1 files changed, 81 insertions, 1 deletions

diff --git a/builtin-archive.c b/builtin-archive.c
index 187491bc17..04385dea05 100644
--- a/builtin-archive.c
+++ b/builtin-archive.c
@@ -10,6 +10,7 @@
 #include "exec_cmd.h"
 #include "pkt-line.h"
 #include "sideband.h"
+#include "attr.h"
 
 static const char archive_usage[] = \
 "git-archive --format=<fmt> [--prefix=<prefix>/] [--verbose] [<extra>] <tree-ish> [path...]";
@@ -80,6 +81,84 @@ static int run_remote_archiver(const char *remote, int argc,
 	return !!rv;
 }
 
+static void format_subst(const struct commit *commit,
+                         const char *src, size_t len,
+                         struct strbuf *buf)
+{
+	char *to_free = NULL;
+	struct strbuf fmt;
+
+	if (src == buf->buf)
+		to_free = strbuf_detach(buf, NULL);
+	strbuf_init(&fmt, 0);
+	for (;;) {
+		const char *b, *c;
+
+		b = memmem(src, len, "$Format:", 8);
+		if (!b || src + len < b + 9)
+			break;
+		c = memchr(b + 8, '$', len - 8);
+		if (!c)
+			break;
+
+		strbuf_reset(&fmt);
+		strbuf_add(&fmt, b + 8, c - b - 8);
+
+		strbuf_add(buf, src, b - src);
+		format_commit_message(commit, fmt.buf, buf);
+		len -= c + 1 - src;
+		src  = c + 1;
+	}
+	strbuf_add(buf, src, len);
+	strbuf_release(&fmt);
+	free(to_free);
+}
+
+static int convert_to_archive(const char *path,
+                              const void *src, size_t len,
+                              struct strbuf *buf,
+                              const struct commit *commit)
+{
+	static struct git_attr *attr_export_subst;
+	struct git_attr_check check[1];
+
+	if (!commit)
+		return 0;
+
+	if (!attr_export_subst)
+		attr_export_subst = git_attr("export-subst", 12);
+
+	check[0].attr = attr_export_subst;
+	if (git_checkattr(path, ARRAY_SIZE(check), check))
+		return 0;
+	if (!ATTR_TRUE(check[0].value))
+		return 0;
+
+	format_subst(commit, src, len, buf);
+	return 1;
+}
+
+void *sha1_file_to_archive(const char *path, const unsigned char *sha1,
+                           unsigned int mode, enum object_type *type,
+                           unsigned long *sizep,
+                           const struct commit *commit)
+{
+	void *buffer;
+
+	buffer = read_sha1_file(sha1, type, sizep);
+	if (buffer && S_ISREG(mode)) {
+		struct strbuf buf;
+
+		strbuf_init(&buf, 0);
+		strbuf_attach(&buf, buffer, *sizep, *sizep + 1);
+		convert_to_working_tree(path, buf.buf, buf.len, &buf);
+		convert_to_archive(path, buf.buf, buf.len, &buf, commit);
+		buffer = strbuf_detach(&buf, sizep);
+	}
+
+	return buffer;
+}
+
 static int init_archiver(const char *name, struct archiver *ar)
 {
 	int rv = -1, i;
@@ -109,7 +188,7 @@ void parse_treeish_arg(const char **argv, struct archiver_args *ar_args,
 	const unsigned char *commit_sha1;
 	time_t archive_time;
 	struct tree *tree;
-	struct commit *commit;
+	const struct commit *commit;
 	unsigned char sha1[20];
 
 	if (get_sha1(name, sha1))
@@ -142,6 +221,7 @@ void parse_treeish_arg(const char **argv, struct archiver_args *ar_args,
 	}
 	ar_args->tree = tree;
 	ar_args->commit_sha1 = commit_sha1;
+	ar_args->commit = commit;
 	ar_args->time = archive_time;
 }