diff: respect textconv in rewrite diffs

Currently we just skip rewrite diffs for binary files; this
patch makes an exception for files which will be textconv'd,
and actually performs the textconv before generating the
diff.

Conceptually, rewrite diffs should be in the exact same
format as the a non-rewrite diff, except that we refuse to
share any context. Thus it makes very little sense for "git
diff" to show a textconv'd diff, but for "git diff -B" to
show "Binary files differ".

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 36 insertions, 12 deletions

diff --git a/diff.c b/diff.c
index 50277b82b2..afefe087bb 100644
--- a/diff.c
+++ b/diff.c
@@ -229,6 +229,8 @@ static void emit_rewrite_diff(const char *name_a,
 			      const char *name_b,
 			      struct diff_filespec *one,
 			      struct diff_filespec *two,
+			      const char *textconv_one,
+			      const char *textconv_two,
 			      struct diff_options *o)
 {
 	int lc_a, lc_b;
@@ -241,6 +243,8 @@ static void emit_rewrite_diff(const char *name_a,
 	const char *reset = diff_get_color(color_diff, DIFF_RESET);
 	static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 	const char *a_prefix, *b_prefix;
+	const char *data_one, *data_two;
+	size_t size_one, size_two;
 
 	if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 		a_prefix = o->b_prefix;
@@ -262,8 +266,27 @@ static void emit_rewrite_diff(const char *name_a,
 
 	diff_populate_filespec(one, 0);
 	diff_populate_filespec(two, 0);
-	lc_a = count_lines(one->data, one->size);
-	lc_b = count_lines(two->data, two->size);
+	if (textconv_one) {
+		data_one = run_textconv(textconv_one, one, &size_one);
+		if (!data_one)
+			die("unable to read files to diff");
+	}
+	else {
+		data_one = one->data;
+		size_one = one->size;
+	}
+	if (textconv_two) {
+		data_two = run_textconv(textconv_two, two, &size_two);
+		if (!data_two)
+			die("unable to read files to diff");
+	}
+	else {
+		data_two = two->data;
+		size_two = two->size;
+	}
+
+	lc_a = count_lines(data_one, size_one);
+	lc_b = count_lines(data_two, size_two);
 	fprintf(o->file,
 		"%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
 		metainfo, a_name.buf, name_a_tab, reset,
@@ -273,9 +296,9 @@ static void emit_rewrite_diff(const char *name_a,
 	print_line_count(o->file, lc_b);
 	fprintf(o->file, " @@%s\n", reset);
 	if (lc_a)
-		copy_file_with_prefix(o->file, '-', one->data, one->size, old, reset);
+		copy_file_with_prefix(o->file, '-', data_one, size_one, old, reset);
 	if (lc_b)
-		copy_file_with_prefix(o->file, '+', two->data, two->size, new, reset);
+		copy_file_with_prefix(o->file, '+', data_two, size_two, new, reset);
 }
 
 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
@@ -1334,6 +1357,11 @@ static void builtin_diff(const char *name_a,
 	const char *a_prefix, *b_prefix;
 	const char *textconv_one = NULL, *textconv_two = NULL;
 
+	if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
+		textconv_one = get_textconv(one);
+		textconv_two = get_textconv(two);
+	}
+
 	diff_set_mnemonic_prefix(o, "a/", "b/");
 	if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
 		a_prefix = o->b_prefix;
@@ -1377,9 +1405,10 @@ static void builtin_diff(const char *name_a,
 		if ((one->mode ^ two->mode) & S_IFMT)
 			goto free_ab_and_return;
 		if (complete_rewrite &&
-		    !diff_filespec_is_binary(one) &&
-		    !diff_filespec_is_binary(two)) {
-			emit_rewrite_diff(name_a, name_b, one, two, o);
+		    (textconv_one || !diff_filespec_is_binary(one)) &&
+		    (textconv_two || !diff_filespec_is_binary(two))) {
+			emit_rewrite_diff(name_a, name_b, one, two,
+						textconv_one, textconv_two, o);
 			o->found_changes = 1;
 			goto free_ab_and_return;
 		}
@@ -1388,11 +1417,6 @@ 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 (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
-		textconv_one = get_textconv(one);
-		textconv_two = get_textconv(two);
-	}
-
 	if (!DIFF_OPT_TST(o, TEXT) &&
 	    ( (diff_filespec_is_binary(one) && !textconv_one) ||
 	      (diff_filespec_is_binary(two) && !textconv_two) )) {