git-archive: convert archive entries like checkouts do

As noted by Johan Herland, git-archive is a kind of checkout and needs
to apply any checkout filters that might be configured.

This patch adds the convenience function convert_sha1_file which returns
a buffer containing the object's contents, after converting, if necessary
(i.e. it's a combination of read_sha1_file and convert_to_working_tree).
Direct calls to read_sha1_file in git-archive are then replaced by calls
to convert_sha1_file.

Since convert_sha1_file expects its path argument to be NUL-terminated --
a convention it inherits from convert_to_working_tree -- the patch also
changes the path handling in archive-tar.c to always NUL-terminate the
string.  It used to solely rely on the len field of struct strbuf before.

archive-zip.c already NUL-terminates the path and thus needs no such
change.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 15 insertions, 0 deletions

diff --git a/convert.c b/convert.c
index 12abdaf2a..c64880bdf 100644
--- a/convert.c
+++ b/convert.c
@@ -652,3 +652,18 @@ char *convert_to_working_tree(const char *path, const char *src, unsigned long *
 
 	return buf;
 }
+
+void *convert_sha1_file(const char *path, const unsigned char *sha1,
+                        unsigned int mode, enum object_type *type,
+                        unsigned long *size)
+{
+	void *buffer = read_sha1_file(sha1, type, size);
+	if (S_ISREG(mode) && buffer) {
+		void *converted = convert_to_working_tree(path, buffer, size);
+		if (converted) {
+			free(buffer);
+			buffer = converted;
+		}
+	}
+	return buffer;
+}