Narebski
2018-04-23 14:49         ` Derrick Stolee
2018-04-17 17:00     ` [PATCH v3 9/9] merge: check config before loading commits Derrick Stolee
2018-04-19  0:04     ` [PATCH v3 0/9] Compute and consume generation numbers Jakub Narebski
2018-04-23 14:54       ` Derrick Stolee
2018-04-25 14:37     ` [PATCH v4 00/10] " Derrick Stolee
2018-04-25 14:37       ` [PATCH v4 01/10] ref-filter: fix outdated comment on in_commit_list Derrick Stolee
2018-04-28 17:54         ` Jakub Narebski
2018-04-25 14:37       ` [PATCH v4 02/10] commit: add generation number to struct commmit Derrick Stolee
2018-04-28 22:35         ` Jakub Narebski
2018-04-30 12:05           ` Derrick Stolee
2018-04-25 14:37       ` [PATCH v4 03/10] commit-graph: compute generation numbers Derrick Stolee
2018-04-26  2:35         ` Junio C Hamano
2018-04-26 12:58           ` Derrick Stolee
2018-04-26 13:49             ` Derrick Stolee
2018-04-29  9:08         ` Jakub Narebski
2018-05-01 12:10           ` Derrick Stolee
2018-05-02 16:15             ` Jakub Narebski
2018-04-25 14:37       ` [PATCH v4 04/10] commit: use generations in paint_down_to_common() Derrick Stolee
2018-04-26  3:22         ` Junio C Hamano
2018-04-26  9:02           ` Jakub Narebski
2018-04-28 14:38             ` Jakub Narebski
2018-04-29 15:40         ` Jakub Narebski
2018-04-25 14:37       ` [PATCH v4 05/10] commit-graph: always load commit-graph information Derrick Stolee
2018-04-29 22:14         ` Jakub Narebski
2018-05-01 12:19           ` Derrick Stolee
2018-04-29 22:18         ` Jakub Narebski
2018-04-25 14:37       ` [PATCH v4 06/10] ref-filter: use generation number for --contains Derrick Stolee
2018-04-30 16:34         ` Jakub Narebski
2018-04-25 14:37       ` [PATCH v4 07/10] commit: use generation numbers for in_merge_bases() Derrick Stolee
2018-04-30 17:05         ` Jakub Narebski
2018-04-25 14:38       ` [PATCH v4 08/10] commit: add short-circuit to paint_down_to_common() Derrick Stolee
2018-04-30 22:19         ` Jakub Narebski
2018-05-01 11:47           ` Derrick Stolee
2018-05-02 13:05             ` Jakub Narebski
2018-05-02 13:42               ` Derrick Stolee
2018-04-25 14:38       ` [PATCH v4 09/10] merge: check config before loading commits Derrick Stolee
2018-04-30 22:54         ` Jakub Narebski
2018-05-01 11:52           ` Derrick Stolee
2018-05-02 11:41             ` Jakub Narebski
2018-04-25 14:38       ` [PATCH v4 10/10] commit-graph.txt: update design document Derrick Stolee
2018-04-30 23:32         ` Jakub Narebski
2018-05-01 12:00           ` Derrick Stolee
2018-05-02  7:57             ` Jakub Narebski
2018-04-25 14:40       ` [PATCH v4 00/10] Compute and consume generation numbers Derrick Stolee
2018-04-28 17:28         ` Jakub Narebski
2018-05-01 12:47       ` [PATCH v5 00/11] " Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 01/11] ref-filter: fix outdated comment on in_commit_list Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 02/11] commit: add generation number to struct commmit Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 03/11] commit-graph: compute generation numbers Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 04/11] commit: use generations in paint_down_to_common() Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 05/11] commit-graph: always load commit-graph information Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 06/11] ref-filter: use generation number for --contains Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 07/11] commit: use generation numbers for in_merge_bases() Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 08/11] commit: add short-circuit to paint_down_to_common() Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 09/11] commit: use generation number in remove_redundant() Derrick Stolee
2018-05-01 15:37           ` Derrick Stolee
2018-05-03 18:45           ` Jakub Narebski
2018-05-01 12:47         ` [PATCH v5 10/11] merge: check config before loading commits Derrick Stolee
2018-05-01 12:47         ` [PATCH v5 11/11] commit-graph.txt: update design document Derrick Stolee
2018-05-03 11:18         ` [PATCH v5 00/11] Compute and consume generation numbers Jakub Narebski

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