1 files changed, 97 insertions, 1 deletions

diff --git a/builtin-archive.c b/builtin-archive.c
index 187491b..a90c65c 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 +81,100 @@ static int run_remote_archiver(const char *remote, int argc,
 	return !!rv;
 }
 
+static void *format_subst(const struct commit *commit, const char *format,
+                          unsigned long *sizep)
+{
+	unsigned long len = *sizep, result_len = 0;
+	const char *a = format;
+	char *result = NULL;
+
+	for (;;) {
+		const char *b, *c;
+		char *fmt, *formatted = NULL;
+		unsigned long a_len, fmt_len, formatted_len, allocated = 0;
+
+		b = memmem(a, len, "$Format:", 8);
+		if (!b || a + len < b + 9)
+			break;
+		c = memchr(b + 8, '$', len - 8);
+		if (!c)
+			break;
+
+		a_len = b - a;
+		fmt_len = c - b - 8;
+		fmt = xmalloc(fmt_len + 1);
+		memcpy(fmt, b + 8, fmt_len);
+		fmt[fmt_len] = '\0';
+
+		formatted_len = format_commit_message(commit, fmt, &formatted,
+		                                      &allocated);
+		free(fmt);
+		result = xrealloc(result, result_len + a_len + formatted_len);
+		memcpy(result + result_len, a, a_len);
+		memcpy(result + result_len + a_len, formatted, formatted_len);
+		result_len += a_len + formatted_len;
+		len -= c + 1 - a;
+		a = c + 1;
+	}
+
+	if (result && len) {
+		result = xrealloc(result, result_len + len);
+		memcpy(result + result_len, a, len);
+		result_len += len;
+	}
+
+	*sizep = result_len;
+
+	return result;
+}
+
+static void *convert_to_archive(const char *path,
+                                const void *src, unsigned long *sizep,
+                                const struct commit *commit)
+{
+	static struct git_attr *attr_export_subst;
+	struct git_attr_check check[1];
+
+	if (!commit)
+		return NULL;
+
+        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 NULL;
+	if (!ATTR_TRUE(check[0].value))
+		return NULL;
+
+	return format_subst(commit, src, sizep);
+}
+
+void *sha1_file_to_archive(const char *path, const unsigned char *sha1,
+                           unsigned int mode, enum object_type *type,
+                           unsigned long *size,
+                           const struct commit *commit)
+{
+	void *buffer, *converted;
+
+	buffer = read_sha1_file(sha1, type, size);
+	if (buffer && S_ISREG(mode)) {
+		converted = convert_to_working_tree(path, buffer, size);
+		if (converted) {
+			free(buffer);
+			buffer = converted;
+		}
+
+		converted = convert_to_archive(path, buffer, size, commit);
+		if (converted) {
+			free(buffer);
+			buffer = converted;
+		}
+	}
+
+	return buffer;
+}
+
 static int init_archiver(const char *name, struct archiver *ar)
 {
 	int rv = -1, i;
@@ -109,7 +204,7 @@ 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 +237,7 @@ 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;
 }