Introduce diff_filespec_is_binary()

This replaces an explicit initialization of filespec->is_binary
field used for rename/break followed by direct access to that
field with a wrapper function that lazily iniaitlizes and
accesses the field.  We would add more attribute accesses for
the use of diff routines, and it would be better to make this
abstraction earlier.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -1102,30 +1102,45 @@ static void setup_diff_attr_check(struct git_attr_check *check)
 {
 	static struct git_attr *attr_diff;
 
-	if (!attr_diff)
+	if (!attr_diff) {
 		attr_diff = git_attr("diff", 4);
-	check->attr = attr_diff;
+	}
+	check[0].attr = attr_diff;
 }
 
-static int file_is_binary(struct diff_filespec *one)
+static void diff_filespec_check_attr(struct diff_filespec *one)
 {
-	struct git_attr_check attr_diff_check;
+	struct git_attr_check attr_diff_check[1];
 
-	setup_diff_attr_check(&attr_diff_check);
-	if (!git_checkattr(one->path, 1, &attr_diff_check)) {
-		const char *value = attr_diff_check.value;
+	if (one->checked_attr)
+		return;
+
+	setup_diff_attr_check(attr_diff_check);
+	one->is_binary = 0;
+
+	if (!git_checkattr(one->path, ARRAY_SIZE(attr_diff_check), attr_diff_check)) {
+		const char *value;
+
+		/* binaryness */
+		value = attr_diff_check[0].value;
 		if (ATTR_TRUE(value))
-			return 0;
+			;
 		else if (ATTR_FALSE(value))
-			return 1;
+			one->is_binary = 1;
 	}
 
-	if (!one->data) {
-		if (!DIFF_FILE_VALID(one))
-			return 0;
+	if (!one->data && DIFF_FILE_VALID(one))
 		diff_populate_filespec(one, 0);
-	}
-	return buffer_is_binary(one->data, one->size);
+
+	if (one->data)
+		one->is_binary = buffer_is_binary(one->data, one->size);
+
+}
+
+int diff_filespec_is_binary(struct diff_filespec *one)
+{
+	diff_filespec_check_attr(one);
+	return one->is_binary;
 }
 
 static void builtin_diff(const char *name_a,
@@ -1182,7 +1197,8 @@ static void builtin_diff(const char *name_a,
 	if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 		die("unable to read files to diff");
 
-	if (!o->text && (file_is_binary(one) || file_is_binary(two))) {
+	if (!o->text &&
+	    (diff_filespec_is_binary(one) || diff_filespec_is_binary(two))) {
 		/* Quite common confusing case */
 		if (mf1.size == mf2.size &&
 		    !memcmp(mf1.ptr, mf2.ptr, mf1.size))
@@ -1260,7 +1276,7 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 	if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 		die("unable to read files to diff");
 
-	if (file_is_binary(one) || file_is_binary(two)) {
+	if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
 		data->is_binary = 1;
 		data->added = mf2.size;
 		data->deleted = mf1.size;
@@ -1302,7 +1318,7 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
 	if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 		die("unable to read files to diff");
 
-	if (file_is_binary(two))
+	if (diff_filespec_is_binary(two))
 		goto free_and_return;
 	else {
 		/* Crazy xdl interfaces.. */
@@ -1880,8 +1896,8 @@ static void run_diff(struct diff_filepair *p, struct diff_options *o)
 
 		if (o->binary) {
 			mmfile_t mf;
-			if ((!fill_mmfile(&mf, one) && file_is_binary(one)) ||
-			    (!fill_mmfile(&mf, two) && file_is_binary(two)))
+			if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
+			    (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
 				abbrev = 40;
 		}
 		len += snprintf(msg + len, sizeof(msg) - len,
@@ -2783,7 +2799,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 			return error("unable to read files to diff");
 
 		/* Maybe hash p->two? into the patch id? */
-		if (file_is_binary(p->two))
+		if (diff_filespec_is_binary(p->two))
 			continue;
 
 		len1 = remove_space(p->one->path, strlen(p->one->path));
@@ -3011,21 +3027,6 @@ void diffcore_std(struct diff_options *options)
 	if (options->quiet)
 		return;
 
-	/*
-	 * break/rename count similarity differently depending on
-	 * the binary-ness.
-	 */
-	if ((options->break_opt != -1) || (options->detect_rename)) {
-		struct diff_queue_struct *q = &diff_queued_diff;
-		int i;
-
-		for (i = 0; i < q->nr; i++) {
-			struct diff_filepair *p = q->queue[i];
-			p->one->is_binary = file_is_binary(p->one);
-			p->two->is_binary = file_is_binary(p->two);
-		}
-	}
-
 	if (options->break_opt != -1)
 		diffcore_break(options->break_opt);
 	if (options->detect_rename)

diffcore-delta.c

@@ -129,7 +129,7 @@ static struct spanhash_top *hash_chars(struct diff_filespec *one)
 	struct spanhash_top *hash;
 	unsigned char *buf = one->data;
 	unsigned int sz = one->size;
-	int is_text = !one->is_binary;
+	int is_text = !diff_filespec_is_binary(one);
 
 	i = INITIAL_HASH_SIZE;
 	hash = xmalloc(sizeof(*hash) + sizeof(struct spanhash) * (1<<i));

diffcore.h

@@ -37,6 +37,7 @@ struct diff_filespec {
 #define DIFF_FILE_VALID(spec) (((spec)->mode) != 0)
 	unsigned should_free : 1; /* data should be free()'ed */
 	unsigned should_munmap : 1; /* data should be munmap()'ed */
+	unsigned checked_attr : 1;
 	unsigned is_binary : 1; /* data should be considered "binary" */
 };
 
@@ -46,6 +47,7 @@ extern void fill_filespec(struct diff_filespec *, const unsigned char *,
 
 extern int diff_populate_filespec(struct diff_filespec *, int);
 extern void diff_free_filespec_data(struct diff_filespec *);
+extern int diff_filespec_is_binary(struct diff_filespec *);
 
 struct diff_filepair {
 	struct diff_filespec *one;