1 files changed, 93 insertions, 0 deletions
diff --git a/builtin-write-tree.c b/builtin-write-tree.c
new file mode 100644
index 0000000..88f34ba
--- /dev/null
+++ b/builtin-write-tree.c
@@ -0,0 +1,93 @@
+/*
+ * GIT - The information manager from hell
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ */
+#include "builtin.h"
+#include "cache.h"
+#include "tree.h"
+#include "cache-tree.h"
+
+static const char write_tree_usage[] =
+"git-write-tree [--missing-ok] [--prefix=<prefix>/]";
+
+int write_tree(unsigned char *sha1, int missing_ok, const char *prefix)
+{
+	int entries, was_valid, newfd;
+
+	/* We can't free this memory, it becomes part of a linked list parsed atexit() */
+	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+
+	newfd = hold_locked_index(lock_file, 1);
+
+	entries = read_cache();
+	if (entries < 0)
+		die("git-write-tree: error reading cache");
+
+	if (!active_cache_tree)
+		active_cache_tree = cache_tree();
+
+	was_valid = cache_tree_fully_valid(active_cache_tree);
+
+	if (!was_valid) {
+		if (cache_tree_update(active_cache_tree,
+				      active_cache, active_nr,
+				      missing_ok, 0) < 0)
+			die("git-write-tree: error building trees");
+		if (0 <= newfd) {
+			if (!write_cache(newfd, active_cache, active_nr)
+					&& !close(newfd)) {
+				commit_lock_file(lock_file);
+				newfd = -1;
+			}
+		}
+		/* Not being able to write is fine -- we are only interested
+		 * in updating the cache-tree part, and if the next caller
+		 * ends up using the old index with unupdated cache-tree part
+		 * it misses the work we did here, but that is just a
+		 * performance penalty and not a big deal.
+		 */
+	}
+
+	if (prefix) {
+		struct cache_tree *subtree =
+			cache_tree_find(active_cache_tree, prefix);
+		if (!subtree)
+			die("git-write-tree: prefix %s not found", prefix);
+		hashcpy(sha1, subtree->sha1);
+	}
+	else
+		hashcpy(sha1, active_cache_tree->sha1);
+
+	if (0 <= newfd)
+		close(newfd);
+	rollback_lock_file(lock_file);
+
+	return 0;
+}
+
+int cmd_write_tree(int argc, const char **argv, const char *unused_prefix)
+{
+	int missing_ok = 0, ret;
+	const char *prefix = NULL;
+	unsigned char sha1[20];
+
+	while (1 < argc) {
+		const char *arg = argv[1];
+		if (!strcmp(arg, "--missing-ok"))
+			missing_ok = 1;
+		else if (!prefixcmp(arg, "--prefix="))
+			prefix = arg + 9;
+		else
+			usage(write_tree_usage);
+		argc--; argv++;
+	}
+
+	if (argc > 2)
+		die("too many options");
+
+	ret = write_tree(sha1, missing_ok, prefix);
+	printf("%s\n", sha1_to_hex(sha1));
+
+	return ret;
+}