/*
 * Check-out files from the "current cache directory"
 *
 * Copyright (C) 2005 Linus Torvalds
 *
 * Careful: order of argument flags does matter. For example,
 *
 *	checkout-cache -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 "checkout-cache" does nothing. You probably
 * meant "checkout-cache -a". And if you want to force it, you
 * want "checkout-cache -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 checkout-cache -f --
 *
 * 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"

static int force = 0, quiet = 0;

static int write_entry(struct cache_entry *ce)
{
	int fd;
	void *new;
	unsigned long size;
	long wrote;

	new = read_sha1_file(ce->sha1, "blob", &size);
	if (!new) {
		fprintf(stderr, "checkout-cache: unable to read sha1 file of %s (%s)",
			ce->name, sha1_to_hex(ce->sha1));
		return -1;
	}
	fd = open(ce->name, O_WRONLY | O_CREAT | O_TRUNC, 0600);
	if (fd < 0) {
		fprintf(stderr, "checkout-cache: unable to create %s (%s)",
			ce->name, strerror(errno));
		free(new);
		return -1;
	}
	wrote = write(fd, new, size);
	close(fd);
	free(new);
	if (wrote == size)
		return 0;
	fprintf(stderr, "checkout-cache: unable to write %s", ce->name);
	return -1;
}

static int checkout_entry(struct cache_entry *ce)
{
	if (!force) {
		struct stat st;

		if (!stat(ce->name, &st)) {
			unsigned changed = cache_match_stat(ce, &st);
			if (!changed)
				return 0;
			if (!quiet)
				fprintf(stderr, "checkout-cache: %s already exists", ce->name);
			return -1;
		}
	}
	return write_entry(ce);
}

static int checkout_file(const char *name)
{
	int pos = cache_name_pos(name, strlen(name));
	if (pos < 0) {
		if (!quiet)
			fprintf(stderr, "checkout-cache: %s is not in the cache", name);
		return -1;
	}
	return checkout_entry(active_cache[pos]);
}

static int checkout_all(void)
{
	int i;

	for (i = 0; i < active_nr ; i++) {
		struct cache_entry *ce = active_cache[i];
		if (checkout_entry(ce) < 0)
			return -1;
	}
	return 0;
}

int main(int argc, char **argv)
{
	int i, force_filename = 0;

	if (read_cache() < 0) {
		fprintf(stderr, "Invalid cache");
		exit(1);
	}

	for (i = 1; i < argc; i++) {
		const char *arg = argv[i];
		if (!force_filename) {
			if (!strcmp(arg, "-a")) {
				checkout_all();
				continue;
			}
			if (!strcmp(arg, "--")) {
				force_filename = 1;
				continue;
			}
			if (!strcmp(arg, "-f")) {
				force = 1;
				continue;
			}
			if (!strcmp(arg, "-q")) {
				quiet = 1;
				continue;
			}
		}
		checkout_file(arg);
	}
	return 0;
}