play: Fix segfault if decoder is not supported.

[paraslash.git] / play.c

/*
 * Copyright (C) 2012 Andre Noll <maan@systemlinux.org>
 *
 * Licensed under the GPL v2. For licencing details see COPYING.
 */

/** \file play.c Paraslash's standalone player. */

#include <regex.h>
#include <sys/time.h>
#include <fnmatch.h>
#include <signal.h>

#include "para.h"
#include "list.h"
#include "play.cmdline.h"
#include "filter.cmdline.h"
#include "error.h"
#include "ggo.h"
#include "buffer_tree.h"
#include "version.h"
#include "string.h"
#include "sched.h"
#include "filter.h"
#include "afh.h"
#include "recv.h"
#include "write.h"
#include "write_common.h"
#include "fd.h"

/**
 * Besides playback tasks which correspond to the receiver/filter/writer nodes,
 * para_play creates two further tasks: The play task and the i9e task. It is
 * important whether a function can be called in the context of para_play or
 * i9e or both. As a rule, all command handlers are called only in i9e context via
 * the line handler (input mode) or the key handler (command mode) below.
 *
 * Playlist handling is done exclusively in play context.
 */

/**
 * Describes a request to change the state of para_play.
 *
 * There is only one variable of this type: \a rq of the global play task
 * structure. Command handlers only set this variable and the post_select()
 * function of the play task investigates its value during each iteration of
 * the scheduler run and performs the actual work.
 */
enum state_change_request_type {
        /** Everybody is happy. */
        CRT_NONE,
        /** Stream must be repositioned (com_jmp(), com_ff()). */
        CRT_REPOS,
        /** New file should be loaded (com_next()). */
        CRT_FILE_CHANGE,
        /** Someone wants us for dead (com_quit()). */
        CRT_TERM_RQ
};

struct play_task {
        struct task task;
        /* A bit array of invalid files (those will be skipped). */
        bool *invalid;
        /* The file which is currently open. */
        unsigned current_file;
        /* When to update the status again. */
        struct timeval next_update;

        /* Root of the buffer tree for command and status output. */
        struct btr_node *btrn;

        /* The decoding machinery.  */
        struct receiver_node rn;
        struct filter_node fn;
        struct writer_node wn;

        /* See comment to enum state_change_request_type above */
        enum state_change_request_type rq;
        /* only relevant if rq == CRT_FILE_CHANGE */
        unsigned next_file;
        /*
                bg: read lines at prompt, fg: display status and wait
                for keystroke.
        */
        bool background;

        /* We have the *intention* to play. Set by com_play(). */
        bool playing;

        /* as returned by afh_recv->open() */
        int audio_format_num;

        /* retrieved via the btr exec mechanism */
        long unsigned start_chunk;
        long unsigned seconds;
        long unsigned num_chunks;
        char *afhi_txt;
};

/** Initialize the array of errors for para_play. */
INIT_PLAY_ERRLISTS;

/* Activate the afh receiver. */
extern void afh_recv_init(struct receiver *r);
#undef AFH_RECEIVER
/** Initialization code for a receiver struct. */
#define AFH_RECEIVER {.name = "afh", .init = afh_recv_init},
/** This expands to the array of all receivers. */
DEFINE_RECEIVER_ARRAY;

static int loglevel = LL_WARNING;

/** The log function which writes log messages to stderr. */
INIT_STDERR_LOGGING(loglevel);

char *stat_item_values[NUM_STAT_ITEMS] = {NULL};

/** Iterate over all files in the playlist. */
#define FOR_EACH_PLAYLIST_FILE(i) for (i = 0; i < conf.inputs_num; i++)
static struct play_args_info conf;

static struct sched sched = {.max_fileno = 0};
static struct play_task play_task;
static struct receiver *afh_recv;

static void check_afh_receiver_or_die(void)
{
        int i;

        FOR_EACH_RECEIVER(i) {
                struct receiver *r = receivers + i;
                if (strcmp(r->name, "afh"))
                        continue;
                afh_recv = r;
                return;
        }
        PARA_EMERG_LOG("fatal: afh receiver not found\n");
        exit(EXIT_FAILURE);
}

/** Description to be included in the --detailed-help output. */
#define PP_DESC \
"para_play is a command line audio player.\n" \
"\n" \
"It operates either in command mode or in insert mode. In insert mode it\n" \
"presents a prompt and allows to enter para_play commands like stop, play, pause\n" \
"etc. In command mode, the current audio file is shown and the program reads\n" \
"single key strokes from stdin. Keys may be mapped to para_play commands.\n" \
"Whenever a mapped key is pressed, the associated command is executed.\n" \

__noreturn static void print_help_and_die(void)
{
        int d = conf.detailed_help_given;
        const char **p = d? play_args_info_detailed_help
                : play_args_info_help;

//      printf_or_die("%s\n\n", PLAY_CMDLINE_PARSER_PACKAGE "-"
//              PLAY_CMDLINE_PARSER_VERSION);

        printf_or_die("%s\n\n", play_args_info_usage);
        if (d)
                printf_or_die("%s\n", PP_DESC);
        for (; *p; p++)
                printf_or_die("%s\n", *p);
        exit(0);
}

static void parse_config_or_die(int argc, char *argv[])
{
        int i, ret;
        char *config_file;
        struct play_cmdline_parser_params params = {
                .override = 0,
                .initialize = 1,
                .check_required = 0,
                .check_ambiguity = 0,
                .print_errors = 1
        };

        if (play_cmdline_parser_ext(argc, argv, &conf, &params))
                exit(EXIT_FAILURE);
        HANDLE_VERSION_FLAG("play", conf);
        if (conf.help_given || conf.detailed_help_given)
                print_help_and_die();
        loglevel = get_loglevel_by_name(conf.loglevel_arg);
        if (conf.config_file_given)
                config_file = para_strdup(conf.config_file_arg);
        else {
                char *home = para_homedir();
                config_file = make_message("%s/.paraslash/play.conf", home);
                free(home);
        }
        ret = file_exists(config_file);
        if (conf.config_file_given && !ret) {
                PARA_EMERG_LOG("can not read config file %s\n", config_file);
                goto err;
        }
        if (ret) {
                params.initialize = 0;
                params.check_required = 1;
                play_cmdline_parser_config_file(config_file, &conf, &params);
        }
        for (i = 0; i < conf.key_map_given; i++) {
                char *s = strchr(conf.key_map_arg[i] + 1, ':');
                if (s)
                        continue;
                PARA_EMERG_LOG("invalid key map arg: %s\n", conf.key_map_arg[i]);
                goto err;
        }
        free(config_file);
        return;
err:
        free(config_file);
        exit(EXIT_FAILURE);
}

static char get_playback_state(struct play_task *pt)
{
        switch (pt->rq) {
        case CRT_NONE: return pt->playing? 'P' : 'U';
        case CRT_REPOS: return 'R';
        case CRT_FILE_CHANGE: return 'F';
        case CRT_TERM_RQ: return 'X';
        }
        assert(false);
};

static long unsigned get_play_time(struct play_task *pt)
{
        char state = get_playback_state(pt);
        long unsigned result;

        if (state != 'P' && state != 'U')
                return 0;
        if (pt->num_chunks == 0 || pt->seconds == 0)
                return 0;
        /* where the stream started (in seconds) */
        result = pt->start_chunk * pt->seconds / pt->num_chunks;
        if (pt->wn.btrn) { /* Add the uptime of the writer node */
                struct timeval diff = {.tv_sec = 0}, wstime;
                btr_get_node_start(pt->wn.btrn, &wstime);
                if (wstime.tv_sec > 0)
                        tv_diff(now, &wstime, &diff);
                result += diff.tv_sec;
        }
        result = PARA_MIN(result, pt->seconds);
        result = PARA_MAX(result, 0UL);
        return result;
}

static void wipe_receiver_node(struct play_task *pt)
{
        PARA_NOTICE_LOG("cleaning up receiver node\n");
        btr_remove_node(&pt->rn.btrn);
        afh_recv->close(&pt->rn);
        afh_recv->free_config(pt->rn.conf);
        memset(&pt->rn, 0, sizeof(struct receiver_node));
}

/* returns: 0 not eof, 1: eof, < 0: fatal error.  */
static int get_playback_error(struct play_task *pt)
{
        int err = pt->wn.task.error;

        if (err >= 0)
                return 0;
        if (pt->fn.task.error >= 0)
                return 0;
        if (pt->rn.task.error >= 0)
                return 0;
        if (err == -E_BTR_EOF || err == -E_RECV_EOF || err == -E_EOF
                        || err == -E_WRITE_COMMON_EOF)
                return 1;
        return err;
}

static int eof_cleanup(struct play_task *pt)
{
        struct writer *w = writers + DEFAULT_WRITER;
        struct filter *decoder = filters + pt->fn.filter_num;
        int ret;

        ret = get_playback_error(pt);
        if (ret == 0)
                return ret;
        PARA_NOTICE_LOG("cleaning up wn/fn nodes\n");
        w->close(&pt->wn);
        btr_remove_node(&pt->wn.btrn);
        w->free_config(pt->wn.conf);
        memset(&pt->wn, 0, sizeof(struct writer_node));

        decoder->close(&pt->fn);
        btr_remove_node(&pt->fn.btrn);
        free(pt->fn.conf);
        memset(&pt->fn, 0, sizeof(struct filter_node));

        btr_remove_node(&pt->rn.btrn);
        /*
         * On eof (ret > 0), we do not wipe the receiver node struct until a
         * new file is loaded because we still need it for jumping around when
         * paused.
         */
        if (ret < 0)
                wipe_receiver_node(pt);
        return ret;
}

static int shuffle_compare(__a_unused const void *a, __a_unused const void *b)
{
        return para_random(100) - 50;
}

static void shuffle(char **base, size_t num)
{
        srandom(now->tv_sec);
        qsort(base, num, sizeof(char *), shuffle_compare);
}

static struct btr_node *new_recv_btrn(struct receiver_node *rn)
{
        return btr_new_node(&(struct btr_node_description)
                EMBRACE(.name = afh_recv->name, .context = rn,
                        .handler = afh_recv->execute));
}

static int open_new_file(struct play_task *pt)
{
        int ret;
        char *tmp, *path = conf.inputs[pt->next_file], *afh_recv_conf[] =
                {"play", "-f", path, "-b", "0", NULL};

        PARA_NOTICE_LOG("next file: %s\n", path);
        wipe_receiver_node(pt);
        pt->start_chunk = 0;
        pt->rn.btrn = new_recv_btrn(&pt->rn);
        pt->rn.conf = afh_recv->parse_config(ARRAY_SIZE(afh_recv_conf) - 1,
                afh_recv_conf);
        assert(pt->rn.conf);
        pt->rn.receiver = afh_recv;
        ret = afh_recv->open(&pt->rn);
        if (ret < 0) {
                PARA_ERROR_LOG("could not open %s: %s\n", path,
                        para_strerror(-ret));
                goto fail;
        }
        pt->audio_format_num = ret;
        free(pt->afhi_txt);
        ret = btr_exec_up(pt->rn.btrn, "afhi", &pt->afhi_txt);
        if (ret < 0)
                pt->afhi_txt = make_message("[afhi command failed]\n");
        ret = btr_exec_up(pt->rn.btrn, "seconds_total", &tmp);
        if (ret < 0)
                pt->seconds = 1;
        else {
                int32_t x;
                ret = para_atoi32(tmp, &x);
                pt->seconds = ret < 0? 1 : x;
                free(tmp);
                tmp = NULL;
        }
        ret = btr_exec_up(pt->rn.btrn, "chunks_total", &tmp);
        if (ret < 0)
                pt->num_chunks = 1;
        else {
                int32_t x;
                ret = para_atoi32(tmp, &x);
                pt->num_chunks = ret < 0? 1 : x;
                free(tmp);
                tmp = NULL;
        }
        pt->rn.task.pre_select = afh_recv->pre_select;
        pt->rn.task.post_select = afh_recv->post_select;
        sprintf(pt->rn.task.status, "%s receiver node", afh_recv->name);
        return 1;
fail:
        wipe_receiver_node(pt);
        return ret;
}

static int load_file(struct play_task *pt)
{
        const char *af;
        char *tmp;
        int ret;
        struct filter *decoder;

        btr_remove_node(&pt->rn.btrn);
        if (!pt->rn.receiver || pt->next_file != pt->current_file) {
                ret = open_new_file(pt);
                if (ret < 0)
                        return ret;
        } else {
                char buf[20];
                pt->rn.btrn = new_recv_btrn(&pt->rn);
                sprintf(buf, "repos %lu", pt->start_chunk);
                ret = btr_exec_up(pt->rn.btrn, buf, &tmp);
                if (ret < 0)
                        PARA_CRIT_LOG("repos failed: %s\n", para_strerror(-ret));
                freep(&tmp);
        }
        if (!pt->playing)
                return 0;
        /* set up decoding filter */
        af = audio_format_name(pt->audio_format_num);
        tmp = make_message("%sdec", af);
        ret = check_filter_arg(tmp, &pt->fn.conf);
        freep(&tmp);
        if (ret < 0)
                goto fail;
        pt->fn.filter_num = ret;
        decoder = filters + ret;
        pt->fn.task.pre_select = decoder->pre_select;
        pt->fn.task.post_select = decoder->post_select;
        sprintf(pt->fn.task.status, "%s decoder", af);
        pt->fn.btrn = btr_new_node(&(struct btr_node_description)
                EMBRACE(.name = decoder->name, .parent = pt->rn.btrn,
                        .handler = decoder->execute, .context = &pt->fn));
        decoder->open(&pt->fn);

        /* setup default writer */
        pt->wn.conf = check_writer_arg_or_die(NULL, &pt->wn.writer_num);
        pt->wn.task.error = 0;

        /* success, register tasks */
        register_task(&sched, &pt->rn.task);
        register_task(&sched, &pt->fn.task);
        register_writer_node(&pt->wn, pt->fn.btrn, &sched);
        return 1;
fail:
        wipe_receiver_node(pt);
        return ret;
}

static int next_valid_file(struct play_task *pt)
{
        int i, j = pt->current_file;

        FOR_EACH_PLAYLIST_FILE(i) {
                j = (j + 1) % conf.inputs_num;
                if (!pt->invalid[j])
                        return j;
        }
        return -E_NO_VALID_FILES;
}

static int load_next_file(struct play_task *pt)
{
        int ret;

again:
        if (pt->rq == CRT_NONE || pt->rq == CRT_FILE_CHANGE) {
                pt->start_chunk = 0;
                ret = next_valid_file(pt);
                if (ret < 0)
                        return ret;
                pt->next_file = ret;
        } else if (pt->rq == CRT_REPOS)
                pt->next_file = pt->current_file;
        ret = load_file(pt);
        if (ret < 0) {
                pt->invalid[pt->next_file] = true;
                pt->rq = CRT_NONE;
                goto again;
        }
        pt->current_file = pt->next_file;
        pt->rq = CRT_NONE;
        return ret;
}

static void kill_stream(struct play_task *pt)
{
        task_notify(&pt->wn.task, E_EOF);
}

#ifdef HAVE_READLINE

/* only called from com_prev(), nec. only if we have readline */
static int previous_valid_file(struct play_task *pt)
{
        int i, j = pt->current_file;

        FOR_EACH_PLAYLIST_FILE(i) {
                j--;
                if (j < 0)
                        j = conf.inputs_num - 1;
                if (!pt->invalid[j])
                        return j;
        }
        return -E_NO_VALID_FILES;
}

#include "interactive.h"

/*
 * Define the default (internal) key mappings and helper functions to get the
 * key sequence or the command from a key id, which is what we obtain from
 * i9e/readline when the key is pressed.
 *
 * In some of these helper functions we could return pointers to the constant
 * arrays defined below. However, for others we can not, so let's better be
 * consistent and allocate all returned strings on the heap.
 */

#define INTERNAL_KEYMAP_ENTRIES \
        KEYMAP_ENTRY("^", "jmp 0"), \
        KEYMAP_ENTRY("1", "jmp 10"), \
        KEYMAP_ENTRY("2", "jmp 21"), \
        KEYMAP_ENTRY("3", "jmp 32"), \
        KEYMAP_ENTRY("4", "jmp 43"), \
        KEYMAP_ENTRY("5", "jmp 54"), \
        KEYMAP_ENTRY("6", "jmp 65"), \
        KEYMAP_ENTRY("7", "jmp 76"), \
        KEYMAP_ENTRY("8", "jmp 87"), \
        KEYMAP_ENTRY("9", "jmp 98"), \
        KEYMAP_ENTRY("+", "next"), \
        KEYMAP_ENTRY("-", "prev"), \
        KEYMAP_ENTRY(":", "bg"), \
        KEYMAP_ENTRY("i", "info"), \
        KEYMAP_ENTRY("l", "ls"), \
        KEYMAP_ENTRY("s", "play"), \
        KEYMAP_ENTRY("p", "pause"), \
        KEYMAP_ENTRY("q", "quit"), \
        KEYMAP_ENTRY("?", "help"), \
        KEYMAP_ENTRY("\033[D", "ff -10"), \
        KEYMAP_ENTRY("\033[C", "ff 10"), \
        KEYMAP_ENTRY("\033[A", "ff 60"), \
        KEYMAP_ENTRY("\033[B", "ff -60"), \

#define KEYMAP_ENTRY(a, b) a
static const char *default_keyseqs[] = {INTERNAL_KEYMAP_ENTRIES};
#undef KEYMAP_ENTRY
#define KEYMAP_ENTRY(a, b) b
static const char *default_commands[] = {INTERNAL_KEYMAP_ENTRIES};
#undef KEYMAP_ENTRY
#define NUM_INTERNALLY_MAPPED_KEYS ARRAY_SIZE(default_commands)
#define NUM_MAPPED_KEYS (NUM_INTERNALLY_MAPPED_KEYS + conf.key_map_given)
#define FOR_EACH_MAPPED_KEY(i) for (i = 0; i < NUM_MAPPED_KEYS; i++)

static inline bool is_internal_key(int key)
{
        return key < NUM_INTERNALLY_MAPPED_KEYS;
}

/* for internal keys, the key id is just the array index. */
static inline int get_internal_key_map_idx(int key)
{
        assert(is_internal_key(key));
        return key;
}

/*
 * For user-defined keys, we have to subtract NUM_INTERNALLY_MAPPED_KEYS. The
 * difference is the index to the array of user defined key maps.
 */
static inline int get_user_key_map_idx(int key)
{
        assert(!is_internal_key(key));
        return key - NUM_INTERNALLY_MAPPED_KEYS;
}

static inline int get_key_map_idx(int key)
{
        return is_internal_key(key)?
                get_internal_key_map_idx(key) : get_user_key_map_idx(key);
}

static inline char *get_user_key_map_arg(int key)
{
        return conf.key_map_arg[get_user_key_map_idx(key)];
}

static inline char *get_internal_key_map_seq(int key)
{
        return para_strdup(default_keyseqs[get_internal_key_map_idx(key)]);
}

static char *get_user_key_map_seq(int key)
{
        const char *kma = get_user_key_map_arg(key);
        const char *p = strchr(kma + 1, ':');
        char *result;
        int len;

        if (!p)
                return NULL;
        len = p - kma;
        result = para_malloc(len + 1);
        memcpy(result, kma, len);
        result[len] = '\0';
        return result;
}

static char *get_key_map_seq(int key)
{
        return is_internal_key(key)?
                get_internal_key_map_seq(key) : get_user_key_map_seq(key);
}

static inline char *get_internal_key_map_cmd(int key)
{
        return para_strdup(default_commands[get_internal_key_map_idx(key)]);
}

static char *get_user_key_map_cmd(int key)
{
        const char *kma = get_user_key_map_arg(key);
        const char *p = strchr(kma + 1, ':');

        if (!p)
                return NULL;
        return para_strdup(p + 1);
}

static char *get_key_map_cmd(int key)
{
        return is_internal_key(key)?
                get_internal_key_map_cmd(key) : get_user_key_map_cmd(key);
}

static char **get_mapped_keyseqs(void)
{
        char **result;
        int i;

        result = para_malloc((NUM_MAPPED_KEYS + 1) * sizeof(char *));
        FOR_EACH_MAPPED_KEY(i) {
                int idx = get_key_map_idx(i);
                char *seq = get_key_map_seq(i);
                char *cmd = get_key_map_cmd(i);
                bool internal = is_internal_key(i);
                PARA_DEBUG_LOG("%s key sequence #%d: %s -> %s\n",
                        internal? "internal" : "user-defined",
                        idx, seq, cmd);
                result[i] = seq;
                free(cmd);
        }
        result[i] = NULL;
        return result;
}

#include "play_completion.h"


/* defines one command of para_play */
struct pp_command {
        const char *name;
        int (*handler)(struct play_task *, int, char**);
        const char *description;
        const char *usage;
        const char *help;
};

#include "play_command_list.h"
static struct pp_command pp_cmds[] = {DEFINE_PLAY_CMD_ARRAY};
#define FOR_EACH_COMMAND(c) for (c = 0; pp_cmds[c].name; c++)

#include "play_completion.h"
static struct i9e_completer pp_completers[];

I9E_DUMMY_COMPLETER(jmp);
I9E_DUMMY_COMPLETER(next);
I9E_DUMMY_COMPLETER(prev);
I9E_DUMMY_COMPLETER(fg);
I9E_DUMMY_COMPLETER(bg);
I9E_DUMMY_COMPLETER(ls);
I9E_DUMMY_COMPLETER(info);
I9E_DUMMY_COMPLETER(play);
I9E_DUMMY_COMPLETER(pause);
I9E_DUMMY_COMPLETER(stop);
I9E_DUMMY_COMPLETER(tasks);
I9E_DUMMY_COMPLETER(quit);
I9E_DUMMY_COMPLETER(ff);

static void help_completer(struct i9e_completion_info *ci,
                struct i9e_completion_result *result)
{
        result->matches = i9e_complete_commands(ci->word, pp_completers);
}

static struct i9e_completer pp_completers[] = {PLAY_COMPLETERS {.name = NULL}};

static void attach_stdout(struct play_task *pt, const char *name)
{
        if (pt->btrn)
                return;
        pt->btrn = btr_new_node(&(struct btr_node_description)
                EMBRACE(.name = name));
        i9e_attach_to_stdout(pt->btrn);
}

static void detach_stdout(struct play_task *pt)
{
        btr_remove_node(&pt->btrn);
}

static int com_quit(struct play_task *pt, int argc, __a_unused char **argv)
{
        if (argc != 1)
                return -E_PLAY_SYNTAX;
        pt->rq = CRT_TERM_RQ;
        return 0;
}

static int com_help(struct play_task *pt, int argc, char **argv)
{
        int i;
        char *buf;
        size_t sz;

        if (argc > 2)
                return -E_PLAY_SYNTAX;
        if (argc < 2) {
                if (pt->background)
                        FOR_EACH_COMMAND(i) {
                                sz = xasprintf(&buf, "%s\t%s\n", pp_cmds[i].name,
                                        pp_cmds[i].description);
                                btr_add_output(buf, sz, pt->btrn);
                        }
                else {
                        FOR_EACH_MAPPED_KEY(i) {
                                bool internal = is_internal_key(i);
                                int idx = get_key_map_idx(i);
                                char *seq = get_key_map_seq(i);
                                char *cmd = get_key_map_cmd(i);
                                sz = xasprintf(&buf,
                                        "%s key #%d: %s -> %s\n",
                                        internal? "internal" : "user-defined",
                                        idx, seq, cmd);
                                btr_add_output(buf, sz, pt->btrn);
                                free(seq);
                                free(cmd);
                        }
                }
                return 0;
        }
        FOR_EACH_COMMAND(i) {
                if (strcmp(pp_cmds[i].name, argv[1]))
                        continue;
                sz = xasprintf(&buf,
                        "NAME\n\t%s -- %s\n"
                        "SYNOPSIS\n\t%s\n"
                        "DESCRIPTION\n%s\n",
                        argv[1],
                        pp_cmds[i].description,
                        pp_cmds[i].usage,
                        pp_cmds[i].help
                );
                btr_add_output(buf, sz, pt->btrn);
                return 0;
        }
        return -E_BAD_PLAY_CMD;
}

static int com_info(struct play_task *pt, int argc, __a_unused char **argv)
{
        char *buf;
        size_t sz;
        static char dflt[] = "[no information available]";

        if (argc != 1)
                return -E_PLAY_SYNTAX;
        sz = xasprintf(&buf, "playlist_pos: %u\npath: %s\n",
                pt->current_file, conf.inputs[pt->current_file]);
        btr_add_output(buf, sz, pt->btrn);
        buf = pt->afhi_txt? pt->afhi_txt : dflt;
        btr_add_output_dont_free(buf, strlen(buf), pt->btrn);
        return 0;
}

static void list_file(struct play_task *pt, int num)
{
        char *buf;
        size_t sz;

        sz = xasprintf(&buf, "%s %4u %s\n", num == pt->current_file?
                "*" : " ", num, conf.inputs[num]);
        btr_add_output(buf, sz, pt->btrn);
}

static int com_tasks(struct play_task *pt, int argc, __a_unused char **argv)
{
        static char state;
        char *buf;
        size_t sz;

        if (argc != 1)
                return -E_PLAY_SYNTAX;

        buf = get_task_list(&sched);
        btr_add_output(buf, strlen(buf), pt->btrn);
        state = get_playback_state(pt);
        sz = xasprintf(&buf, "state: %c\n", state);
        btr_add_output(buf, sz, pt->btrn);
        return 0;
}

static int com_ls(struct play_task *pt, int argc, char **argv)
{
        int i, j, ret;

        if (argc == 1) {
                FOR_EACH_PLAYLIST_FILE(i)
                        list_file(pt, i);
                return 0;
        }
        for (j = 1; j < argc; j++) {
                FOR_EACH_PLAYLIST_FILE(i) {
                        ret = fnmatch(argv[j], conf.inputs[i], 0);
                        if (ret == 0) /* match */
                                list_file(pt, i);
                }
        }
        return 0;
}

static int com_play(struct play_task *pt, int argc, char **argv)
{
        int32_t x;
        int ret;
        char state;

        if (argc > 2)
                return -E_PLAY_SYNTAX;
        state = get_playback_state(pt);
        if (argc == 1) {
                if (state == 'P')
                        return 0;
                pt->next_file = pt->current_file;
                pt->rq = CRT_REPOS;
                pt->playing = true;
                return 0;
        }
        ret = para_atoi32(argv[1], &x);
        if (ret < 0)
                return ret;
        if (x < 0 || x >= conf.inputs_num)
                return -ERRNO_TO_PARA_ERROR(EINVAL);
        kill_stream(pt);
        pt->next_file = x;
        pt->rq = CRT_FILE_CHANGE;
        return 0;
}

static int com_pause(struct play_task *pt, int argc, __a_unused char **argv)
{
        char state;
        long unsigned seconds, ss;

        if (argc != 1)
                return -E_PLAY_SYNTAX;
        state = get_playback_state(pt);
        pt->playing = false;
        if (state != 'P')
                return 0;
        seconds = get_play_time(pt);
        pt->playing = false;
        ss = 0;
        if (pt->seconds > 0)
                ss = seconds * pt->num_chunks / pt->seconds + 1;
        ss = PARA_MAX(ss, 0UL);
        ss = PARA_MIN(ss, pt->num_chunks);
        pt->start_chunk = ss;
        kill_stream(pt);
        return 0;
}

static int com_prev(struct play_task *pt, int argc, __a_unused char **argv)

{
        int ret;

        if (argc != 1)
                return -E_PLAY_SYNTAX;
        ret = previous_valid_file(pt);
        if (ret < 0)
                return ret;
        kill_stream(pt);
        pt->next_file = ret;
        pt->rq = CRT_FILE_CHANGE;
        return 0;
}

static int com_next(struct play_task *pt, int argc, __a_unused char **argv)
{
        int ret;

        if (argc != 1)
                return -E_PLAY_SYNTAX;
        ret = next_valid_file(pt);
        if (ret < 0)
                return ret;
        kill_stream(pt);
        pt->next_file = ret;
        pt->rq = CRT_FILE_CHANGE;
        return 0;
}

static int com_fg(struct play_task *pt, int argc, __a_unused char **argv)
{
        if (argc != 1)
                return -E_PLAY_SYNTAX;
        pt->background = false;
        return 0;
}

static int com_bg(struct play_task *pt, int argc, __a_unused char **argv)
{
        if (argc != 1)
                return -E_PLAY_SYNTAX;
        pt->background = true;
        return 0;
}

static int com_jmp(struct play_task *pt, int argc, char **argv)
{
        int32_t percent;
        int ret;

        if (argc != 2)
                return -E_PLAY_SYNTAX;
        ret = para_atoi32(argv[1], &percent);
        if (ret < 0)
                return ret;
        if (percent < 0 || percent > 100)
                return -ERRNO_TO_PARA_ERROR(EINVAL);
        if (pt->playing && !pt->fn.btrn)
                return 0;
        pt->start_chunk = percent * pt->num_chunks / 100;
        if (!pt->playing)
                return 0;
        pt->rq = CRT_REPOS;
        kill_stream(pt);
        return 0;
}

static int com_ff(struct play_task *pt, int argc, char **argv)
{
        int32_t seconds;
        int ret;

        if (argc != 2)
                return -E_PLAY_SYNTAX;
        ret = para_atoi32(argv[1], &seconds);
        if (ret < 0)
                return ret;
        if (pt->playing && !pt->fn.btrn)
                return 0;
        seconds += get_play_time(pt);
        seconds = PARA_MIN(seconds, (typeof(seconds))pt->seconds - 4);
        seconds = PARA_MAX(seconds, 0);
        pt->start_chunk = pt->num_chunks * seconds / pt->seconds;
        pt->start_chunk = PARA_MIN(pt->start_chunk, pt->num_chunks - 1);
        pt->start_chunk = PARA_MAX(pt->start_chunk, 0UL);
        if (!pt->playing)
                return 0;
        pt->rq = CRT_REPOS;
        kill_stream(pt);
        return 0;
}

static int run_command(char *line, struct play_task *pt)
{
        int i, ret, argc;
        char **argv = NULL;

        attach_stdout(pt, __FUNCTION__);
        ret = create_argv(line, " ", &argv);
        if (ret < 0) {
                PARA_ERROR_LOG("parse error: %s\n", para_strerror(-ret));
                return 0;
        }
        if (ret == 0)
                goto out;
        argc = ret;
        FOR_EACH_COMMAND(i) {
                if (strcmp(pp_cmds[i].name, argv[0]))
                        continue;
                ret = pp_cmds[i].handler(pt, argc, argv);
                if (ret < 0)
                        PARA_WARNING_LOG("%s: %s\n", pt->background?
                                "" : argv[0], para_strerror(-ret));
                ret = 1;
                goto out;
        }
        PARA_WARNING_LOG("invalid command: %s\n", argv[0]);
        ret = 0;
out:
        free_argv(argv);
        return ret;
}

static int play_i9e_line_handler(char *line)
{
        struct play_task *pt = &play_task;
        int ret;

        if (line == NULL || !*line)
                return 0;
        ret = run_command(line, pt);
        if (ret < 0)
                return ret;
        return 0;
}

static int play_i9e_key_handler(int key)
{
        struct play_task *pt = &play_task;
        int idx = get_key_map_idx(key);
        char *seq = get_key_map_seq(key);
        char *cmd = get_key_map_cmd(key);
        bool internal = is_internal_key(key);

        PARA_NOTICE_LOG("pressed %d: %s key #%d (%s -> %s)\n",
                key, internal? "internal" : "user-defined",
                idx, seq, cmd);
        run_command(cmd, pt);
        free(seq);
        free(cmd);
        pt->next_update = *now;
        return 0;
}

static struct i9e_client_info ici = {
        .fds = {0, 1, 2},
        .prompt = "para_play> ",
        .line_handler = play_i9e_line_handler,
        .key_handler = play_i9e_key_handler,
        .completers = pp_completers,
};

static void sigint_handler(int sig)
{
        play_task.background = true;
        i9e_signal_dispatch(sig);
}

/*
 * We start with para_log() set to the standard log function which writes to
 * stderr. Once the i9e subsystem has been initialized, we switch to the i9e
 * log facility.
 */
static void session_open(__a_unused struct play_task *pt)
{
        int ret;
        char *history_file;
        struct sigaction act;

        PARA_NOTICE_LOG("\n%s\n", VERSION_TEXT("play"));
        if (conf.history_file_given)
                history_file = para_strdup(conf.history_file_arg);
        else {
                char *home = para_homedir();
                history_file = make_message("%s/.paraslash/play.history",
                        home);
                free(home);
        }
        ici.history_file = history_file;
        ici.loglevel = loglevel;

        act.sa_handler = sigint_handler;
        sigemptyset(&act.sa_mask);
        act.sa_flags = 0;
        sigaction(SIGINT, &act, NULL);
        act.sa_handler = i9e_signal_dispatch;
        sigemptyset(&act.sa_mask);
        act.sa_flags = 0;
        sigaction(SIGWINCH, &act, NULL);
        sched.select_function = i9e_select;

        ici.bound_keyseqs = get_mapped_keyseqs();
        pt->btrn = ici.producer = btr_new_node(&(struct btr_node_description)
                EMBRACE(.name = __FUNCTION__));
        ret = i9e_open(&ici, &sched);
        if (ret < 0)
                goto out;
        para_log = i9e_log;
        return;
out:
        free(history_file);
        if (ret >= 0)
                return;
        PARA_EMERG_LOG("fatal: %s\n", para_strerror(-ret));
        exit(EXIT_FAILURE);
}

static void session_update_time_string(struct play_task *pt, char *str, unsigned len)
{
        if (pt->background)
                return;
        if (pt->btrn) {
                if (btr_get_output_queue_size(pt->btrn) > 0)
                        return;
                if (btr_get_input_queue_size(pt->btrn) > 0)
                        return;
        }
        ie9_print_status_bar(str, len);
}

/*
 * If we are about to die we must call i9e_close() to reset the terminal.
 * However, i9e_close() must be called in *this* context, i.e. from
 * play_task.post_select() rather than from i9e_post_select(), because
 * otherwise i9e would access freed memory upon return. So the play task must
 * stay alive until the i9e task terminates.
 *
 * We achieve this by sending a fake SIGTERM signal via i9e_signal_dispatch()
 * and reschedule. In the next iteration, i9e->post_select returns an error and
 * terminates. Subsequent calls to i9e_get_error() then return negative and we
 * are allowed to call i9e_close() and terminate as well.
 */
static int session_post_select(__a_unused struct sched *s, struct task *t)
{
        struct play_task *pt = container_of(t, struct play_task, task);
        int ret;

        if (pt->background)
                detach_stdout(pt);
        else
                attach_stdout(pt, __FUNCTION__);
        ret = i9e_get_error();
        if (ret < 0) {
                kill_stream(pt);
                i9e_close();
                para_log = stderr_log;
                free(ici.history_file);
                return ret;
        }
        if (get_playback_state(pt) == 'X')
                i9e_signal_dispatch(SIGTERM);
        return 0;
}

#else /* HAVE_READLINE */

static int session_post_select(struct sched *s, struct task *t)
{
        struct play_task *pt = container_of(t, struct play_task, task);
        char c;

        if (!FD_ISSET(STDIN_FILENO, &s->rfds))
                return 0;
        if (read(STDIN_FILENO, &c, 1))
                do_nothing;
        kill_stream(pt);
        return 1;
}

static void session_open(__a_unused struct play_task *pt)
{
}

static void session_update_time_string(__a_unused struct play_task *pt,
                char *str, __a_unused unsigned len)
{
        printf("\r%s     ", str);
        fflush(stdout);
}
#endif /* HAVE_READLINE */

static void play_pre_select(struct sched *s, struct task *t)
{
        struct play_task *pt = container_of(t, struct play_task, task);
        char state;

        para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
        state = get_playback_state(pt);
        if (state == 'R' || state == 'F' || state == 'X')
                return sched_min_delay(s);
        sched_request_barrier_or_min_delay(&pt->next_update, s);
}

static unsigned get_time_string(struct play_task *pt, char **result)
{
        int seconds, length;
        char state = get_playback_state(pt);

        /* do not return anything if things are about to change */
        if (state != 'P' && state != 'U') {
                *result = NULL;
                return 0;
        }
        length = pt->seconds;
        if (length == 0)
                return xasprintf(result, "0:00 [0:00] (0%%/0:00)");
        seconds = get_play_time(pt);
        return xasprintf(result, "#%u: %d:%02d [%d:%02d] (%d%%/%d:%02d) %s",
                pt->current_file,
                seconds / 60,
                seconds % 60,
                (length - seconds) / 60,
                (length - seconds) % 60,
                length? (seconds * 100 + length / 2) / length : 0,
                length / 60,
                length % 60,
                conf.inputs[pt->current_file]
        );
}

static void play_post_select(struct sched *s, struct task *t)
{
        struct play_task *pt = container_of(t, struct play_task, task);
        int ret;

        ret = eof_cleanup(pt);
        if (ret < 0) {
                pt->rq = CRT_TERM_RQ;
                return;
        }
        ret = session_post_select(s, t);
        if (ret < 0)
                goto out;
        if (!pt->wn.btrn && !pt->fn.btrn) {
                char state = get_playback_state(pt);
                if (state == 'P' || state == 'R' || state == 'F') {
                        PARA_NOTICE_LOG("state: %c\n", state);
                        ret = load_next_file(pt);
                        if (ret < 0) {
                                PARA_ERROR_LOG("%s\n", para_strerror(-ret));
                                pt->rq = CRT_TERM_RQ;
                                ret = 1;
                                goto out;
                        }
                        pt->next_update = *now;
                }
        }
        if (tv_diff(now, &pt->next_update, NULL) >= 0) {
                char *str;
                unsigned len = get_time_string(pt, &str);
                struct timeval delay = {.tv_sec = 0, .tv_usec = 100 * 1000};
                if (str && len > 0)
                        session_update_time_string(pt, str, len);
                free(str);
                tv_add(now, &delay, &pt->next_update);
        }
        ret = 1;
out:
        t->error = ret;
}

/**
 * The main function of para_play.
 *
 * \param argc Standard.
 * \param argv Standard.
 *
 * \return \p EXIT_FAILURE or \p EXIT_SUCCESS.
 */
int main(int argc, char *argv[])
{
        int ret;
        struct play_task *pt = &play_task;

        /* needed this early to make help work */
        recv_init();
        filter_init();
        writer_init();

        gettimeofday(now, NULL);
        sched.default_timeout.tv_sec = 5;

        parse_config_or_die(argc, argv);
        if (conf.inputs_num == 0)
                print_help_and_die();
        check_afh_receiver_or_die();

        session_open(pt);
        if (conf.randomize_given)
                shuffle(conf.inputs, conf.inputs_num);
        pt->invalid = para_calloc(sizeof(*pt->invalid) * conf.inputs_num);
        pt->rq = CRT_FILE_CHANGE;
        pt->current_file = conf.inputs_num - 1;
        pt->playing = true;
        pt->task.pre_select = play_pre_select;
        pt->task.post_select = play_post_select;
        sprintf(pt->task.status, "play task");
        register_task(&sched, &pt->task);
        ret = schedule(&sched);
        if (ret < 0)
                PARA_ERROR_LOG("%s\n", para_strerror(-ret));
        return ret < 0? EXIT_FAILURE : EXIT_SUCCESS;
}