lua events from rockbox

This library allows events to be subscribed / recieved within a lua script
most events in rb are synchronous so flags are set and later checked by a
secondary thread to make them (semi?) asynchronous.

There are a few caveats to be aware of:

FIRST, The main lua state is halted till the lua callback(s) are finished
Yielding will not return control to your script from within a callback
Also, subsequent callbacks may be delayed by the code in your lua callback
SECOND, You must store the value returned from the event_register function
you might get away with it for a bit but gc will destroy your callback
eventually if you do not store the event
THIRD, You only get one cb per event type
["action", "button", "custom", "playback", "timer"]
(Re-registration of an event overwrites the previous one)

Usage:
possible events =["action", "button", "custom", "playback", "timer"]

local evX = rockev.register("event", cb_function, [timeout / flags])
cb_function([id] [, data]) ... end

rockev.suspend(["event"/nil][true/false]) passing nil affects all events
stops event from executing, any but the last event before
re-enabling will be lost, passing false, unregistering or re-registering
an event will clear the suspend

rockev.trigger("event", [true/false], [id])
sets an event to triggered,
NOTE!, CUSTOM_EVENT must be unset manually
id is only passed to callback by custom and playback events

rockev.unregister(evX)
Use unregister(evX) to remove an event
Unregistering is not necessary before script end, it will be
cleaned up on script exit

Change-Id: Iea12a5cc0c0295b955dcc1cdf2eec835ca7e354d

apps/plugins/lua/SOURCES

···
 strstr.c
 rocklua.c
 luadir.c
+rocklib_events.c

apps/plugins/lua/rbdefines_helper.pl

···
     '^SCREEN_REMOTE$',
     '^FONT_SYSFIXED$',
     '^FONT_UI$',
+    '^PLAYBACK_EVENT_.*',
     '^PLAYLIST_(INSERT|PREPEND|REPLACE)',
     '^TOUCHSCREEN_(POINT|BUTTON)$',
+    '^SYS_CHARGER_(DIS|)CONNECTED$',
+    '^SYS_(TIMEOUT|POWEROFF)$',
+    '^SYS_USB_(DIS|)CONNECTED$',
     '^HOME_DIR$',
     '^PLUGIN_DIR$',
     '^PLUGIN(_APPS_|_GAMES_|_)DATA_DIR$',

apps/plugins/lua/rockaux.c

···
 #include "plugin.h"
 #define _ROCKCONF_H_ /* Protect against unwanted include */
 #include "lua.h"
+#include "lib/pluginlib_actions.h"
 
 extern long strtol(const char *nptr, char **endptr, int base);
 
···
     return retn;
 }
 
+int get_plugin_action(int timeout, bool with_remote)
+{
+    static const struct button_mapping *m1[] = { pla_main_ctx };
+    int btn;
+
+#ifndef HAVE_REMOTE_LCD
+    (void) with_remote;
+#else
+    static const struct button_mapping *m2[] = { pla_main_ctx, pla_remote_ctx };
+
+    if (with_remote)
+        btn = pluginlib_getaction(timeout, m2, 2);
+    else
+#endif
+    btn = pluginlib_getaction(timeout, m1, 1);
+
+    return btn;
+}

apps/plugins/lua/rocklib.c

···
 #include "lauxlib.h"
 #include "rocklib.h"
 #include "lib/helper.h"
-#include "lib/pluginlib_actions.h"
 
 /*
  * http://www.lua.org/manual/5.1/manual.html#lua_CFunction
···
 
 RB_WRAP(get_plugin_action)
 {
-    static const struct button_mapping *m1[] = { pla_main_ctx };
     int timeout = luaL_checkint(L, 1);
-    int btn;
-
-#ifdef HAVE_REMOTE_LCD
-    static const struct button_mapping *m2[] = { pla_main_ctx, pla_remote_ctx };
     bool with_remote = luaL_optint(L, 2, 0);
-    if (with_remote)
-        btn = pluginlib_getaction(timeout, m2, 2);
-    else
-#endif
-        btn = pluginlib_getaction(timeout, m1, 1);
-
+    int btn = get_plugin_action(timeout, with_remote);
     lua_pushinteger(L, btn);
     return 1;
 }
···
         RB_CONSTANT(PLAYLIST_INSERT_SHUFFLED),
         RB_CONSTANT(PLAYLIST_PREPEND),
         RB_CONSTANT(PLAYLIST_REPLACE),
+
+/* queue sys events */
+        RB_CONSTANT(SYS_USB_CONNECTED),
+        RB_CONSTANT(SYS_USB_DISCONNECTED),
+        RB_CONSTANT(SYS_TIMEOUT),
+        RB_CONSTANT(SYS_POWEROFF),
+        RB_CONSTANT(SYS_CHARGER_CONNECTED),
+        RB_CONSTANT(SYS_CHARGER_DISCONNECTED),
 
 #ifdef HAVE_TOUCHSCREEN
         RB_CONSTANT(TOUCHSCREEN_POINT),

apps/plugins/lua/rocklib.h

···
 };
 
 LUALIB_API int (luaopen_rock) (lua_State *L) __attribute__((aligned(0x8)));
+/* in rockaux.c */
 int get_current_path(lua_State *L, int level);
 int filetol(int fd, long *num);
+int get_plugin_action(int timeout, bool with_remote);
 
 #endif /* _ROCKLIB_H_ */
 

apps/plugins/lua/rocklib_events.c

···
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2019 William Wilgus
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+/* lua events from rockbox *****************************************************
+ * This library allows events to be subscribed / recieved within a lua script
+ * most events in rb are synchronous so flags are set and later checked by a
+ * secondary thread to make them (semi?) asynchronous.
+ *
+ * There are a few caveats to be aware of:
+ * FIRST, The main lua state is halted till the lua callback(s) are finished
+ *     Yielding will not return control to your script from within a callback
+ *     Also, subsequent callbacks may be delayed by the code in your lua callback
+ * SECOND, You must store the value returned from the event_register function
+ *         you might get away with it for a bit but gc will destroy your callback
+ *         eventually if you do not store the event
+ * THIRD, You only get one cb per event type
+ *     ["action", "button", "custom", "playback", "timer"]
+ * (Re-registration of an event overwrites the previous one)
+ *
+ * Usage:
+ * possible events =["action", "button", "custom", "playback", "timer"]
+ *
+ * local ev = rockev.register("event", cb_function, [timeout / flags])
+ *    cb_function([id] [, data]) ... end
+ *
+ *
+ * rockev.trigger("event", [true/false], [id])
+ * sets an event to triggered,
+ * NOTE!, CUSTOM_EVENT must be unset manually
+ * id is only passed to callback by custom and playback events
+ *
+ * rockev.suspend(["event"/nil][true/false]) passing nil affects all events
+ * stops event from executing, any but the last event before
+ * re-enabling will be lost. Passing false, unregistering or re-registering
+ * an event will clear the suspend
+ *
+ * rockev.unregister(evX)
+ * Use unregister(evX) to remove an event
+ * Unregistering is not necessary before script end, it will be
+ * cleaned up on script exit
+ *
+ *******************************************************************************
+ * *
+ */
+
+#define LUA_LIB
+
+#define _ROCKCONF_H_ /* We don't need strcmp() etc. wrappers */
+#include "lua.h"
+#include "lauxlib.h"
+#include "plugin.h"
+#include "rocklib_events.h"
+
+#define EVENT_METATABLE "event metatable"
+
+#define EVENT_THREAD LUA_ROCKEVENTSNAME ".thread"
+
+#define LUA_SUCCESS 0
+#define EV_TIMER_FREQ (TIMER_FREQ / HZ)
+#define EV_TICKS (HZ / 5)
+#define EV_INPUT (HZ / 4)
+//#define DEBUG_EV
+
+enum e_thread_state_flags{
+    THREAD_QUIT        = 0x0,
+    THREAD_YIELD       = 0x1,
+    THREAD_TIMEREVENT  = 0x2,
+    THREAD_PLAYBKEVENT = 0x4,
+    THREAD_ACTEVENT    = 0x8,
+    THREAD_BUTEVENT    = 0x10,
+    THREAD_CUSTOMEVENT = 0x20,
+  //THREAD_AVAILEVENT  = 0x40,
+  //THREAD_AVAILEVENT  = 0x80,
+/* thread state holds 3 status items using masks and bitshifts */
+    THREAD_STATEMASK   = 0x00FF,
+    THREAD_SUSPENDMASK = 0xFF00,
+    THREAD_INPUTMASK   = 0xFF0000,
+};
+
+enum {
+    ACTEVENT = 0,
+    BUTEVENT,
+    CUSTOMEVENT,
+    PLAYBKEVENT,
+    TIMEREVENT,
+    EVENT_CT
+};
+
+static const unsigned char thread_ev_states[EVENT_CT] =
+{
+    [ACTEVENT] = THREAD_ACTEVENT,
+    [BUTEVENT] = THREAD_BUTEVENT,
+    [CUSTOMEVENT] = THREAD_CUSTOMEVENT,
+    [PLAYBKEVENT] = THREAD_PLAYBKEVENT,
+    [TIMEREVENT] = THREAD_TIMEREVENT,
+};
+
+static const char *const ev_map[EVENT_CT] =
+{
+    [ACTEVENT] = "action",
+    [BUTEVENT] = "button",
+    [CUSTOMEVENT] = "custom",
+    [PLAYBKEVENT] = "playback",
+    [TIMEREVENT] = "timer",
+};
+
+struct cb_data {
+    int            cb_ref;
+    unsigned long  id;
+    void           *data;
+};
+
+struct event_data {
+    /* lua */
+    lua_State      *L;
+    lua_State      *NEWL;
+    /* rockbox */
+    unsigned int    thread_id;
+    int             thread_state;
+    long           *event_stack;
+    long            timer_ticks;
+    short           next_input;
+    short           next_event;
+    /* callbacks */
+    struct cb_data *cb[EVENT_CT];
+};
+
+static struct event_data ev_data;
+static struct mutex rev_mtx SHAREDBSS_ATTR;
+
+#ifdef DEBUG_EV
+static int dbg_hook_calls = 0;
+#endif
+
+static inline bool has_event(int ev_flag)
+{
+    return ((THREAD_STATEMASK & (ev_data.thread_state & ev_flag)) == ev_flag);
+}
+
+static inline bool is_suspend(int ev_flag)
+{
+    ev_flag <<= 8;
+    return ((THREAD_SUSPENDMASK & (ev_data.thread_state & ev_flag)) == ev_flag);
+}
+
+static void init_event_data(lua_State *L, struct event_data *ev_data)
+{
+    /* lua */
+    ev_data->L = L;
+    //ev_data->NEWL = NULL;
+    /* rockbox */
+    ev_data->thread_id = UINT_MAX;
+    ev_data->thread_state = THREAD_YIELD;
+    //ev_data->event_stack = NULL;
+    //ev_data->timer_ticks = 0;
+    ev_data->next_input  = EV_TICKS;
+    ev_data->next_event  = EV_INPUT;
+    /* callbacks */
+    for (int i= 0; i < EVENT_CT; i++)
+        ev_data->cb[i] = NULL;
+}
+
+/* lock and unlock routines allow us to execute the event thread without
+ * trashing the lua state on error, yield, or sleep in the callback functions */
+
+static inline void rev_lock_mtx(void)
+{
+    rb->mutex_lock(&rev_mtx);
+}
+
+static inline void rev_unlock_mtx(void)
+{
+    rb->mutex_unlock(&rev_mtx);
+}
+
+static void lua_interrupt_callback( lua_State *L, lua_Debug *ar)
+{
+    (void) L;
+    (void) ar;
+#ifdef DEBUG_EV
+    dbg_hook_calls++;
+#endif
+
+    rb->yield();
+
+    rev_lock_mtx();
+    rev_unlock_mtx(); /* must wait till event thread is done to continue */
+
+#ifdef DEBUG_EV
+    rb->splashf(0, "spin %d, hooked %d", dbg_hook_calls, (lua_gethookmask(L) != 0));
+    unsigned char delay = -1;
+    /* we can't sleep or yield without affecting count so lets spin in a loop */
+    while(delay > 0) {delay--;}
+    if (lua_gethookmask(L) == 0)
+        dbg_hook_calls = 0;
+#endif
+
+    /* if callback error, pass error to the main lua state */
+    if (lua_status(ev_data.NEWL) != LUA_SUCCESS)
+        luaL_error (L, lua_tostring (ev_data.NEWL, -1));
+}
+
+static void lua_interrupt_set(lua_State *L, bool is_enabled)
+{
+    const int hookmask = LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT;
+
+    if (is_enabled)
+        lua_sethook(L, lua_interrupt_callback, hookmask, 1 );
+    else
+        lua_sethook(L, NULL, 0, 0 );
+}
+
+static int lua_rev_callback(lua_State *L, struct cb_data *cbd)
+{
+    int lua_status = LUA_ERRRUN;
+
+    if (L != NULL)
+    {
+        /* load cb function from lua registry */
+        lua_rawgeti(L, LUA_REGISTRYINDEX, cbd->cb_ref);
+
+        lua_pushinteger(L, cbd->id);
+        lua_pushlightuserdata (L, cbd->data);
+
+        lua_status = lua_resume(L, 2);
+        if (lua_status == LUA_YIELD) /* coroutine.yield() disallowed */
+            luaL_where(L, 0); /* push error string on stack */
+    }
+    return lua_status;
+}
+
+static void event_thread(void)
+{
+    unsigned long action;
+    int event;
+    int ev_flag;
+
+    while(ev_data.thread_state != THREAD_QUIT && lua_status(ev_data.L) == LUA_SUCCESS)
+    {
+        rev_lock_mtx();
+        lua_interrupt_set(ev_data.L, true);
+
+        for (event = 0; event < EVENT_CT; event++)
+        {
+            ev_flag = thread_ev_states[event];
+            if (!has_event(ev_flag) || is_suspend(ev_flag))
+                continue; /* check next event */
+
+            ev_data.thread_state &= ~(ev_flag); /* event handled */
+
+            switch (event)
+            {
+                case ACTEVENT:
+                    action = get_plugin_action(TIMEOUT_NOBLOCK, true);
+                    if (action == ACTION_UNKNOWN)
+                        continue; /* check next event */
+                    else if (action == ACTION_NONE)
+                    {
+                        /* only send ACTION_NONE once */
+                        if (ev_data.cb[ACTEVENT]->id == ACTION_NONE ||
+                            rb->button_status() != 0)
+                            continue; /* check next event */
+                    }
+                    ev_data.cb[ACTEVENT]->id = action;
+                    break;
+                case BUTEVENT:
+                    ev_data.cb[BUTEVENT]->id = rb->button_get(false);
+                    if (ev_data.cb[BUTEVENT]->id == 0)
+                        continue; /* check next event */
+                    break;
+                case CUSTOMEVENT:
+                    ev_data.thread_state |= thread_ev_states[CUSTOMEVENT]; // don't reset */
+                    break;
+                case PLAYBKEVENT:
+                    break;
+                case TIMEREVENT:
+                    ev_data.cb[TIMEREVENT]->id = *rb->current_tick + ev_data.timer_ticks;
+                    break;
+
+            }
+
+            if (lua_rev_callback(ev_data.NEWL, ev_data.cb[event]) != LUA_SUCCESS)
+            {
+                rev_unlock_mtx();
+                goto event_error;
+            }
+        }
+        rev_unlock_mtx(); /* we are safe to release back to main lua state */
+
+        do
+        {
+#ifdef DEBUG_EV
+            dbg_hook_calls--;
+#endif
+            lua_interrupt_set(ev_data.L, false);
+            ev_data.next_event = EV_TICKS;
+            rb->yield();
+        } while(ev_data.thread_state == THREAD_YIELD || is_suspend(THREAD_SUSPENDMASK));
+
+    }
+
+event_error:
+
+    /* thread is exiting -- clean up */
+    rb->timer_unregister();
+    rb->yield();
+    rb->thread_exit();
+
+    return;
+}
+
+/* timer interrupt callback */
+static void rev_timer_isr(void)
+{
+    ev_data.next_event--;
+    ev_data.next_input--;
+
+    if (ev_data.next_input <=0)
+    {
+        ev_data.thread_state |= ((ev_data.thread_state & THREAD_INPUTMASK) >> 16);
+        ev_data.next_input = EV_INPUT;
+    }
+
+    if (ev_data.cb[TIMEREVENT] != NULL && !is_suspend(TIMEREVENT))
+    {
+        if (TIME_AFTER(*rb->current_tick, ev_data.cb[TIMEREVENT]->id))
+        {
+            ev_data.thread_state |= thread_ev_states[TIMEREVENT];
+            ev_data.next_event = 0;
+        }
+    }
+
+    if (ev_data.next_event <= 0)
+        lua_interrupt_set(ev_data.L, true);
+}
+
+static void create_event_thread_ref(struct event_data *ev_data)
+{
+    lua_State *L = ev_data->L;
+
+    lua_createtable(L, 2, 0);
+
+    ev_data->event_stack = (long *) lua_newuserdata (L, DEFAULT_STACK_SIZE);
+
+    /* attach EVENT_METATABLE to ud so we get notified on garbage collection */
+    luaL_getmetatable (L, EVENT_METATABLE);
+    lua_setmetatable (L, -2);
+    lua_rawseti(L, -2, 1);
+
+    ev_data->NEWL = lua_newthread(L);
+    lua_rawseti(L, -2, 2);
+
+    lua_setfield (L, LUA_REGISTRYINDEX, EVENT_THREAD); /* store references */
+}
+
+static void destroy_event_thread_ref(struct event_data *ev_data)
+{
+    lua_State *L = ev_data->L;
+    ev_data->event_stack = NULL;
+    ev_data->NEWL = NULL;
+    lua_pushnil(L);
+    lua_setfield (L, LUA_REGISTRYINDEX, EVENT_THREAD); /* free references */
+}
+
+static void exit_event_thread(struct event_data *ev_data)
+{
+    ev_data->thread_state = THREAD_QUIT;
+    rb->thread_wait(ev_data->thread_id); /* wait for thread to exit */
+
+    ev_data->thread_state = THREAD_YIELD;
+    ev_data->thread_id = UINT_MAX;
+}
+
+static void init_event_thread(bool init, struct event_data *ev_data)
+{
+    if (ev_data->event_stack != NULL) /* make sure we don't double free */
+    {
+        if (!init && ev_data->thread_id != UINT_MAX)
+        {
+            exit_event_thread(ev_data);
+            destroy_event_thread_ref(ev_data);
+            lua_interrupt_set(ev_data->L, false);
+        }
+        return;
+    }
+    else if (!init)
+        return;
+
+    create_event_thread_ref(ev_data);
+    if (ev_data->NEWL == NULL || ev_data->event_stack == NULL)
+        return;
+
+    ev_data->thread_id = rb->create_thread(&event_thread,
+                                           ev_data->event_stack,
+                                           DEFAULT_STACK_SIZE,
+                                           0,
+                                           EVENT_THREAD
+                                           IF_PRIO(, PRIORITY_SYSTEM)
+                                           IF_COP(, COP));
+
+    /* Timer is used to poll waiting events */
+    rb->timer_register(0, NULL, EV_TIMER_FREQ, rev_timer_isr IF_COP(, CPU));
+}
+
+static void playback_event_callback(unsigned short id, void *data)
+{
+    /* playback events are synchronous we need to return ASAP so set a flag */
+    ev_data.thread_state |= thread_ev_states[PLAYBKEVENT];
+    ev_data.cb[PLAYBKEVENT]->id = id;
+    ev_data.cb[PLAYBKEVENT]->data = data;
+    lua_interrupt_set(ev_data.L, true);
+}
+
+static void register_playbk_events(int flag_events,
+                           void (*handler)(unsigned short id, void *data))
+{
+    long unsigned int i = 0;
+    const unsigned short playback_events[7] =
+    {                                         /*flags*/
+        PLAYBACK_EVENT_START_PLAYBACK,        /* 0x1 */
+        PLAYBACK_EVENT_TRACK_BUFFER,          /* 0x2 */
+        PLAYBACK_EVENT_CUR_TRACK_READY,       /* 0x4 */
+        PLAYBACK_EVENT_TRACK_FINISH,          /* 0x8 */
+        PLAYBACK_EVENT_TRACK_CHANGE,          /* 0x10*/
+        PLAYBACK_EVENT_TRACK_SKIP,            /* 0x20*/
+        PLAYBACK_EVENT_NEXTTRACKID3_AVAILABLE /* 0x40*/
+    };
+
+    for(; i < ARRAYLEN(playback_events); i++, flag_events >>= 1)
+    {
+        if (flag_events == 0) /* remove events */
+            rb->remove_event(playback_events[i], handler);
+        else /* add events */
+            if ((flag_events & 0x1) == 0x1)
+                rb->add_event(playback_events[i], handler);
+    }
+}
+
+static void destroy_event_userdata(lua_State *L, int event)
+{
+    if (ev_data.cb[event] != NULL)
+    {
+        int ev_flag = thread_ev_states[event];
+        ev_data.thread_state &=  ~(ev_flag | (ev_flag << 8) | (ev_flag << 16));
+
+        luaL_unref (L, LUA_REGISTRYINDEX, ev_data.cb[event]->cb_ref);
+        ev_data.cb[event] = NULL;
+    }
+}
+
+static void create_event_userdata(lua_State *L, int event, int index)
+{
+    /* if function is already registered , unregister it */
+    destroy_event_userdata(L, event);
+
+    if (!lua_isfunction (L, index))
+    {
+        init_event_thread(false, &ev_data);
+        luaL_typerror (L, index, "function");
+        return;
+    }
+
+    lua_pushvalue (L, index); /* copy passed lua function on top of stack */
+    int ref_lua = luaL_ref(L, LUA_REGISTRYINDEX);
+
+    ev_data.cb[event] = (struct cb_data *)lua_newuserdata(L, sizeof(struct cb_data));
+
+    ev_data.cb[event]->cb_ref = ref_lua; /* store ref for later call/release */
+
+    /* attach EVENT_METATABLE to ud so we get notified on garbage collection */
+    luaL_getmetatable (L, EVENT_METATABLE);
+    lua_setmetatable (L, -2);
+    /* cb_data is on top of stack */
+}
+
+static int rockev_gc(lua_State *L) {
+    bool has_events = false;
+    void *d = (void *) lua_touserdata (L, 1);
+
+    if (d == NULL)
+        return 0;
+    else if (d == ev_data.event_stack) /* thread stack is gc'd kill thread */
+        init_event_thread(false, &ev_data);
+    else if (d == ev_data.cb[PLAYBKEVENT])
+        register_playbk_events(0, &playback_event_callback);
+
+    for( int i= 0; i < EVENT_CT; i++)
+    {
+        if (d == ev_data.cb[i])
+            destroy_event_userdata(L, i);
+        else if (ev_data.cb[i] != NULL)
+            has_events = true;
+    }
+
+    if (!has_events) /* nothing to wait for kill thread */
+        init_event_thread(false, &ev_data);
+
+  return 0;
+}
+
+/******************************************************************************
+ * LUA INTERFACE **************************************************************
+*******************************************************************************
+*/
+
+static int rockev_register(lua_State *L)
+{
+    int event = luaL_checkoption(L, 1, NULL, ev_map);
+    int ev_flag = thread_ev_states[event];
+    int playbk_events;
+
+    lua_settop (L, 3); /* we need to lock our optional args before...*/
+    create_event_userdata(L, event, 2);/* cb_data is on top of stack */
+
+    switch (event)
+    {
+        case ACTEVENT:
+            /* fall through */
+        case BUTEVENT:
+            ev_data.thread_state |= (ev_flag | (ev_flag << 16));
+            break;
+        case CUSTOMEVENT:
+            break;
+        case PLAYBKEVENT:
+            /* see register_playbk_events() for flags */
+            playbk_events = luaL_optinteger(L, 3, 0x3F);
+            register_playbk_events(playbk_events, &playback_event_callback);
+            break;
+        case TIMEREVENT:
+            ev_data.timer_ticks = luaL_checkinteger(L, 3);
+            ev_data.cb[TIMEREVENT]->id = *rb->current_tick + ev_data.timer_ticks;
+            break;
+    }
+
+    init_event_thread(true, &ev_data);
+
+    return 1; /* returns cb_data */
+}
+
+static int rockev_suspend(lua_State *L)
+{
+    int event; /*Arg 1 is event pass nil to suspend all */
+    bool suspend = luaL_optboolean(L, 2, true);
+    int ev_flag = THREAD_SUSPENDMASK;
+
+    if (!lua_isnoneornil(L, 1))
+    {
+        event = luaL_checkoption(L, 1, NULL, ev_map);
+        ev_flag = thread_ev_states[event] << 8;
+    }
+
+    if (suspend)
+        ev_data.thread_state |= ev_flag;
+    else
+        ev_data.thread_state &= ~(ev_flag);
+
+    return 0;
+}
+
+static int rockev_trigger(lua_State *L)
+{
+    int event = luaL_checkoption(L, 1, NULL, ev_map);
+    bool enable = luaL_optboolean(L, 2, true);
+
+    int ev_flag;
+
+    /* protect from invalid events */
+    if (ev_data.cb[event] != NULL)
+    {
+        ev_flag = thread_ev_states[event];
+        /* allow user to pass an id to some of the callback functions */
+        ev_data.cb[event]->id = luaL_optinteger(L, 3, ev_data.cb[event]->id);
+
+        if (enable)
+            ev_data.thread_state |= ev_flag;
+        else
+            ev_data.thread_state &= ~(ev_flag);
+    }
+    return 0;
+}
+
+static int rockev_unregister(lua_State *L)
+{
+    luaL_checkudata (L, 1, EVENT_METATABLE);
+    rockev_gc(L);
+    lua_pushnil(L);
+    return 1;
+}
+/*
+** Creates events metatable.
+*/
+static int event_create_meta (lua_State *L) {
+    luaL_newmetatable (L, EVENT_METATABLE);
+    /* set __gc field so we can clean-up our objects */
+    lua_pushcfunction (L, rockev_gc);
+    lua_setfield (L, -2, "__gc");
+    return 1;
+}
+
+static const struct luaL_reg evlib[] = {
+    {"register",  rockev_register},
+    {"suspend", rockev_suspend},
+    {"trigger",    rockev_trigger},
+    {"unregister", rockev_unregister},
+    {NULL, NULL}
+};
+
+int luaopen_rockevents (lua_State *L) {
+    rb->mutex_init(&rev_mtx);
+    init_event_data(L, &ev_data);
+    event_create_meta (L);
+    luaL_register (L, LUA_ROCKEVENTSNAME, evlib);
+    return 1;
+}

apps/plugins/lua/rocklib_events.h

···
+#define LUA_ROCKEVENTSNAME "rockev"
+int luaopen_rockevents (lua_State *L);
+
+/* in rockaux.c */
+int get_plugin_action(int timeout, bool with_remote);

apps/plugins/lua/rocklua.c

···
 #include "rocklib.h"
 #include "rocklib_img.h"
 #include "luadir.h"
-
+#include "rocklib_events.h"
 
 
 static const luaL_Reg lualibs[] = {
···
   {LUA_OSLIBNAME,   luaopen_os},
   {LUA_ROCKLIBNAME, luaopen_rock},
   {LUA_ROCKLIBNAME, luaopen_rock_img},
+  {LUA_ROCKEVENTSNAME, luaopen_rockevents},
   {LUA_DIRLIBNAME,  luaopen_luadir},
   {NULL, NULL}
 };