cleanup duplicate name_compare() functions

We often represent our strings as a counted string, i.e. a pair of
the pointer to the beginning of the string and its length, and the
string may not be NUL terminated to that length.

To compare a pair of such counted strings, unpack-trees.c and
read-cache.c implement their own name_compare() functions
identically.  In addition, the cache_name_compare() function in
read-cache.c is nearly identical.  The only difference is when one
string is the prefix of the other string, in which case
name_compare() returns -1/+1 to show which one is longer, and
cache_name_compare() returns the difference of the lengths to show
the same information.

Unify these three functions by using the implementation from
cache_name_compare().  This does not make any difference to the
existing and future callers, as they must be paying attention only
to the sign of the returned value (and not the magnitude) because
the original implementations of these two functions return values
returned by memcmp(3) when the one string is not a prefix of the
other string, and the only thing memcmp(3) guarantees its callers is
the sign of the returned value, not the magnitude.

Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index cbe1935ba6b17b6ccc37a400ea7cf0f67830e1d0..df65231ac3db7ae08b5d9cfd37c505c4573c1675 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -999,7 +999,7 @@ 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 797805d6a1d33ef66ccb61155135cdcd1a53d9d0..e65888dfad187960bf77904708e60f532ef19e1a 100644 (file)
--- 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/read-cache.c b/read-cache.c
index 7f5645e74546e459efdb584dbf63e1fd75857317..6a45966ec499b47efbc76719046b53633e8839a1 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -422,18 +422,26 @@ 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;
@@ -442,11 +450,6 @@ 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 4dc86c7fe5f66b858b6bd7834a76b1dbbb63a339..5dd9a718047bc14e9ae840a46d1f71cb435fd6d7 100644 (file)
--- 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 97fc9954672f2c374541cad827bb5c459abebcdc..e9a05b908589a0fa8c446b1896821b77aa24596c 100644 (file)
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -622,17 +622,6 @@ 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