Make git-checkout-index a builtin

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/builtin-checkout-index.c b/builtin-checkout-index.c
new file mode 100644
index 0000000..29ea6fd
--- /dev/null
+++ b/builtin-checkout-index.c
@@ -0,0 +1,309 @@
+/*
+ * Check-out files from the "current cache directory"
+ *
+ * Copyright (C) 2005 Linus Torvalds
+ *
+ * Careful: order of argument flags does matter. For example,
+ *
+ *	git-checkout-index -a -f file.c
+ *
+ * Will first check out all files listed in the cache (but not
+ * overwrite any old ones), and then force-checkout "file.c" a
+ * second time (ie that one _will_ overwrite any old contents
+ * with the same filename).
+ *
+ * Also, just doing "git-checkout-index" does nothing. You probably
+ * meant "git-checkout-index -a". And if you want to force it, you
+ * want "git-checkout-index -f -a".
+ *
+ * Intuitiveness is not the goal here. Repeatability is. The
+ * reason for the "no arguments means no work" thing is that
+ * from scripts you are supposed to be able to do things like
+ *
+ *	find . -name '*.h' -print0 | xargs -0 git-checkout-index -f --
+ *
+ * or:
+ *
+ *	find . -name '*.h' -print0 | git-checkout-index -f -z --stdin
+ *
+ * which will force all existing *.h files to be replaced with
+ * their cached copies. If an empty command line implied "all",
+ * then this would force-refresh everything in the cache, which
+ * was not the point.
+ *
+ * Oh, and the "--" is just a good idea when you know the rest
+ * will be filenames. Just so that you wouldn't have a filename
+ * of "-a" causing problems (not possible in the above example,
+ * but get used to it in scripting!).
+ */
+#include "cache.h"
+#include "strbuf.h"
+#include "quote.h"
+#include "cache-tree.h"
+
+#define CHECKOUT_ALL 4
+static int line_termination = '\n';
+static int checkout_stage; /* default to checkout stage0 */
+static int to_tempfile;
+static char topath[4][MAXPATHLEN+1];
+
+static struct checkout state;
+
+static void write_tempfile_record(const char *name, int prefix_length)
+{
+	int i;
+
+	if (CHECKOUT_ALL == checkout_stage) {
+		for (i = 1; i < 4; i++) {
+			if (i > 1)
+				putchar(' ');
+			if (topath[i][0])
+				fputs(topath[i], stdout);
+			else
+				putchar('.');
+		}
+	} else
+		fputs(topath[checkout_stage], stdout);
+
+	putchar('\t');
+	write_name_quoted("", 0, name + prefix_length,
+		line_termination, stdout);
+	putchar(line_termination);
+
+	for (i = 0; i < 4; i++) {
+		topath[i][0] = 0;
+	}
+}
+
+static int checkout_file(const char *name, int prefix_length)
+{
+	int namelen = strlen(name);
+	int pos = cache_name_pos(name, namelen);
+	int has_same_name = 0;
+	int did_checkout = 0;
+	int errs = 0;
+
+	if (pos < 0)
+		pos = -pos - 1;
+
+	while (pos < active_nr) {
+		struct cache_entry *ce = active_cache[pos];
+		if (ce_namelen(ce) != namelen ||
+		    memcmp(ce->name, name, namelen))
+			break;
+		has_same_name = 1;
+		pos++;
+		if (ce_stage(ce) != checkout_stage
+		    && (CHECKOUT_ALL != checkout_stage || !ce_stage(ce)))
+			continue;
+		did_checkout = 1;
+		if (checkout_entry(ce, &state,
+		    to_tempfile ? topath[ce_stage(ce)] : NULL) < 0)
+			errs++;
+	}
+
+	if (did_checkout) {
+		if (to_tempfile)
+			write_tempfile_record(name, prefix_length);
+		return errs > 0 ? -1 : 0;
+	}
+
+	if (!state.quiet) {
+		fprintf(stderr, "git-checkout-index: %s ", name);
+		if (!has_same_name)
+			fprintf(stderr, "is not in the cache");
+		else if (checkout_stage)
+			fprintf(stderr, "does not exist at stage %d",
+				checkout_stage);
+		else
+			fprintf(stderr, "is unmerged");
+		fputc('\n', stderr);
+	}
+	return -1;
+}
+
+static int checkout_all(const char *prefix, int prefix_length)
+{
+	int i, errs = 0;
+	struct cache_entry* last_ce = NULL;
+
+	for (i = 0; i < active_nr ; i++) {
+		struct cache_entry *ce = active_cache[i];
+		if (ce_stage(ce) != checkout_stage
+		    && (CHECKOUT_ALL != checkout_stage || !ce_stage(ce)))
+			continue;
+		if (prefix && *prefix &&
+		    (ce_namelen(ce) <= prefix_length ||
+		     memcmp(prefix, ce->name, prefix_length)))
+			continue;
+		if (last_ce && to_tempfile) {
+			if (ce_namelen(last_ce) != ce_namelen(ce)
+			    || memcmp(last_ce->name, ce->name, ce_namelen(ce)))
+				write_tempfile_record(last_ce->name, prefix_length);
+		}
+		if (checkout_entry(ce, &state,
+		    to_tempfile ? topath[ce_stage(ce)] : NULL) < 0)
+			errs++;
+		last_ce = ce;
+	}
+	if (last_ce && to_tempfile)
+		write_tempfile_record(last_ce->name, prefix_length);
+	if (errs)
+		/* we have already done our error reporting.
+		 * exit with the same code as die().
+		 */
+		exit(128);
+	return 0;
+}
+
+static const char checkout_cache_usage[] =
+"git-checkout-index [-u] [-q] [-a] [-f] [-n] [--stage=[123]|all] [--prefix=<string>] [--temp] [--] <file>...";
+
+static struct lock_file lock_file;
+
+int cmd_checkout_index(int argc, const char **argv, const char *prefix)
+{
+	int i;
+	int newfd = -1;
+	int all = 0;
+	int read_from_stdin = 0;
+	int prefix_length;
+
+	git_config(git_default_config);
+	state.base_dir = "";
+	prefix_length = prefix ? strlen(prefix) : 0;
+
+	if (read_cache() < 0) {
+		die("invalid cache");
+	}
+
+	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+
+		if (!strcmp(arg, "--")) {
+			i++;
+			break;
+		}
+		if (!strcmp(arg, "-a") || !strcmp(arg, "--all")) {
+			all = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-f") || !strcmp(arg, "--force")) {
+			state.force = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-q") || !strcmp(arg, "--quiet")) {
+			state.quiet = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-n") || !strcmp(arg, "--no-create")) {
+			state.not_new = 1;
+			continue;
+		}
+		if (!strcmp(arg, "-u") || !strcmp(arg, "--index")) {
+			state.refresh_cache = 1;
+			if (newfd < 0)
+				newfd = hold_lock_file_for_update
+					(&lock_file, get_index_file());
+			if (newfd < 0)
+				die("cannot open index.lock file.");
+			continue;
+		}
+		if (!strcmp(arg, "-z")) {
+			line_termination = 0;
+			continue;
+		}
+		if (!strcmp(arg, "--stdin")) {
+			if (i != argc - 1)
+				die("--stdin must be at the end");
+			read_from_stdin = 1;
+			i++; /* do not consider arg as a file name */
+			break;
+		}
+		if (!strcmp(arg, "--temp")) {
+			to_tempfile = 1;
+			continue;
+		}
+		if (!strncmp(arg, "--prefix=", 9)) {
+			state.base_dir = arg+9;
+			state.base_dir_len = strlen(state.base_dir);
+			continue;
+		}
+		if (!strncmp(arg, "--stage=", 8)) {
+			if (!strcmp(arg + 8, "all")) {
+				to_tempfile = 1;
+				checkout_stage = CHECKOUT_ALL;
+			} else {
+				int ch = arg[8];
+				if ('1' <= ch && ch <= '3')
+					checkout_stage = arg[8] - '0';
+				else
+					die("stage should be between 1 and 3 or all");
+			}
+			continue;
+		}
+		if (arg[0] == '-')
+			usage(checkout_cache_usage);
+		break;
+	}
+
+	if (state.base_dir_len || to_tempfile) {
+		/* when --prefix is specified we do not
+		 * want to update cache.
+		 */
+		if (state.refresh_cache) {
+			close(newfd); newfd = -1;
+			rollback_lock_file(&lock_file);
+		}
+		state.refresh_cache = 0;
+	}
+
+	/* Check out named files first */
+	for ( ; i < argc; i++) {
+		const char *arg = argv[i];
+		const char *p;
+
+		if (all)
+			die("git-checkout-index: don't mix '--all' and explicit filenames");
+		if (read_from_stdin)
+			die("git-checkout-index: don't mix '--stdin' and explicit filenames");
+		p = prefix_path(prefix, prefix_length, arg);
+		checkout_file(p, prefix_length);
+		if (p < arg || p > arg + strlen(arg))
+			free((char*)p);
+	}
+
+	if (read_from_stdin) {
+		struct strbuf buf;
+		if (all)
+			die("git-checkout-index: don't mix '--all' and '--stdin'");
+		strbuf_init(&buf);
+		while (1) {
+			char *path_name;
+			const char *p;
+
+			read_line(&buf, stdin, line_termination);
+			if (buf.eof)
+				break;
+			if (line_termination && buf.buf[0] == '"')
+				path_name = unquote_c_style(buf.buf, NULL);
+			else
+				path_name = buf.buf;
+			p = prefix_path(prefix, prefix_length, path_name);
+			checkout_file(p, prefix_length);
+			if (p < path_name || p > path_name + strlen(path_name))
+				free((char *)p);
+			if (path_name != buf.buf)
+				free(path_name);
+		}
+	}
+
+	if (all)
+		checkout_all(prefix, prefix_length);
+
+	if (0 <= newfd &&
+	    (write_cache(newfd, active_cache, active_nr) ||
+	     close(newfd) || commit_lock_file(&lock_file)))
+		die("Unable to write new index file");
+	return 0;
+}