1 files changed, 632 insertions, 0 deletions

diff --git a/apps/plugins/lua/rocklib_events.c b/apps/plugins/lua/rocklib_events.c
new file mode 100644
index 0000000000..9e363edbdd
--- /dev/null
+++ b/apps/plugins/lua/rocklib_events.c
@@ -0,0 +1,632 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   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;
+}