tree_entry_interesting(): give meaningful names to return values

It is a basic code hygiene to avoid magic constants that are unnamed.
Besides, this helps extending the value later on for "interesting, but
cannot decide if the entry truely matches yet" (ie. prefix matches)

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

6 files changed, 56 insertions, 44 deletions

diff --git a/builtin/grep.c b/builtin/grep.c
index 2cd06126d2..2fc51fa2dc 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -542,18 +542,19 @@ static int grep_cache(struct grep_opt *opt, const struct pathspec *pathspec, int
 static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 		     struct tree_desc *tree, struct strbuf *base, int tn_len)
 {
-	int hit = 0, match = 0;
+	int hit = 0;
+	enum interesting match = entry_not_interesting;
 	struct name_entry entry;
 	int old_baselen = base->len;
 
 	while (tree_entry(tree, &entry)) {
 		int te_len = tree_entry_len(&entry);
 
-		if (match != 2) {
+		if (match != all_entries_interesting) {
 			match = tree_entry_interesting(&entry, base, tn_len, pathspec);
-			if (match < 0)
+			if (match == all_entries_not_interesting)
 				break;
-			if (match == 0)
+			if (match == entry_not_interesting)
 				continue;
 		}
 
diff --git a/list-objects.c b/list-objects.c
index 39d80c0175..3dd4a96019 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -71,7 +71,8 @@ static void process_tree(struct rev_info *revs,
 	struct tree_desc desc;
 	struct name_entry entry;
 	struct name_path me;
-	int match = revs->diffopt.pathspec.nr == 0 ? 2 : 0;
+	enum interesting match = revs->diffopt.pathspec.nr == 0 ?
+		all_entries_interesting: entry_not_interesting;
 	int baselen = base->len;
 
 	if (!revs->tree_objects)
@@ -97,12 +98,12 @@ static void process_tree(struct rev_info *revs,
 	init_tree_desc(&desc, tree->buffer, tree->size);
 
 	while (tree_entry(&desc, &entry)) {
-		if (match != 2) {
+		if (match != all_entries_interesting) {
 			match = tree_entry_interesting(&entry, base, 0,
 						       &revs->diffopt.pathspec);
-			if (match < 0)
+			if (match == all_entries_not_interesting)
 				break;
-			if (match == 0)
+			if (match == entry_not_interesting)
 				continue;
 		}
 
diff --git a/tree-diff.c b/tree-diff.c
index 6782484489..7a51d091b5 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -64,14 +64,14 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
 static void show_tree(struct diff_options *opt, const char *prefix,
 		      struct tree_desc *desc, struct strbuf *base)
 {
-	int match = 0;
+	enum interesting match = entry_not_interesting;
 	for (; desc->size; update_tree_entry(desc)) {
-		if (match != 2) {
+		if (match != all_entries_interesting) {
 			match = tree_entry_interesting(&desc->entry, base, 0,
 						       &opt->pathspec);
-			if (match < 0)
+			if (match == all_entries_not_interesting)
 				break;
-			if (match == 0)
+			if (match == entry_not_interesting)
 				continue;
 		}
 		show_entry(opt, prefix, desc, base);
@@ -114,12 +114,13 @@ static void show_entry(struct diff_options *opt, const char *prefix,
 }
 
 static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
-			       struct diff_options *opt, int *match)
+			       struct diff_options *opt,
+			       enum interesting *match)
 {
 	while (t->size) {
 		*match = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec);
 		if (*match) {
-			if (*match < 0)
+			if (*match == all_entries_not_interesting)
 				t->size = 0;
 			break;
 		}
@@ -132,7 +133,8 @@ int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
 {
 	struct strbuf base;
 	int baselen = strlen(base_str);
-	int t1_match = 0, t2_match = 0;
+	enum interesting t1_match = entry_not_interesting;
+	enum interesting t2_match = entry_not_interesting;
 
 	/* Enable recursion indefinitely */
 	opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
diff --git a/tree-walk.c b/tree-walk.c
index cc2f14a0d6..4a03e9bd21 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -577,27 +577,23 @@ static int match_dir_prefix(const char *base,
  *
  * Pre-condition: either baselen == base_offset (i.e. empty path)
  * or base[baselen-1] == '/' (i.e. with trailing slash).
- *
- * Return:
- *  - 2 for "yes, and all subsequent entries will be"
- *  - 1 for yes
- *  - zero for no
- *  - negative for "no, and no subsequent entries will be either"
  */
-int tree_entry_interesting(const struct name_entry *entry,
-			   struct strbuf *base, int base_offset,
-			   const struct pathspec *ps)
+enum interesting tree_entry_interesting(const struct name_entry *entry,
+					struct strbuf *base, int base_offset,
+					const struct pathspec *ps)
 {
 	int i;
 	int pathlen, baselen = base->len - base_offset;
-	int never_interesting = ps->has_wildcard ? 0 : -1;
+	int never_interesting = ps->has_wildcard ?
+		entry_not_interesting : all_entries_not_interesting;
 
 	if (!ps->nr) {
 		if (!ps->recursive || ps->max_depth == -1)
-			return 2;
-		return !!within_depth(base->buf + base_offset, baselen,
-				      !!S_ISDIR(entry->mode),
-				      ps->max_depth);
+			return all_entries_interesting;
+		return within_depth(base->buf + base_offset, baselen,
+				    !!S_ISDIR(entry->mode),
+				    ps->max_depth) ?
+			entry_interesting : entry_not_interesting;
 	}
 
 	pathlen = tree_entry_len(entry);
@@ -614,12 +610,13 @@ int tree_entry_interesting(const struct name_entry *entry,
 				goto match_wildcards;
 
 			if (!ps->recursive || ps->max_depth == -1)
-				return 2;
+				return all_entries_interesting;
 
-			return !!within_depth(base_str + matchlen + 1,
-					      baselen - matchlen - 1,
-					      !!S_ISDIR(entry->mode),
-					      ps->max_depth);
+			return within_depth(base_str + matchlen + 1,
+					    baselen - matchlen - 1,
+					    !!S_ISDIR(entry->mode),
+					    ps->max_depth) ?
+				entry_interesting : entry_not_interesting;
 		}
 
 		/* Either there must be no base, or the base must match. */
@@ -627,18 +624,18 @@ int tree_entry_interesting(const struct name_entry *entry,
 			if (match_entry(entry, pathlen,
 					match + baselen, matchlen - baselen,
 					&never_interesting))
-				return 1;
+				return entry_interesting;
 
 			if (ps->items[i].use_wildcard) {
 				if (!fnmatch(match + baselen, entry->path, 0))
-					return 1;
+					return entry_interesting;
 
 				/*
 				 * Match all directories. We'll try to
 				 * match files later on.
 				 */
 				if (ps->recursive && S_ISDIR(entry->mode))
-					return 1;
+					return entry_interesting;
 			}
 
 			continue;
@@ -657,7 +654,7 @@ match_wildcards:
 
 		if (!fnmatch(match, base->buf + base_offset, 0)) {
 			strbuf_setlen(base, base_offset + baselen);
-			return 1;
+			return entry_interesting;
 		}
 		strbuf_setlen(base, base_offset + baselen);
 
@@ -666,7 +663,7 @@ match_wildcards:
 		 * later on.
 		 */
 		if (ps->recursive && S_ISDIR(entry->mode))
-			return 1;
+			return entry_interesting;
 	}
 	return never_interesting; /* No matches */
 }
diff --git a/tree-walk.h b/tree-walk.h
index 884d01ac33..2bf0db9814 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -61,6 +61,16 @@ static inline int traverse_path_len(const struct traverse_info *info, const stru
 	return info->pathlen + tree_entry_len(n);
 }
 
-extern int tree_entry_interesting(const struct name_entry *, struct strbuf *, int, const struct pathspec *ps);
+/* in general, positive means "kind of interesting" */
+enum interesting {
+	all_entries_not_interesting = -1, /* no, and no subsequent entries will be either */
+	entry_not_interesting = 0,
+	entry_interesting = 1,
+	all_entries_interesting = 2 /* yes, and all subsequent entries will be */
+};
+
+extern enum interesting tree_entry_interesting(const struct name_entry *,
+					       struct strbuf *, int,
+					       const struct pathspec *ps);
 
 #endif
diff --git a/tree.c b/tree.c
index e62219803b..676e9f710c 100644
--- a/tree.c
+++ b/tree.c
@@ -52,7 +52,8 @@ static int read_tree_1(struct tree *tree, struct strbuf *base,
 	struct tree_desc desc;
 	struct name_entry entry;
 	unsigned char sha1[20];
-	int len, retval = 0, oldlen = base->len;
+	int len, oldlen = base->len;
+	enum interesting retval = entry_not_interesting;
 
 	if (parse_tree(tree))
 		return -1;
@@ -60,11 +61,11 @@ static int read_tree_1(struct tree *tree, struct strbuf *base,
 	init_tree_desc(&desc, tree->buffer, tree->size);
 
 	while (tree_entry(&desc, &entry)) {
-		if (retval != 2) {
+		if (retval != all_entries_interesting) {
 			retval = tree_entry_interesting(&entry, base, 0, pathspec);
-			if (retval < 0)
+			if (retval == all_entries_not_interesting)
 				break;
-			if (retval == 0)
+			if (retval == entry_not_interesting)
 				continue;
 		}