diff options
author | Derrick Stolee <dstolee@microsoft.com> | 2018-05-01 15:47:11 +0300 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2018-05-22 06:36:34 +0300 |
commit | 3afc679b3c13d99e4f02bceb686f11d51576d3ae (patch) | |
tree | 74add9b002a7fa5dca0177708b6c8a6dc7b17ad7 /commit.c | |
parent | 3258c66332abaf6e3e8fd81cab07ae804760cd08 (diff) |
commit: use generations in paint_down_to_common()
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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'commit.c')
-rw-r--r-- | commit.c | 20 |
1 files changed, 19 insertions, 1 deletions
@@ -640,6 +640,24 @@ 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_; + + /* newer commits first */ + if (a->generation < b->generation) + return 1; + else if (a->generation > b->generation) + return -1; + + /* use date as a heuristic when generations are equal */ + 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_; @@ -789,7 +807,7 @@ 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; |