Add 'df_name_compare()' helper function

This new helper is identical to base_name_compare(), except it compares
conflicting directory/file entries as equal in order to help handling DF
conflicts (thus the name).

Note that while a directory name compares as equal to a regular file
with the new helper, they then individually compare _differently_ to a
filename that has a dot after the basename (because '\0' < '.' < '/').

So a directory called "foo/" will compare equal to a file "foo", even
though "foo.c" will compare after "foo" and before "foo/"

This will be used by routines that want to traverse the git namespace
but then handle conflicting entries together when possible.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index e23030262328761669f4704a3e3731a5e93d5b0c..6eb16cb0df4cf39602fa3fbb7a666a7343962aa9 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -536,6 +536,7 @@ extern int create_symref(const char *ref, const char *refs_heads_master, const c
 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 void *read_object_with_reference(const unsigned char *sha1,

diff --git a/read-cache.c b/read-cache.c
index 657f0c5894c65831b80ceee54d161d0beac1d733..bf649a31a887154ae2e6383d7452915287ae62d6 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -351,6 +351,41 @@ int base_name_compare(const char *name1, int len1, int mode1,
        return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
 }
 
+/*
+ * df_name_compare() is identical to base_name_compare(), except it
+ * compares conflicting directory/file entries as equal. Note that
+ * while a directory name compares as equal to a regular file, they
+ * then individually compare _differently_ to a filename that has
+ * a dot after the basename (because '\0' < '.' < '/').
+ *
+ * This is used by routines that want to traverse the git namespace
+ * but then handle conflicting entries together when possible.
+ */
+int df_name_compare(const char *name1, int len1, int mode1,
+                   const char *name2, int len2, int mode2)
+{
+       int len = len1 < len2 ? len1 : len2, cmp;
+       unsigned char c1, c2;
+
+       cmp = memcmp(name1, name2, len);
+       if (cmp)
+               return cmp;
+       /* Directories and files compare equal (same length, same name) */
+       if (len1 == len2)
+               return 0;
+       c1 = name1[len];
+       if (!c1 && S_ISDIR(mode1))
+               c1 = '/';
+       c2 = name2[len];
+       if (!c2 && S_ISDIR(mode2))
+               c2 = '/';
+       if (c1 == '/' && !c2)
+               return 0;
+       if (c2 == '/' && !c1)
+               return 0;
+       return c1 - c2;
+}
+
 int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
 {
        int len1 = flags1 & CE_NAMEMASK;