1 files changed, 244 insertions, 0 deletions
diff --git a/builtin-read-tree.c b/builtin-read-tree.c
new file mode 100644
index 0000000000..72a6de302f
--- /dev/null
+++ b/builtin-read-tree.c
@@ -0,0 +1,244 @@
+/*
+ * GIT - The information manager from hell
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ */
+
+#include "cache.h"
+#include "object.h"
+#include "tree.h"
+#include "tree-walk.h"
+#include "cache-tree.h"
+#include "unpack-trees.h"
+#include "dir.h"
+#include "builtin.h"
+
+static int nr_trees;
+static struct tree *trees[MAX_UNPACK_TREES];
+
+static int list_tree(unsigned char *sha1)
+{
+	struct tree *tree;
+
+	if (nr_trees >= MAX_UNPACK_TREES)
+		die("I cannot read more than %d trees", MAX_UNPACK_TREES);
+	tree = parse_tree_indirect(sha1);
+	if (!tree)
+		return -1;
+	trees[nr_trees++] = tree;
+	return 0;
+}
+
+static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
+{
+	struct tree_desc desc;
+	struct name_entry entry;
+	int cnt;
+
+	hashcpy(it->sha1, tree->object.sha1);
+	init_tree_desc(&desc, tree->buffer, tree->size);
+	cnt = 0;
+	while (tree_entry(&desc, &entry)) {
+		if (!S_ISDIR(entry.mode))
+			cnt++;
+		else {
+			struct cache_tree_sub *sub;
+			struct tree *subtree = lookup_tree(entry.sha1);
+			if (!subtree->object.parsed)
+				parse_tree(subtree);
+			sub = cache_tree_sub(it, entry.path);
+			sub->cache_tree = cache_tree();
+			prime_cache_tree_rec(sub->cache_tree, subtree);
+			cnt += sub->cache_tree->entry_count;
+		}
+	}
+	it->entry_count = cnt;
+}
+
+static void prime_cache_tree(void)
+{
+	if (!nr_trees)
+		return;
+	active_cache_tree = cache_tree();
+	prime_cache_tree_rec(active_cache_tree, trees[0]);
+
+}
+
+static const char read_tree_usage[] = "git-read-tree (<sha> | [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] [--exclude-per-directory=<gitignore>] [--index-output=<file>] <sha1> [<sha2> [<sha3>]])";
+
+static struct lock_file lock_file;
+
+int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
+{
+	int i, newfd, stage = 0;
+	unsigned char sha1[20];
+	struct tree_desc t[MAX_UNPACK_TREES];
+	struct unpack_trees_options opts;
+
+	memset(&opts, 0, sizeof(opts));
+	opts.head_idx = -1;
+	opts.src_index = &the_index;
+	opts.dst_index = &the_index;
+
+	git_config(git_default_config, NULL);
+
+	newfd = hold_locked_index(&lock_file, 1);
+
+	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+
+		/* "-u" means "update", meaning that a merge will update
+		 * the working tree.
+		 */
+		if (!strcmp(arg, "-u")) {
+			opts.update = 1;
+			continue;
+		}
+
+		if (!strcmp(arg, "-v")) {
+			opts.verbose_update = 1;
+			continue;
+		}
+
+		/* "-i" means "index only", meaning that a merge will
+		 * not even look at the working tree.
+		 */
+		if (!strcmp(arg, "-i")) {
+			opts.index_only = 1;
+			continue;
+		}
+
+		if (!prefixcmp(arg, "--index-output=")) {
+			set_alternate_index_output(arg + 15);
+			continue;
+		}
+
+		/* "--prefix=<subdirectory>/" means keep the current index
+		 *  entries and put the entries from the tree under the
+		 * given subdirectory.
+		 */
+		if (!prefixcmp(arg, "--prefix=")) {
+			if (stage || opts.merge || opts.prefix)
+				usage(read_tree_usage);
+			opts.prefix = arg + 9;
+			opts.merge = 1;
+			stage = 1;
+			if (read_cache_unmerged())
+				die("you need to resolve your current index first");
+			continue;
+		}
+
+		/* This differs from "-m" in that we'll silently ignore
+		 * unmerged entries and overwrite working tree files that
+		 * correspond to them.
+		 */
+		if (!strcmp(arg, "--reset")) {
+			if (stage || opts.merge || opts.prefix)
+				usage(read_tree_usage);
+			opts.reset = 1;
+			opts.merge = 1;
+			stage = 1;
+			read_cache_unmerged();
+			continue;
+		}
+
+		if (!strcmp(arg, "--trivial")) {
+			opts.trivial_merges_only = 1;
+			continue;
+		}
+
+		if (!strcmp(arg, "--aggressive")) {
+			opts.aggressive = 1;
+			continue;
+		}
+
+		/* "-m" stands for "merge", meaning we start in stage 1 */
+		if (!strcmp(arg, "-m")) {
+			if (stage || opts.merge || opts.prefix)
+				usage(read_tree_usage);
+			if (read_cache_unmerged())
+				die("you need to resolve your current index first");
+			stage = 1;
+			opts.merge = 1;
+			continue;
+		}
+
+		if (!prefixcmp(arg, "--exclude-per-directory=")) {
+			struct dir_struct *dir;
+
+			if (opts.dir)
+				die("more than one --exclude-per-directory are given.");
+
+			dir = xcalloc(1, sizeof(*opts.dir));
+			dir->show_ignored = 1;
+			dir->exclude_per_dir = arg + 24;
+			opts.dir = dir;
+			/* We do not need to nor want to do read-directory
+			 * here; we are merely interested in reusing the
+			 * per directory ignore stack mechanism.
+			 */
+			continue;
+		}
+
+		/* using -u and -i at the same time makes no sense */
+		if (1 < opts.index_only + opts.update)
+			usage(read_tree_usage);
+
+		if (get_sha1(arg, sha1))
+			die("Not a valid object name %s", arg);
+		if (list_tree(sha1) < 0)
+			die("failed to unpack tree object %s", arg);
+		stage++;
+	}
+	if ((opts.update||opts.index_only) && !opts.merge)
+		usage(read_tree_usage);
+	if ((opts.dir && !opts.update))
+		die("--exclude-per-directory is meaningless unless -u");
+
+	if (opts.merge) {
+		if (stage < 2)
+			die("just how do you expect me to merge %d trees?", stage-1);
+		switch (stage - 1) {
+		case 1:
+			opts.fn = opts.prefix ? bind_merge : oneway_merge;
+			break;
+		case 2:
+			opts.fn = twoway_merge;
+			break;
+		case 3:
+		default:
+			opts.fn = threeway_merge;
+			cache_tree_free(&active_cache_tree);
+			break;
+		}
+
+		if (stage - 1 >= 3)
+			opts.head_idx = stage - 2;
+		else
+			opts.head_idx = 1;
+	}
+
+	for (i = 0; i < nr_trees; i++) {
+		struct tree *tree = trees[i];
+		parse_tree(tree);
+		init_tree_desc(t+i, tree->buffer, tree->size);
+	}
+	if (unpack_trees(nr_trees, t, &opts))
+		return 128;
+
+	/*
+	 * When reading only one tree (either the most basic form,
+	 * "-m ent" or "--reset ent" form), we can obtain a fully
+	 * valid cache-tree because the index must match exactly
+	 * what came from the tree.
+	 */
+	if (nr_trees && !opts.prefix && (!opts.merge || (stage == 2))) {
+		cache_tree_free(&active_cache_tree);
+		prime_cache_tree();
+	}
+
+	if (write_cache(newfd, active_cache, active_nr) ||
+	    commit_locked_index(&lock_file))
+		die("unable to write new index file");
+	return 0;
+}