[AGGREGATED PATCH] Fix in-place editing functions in convert.c

[Pierre Habouzit <madcoder@debian.org>]

* crlf_to_git and ident_to_git:

  Don't grow the buffer if there is enough space in the first place.
  As a side effect, when the editing is done "in place", we don't grow, so
  the buffer pointer doesn't changes, and `src' isn't invalidated anymore.

  Thanks to Bernt Hansen for the bug report.

* apply_filter:

  Fix memory leak due to fake in-place editing that didn't collected the
  old buffer when the filter succeeds. Also a cosmetic fix.

Signed-off-by: Pierre Habouzit <madcoder@debian.org>
---

This patch is on top of master, and supersedes both patch I sent before.
Following dscho's remark, I only grow the buffer if they aren't big enough
in the first place, which ensures that buffers are not touched if edited in
place.

 convert.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/convert.c b/convert.c
index 0d5e909..aa95834 100644
--- a/convert.c
+++ b/convert.c
@@ -110,7 +110,9 @@ static int crlf_to_git(const char *path, const char *src, size_t len,
 			return 0;
 	}
 
-	strbuf_grow(buf, len);
+	/* only grow if not in place */
+	if (strbuf_avail(buf) + buf->len < len)
+		strbuf_grow(buf, len - buf->len);
 	dst = buf->buf;
 	if (action == CRLF_GUESS) {
 		/*
@@ -281,20 +283,19 @@ static int apply_filter(const char *path, const char *src, size_t len,
 		ret = 0;
 	}
 	if (close(pipe_feed[0])) {
-		ret = error("read from external filter %s failed", cmd);
+		error("read from external filter %s failed", cmd);
 		ret = 0;
 	}
 	status = finish_command(&child_process);
 	if (status) {
-		ret = error("external filter %s failed %d", cmd, -status);
+		error("external filter %s failed %d", cmd, -status);
 		ret = 0;
 	}
 
 	if (ret) {
-		*dst = nbuf;
-	} else {
-		strbuf_release(&nbuf);
+		strbuf_swap(dst, &nbuf);
 	}
+	strbuf_release(&nbuf);
 	return ret;
 }
 
@@ -422,7 +423,9 @@ static int ident_to_git(const char *path, const char *src, size_t len,
 	if (!ident || !count_ident(src, len))
 		return 0;
 
-	strbuf_grow(buf, len);
+	/* only grow if not in place */
+	if (strbuf_avail(buf) + buf->len < len)
+		strbuf_grow(buf, len - buf->len);
 	dst = buf->buf;
 	for (;;) {
 		dollar = memchr(src, '$', len);
-- 
1.5.3.4.207.gb504-dirty