1 files changed, 121 insertions, 0 deletions
diff --git a/builtin-commit-tree.c b/builtin-commit-tree.c
new file mode 100644
index 0000000000..e5e4bdbe86
--- /dev/null
+++ b/builtin-commit-tree.c
@@ -0,0 +1,121 @@
+/*
+ * GIT - The information manager from hell
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ */
+#include "cache.h"
+#include "commit.h"
+#include "tree.h"
+#include "builtin.h"
+#include "utf8.h"
+
+#define BLOCKING (1ul << 14)
+
+/*
+ * FIXME! Share the code with "write-tree.c"
+ */
+static void check_valid(unsigned char *sha1, enum object_type expect)
+{
+	enum object_type type = sha1_object_info(sha1, NULL);
+	if (type < 0)
+		die("%s is not a valid object", sha1_to_hex(sha1));
+	if (type != expect)
+		die("%s is not a valid '%s' object", sha1_to_hex(sha1),
+		    typename(expect));
+}
+
+/*
+ * Having more than two parents is not strange at all, and this is
+ * how multi-way merges are represented.
+ */
+#define MAXPARENT (16)
+static unsigned char parent_sha1[MAXPARENT][20];
+
+static const char commit_tree_usage[] = "git-commit-tree <sha1> [-p <sha1>]* < changelog";
+
+static int new_parent(int idx)
+{
+	int i;
+	unsigned char *sha1 = parent_sha1[idx];
+	for (i = 0; i < idx; i++) {
+		if (!hashcmp(parent_sha1[i], sha1)) {
+			error("duplicate parent %s ignored", sha1_to_hex(sha1));
+			return 0;
+		}
+	}
+	return 1;
+}
+
+static const char commit_utf8_warn[] =
+"Warning: commit message does not conform to UTF-8.\n"
+"You may want to amend it after fixing the message, or set the config\n"
+"variable i18n.commitencoding to the encoding your project uses.\n";
+
+int cmd_commit_tree(int argc, const char **argv, const char *prefix)
+{
+	int i;
+	int parents = 0;
+	unsigned char tree_sha1[20];
+	unsigned char commit_sha1[20];
+	struct strbuf buffer;
+	int encoding_is_utf8;
+
+	git_config(git_default_config, NULL);
+
+	if (argc < 2)
+		usage(commit_tree_usage);
+	if (get_sha1(argv[1], tree_sha1))
+		die("Not a valid object name %s", argv[1]);
+
+	check_valid(tree_sha1, OBJ_TREE);
+	for (i = 2; i < argc; i += 2) {
+		const char *a, *b;
+		a = argv[i]; b = argv[i+1];
+		if (!b || strcmp(a, "-p"))
+			usage(commit_tree_usage);
+
+		if (parents >= MAXPARENT)
+			die("Too many parents (%d max)", MAXPARENT);
+		if (get_sha1(b, parent_sha1[parents]))
+			die("Not a valid object name %s", b);
+		check_valid(parent_sha1[parents], OBJ_COMMIT);
+		if (new_parent(parents))
+			parents++;
+	}
+
+	/* Not having i18n.commitencoding is the same as having utf-8 */
+	encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
+
+	strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
+	strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree_sha1));
+
+	/*
+	 * NOTE! This ordering means that the same exact tree merged with a
+	 * different order of parents will be a _different_ changeset even
+	 * if everything else stays the same.
+	 */
+	for (i = 0; i < parents; i++)
+		strbuf_addf(&buffer, "parent %s\n", sha1_to_hex(parent_sha1[i]));
+
+	/* Person/date information */
+	strbuf_addf(&buffer, "author %s\n", git_author_info(IDENT_ERROR_ON_NO_NAME));
+	strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_ERROR_ON_NO_NAME));
+	if (!encoding_is_utf8)
+		strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
+	strbuf_addch(&buffer, '\n');
+
+	/* And add the comment */
+	if (strbuf_read(&buffer, 0, 0) < 0)
+		die("git-commit-tree: read returned %s", strerror(errno));
+
+	/* And check the encoding */
+	if (encoding_is_utf8 && !is_utf8(buffer.buf))
+		fprintf(stderr, commit_utf8_warn);
+
+	if (!write_sha1_file(buffer.buf, buffer.len, commit_type, commit_sha1)) {
+		printf("%s\n", sha1_to_hex(commit_sha1));
+		return 0;
+	}
+	else
+		return 1;
+}