Rewrite convert_to_{git,working_tree} to use strbuf's.

* Now, those functions take an "out" strbuf argument, where they store their
  result if any. In that case, it also returns 1, else it returns 0.
* those functions support "in place" editing, in the sense that it's OK to
  call them this way:
    convert_to_git(path, sb->buf, sb->len, sb);
  When doable, conversions are done in place for real, else the strbuf
  content is just replaced with the new one, transparentely for the caller.

If you want to create a new filter working this way, being the accumulation
of filter1, filter2, ... filtern, then your meta_filter would be:

    int meta_filter(..., const char *src, size_t len, struct strbuf *sb)
    {
        int ret = 0;
        ret |= filter1(...., src, len, sb);
        if (ret) {
            src = sb->buf;
            len = sb->len;
        }
        ret |= filter2(...., src, len, sb);
        if (ret) {
            src = sb->buf;
            len = sb->len;
        }
        ....
        return ret | filtern(..., src, len, sb);
    }

That's why subfilters the convert_to_* functions called were also rewritten
to work this way.

Signed-off-by: Pierre Habouzit <madcoder@debian.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 13 insertions, 14 deletions

diff --git a/builtin-apply.c b/builtin-apply.c
index 988e85f1e..e5c29ebf3 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -1446,8 +1446,7 @@ static int read_old_data(struct stat *st, const char *path, char **buf_p, unsign
 {
 	int fd;
 	unsigned long got;
-	unsigned long nsize;
-	char *nbuf;
+	struct strbuf nbuf;
 	unsigned long size = *size_p;
 	char *buf = *buf_p;
 
@@ -1466,13 +1465,12 @@ static int read_old_data(struct stat *st, const char *path, char **buf_p, unsign
 			got += ret;
 		}
 		close(fd);
-		nsize = got;
-		nbuf = convert_to_git(path, buf, &nsize);
-		if (nbuf) {
+		strbuf_init(&nbuf, 0);
+		if (convert_to_git(path, buf, size, &nbuf)) {
 			free(buf);
-			*buf_p = nbuf;
-			*alloc_p = nsize;
-			*size_p = nsize;
+			*buf_p = nbuf.buf;
+			*alloc_p = nbuf.alloc;
+			*size_p = nbuf.len;
 		}
 		return got != size;
 	default:
@@ -2439,7 +2437,7 @@ static void add_index_file(const char *path, unsigned mode, void *buf, unsigned
 static int try_create_file(const char *path, unsigned int mode, const char *buf, unsigned long size)
 {
 	int fd;
-	char *nbuf;
+	struct strbuf nbuf;
 
 	if (S_ISGITLINK(mode)) {
 		struct stat st;
@@ -2458,9 +2456,11 @@ static int try_create_file(const char *path, unsigned int mode, const char *buf,
 	if (fd < 0)
 		return -1;
 
-	nbuf = convert_to_working_tree(path, buf, &size);
-	if (nbuf)
-		buf = nbuf;
+	strbuf_init(&nbuf, 0);
+	if (convert_to_working_tree(path, buf, size, &nbuf)) {
+		size = nbuf.len;
+		buf  = nbuf.buf;
+	}
 
 	while (size) {
 		int written = xwrite(fd, buf, size);
@@ -2473,8 +2473,7 @@ static int try_create_file(const char *path, unsigned int mode, const char *buf,
 	}
 	if (close(fd) < 0)
 		die("closing file %s: %s", path, strerror(errno));
-	if (nbuf)
-		free(nbuf);
+	strbuf_release(&nbuf);
 	return 0;
 }