1 files changed, 235 insertions, 0 deletions
diff --git a/builtin/read-tree.c b/builtin/read-tree.c
new file mode 100644
index 0000000000..8bdcab1138
--- /dev/null
+++ b/builtin/read-tree.c
@@ -0,0 +1,235 @@
+/*
+ * 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"
+#include "parse-options.h"
+#include "resolve-undo.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 const char * const read_tree_usage[] = {
+	"git read-tree [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u [--exclude-per-directory=<gitignore>] | -i]] [--no-sparse-checkout] [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]]",
+	NULL
+};
+
+static int index_output_cb(const struct option *opt, const char *arg,
+				 int unset)
+{
+	set_alternate_index_output(arg);
+	return 0;
+}
+
+static int exclude_per_directory_cb(const struct option *opt, const char *arg,
+				    int unset)
+{
+	struct dir_struct *dir;
+	struct unpack_trees_options *opts;
+
+	opts = (struct unpack_trees_options *)opt->value;
+
+	if (opts->dir)
+		die("more than one --exclude-per-directory given.");
+
+	dir = xcalloc(1, sizeof(*opts->dir));
+	dir->flags |= DIR_SHOW_IGNORED;
+	dir->exclude_per_dir = arg;
+	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.
+	 */
+	return 0;
+}
+
+static void debug_stage(const char *label, struct cache_entry *ce,
+			struct unpack_trees_options *o)
+{
+	printf("%s ", label);
+	if (!ce)
+		printf("(missing)\n");
+	else if (ce == o->df_conflict_entry)
+		printf("(conflict)\n");
+	else
+		printf("%06o #%d %s %.8s\n",
+		       ce->ce_mode, ce_stage(ce), ce->name,
+		       sha1_to_hex(ce->sha1));
+}
+
+static int debug_merge(struct cache_entry **stages, struct unpack_trees_options *o)
+{
+	int i;
+
+	printf("* %d-way merge\n", o->merge_size);
+	debug_stage("index", stages[0], o);
+	for (i = 1; i <= o->merge_size; i++) {
+		char buf[24];
+		sprintf(buf, "ent#%d", i);
+		debug_stage(buf, stages[i], o);
+	}
+	return 0;
+}
+
+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;
+	int prefix_set = 0;
+	const struct option read_tree_options[] = {
+		{ OPTION_CALLBACK, 0, "index-output", NULL, "FILE",
+		  "write resulting index to <FILE>",
+		  PARSE_OPT_NONEG, index_output_cb },
+		OPT__VERBOSE(&opts.verbose_update),
+		OPT_GROUP("Merging"),
+		OPT_SET_INT('m', NULL, &opts.merge,
+			    "perform a merge in addition to a read", 1),
+		OPT_SET_INT(0, "trivial", &opts.trivial_merges_only,
+			    "3-way merge if no file level merging required", 1),
+		OPT_SET_INT(0, "aggressive", &opts.aggressive,
+			    "3-way merge in presence of adds and removes", 1),
+		OPT_SET_INT(0, "reset", &opts.reset,
+			    "same as -m, but discard unmerged entries", 1),
+		{ OPTION_STRING, 0, "prefix", &opts.prefix, "<subdirectory>/",
+		  "read the tree into the index under <subdirectory>/",
+		  PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP },
+		OPT_SET_INT('u', NULL, &opts.update,
+			    "update working tree with merge result", 1),
+		{ OPTION_CALLBACK, 0, "exclude-per-directory", &opts,
+		  "gitignore",
+		  "allow explicitly ignored files to be overwritten",
+		  PARSE_OPT_NONEG, exclude_per_directory_cb },
+		OPT_SET_INT('i', NULL, &opts.index_only,
+			    "don't check the working tree after merging", 1),
+		OPT_SET_INT(0, "no-sparse-checkout", &opts.skip_sparse_checkout,
+			    "skip applying sparse checkout filter", 1),
+		OPT_SET_INT(0, "debug-unpack", &opts.debug_unpack,
+			    "debug unpack-trees", 1),
+		OPT_END()
+	};
+
+	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);
+
+	argc = parse_options(argc, argv, unused_prefix, read_tree_options,
+			     read_tree_usage, 0);
+
+	newfd = hold_locked_index(&lock_file, 1);
+
+	prefix_set = opts.prefix ? 1 : 0;
+	if (1 < opts.merge + opts.reset + prefix_set)
+		die("Which one? -m, --reset, or --prefix?");
+
+	if (opts.reset || opts.merge || opts.prefix) {
+		if (read_cache_unmerged() && (opts.prefix || opts.merge))
+			die("You need to resolve your current index first");
+		stage = opts.merge = 1;
+	}
+	resolve_undo_clear();
+
+	for (i = 0; i < argc; i++) {
+		const char *arg = argv[i];
+
+		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 (1 < opts.index_only + opts.update)
+		die("-u and -i at the same time makes no sense");
+	if ((opts.update||opts.index_only) && !opts.merge)
+		die("%s is meaningless without -m, --reset, or --prefix",
+		    opts.update ? "-u" : "-i");
+	if ((opts.dir && !opts.update))
+		die("--exclude-per-directory is meaningless unless -u");
+	if (opts.merge && !opts.index_only)
+		setup_work_tree();
+
+	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;
+			opts.initial_checkout = is_cache_unborn();
+			break;
+		case 3:
+		default:
+			opts.fn = threeway_merge;
+			break;
+		}
+
+		if (stage - 1 >= 3)
+			opts.head_idx = stage - 2;
+		else
+			opts.head_idx = 1;
+	}
+
+	if (opts.debug_unpack)
+		opts.fn = debug_merge;
+
+	cache_tree_free(&active_cache_tree);
+	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;
+
+	if (opts.debug_unpack)
+		return 0; /* do not write the index out */
+
+	/*
+	 * 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.
+	 *
+	 * The same holds true if we are switching between two trees
+	 * using read-tree -m A B.  The index must match B after that.
+	 */
+	if (nr_trees == 1 && !opts.prefix)
+		prime_cache_tree(&active_cache_tree, trees[0]);
+	else if (nr_trees == 2 && opts.merge)
+		prime_cache_tree(&active_cache_tree, trees[1]);
+
+	if (write_cache(newfd, active_cache, active_nr) ||
+	    commit_locked_index(&lock_file))
+		die("unable to write new index file");
+	return 0;
+}