git-archive: wire up TAR format.

This is based on Rene Scharfe's earlier patch, but uses the
archiver support introduced by the previous patch.

Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>
Acked-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>

archive.h

@@ -37,5 +37,9 @@ extern void parse_treeish_arg(const char **treeish,
 
 extern void parse_pathspec_arg(const char **pathspec,
 			       struct archiver_args *args);
+/*
+ * Archive-format specific backends.
+ */
+extern int write_tar_archive(struct archiver_args *);
 
 #endif	/* ARCHIVE_H */

builtin-archive.c

@@ -15,7 +15,7 @@ static const char archive_usage[] = \
 "git-archive --format=<fmt> [--prefix=<prefix>/] [<extra>] <tree-ish> [path...]";
 
 struct archiver archivers[] = {
-	{ "" /* dummy */ },
+	{ .name = "tar", .write_archive = write_tar_archive },
 };
 
 static int run_remote_archiver(struct archiver *ar, int argc,

builtin-tar-tree.c

@@ -9,6 +9,7 @@
 #include "tar.h"
 #include "builtin.h"
 #include "pkt-line.h"
+#include "archive.h"
 
 #define RECORDSIZE	(512)
 #define BLOCKSIZE	(RECORDSIZE * 20)
@@ -338,6 +339,72 @@ static int generate_tar(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+static int write_tar_entry(const unsigned char *sha1,
+                           const char *base, int baselen,
+                           const char *filename, unsigned mode, int stage)
+{
+	static struct strbuf path;
+	int filenamelen = strlen(filename);
+	void *buffer;
+	char type[20];
+	unsigned long size;
+
+	if (!path.alloc) {
+		path.buf = xmalloc(PATH_MAX);
+		path.alloc = PATH_MAX;
+		path.len = path.eof = 0;
+	}
+	if (path.alloc < baselen + filenamelen) {
+		free(path.buf);
+		path.buf = xmalloc(baselen + filenamelen);
+		path.alloc = baselen + filenamelen;
+	}
+	memcpy(path.buf, base, baselen);
+	memcpy(path.buf + baselen, filename, filenamelen);
+	path.len = baselen + filenamelen;
+	if (S_ISDIR(mode)) {
+		strbuf_append_string(&path, "/");
+		buffer = NULL;
+		size = 0;
+	} else {
+		buffer = read_sha1_file(sha1, type, &size);
+		if (!buffer)
+			die("cannot read %s", sha1_to_hex(sha1));
+	}
+
+	write_entry(sha1, &path, mode, buffer, size);
+	free(buffer);
+
+	return READ_TREE_RECURSIVE;
+}
+
+int write_tar_archive(struct archiver_args *args)
+{
+	int plen = strlen(args->base);
+
+	git_config(git_tar_config);
+
+	archive_time = args->time;
+
+	if (args->commit_sha1)
+		write_global_extended_header(args->commit_sha1);
+
+	if (args->base && plen > 0 && args->base[plen - 1] == '/') {
+		char *base = strdup(args->base);
+		int baselen = strlen(base);
+
+		while (baselen > 0 && base[baselen - 1] == '/')
+			base[--baselen] = '\0';
+		write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
+		free(base);
+	}
+	read_tree_recursive(args->tree, args->base, plen, 0,
+			    args->pathspec, write_tar_entry);
+	write_trailer();
+
+	return 0;
+}
+
 static const char *exec = "git-upload-tar";
 
 static int remote_tar(int argc, const char **argv)