make inline is_null_sha1 global

Replace sha1 comparisons to null_sha1 with a global inline (which previously an
unused static inline in builtin-apply.c)

[jc: with a fix from Jonas Fonseca.]

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-apply.c

@@ -1684,7 +1684,7 @@ static int apply_binary(struct buffer_desc *desc, struct patch *patch)
 	}
 
 	get_sha1_hex(patch->new_sha1_prefix, sha1);
-	if (!memcmp(sha1, null_sha1, 20)) {
+	if (is_null_sha1(sha1)) {
 		free(desc->buffer);
 		desc->alloc = desc->size = 0;
 		desc->buffer = NULL;
@@ -1916,11 +1916,6 @@ static int check_patch_list(struct patch *patch)
 	return error;
 }
 
-static inline int is_null_sha1(const unsigned char *sha1)
-{
-	return !memcmp(sha1, null_sha1, 20);
-}
-
 static void show_index_list(struct patch *list)
 {
 	struct patch *patch;

builtin-diff.c

@@ -68,8 +68,7 @@ static void stuff_change(struct diff_options *opt,
 {
 	struct diff_filespec *one, *two;
 
-	if (memcmp(null_sha1, old_sha1, 20) &&
-	    memcmp(null_sha1, new_sha1, 20) &&
+	if (!is_null_sha1(old_sha1) && !is_null_sha1(new_sha1) &&
 	    !memcmp(old_sha1, new_sha1, 20))
 		return;
 

cache.h

@@ -210,6 +210,10 @@ extern char *sha1_pack_name(const unsigned char *sha1);
 extern char *sha1_pack_index_name(const unsigned char *sha1);
 extern const char *find_unique_abbrev(const unsigned char *sha1, int);
 extern const unsigned char null_sha1[20];
+static inline int is_null_sha1(const unsigned char *sha1)
+{
+	return !memcmp(sha1, null_sha1, 20);
+}
 
 int git_mkstemp(char *path, size_t n, const char *template);
 

combine-diff.c

@@ -94,7 +94,7 @@ static char *grab_blob(const unsigned char *sha1, unsigned long *size)
 {
 	char *blob;
 	char type[20];
-	if (!memcmp(sha1, null_sha1, 20)) {
+	if (is_null_sha1(sha1)) {
 		/* deleted blob */
 		*size = 0;
 		return xcalloc(1, 1);
@@ -611,7 +611,7 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 	struct sline *sline; /* survived lines */
 	int mode_differs = 0;
 	int i, show_hunks;
-	int working_tree_file = !memcmp(elem->sha1, null_sha1, 20);
+	int working_tree_file = is_null_sha1(elem->sha1);
 	int abbrev = opt->full_index ? 40 : DEFAULT_ABBREV;
 	mmfile_t result_file;
 

diff.c

@@ -1102,7 +1102,7 @@ void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 	if (mode) {
 		spec->mode = canon_mode(mode);
 		memcpy(spec->sha1, sha1, 20);
-		spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
+		spec->sha1_valid = !is_null_sha1(sha1);
 	}
 }
 

fsck-objects.c

@@ -452,7 +452,7 @@ static int fsck_head_link(void)
 	if (strncmp(git_refs_heads_master + pfxlen, "refs/heads/", 11))
 		return error("HEAD points to something strange (%s)",
 			     git_refs_heads_master + pfxlen);
-	if (!memcmp(null_sha1, sha1, 20))
+	if (is_null_sha1(sha1))
 		return error("HEAD: not a valid git pointer");
 	return 0;
 }

sha1_name.c

@@ -191,7 +191,7 @@ const char *find_unique_abbrev(const unsigned char *sha1, int len)
 	int status, is_null;
 	static char hex[41];
 
-	is_null = !memcmp(sha1, null_sha1, 20);
+	is_null = is_null_sha1(sha1);
 	memcpy(hex, sha1_to_hex(sha1), 40);
 	if (len == 40 || !len)
 		return hex;