[PATCH 2/2] git apply: preserve original whitespace with --ignore-whitespace

[Giuseppe Bilotta <giuseppe.bilotta@gmail.com>]

---
 builtin-apply.c |   32 +++++++++++++++++++++++++++++---
 1 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/builtin-apply.c b/builtin-apply.c
index 86860d6..d213cce 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -1640,6 +1640,10 @@ static void update_pre_post_images(struct image *preimage,
 	int i, ctx;
 	char *new, *old, *fixed;
 	struct image fixed_preimage;
+	/* Do we need more space for the postimage? */
+	size_t newlen = postimage->len;
+	if (len > preimage->len)
+		newlen += len - preimage->len;
 
 	/*
 	 * Update the preimage with whitespace fixes.  Note that we
@@ -1654,11 +1658,16 @@ static void update_pre_post_images(struct image *preimage,
 	*preimage = fixed_preimage;
 
 	/*
-	 * Adjust the common context lines in postimage, in place.
+	 * Adjust the common context lines in postimage, in place
+	 * if we are not ignoring whitespace differences.
 	 * This is possible because whitespace fixing does not make
 	 * the string grow.
 	 */
-	new = old = postimage->buf;
+	old = postimage->buf;
+	if (ignore_whitespace)
+		new = postimage->buf = xmalloc(newlen);
+	else
+		new = old;
 	fixed = preimage->buf;
 	for (i = ctx = 0; i < postimage->nr; i++) {
 		size_t len = postimage->line[i].len;
@@ -1730,8 +1739,25 @@ static int match_fragment(struct image *img,
 	if ((match_end
 	     ? (try + preimage->len == img->len)
 	     : (try + preimage->len <= img->len)) &&
-	    !memcmp_switch(img->buf + try, preimage->buf, preimage->len))
+	    !memcmp_switch(img->buf + try, preimage->buf, preimage->len)) {
+		if (ignore_whitespace) {
+			/*
+			 * Replace the preimage whitespace with the original one
+			 */
+			size_t newlen = 0;
+			for (i = 0; i < preimage->nr; i++) {
+				newlen += preimage->line[i].len =
+				          img->line[try_lno + i].len;
+			}
+			fixed_buf = xmalloc(newlen);
+			memcpy(fixed_buf, img->buf + try, newlen);
+
+			update_pre_post_images(
+				preimage, postimage,
+				fixed_buf, newlen);
+		}
 		return 1;
+	}
 
 	if (!ignore_whitespace && (ws_error_action != correct_ws_error))
 		return 0;
-- 
1.6.3.3.512.g1f6a.dirty