[PATCH v4] cleanup duplicate name_compare() functions

[Jeremiah Mahler <jmmahler@gmail.com>]

Both unpack-trees.c and read-cache.c have their own name_compare()
function, which are identical.  And read-cache.c has a
cache_name_compare() function which is nearly identical to
name_compare() [1].  The cache_name_compare() function is not specific
to a cache, other than by being part of cache.h.

Generalize the cache_name_compare() function by renaming it to
name_compare().  Simplify the cache_name_stage_compare() function using
name_compare().  Then change the few instances which used
cache_name_compare() to name_compare() [2].

[1] cache_name_compare() is not identical to name_compare().  The former
    returns +1, -1, whereas the latter returns +N, -N.  But there is no
    place where name_compare() is used that needs the magnitude so this
    difference does not alter its behavior.

[2] The instances where cache_name_compare() is used have nothing to do
    with a cache.  The new name, name_compare(), makes it clear that no
    cache is involved.

Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
---
 cache.h        |  2 +-
 dir.c          |  3 +--
 name-hash.c    |  2 +-
 read-cache.c   | 23 +++++++++++++----------
 tree-walk.c    | 10 ----------
 unpack-trees.c | 11 -----------
 6 files changed, 16 insertions(+), 35 deletions(-)

diff --git a/cache.h b/cache.h
index c498a30..e3205fe 100644
--- a/cache.h
+++ b/cache.h
@@ -1027,7 +1027,7 @@ extern int validate_headref(const char *ref);
 
 extern int base_name_compare(const char *name1, int len1, int mode1, const char *name2, int len2, int mode2);
 extern int df_name_compare(const char *name1, int len1, int mode1, const char *name2, int len2, int mode2);
-extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
+extern int name_compare(const char *name1, size_t len1, const char *name2, size_t len2);
 extern int cache_name_stage_compare(const char *name1, int len1, int stage1, const char *name2, int len2, int stage2);
 
 extern void *read_object_with_reference(const unsigned char *sha1,
diff --git a/dir.c b/dir.c
index 797805d..e65888d 100644
--- a/dir.c
+++ b/dir.c
@@ -1354,8 +1354,7 @@ static int cmp_name(const void *p1, const void *p2)
 	const struct dir_entry *e1 = *(const struct dir_entry **)p1;
 	const struct dir_entry *e2 = *(const struct dir_entry **)p2;
 
-	return cache_name_compare(e1->name, e1->len,
-				  e2->name, e2->len);
+	return name_compare(e1->name, e1->len, e2->name, e2->len);
 }
 
 static struct path_simplify *create_simplify(const char **pathspec)
diff --git a/name-hash.c b/name-hash.c
index be7c4ae..e2bea88 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -179,7 +179,7 @@ static int same_name(const struct cache_entry *ce, const char *name, int namelen
 	 * Always do exact compare, even if we want a case-ignoring comparison;
 	 * we do the quick exact one first, because it will be the common case.
 	 */
-	if (len == namelen && !cache_name_compare(name, namelen, ce->name, len))
+	if (len == namelen && !name_compare(name, namelen, ce->name, len))
 		return 1;
 
 	if (!icase)
diff --git a/read-cache.c b/read-cache.c
index 9f56d76..158241d 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -434,18 +434,26 @@ int df_name_compare(const char *name1, int len1, int mode1,
 	return c1 - c2;
 }
 
-int cache_name_stage_compare(const char *name1, int len1, int stage1, const char *name2, int len2, int stage2)
+int name_compare(const char *name1, size_t len1, const char *name2, size_t len2)
 {
-	int len = len1 < len2 ? len1 : len2;
-	int cmp;
-
-	cmp = memcmp(name1, name2, len);
+	size_t min_len = (len1 < len2) ? len1 : len2;
+	int cmp = memcmp(name1, name2, min_len);
 	if (cmp)
 		return cmp;
 	if (len1 < len2)
 		return -1;
 	if (len1 > len2)
 		return 1;
+	return 0;
+}
+
+int cache_name_stage_compare(const char *name1, int len1, int stage1, const char *name2, int len2, int stage2)
+{
+	int cmp;
+
+	cmp = name_compare(name1, len1, name2, len2);
+	if (cmp)
+		return cmp;
 
 	if (stage1 < stage2)
 		return -1;
@@ -454,11 +462,6 @@ int cache_name_stage_compare(const char *name1, int len1, int stage1, const char
 	return 0;
 }
 
-int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
-{
-	return cache_name_stage_compare(name1, len1, 0, name2, len2, 0);
-}
-
 static int index_name_stage_pos(const struct index_state *istate, const char *name, int namelen, int stage)
 {
 	int first, last;
diff --git a/tree-walk.c b/tree-walk.c
index 4dc86c7..5dd9a71 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -144,16 +144,6 @@ struct tree_desc_x {
 	struct tree_desc_skip *skip;
 };
 
-static int name_compare(const char *a, int a_len,
-			const char *b, int b_len)
-{
-	int len = (a_len < b_len) ? a_len : b_len;
-	int cmp = memcmp(a, b, len);
-	if (cmp)
-		return cmp;
-	return (a_len - b_len);
-}
-
 static int check_entry_match(const char *a, int a_len, const char *b, int b_len)
 {
 	/*
diff --git a/unpack-trees.c b/unpack-trees.c
index 4a9cdf2..c4a97ca 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -629,17 +629,6 @@ static int unpack_failed(struct unpack_trees_options *o, const char *message)
 	return -1;
 }
 
-/* NEEDSWORK: give this a better name and share with tree-walk.c */
-static int name_compare(const char *a, int a_len,
-			const char *b, int b_len)
-{
-	int len = (a_len < b_len) ? a_len : b_len;
-	int cmp = memcmp(a, b, len);
-	if (cmp)
-		return cmp;
-	return (a_len - b_len);
-}
-
 /*
  * The tree traversal is looking at name p.  If we have a matching entry,
  * return it.  If name p is a directory in the index, do not return
-- 
2.0.0