[v2,3/3] bisect: combine args passed to find_bisection()

Commit Message

Aaron Lipman July 30, 2020, 12:27 a.m. UTC

Now that find_bisection() accepts multiple boolean arguments, these may
be combined into a single unsigned integer in order to declutter some of
the code in bisect.c

Signed-off-by: Aaron Lipman <[e-mail]>
Based-on-patch-by: Harald Nordgren <[e-mail]>
---
 bisect.c           | 37 ++++++++++++++++++++++---------------
 bisect.h           |  5 ++++-
 builtin/rev-list.c |  9 ++++++++-
 3 files changed, 34 insertions(+), 17 deletions(-)

Comments

Junio C Hamano July 30, 2020, 4:32 a.m. UTC | #1

Aaron Lipman <[e-mail]> writes:

> Now that find_bisection() accepts multiple boolean arguments, these may
> be combined into a single unsigned integer in order to declutter some of
> the code in bisect.c

I'd rather call them "flags" without "bisect_".  If we are passing
two sets of flags, one set about "bisect" and the other set about
something else, it would make quite a lot of sense to call the first
set "bisect_flags", but what we are seeing here is not like that.

> +	if (read_first_parent_option())
> +		bisect_flags |= BISECT_FIRST_PARENT;
> +
> +	if (!!skipped_revs.nr)
> +		bisect_flags |= BISECT_FIND_ALL;
> +

You do not care what kind of "true" you are feeding "if()", so I do
not think you would want to keep !! prefix here.  Older API into
find_bisection() may wanted to say "pass 1 to find_all", in which
case, normalizing with !! prefix may have made perfect sense, but 
that no longer holds here.

> +
> +	revs.first_parent_only = !!(bisect_flags & BISECT_FIRST_PARENT);

On the other hand, this !! may make sense; especially since .first_parent_only
could just be a one-bit unsigned bitfield.

>  	revs.limited = 1;
>  
>  	bisect_common(&revs);
>  
> -	find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr, first_parent_only);
> +	find_bisection(&revs.commits, &reaches, &all, bisect_flags);

> @@ -23,6 +23,9 @@ struct commit_list *filter_skipped(struct commit_list *list,
>  #define BISECT_SHOW_ALL		(1<<0)
>  #define REV_LIST_QUIET		(1<<1)
>  
> +#define BISECT_FIND_ALL		(1u<<0)
> +#define BISECT_FIRST_PARENT	(1u<<1)

The set of bits to go to your "bisect_flags" are only these two new
ones, and the existing BISECT_SHOW_ALL does not belong to it (it is
a bit in rev_list_info.flags), but it is not apparent.  I wonder if
there is a good way to help readers easily tell these two sets apart.
These are flags passed to find_bisection(), so perhaps

    #define FIND_BISECTION_ALL (1U<<0)
    #define FIND_BISECTION_FIRST_PARENT_ONLY (1U<<1)

    unsigned flags = 0;
    if (first_parent)
	flags |= FIND_BISECTION_FIRST_PARENT_ONLY;
    ...
    find_bisection(..., flags);

would be a reasonable compromise?

Thanks.

Patch

diff --git a/bisect.c b/bisect.c
index b495a19192..07a7760a72 100644
--- a/bisect.c
+++ b/bisect.c
@@ -88,7 +88,7 @@  static inline void weight_set(struct commit_list *elem, int weight)
 	**commit_weight_at(&commit_weight, elem->item) = weight;
 }
 
-static int count_interesting_parents(struct commit *commit, int first_parent_only)
+static int count_interesting_parents(struct commit *commit, unsigned bisect_flags)
 {
 	struct commit_list *p;
 	int count;
@@ -96,7 +96,7 @@  static int count_interesting_parents(struct commit *commit, int first_parent_onl
 	for (count = 0, p = commit->parents; p; p = p->next) {
 		if (!(p->item->object.flags & UNINTERESTING))
 			count++;
-		if (first_parent_only)
+		if (bisect_flags & BISECT_FIRST_PARENT)
 			break;
 	}
 	return count;
@@ -260,7 +260,7 @@  static struct commit_list *best_bisection_sorted(struct commit_list *list, int n
  */
 static struct commit_list *do_find_bisection(struct commit_list *list,
 					     int nr, int *weights,
-					     int find_all, int first_parent_only)
+					     unsigned bisect_flags)
 {
 	int n, counted;
 	struct commit_list *p;
@@ -272,7 +272,7 @@  static struct commit_list *do_find_bisection(struct commit_list *list,
 		unsigned flags = commit->object.flags;
 
 		*commit_weight_at(&commit_weight, p->item) = &weights[n++];
-		switch (count_interesting_parents(commit, first_parent_only)) {
+		switch (count_interesting_parents(commit, bisect_flags)) {
 		case 0:
 			if (!(flags & TREESAME)) {
 				weight_set(p, 1);
@@ -315,13 +315,13 @@  static struct commit_list *do_find_bisection(struct commit_list *list,
 			continue;
 		if (weight(p) != -2)
 			continue;
-		if (first_parent_only)
+		if (bisect_flags & BISECT_FIRST_PARENT)
 			BUG("shouldn't be calling count-distance in fp mode");
 		weight_set(p, count_distance(p));
 		clear_distance(list);
 
 		/* Does it happen to be at exactly half-way? */
-		if (!find_all && halfway(p, nr))
+		if (!(bisect_flags & BISECT_FIND_ALL) && halfway(p, nr))
 			return p;
 		counted++;
 	}
@@ -338,7 +338,7 @@  static struct commit_list *do_find_bisection(struct commit_list *list,
 
 			for (q = p->item->parents;
 			     q;
-			     q = first_parent_only ? NULL : q->next) {
+			     q = bisect_flags & BISECT_FIRST_PARENT ? NULL : q->next) {
 				if (q->item->object.flags & UNINTERESTING)
 					continue;
 				if (0 <= weight(q))
@@ -362,21 +362,21 @@  static struct commit_list *do_find_bisection(struct commit_list *list,
 				weight_set(p, weight(q));
 
 			/* Does it happen to be at exactly half-way? */
-			if (!find_all && halfway(p, nr))
+			if (!(bisect_flags & BISECT_FIND_ALL) && halfway(p, nr))
 				return p;
 		}
 	}
 
 	show_list("bisection 2 counted all", counted, nr, list);
 
-	if (!find_all)
+	if (!(bisect_flags & BISECT_FIND_ALL))
 		return best_bisection(list, nr);
 	else
 		return best_bisection_sorted(list, nr);
 }
 
 void find_bisection(struct commit_list **commit_list, int *reaches,
-		    int *all, int find_all, int first_parent_only)
+		    int *all, unsigned bisect_flags)
 {
 	int nr, on_list;
 	struct commit_list *list, *p, *best, *next, *last;
@@ -412,9 +412,9 @@  void find_bisection(struct commit_list **commit_list, int *reaches,
 	weights = xcalloc(on_list, sizeof(*weights));
 
 	/* Do the real work of finding bisection commit. */
-	best = do_find_bisection(list, nr, weights, find_all, first_parent_only);
+	best = do_find_bisection(list, nr, weights, bisect_flags);
 	if (best) {
-		if (!find_all) {
+		if (!(bisect_flags & BISECT_FIND_ALL)) {
 			list->item = best->item;
 			free_commit_list(list->next);
 			best = list;
@@ -1004,23 +1004,30 @@  enum bisect_error bisect_next_all(struct repository *r, const char *prefix, int
 	enum bisect_error res = BISECT_OK;
 	struct object_id *bisect_rev;
 	char *steps_msg;
-	int first_parent_only = read_first_parent_option();
+	unsigned bisect_flags = 0;
 
 	read_bisect_terms(&term_bad, &term_good);
 	if (read_bisect_refs())
 		die(_("reading bisect refs failed"));
 
+	if (read_first_parent_option())
+		bisect_flags |= BISECT_FIRST_PARENT;
+
+	if (!!skipped_revs.nr)
+		bisect_flags |= BISECT_FIND_ALL;
+
 	res = check_good_are_ancestors_of_bad(r, prefix, no_checkout);
 	if (res)
 		return res;
 
 	bisect_rev_setup(r, &revs, prefix, "%s", "^%s", 1);
-	revs.first_parent_only = first_parent_only;
+
+	revs.first_parent_only = !!(bisect_flags & BISECT_FIRST_PARENT);
 	revs.limited = 1;
 
 	bisect_common(&revs);
 
-	find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr, first_parent_only);
+	find_bisection(&revs.commits, &reaches, &all, bisect_flags);
 	revs.commits = managed_skipped(revs.commits, &tried);
 
 	if (!revs.commits) {
diff --git a/bisect.h b/bisect.h
index 8ee80f5b48..402ddcfb5e 100644
--- a/bisect.h
+++ b/bisect.h
@@ -12,7 +12,7 @@  struct repository;
  * best commit, as chosen by `find_all`.
  */
 void find_bisection(struct commit_list **list, int *reaches, int *all,
-		    int find_all, int first_parent_only);
+		    unsigned bisect_flags);
 
 struct commit_list *filter_skipped(struct commit_list *list,
 				   struct commit_list **tried,
@@ -23,6 +23,9 @@  struct commit_list *filter_skipped(struct commit_list *list,
 #define BISECT_SHOW_ALL		(1<<0)
 #define REV_LIST_QUIET		(1<<1)
 
+#define BISECT_FIND_ALL		(1u<<0)
+#define BISECT_FIRST_PARENT	(1u<<1)
+
 struct rev_list_info {
 	struct rev_info *revs;
 	int flags;
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index d1a14596b2..1536ea6f28 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -637,8 +637,15 @@  int cmd_rev_list(int argc, const char **argv, const char *prefix)
 
 	if (bisect_list) {
 		int reaches, all;
+		unsigned bisect_flags = 0;
 
-		find_bisection(&revs.commits, &reaches, &all, bisect_find_all, revs.first_parent_only);
+		if (bisect_find_all)
+			bisect_flags |= BISECT_FIND_ALL;
+
+		if (revs.first_parent_only)
+			bisect_flags |= BISECT_FIRST_PARENT;
+
+		find_bisection(&revs.commits, &reaches, &all, bisect_flags);
 
 		if (bisect_show_vars)
 			return show_bisect_vars(&info, reaches, all);