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rockbox/apps/plugins/lua/rocklib_events.c
Aidan MacDonald e8e781b006 lua: rocklib_events fix 
Do not spawn threads on COP as PP lacks cache coherency between cores,
making it unsafe to access cacheable memory that might be accessed by
the other core.

Change-Id: Idf910e9cc9dad3f0bf5bdb63800ed4abaa97558a
2023-01-02 13:38:08 -05:00

686 lines
20 KiB
C
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/***************************************************************************
* __________ __ ___.
* 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 suspends all events.
* stops event from executing, any 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 EV_STACKSZ (DEFAULT_STACK_SIZE * 2)
#define LUA_SUCCESS 0
#define EV_TIMER_TICKS 5 /* timer resolution */
#define EV_TIMER_FREQ ((TIMER_FREQ / HZ) * EV_TIMER_TICKS)
#define EV_TICKS (HZ / 5)
#define ENABLE_LUA_HOOK (LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT)
#define DISABLE_LUA_HOOK (0)
enum {
THREAD_ERROR = 0x0,
/* event & suspend states */
THREAD_ACTEVENT = 0x1,
THREAD_BTNEVENT = 0x2,
THREAD_CUSTOMEVENT = 0x4,
THREAD_PLAYBKEVENT = 0x8,
THREAD_TIMEREVENT = 0x10,
//THREAD_AVAILEVENT = 0x20,
//THREAD_AVAILEVENT = 0x40,
//THREAD_AVAILEVENT = 0x80,
THREAD_EVENT_ALL = 0xFF,
/* thread states */
//THREAD_AVAILSTATE = 0x1,
//THREAD_AVAILSTATE = 0x2,
//THREAD_AVAILSTATE = 0x4,
//THREAD_AVAILSTATE = 0x8,
//THREAD_AVAILSTATE = 0x10,
//THREAD_AVAILSTATE = 0x20,
THREAD_QUIT = 0x40,
//THREAD_AVAILSTATE = 0x80,
};
enum {
ACTEVENT = 0,
BTNEVENT,
CUSTOMEVENT,
PLAYBKEVENT,
TIMEREVENT,
EVENT_CT
};
struct cb_data {
int cb_ref;
unsigned long id;
void *data;
long next_tick;
long ticks;
};
struct thread_status {
uint8_t event;
uint8_t suspended;
uint8_t thread;
uint8_t unused;
};
struct event_data {
/* lua */
lua_State *L;
lua_State *NEWL;
/* rockbox */
unsigned int thread_id;
long *event_stack;
volatile long *get_tick;
struct thread_status status;
/* callbacks */
struct cb_data *cb[EVENT_CT];
};
static void set_event_meta(lua_State *L);
static struct event_data ev_data;
static struct mutex rev_mtx SHAREDBSS_ATTR;
static inline uint8_t event_flag(unsigned int event)
{
return (1UL << event) & 0xFF;
}
static inline bool has_thread_status(uint8_t ev_flag)
{
return (ev_data.status.thread & ev_flag) == ev_flag;
}
static inline void set_evt(uint8_t ev_flag)
{
ev_data.status.event |= ev_flag;
}
static inline bool remove_evt(uint8_t ev_flag)
{
/* returns previous flag status and clears it */
bool has_flag = (ev_data.status.event & ev_flag) == ev_flag;
ev_data.status.event &= ~(ev_flag);
return has_flag;
}
static inline bool is_suspend(uint8_t ev_flag)
{
return (ev_data.status.suspended & ev_flag) == ev_flag;
}
static void suspend_evt(uint8_t ev_flag, bool suspend)
{
if(!suspend && !has_thread_status(THREAD_QUIT))
{
ev_data.status.suspended &= ~(ev_flag);
ev_flag = 0;
}
remove_evt(ev_flag);
ev_data.status.suspended |= ev_flag;
}
/* mutex 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) ar;
rb->yield();
rev_lock_mtx();
rev_unlock_mtx(); /* must wait till event thread is done to continue */
/* 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, int hookmask)
{
lua_Hook hook;
int count;
static lua_Hook oldhook = NULL;
static int oldmask = 0;
static int oldcount = 0;
if (hookmask == ENABLE_LUA_HOOK)
{
hook = lua_gethook(L);
if (hook == lua_interrupt_callback)
return; /* our hook is already active */
/* preserve prior hook */
oldhook = hook;
oldmask = lua_gethookmask(L);
oldcount = lua_gethookcount(L);
hook = lua_interrupt_callback;
count = 10;
}
else
{
hook = oldhook;
hookmask = oldmask;
count = oldcount;
}
lua_sethook(L, hook, hookmask, count);
}
static int lua_rev_callback(lua_State *L, struct cb_data *evt)
{
int lua_status = LUA_ERRRUN;
/* load cb function from lua registry */
lua_rawgeti(L, LUA_REGISTRYINDEX, evt->cb_ref);
lua_pushinteger(L, evt->id);
lua_pushlightuserdata(L, evt->data);
lua_status = lua_resume(L, 2); /* call the saved function */
if (lua_status == LUA_SUCCESS)
lua_settop(L, 0); /* eat any value(s) returned */
else if (lua_status == LUA_YIELD) /* coroutine.yield() disallowed */
luaL_where(L, 1); /* push error string on stack */
return lua_status;
}
/* timer interrupt callback */
static void rev_timer_isr(void)
{
uint8_t ev_flag = 0;
long curr_tick = *(ev_data.get_tick);
struct cb_data *evt;
for (unsigned int i= 0; i < EVENT_CT; i++)
{
if (!is_suspend(event_flag(i)))
{
evt = ev_data.cb[i];
if ((i == ACTEVENT || i == BTNEVENT) &&
(rb->button_queue_count() || rb->button_status() || evt->id))
ev_flag |= event_flag(i); /* any buttons ready? */
else if(evt->ticks > 0 && TIME_AFTER(curr_tick, evt->next_tick))
ev_flag |= event_flag(i);
}
}
set_evt(ev_flag);
if (ev_data.status.event) /* any events ready? */
lua_interrupt_set(ev_data.L, ENABLE_LUA_HOOK);
}
static void event_thread(void)
{
unsigned long action;
uint8_t ev_flag;
unsigned int event;
struct cb_data *evt;
while(!has_thread_status(THREAD_QUIT) && lua_status(ev_data.L) == LUA_SUCCESS)
{
rev_lock_mtx();
lua_interrupt_set(ev_data.L, ENABLE_LUA_HOOK);
for (event = 0; event < EVENT_CT; event++)
{
ev_flag = event_flag(event);
if (!remove_evt(ev_flag) || is_suspend(ev_flag))
continue; /* check next event */
evt = ev_data.cb[event];
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 (evt->id == ACTION_NONE || rb->button_status() != 0)
continue; /* check next event */
}
evt->id = action;
break;
case BTNEVENT:
evt->id = rb->button_get(false);
/* only send BUTTON_NONE once */
if (evt->id == BUTTON_NONE)
continue; /* check next event */
break;
case CUSTOMEVENT:
case PLAYBKEVENT:
case TIMEREVENT:
break;
}
if (lua_rev_callback(ev_data.NEWL, evt) != LUA_SUCCESS)
{
rev_unlock_mtx();
goto event_error;
}
evt->next_tick = *(ev_data.get_tick) + evt->ticks;
}
rev_unlock_mtx(); /* we are safe to release back to main lua state */
do
{
lua_interrupt_set(ev_data.L, DISABLE_LUA_HOOK);
rb->yield();
} while (!has_thread_status(THREAD_QUIT) && (is_suspend(THREAD_EVENT_ALL)
|| !ev_data.status.event));
}
rb->yield();
lua_interrupt_set(ev_data.L, DISABLE_LUA_HOOK);
event_error:
/* thread is exiting -- clean up */
rb->timer_unregister();
rb->thread_exit();
return;
}
static inline 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, EV_STACKSZ);
/* attach EVENT_METATABLE to ud so we get notified on garbage collection */
set_event_meta(L);
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 inline 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 inline void exit_event_thread(struct event_data *ev_data)
{
suspend_evt(THREAD_EVENT_ALL, true);
ev_data->status.thread = THREAD_QUIT;
rb->thread_wait(ev_data->thread_id); /* wait for thread to exit */
destroy_event_thread_ref(ev_data);
ev_data->status.thread = 0;
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);
return;
}
else if (!init)
return;
create_event_thread_ref(ev_data);
ev_data->thread_id = rb->create_thread(&event_thread,
ev_data->event_stack,
EV_STACKSZ,
0,
EVENT_THREAD
IF_PRIO(, PRIORITY_SYSTEM)
IF_COP(, CPU));
/* Timer is used to poll waiting events */
if (!rb->timer_register(1, NULL, EV_TIMER_FREQ, rev_timer_isr IF_COP(, CPU)))
{
rb->splash(100, "No timer available!");
}
}
static void playback_event_callback(unsigned short id, void *data)
{
/* playback events are synchronous we need to return ASAP so set a flag */
struct cb_data *evt = ev_data.cb[PLAYBKEVENT];
evt->id = id;
evt->data = data;
if (!is_suspend(THREAD_PLAYBKEVENT))
{
set_evt(THREAD_PLAYBKEVENT);
lua_interrupt_set(ev_data.L, ENABLE_LUA_HOOK);
}
}
static void register_playbk_events(int flag_events)
{
unsigned short i, pb_evt;
static 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 = 0; i < ARRAYLEN(playback_events); i++)
{
pb_evt = playback_events[i];
if (!(flag_events & (1 << i)))
rb->remove_event(pb_evt, playback_event_callback);
else
rb->add_event(pb_evt, playback_event_callback);
}
}
static void destroy_event_userdata(lua_State *L, unsigned int event)
{
uint8_t ev_flag = event_flag(event);
struct cb_data *evt = ev_data.cb[event];
suspend_evt(ev_flag, true);
if (evt != NULL)
luaL_unref(L, LUA_REGISTRYINDEX, evt->cb_ref);
ev_data.cb[event] = NULL;
}
static void create_event_userdata(lua_State *L, unsigned int event, int index)
{
/* if function is already registered , unregister it */
destroy_event_userdata(L, event);
luaL_checktype(L, index, LUA_TFUNCTION);
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 */
set_event_meta(L);
/* 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)
{
for (unsigned int i= 0; i < EVENT_CT; i++)
{
if (d == ev_data.cb[i] || d == ev_data.event_stack)
{
if (i == PLAYBKEVENT)
register_playbk_events(0);
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;
}
static void set_event_meta(lua_State *L)
{
if (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");
}
lua_setmetatable(L, -2);
}
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->get_tick = rb->current_tick;
ev_data->status.event = 0;
ev_data->status.suspended = THREAD_EVENT_ALL;
ev_data->status.thread = 0;
/*ev_data->event_stack = NULL;*/
/* callbacks */
for (unsigned int i= 0; i < EVENT_CT; i++)
ev_data->cb[i] = NULL;
}
/******************************************************************************
* LUA INTERFACE **************************************************************
*******************************************************************************
*/
static unsigned int get_event_by_name(lua_State *L)
{
static const char *const ev_map[EVENT_CT] =
{
[ACTEVENT] = "action",
[BTNEVENT] = "button",
[CUSTOMEVENT] = "custom",
[PLAYBKEVENT] = "playback",
[TIMEREVENT] = "timer",
};
return luaL_checkoption(L, 1, NULL, ev_map);
}
static int rockev_register(lua_State *L)
{
/* register (event, cb [, args] */
unsigned int event = get_event_by_name(L);
uint8_t ev_flag = event_flag(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 */
init_event_thread(!has_thread_status(THREAD_QUIT), &ev_data);
long event_ticks = 0;
struct cb_data *evt;
switch (event)
{
case ACTEVENT:
/* fall through */
case BTNEVENT:
event_ticks = 0; /* button events not triggered by timeout */
break;
case CUSTOMEVENT:
event_ticks = luaL_optinteger(L, 3, EV_TICKS);
ev_flag = 0; /* don't remove suspend */
break;
case PLAYBKEVENT: /* see register_playbk_events() for flags */
event_ticks = 0; /* playback events are not triggered by timeout */
playbk_events = luaL_optinteger(L, 3, 0x3F);
register_playbk_events(playbk_events);
break;
case TIMEREVENT:
event_ticks = luaL_checkinteger(L, 3);
break;
}
evt = ev_data.cb[event];
evt->ticks = event_ticks;
evt->next_tick = *(ev_data.get_tick) + event_ticks;
suspend_evt(ev_flag, false);
return 1; /* returns cb_data */
}
static int rockev_suspend(lua_State *L)
{
unsigned int event; /*Arg 1 is event, pass nil to suspend all */
bool suspend = luaL_optboolean(L, 2, true);
uint8_t ev_flag = THREAD_EVENT_ALL;
if (!lua_isnoneornil(L, 1))
{
event = get_event_by_name(L);
ev_flag = event_flag(event);
}
suspend_evt(ev_flag, suspend);
/* don't resume invalid events */
for (unsigned int i = 0; i < EVENT_CT; i++)
{
if (ev_data.cb[i] == NULL)
suspend_evt(event_flag(i), true);
}
return 0;
}
static int rockev_trigger(lua_State *L)
{
unsigned int event = get_event_by_name(L);
bool enable = luaL_optboolean(L, 2, true);
uint8_t ev_flag = event_flag(event);
struct cb_data *evt = ev_data.cb[event];
/* don't trigger invalid events */
if (evt != NULL)
{
/* allow user to pass an id to some of the callback functions */
evt->id = luaL_optinteger(L, 3, evt->id);
if (event == CUSTOMEVENT)
suspend_evt(ev_flag, !enable);
if (enable)
set_evt(ev_flag);
else
remove_evt(ev_flag);
}
return 0;
}
static int rockev_unregister(lua_State *L)
{
luaL_checkudata(L, 1, EVENT_METATABLE);
rockev_gc(L);
return 0;
}
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);
luaL_register(L, LUA_ROCKEVENTSNAME, evlib);
return 1;
}
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