unpack-trees: rename 'is_excluded_from_list()'

The first consumer of pattern-matching filenames was the
.gitignore feature. In that context, storing a list of patterns
as a 'struct exclude_list'  makes sense. However, the
sparse-checkout feature then adopted these structures and methods,
but with the opposite meaning: these patterns match the files
that should be included!

Now that this library is renamed to use 'struct pattern_list'
and 'struct pattern', we can now rename the method used by
the sparse-checkout feature to determine which paths should
appear in the working directory.

The method is_excluded_from_list() is only used by the
sparse-checkout logic in unpack-trees and list-objects-filter.
The confusing part is that it returned 1 for "excluded" (i.e.
it matches the list of exclusions) but that really manes that
the path matched the list of patterns for _inclusion_ in the
working directory.

Rename the method to be path_matches_pattern_list() and have
it return an explicit 'enum pattern_match_result'. Here, the
values MATCHED = 1, UNMATCHED = 0, and UNDECIDED = -1 agree
with the previous integer values. This shift allows future
consumers to better understand what the retur values mean,
and provides more type checking for handling those values.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 15 insertions, 14 deletions

diff --git a/list-objects-filter.c b/list-objects-filter.c
index ccd58e6..d624f1c 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -328,12 +328,12 @@ static void filter_blobs_limit__init(
  */
 struct frame {
 	/*
-	 * defval is the usual default include/exclude value that
+	 * default_match is the usual default include/exclude value that
 	 * should be inherited as we recurse into directories based
 	 * upon pattern matching of the directory itself or of a
 	 * containing directory.
 	 */
-	int defval;
+	enum pattern_match_result default_match;
 
 	/*
 	 * 1 if the directory (recursively) contains any provisionally
@@ -363,8 +363,9 @@ static enum list_objects_filter_result filter_sparse(
 	void *filter_data_)
 {
 	struct filter_sparse_data *filter_data = filter_data_;
-	int val, dtype;
+	int dtype;
 	struct frame *frame;
+	enum pattern_match_result match;
 
 	switch (filter_situation) {
 	default:
@@ -373,15 +374,15 @@ static enum list_objects_filter_result filter_sparse(
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		dtype = DT_DIR;
-		val = is_excluded_from_list(pathname, strlen(pathname),
-					    filename, &dtype, &filter_data->pl,
-					    r->index);
-		if (val < 0)
-			val = filter_data->array_frame[filter_data->nr - 1].defval;
+		match = path_matches_pattern_list(pathname, strlen(pathname),
+						  filename, &dtype, &filter_data->pl,
+						  r->index);
+		if (match == UNDECIDED)
+			match = filter_data->array_frame[filter_data->nr - 1].default_match;
 
 		ALLOC_GROW(filter_data->array_frame, filter_data->nr + 1,
 			   filter_data->alloc);
-		filter_data->array_frame[filter_data->nr].defval = val;
+		filter_data->array_frame[filter_data->nr].default_match = match;
 		filter_data->array_frame[filter_data->nr].child_prov_omit = 0;
 		filter_data->nr++;
 
@@ -435,12 +436,12 @@ static enum list_objects_filter_result filter_sparse(
 		frame = &filter_data->array_frame[filter_data->nr - 1];
 
 		dtype = DT_REG;
-		val = is_excluded_from_list(pathname, strlen(pathname),
+		match = path_matches_pattern_list(pathname, strlen(pathname),
 					    filename, &dtype, &filter_data->pl,
 					    r->index);
-		if (val < 0)
-			val = frame->defval;
-		if (val > 0) {
+		if (match == UNDECIDED)
+			match = frame->default_match;
+		if (match == MATCHED) {
 			if (omits)
 				oidset_remove(omits, &obj->oid);
 			return LOFR_MARK_SEEN | LOFR_DO_SHOW;
@@ -487,7 +488,7 @@ static void filter_sparse_oid__init(
 		die("could not load filter specification");
 
 	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
-	d->array_frame[d->nr].defval = 0; /* default to include */
+	d->array_frame[d->nr].default_match = 0; /* default to include */
 	d->array_frame[d->nr].child_prov_omit = 0;
 	d->nr++;