When sorting commits topologically, the primary invariant is to emit
all children before its parent is emitted. When traversing a forked
history like this with "git log C E":
A----B----C
\
D----E
we ensure that A is emitted after all of B, C, D, and E are done, B
has to wait until C is done, and D has to wait until E is done.
In some applications, however, we would further want to control how
these child commits B, C, D and E on two parallel ancestry chains
are shown. Most of the time, we would want to see C and B emitted
together, and then E and D, and finally A. This is the default
behaviour for --topo-order output.
The "lifo" parameter of the sort_in_topological_order() function is
used to control this. After inspecting C, we notice and record that
B needs to be inspected, and by structuring the "work to be done"
set as a LIFO stack, we ensure that B is inspected next, before
other in-flight commits we had known that we will need to inspect,
e.g. E, that have already been in the "work to be done" set.
When showing in --date-order, we would want to see commits ordered
by timestamps, i.e. show C, E, B and D in this order before showing
A, mixing commits from two parallel histories together. When "lifo"
is set to false, the function keeps the "work to be done" set sorted
in the date order to realize this sematics.
But the name "lifo" is too tied to the way how the function implements
its behaviour, and does not describe _what_ is the desired semantcs.
Replace the "lifo" field with an enum rev_sort_order, with two
possible values: REV_SORT_IN_GRAPH_ORDER and REV_SORT_BY_COMMIT_DATE.
The mechanical replacement rule is:
"lifo == 0" is equivalent to "sort_order == REV_SORT_BY_COMMIT_DATE"
"lifo == 1" is equivalent to "sort_order == REV_SORT_IN_GRAPH_ORDER"
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
> As I needed to have an excuse to push jk/commit-info-slab topic
> further (I have an unpublished show-branch rewrite on top of it),
> I may take a look at doing this myself if/when I find some time.
So this is the first step, applies on top of jk/commit-info-slab.
builtin/log.c | 2 +-
builtin/show-branch.c | 14 ++++++++------
commit.c | 12 ++++++++----
commit.h | 14 +++++++++++---
revision.c | 10 +++++-----
revision.h | 6 +++++-
6 files changed, 38 insertions(+), 20 deletions(-)
diff --git a/builtin/log.c b/builtin/log.c
index 8f0b2e8..8d26042 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -205,7 +205,7 @@ static void log_show_early(struct rev_info *revs, struct commit_list *list)
int i = revs->early_output;
int show_header = 1;
- sort_in_topological_order(&list, revs->lifo);
+ sort_in_topological_order(&list, revs->sort_order);
while (list && i) {
struct commit *commit = list->item;
switch (simplify_commit(revs, commit)) {
diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index d208fd6..7c57985 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -631,7 +631,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
int num_rev, i, extra = 0;
int all_heads = 0, all_remotes = 0;
int all_mask, all_revs;
- int lifo = 1;
+ enum rev_sort_order sort_order = REV_SORT_IN_GRAPH_ORDER;
char head[128];
const char *head_p;
int head_len;
@@ -666,15 +666,17 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
N_("show possible merge bases")),
OPT_BOOLEAN(0, "independent", &independent,
N_("show refs unreachable from any other ref")),
- OPT_BOOLEAN(0, "topo-order", &lifo,
- N_("show commits in topological order")),
+ OPT_SET_INT(0, "topo-order", &sort_order,
+ N_("show commits in topological order"),
+ REV_SORT_IN_GRAPH_ORDER),
OPT_BOOLEAN(0, "topics", &topics,
N_("show only commits not on the first branch")),
OPT_SET_INT(0, "sparse", &dense,
N_("show merges reachable from only one tip"), 0),
- OPT_SET_INT(0, "date-order", &lifo,
+ OPT_SET_INT(0, "date-order", &sort_order,
N_("show commits where no parent comes before its "
- "children"), 0),
+ "children"),
+ REV_SORT_BY_COMMIT_DATE),
{ OPTION_CALLBACK, 'g', "reflog", &reflog_base, N_("<n>[,<base>]"),
N_("show <n> most recent ref-log entries starting at "
"base"),
@@ -901,7 +903,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
exit(0);
/* Sort topologically */
- sort_in_topological_order(&seen, lifo);
+ sort_in_topological_order(&seen, sort_order);
/* Give names to commits */
if (!sha1_name && !no_name)
diff --git a/commit.c b/commit.c
index 66a6c00..fc1734b 100644
--- a/commit.c
+++ b/commit.c
@@ -507,7 +507,7 @@ define_commit_slab(indegree_slab, int);
/*
* Performs an in-place topological sort on the list supplied.
*/
-void sort_in_topological_order(struct commit_list ** list, int lifo)
+void sort_in_topological_order(struct commit_list ** list, enum rev_sort_order sort_order)
{
struct commit_list *next, *orig = *list;
struct commit_list *work, **insert;
@@ -556,7 +556,7 @@ void sort_in_topological_order(struct commit_list ** list, int lifo)
}
/* process the list in topological order */
- if (!lifo)
+ if (sort_order != REV_SORT_IN_GRAPH_ORDER)
commit_list_sort_by_date(&work);
pptr = list;
@@ -583,10 +583,14 @@ void sort_in_topological_order(struct commit_list ** list, int lifo)
* guaranteeing topological order.
*/
if (--(*pi) == 1) {
- if (!lifo)
+ switch (sort_order) {
+ case REV_SORT_BY_COMMIT_DATE:
commit_list_insert_by_date(parent, &work);
- else
+ break;
+ default: /* REV_SORT_IN_GRAPH_ORDER */
commit_list_insert(parent, &work);
+ break;
+ }
}
}
/*
diff --git a/commit.h b/commit.h
index 70e749d..247e474 100644
--- a/commit.h
+++ b/commit.h
@@ -139,15 +139,23 @@ struct commit *pop_commit(struct commit_list **stack);
void clear_commit_marks(struct commit *commit, unsigned int mark);
void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark);
+
+enum rev_sort_order {
+ REV_SORT_IN_GRAPH_ORDER = 0,
+ REV_SORT_BY_COMMIT_DATE
+};
+
/*
* Performs an in-place topological sort of list supplied.
*
* invariant of resulting list is:
* a reachable from b => ord(b) < ord(a)
- * in addition, when lifo == 0, commits on parallel tracks are
- * sorted in the dates order.
+ * sort_order further specifies:
+ * REV_SORT_IN_GRAPH_ORDER: try to show a commit on a single-parent
+ * chain together.
+ * REV_SORT_BY_COMMIT_DATE: show eligible commits in committer-date order.
*/
-void sort_in_topological_order(struct commit_list ** list, int lifo);
+void sort_in_topological_order(struct commit_list **, enum rev_sort_order);
struct commit_graft {
unsigned char sha1[20];
diff --git a/revision.c b/revision.c
index cf620c6..966ebbc 100644
--- a/revision.c
+++ b/revision.c
@@ -1038,7 +1038,7 @@ void init_revisions(struct rev_info *revs, const char *prefix)
DIFF_OPT_SET(&revs->pruning, QUICK);
revs->pruning.add_remove = file_add_remove;
revs->pruning.change = file_change;
- revs->lifo = 1;
+ revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
revs->dense = 1;
revs->prefix = prefix;
revs->max_age = -1;
@@ -1373,7 +1373,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
} else if (!strcmp(arg, "--merge")) {
revs->show_merge = 1;
} else if (!strcmp(arg, "--topo-order")) {
- revs->lifo = 1;
+ revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
revs->topo_order = 1;
} else if (!strcmp(arg, "--simplify-merges")) {
revs->simplify_merges = 1;
@@ -1391,7 +1391,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
revs->prune = 1;
load_ref_decorations(DECORATE_SHORT_REFS);
} else if (!strcmp(arg, "--date-order")) {
- revs->lifo = 0;
+ revs->sort_order = REV_SORT_BY_COMMIT_DATE;
revs->topo_order = 1;
} else if (!prefixcmp(arg, "--early-output")) {
int count = 100;
@@ -2165,7 +2165,7 @@ int prepare_revision_walk(struct rev_info *revs)
if (limit_list(revs) < 0)
return -1;
if (revs->topo_order)
- sort_in_topological_order(&revs->commits, revs->lifo);
+ sort_in_topological_order(&revs->commits, revs->sort_order);
if (revs->simplify_merges)
simplify_merges(revs);
if (revs->children.name)
@@ -2480,7 +2480,7 @@ static void create_boundary_commit_list(struct rev_info *revs)
* If revs->topo_order is set, sort the boundary commits
* in topological order
*/
- sort_in_topological_order(&revs->commits, revs->lifo);
+ sort_in_topological_order(&revs->commits, revs->sort_order);
}
static struct commit *get_revision_internal(struct rev_info *revs)
diff --git a/revision.h b/revision.h
index 5da09ee..2a5e325 100644
--- a/revision.h
+++ b/revision.h
@@ -4,6 +4,7 @@
#include "parse-options.h"
#include "grep.h"
#include "notes.h"
+#include "commit.h"
#define SEEN (1u<<0)
#define UNINTERESTING (1u<<1)
@@ -60,6 +61,10 @@ struct rev_info {
const char *prefix;
const char *def;
struct pathspec prune_data;
+
+ /* topo-sort */
+ enum rev_sort_order sort_order;
+
unsigned int early_output:1,
ignore_missing:1;
@@ -70,7 +75,6 @@ struct rev_info {
show_all:1,
remove_empty_trees:1,
simplify_history:1,
- lifo:1,
topo_order:1,
simplify_merges:1,
simplify_by_decoration:1,
--
1.8.3-451-gb703ddf
--
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