/*
 * 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"

static const char *prefix;
static int prefix_length;
static int checkout_stage; /* default to checkout stage0 */

static struct checkout state = {
        .base_dir = "",
        .base_dir_len = 0,
        .force = 0,
        .quiet = 0,
        .not_new = 0,
        .refresh_cache = 0,
};

static int checkout_file(const char *name)
{
        int namelen = strlen(name);
        int pos = cache_name_pos(name, namelen);
        int has_same_name = 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;
                if (checkout_stage == ce_stage(ce))
                        return checkout_entry(ce, &state);
                pos++;
        }

        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(void)
{
        int i, errs = 0;

        for (i = 0; i < active_nr ; i++) {
                struct cache_entry *ce = active_cache[i];
                if (ce_stage(ce) != checkout_stage)
                        continue;
                if (prefix && *prefix &&
                    (ce_namelen(ce) <= prefix_length ||
                     memcmp(prefix, ce->name, prefix_length)))
                        continue;
                if (checkout_entry(ce, &state) < 0)
                        errs++;
        }
        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]] [--prefix=<string>] [--] <file>...";

static struct cache_file cache_file;

int main(int argc, char **argv)
{
        int i;
        int newfd = -1;
        int all = 0;
        int read_from_stdin = 0;
        int line_termination = '\n';

        prefix = setup_git_directory();
        git_config(git_default_config);
        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_index_file_for_update
                                        (&cache_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 (!strncmp(arg, "--prefix=", 9)) {
                        state.base_dir = arg+9;
                        state.base_dir_len = strlen(state.base_dir);
                        continue;
                }
                if (!strncmp(arg, "--stage=", 8)) {
                        int ch = arg[8];
                        if ('1' <= ch && ch <= '3')
                                checkout_stage = arg[8] - '0';
                        else
                                die("stage should be between 1 and 3");
                        continue;
                }
                if (arg[0] == '-')
                        usage(checkout_cache_usage);
                break;
        }

        if (state.base_dir_len) {
                /* when --prefix is specified we do not
                 * want to update cache.
                 */
                if (state.refresh_cache) {
                        close(newfd); newfd = -1;
                        rollback_index_file(&cache_file);
                }
                state.refresh_cache = 0;
        }

        /* Check out named files first */
        for ( ; i < argc; i++) {
                const char *arg = argv[i];

                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");
                checkout_file(prefix_path(prefix, prefix_length, arg));
        }

        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;
                        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;
                        checkout_file(prefix_path(prefix, prefix_length, path_name));
                        if (path_name != buf.buf)
                                free(path_name);
                }
        }

        if (all)
                checkout_all();

        if (0 <= newfd &&
            (write_cache(newfd, active_cache, active_nr) ||
             commit_index_file(&cache_file)))
                die("Unable to write new cachefile");
        return 0;
}