aboutsummaryrefslogtreecommitdiffhomepage
path: root/backends/lua.c
blob: 9a8091e4329d77062ca953959acb4dfc810c5cb3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
#define BACKEND_NAME "lua"

#include "lua.h"
#include <string.h>
#include <unistd.h>
#include <errno.h>
#ifdef MMBACKEND_LUA_TIMERFD
#include <sys/timerfd.h>
#endif

#define LUA_REGISTRY_KEY "_midimonster_lua_instance"
#define LUA_REGISTRY_CURRENT_CHANNEL "_midimonster_lua_channel"

static size_t timers = 0;
static lua_timer* timer = NULL;
uint64_t timer_interval = 0;
#ifdef MMBACKEND_LUA_TIMERFD
static int timer_fd = -1;
#else
static uint64_t last_timestamp;
#endif

MM_PLUGIN_API int init(){
	backend lua = {
		#ifndef MMBACKEND_LUA_TIMERFD
		.interval = lua_interval,
		#endif
		.name = BACKEND_NAME,
		.conf = lua_configure,
		.create = lua_instance,
		.conf_instance = lua_configure_instance,
		.channel = lua_channel,
		.handle = lua_set,
		.process = lua_handle,
		.start = lua_start,
		.shutdown = lua_shutdown
	};

	//register backend
	if(mm_backend_register(lua)){
		LOG("Failed to register backend");
		return 1;
	}

	#ifdef MMBACKEND_LUA_TIMERFD
	//create the timer to expire intervals
	timer_fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
	if(timer_fd < 0){
		LOG("Failed to create timer");
		return 1;
	}
	#endif
	return 0;
}

#ifndef MMBACKEND_LUA_TIMERFD
static uint32_t lua_interval(){
	size_t n = 0;
	uint64_t next_timer = 1000;

	if(timer_interval){
		for(n = 0; n < timers; n++){
			if(timer[n].interval && timer[n].interval - timer[n].delta < next_timer){
				next_timer = timer[n].interval - timer[n].delta;
			}
		}
		return next_timer;
	}
	return 1000;
}
#endif

static int lua_update_timerfd(){
	uint64_t interval = 0, gcd, residual;
	size_t n = 0;
	#ifdef MMBACKEND_LUA_TIMERFD
	struct itimerspec timer_config = {
		{0}
	};
	#endif

	//find the minimum for the lower interval bounds
	for(n = 0; n < timers; n++){
		if(timer[n].interval && (!interval || timer[n].interval < interval)){
			interval = timer[n].interval;
		}
	}

	//calculate gcd of all timers if any are active
	if(interval){
		for(n = 0; n < timers; n++){
			if(timer[n].interval){
				//calculate gcd of current interval and this timers interval
				gcd = timer[n].interval;
				while(gcd){
					residual = interval % gcd;
					interval = gcd;
					gcd = residual;
				}
				//since we round everything, 10 is the lowest interval we get
				if(interval == 10){
					break;
				}
			}
		}

		#ifdef MMBACKEND_LUA_TIMERFD
		timer_config.it_interval.tv_sec = timer_config.it_value.tv_sec = interval / 1000;
		timer_config.it_interval.tv_nsec = timer_config.it_value.tv_nsec = (interval % 1000) * 1e6;
		#endif
	}

	if(interval == timer_interval){
		return 0;
	}

	#ifdef MMBACKEND_LUA_TIMERFD
	//configure the new interval
	timerfd_settime(timer_fd, 0, &timer_config, NULL);
	#endif
	timer_interval = interval;
	return 0;
}

static int lua_callback_output(lua_State* interpreter){
	size_t n = 0;
	channel_value val;
	const char* channel_name = NULL;
	channel* channel = NULL;
	instance* inst = NULL;
	lua_instance_data* data = NULL;

	if(lua_gettop(interpreter) != 2){
		LOGPF("Output function called with %d arguments, expected 2 (string, number)", lua_gettop(interpreter));
		return 0;
	}

	//get instance pointer from registry
	lua_pushstring(interpreter, LUA_REGISTRY_KEY);
	lua_gettable(interpreter, LUA_REGISTRYINDEX);
	inst = (instance*) lua_touserdata(interpreter, -1);
	data = (lua_instance_data*) inst->impl;

	//fetch function parameters
	channel_name = lua_tostring(interpreter, 1);
	val.normalised = clamp(luaL_checknumber(interpreter, 2), 1.0, 0.0);

	//find correct channel & output value
	for(n = 0; n < data->channels; n++){
		if(!strcmp(channel_name, data->channel_name[n])){
			channel = mm_channel(inst, n, 0);
			if(!channel){
				return 0;
			}
			mm_channel_event(channel, val);
			data->output[n] = val.normalised;
			return 0;
		}
	}

	LOGPF("Tried to set unknown channel %s.%s", inst->name, channel_name);
	return 0;
}

static int lua_callback_interval(lua_State* interpreter){
	size_t n = 0;
	uint64_t interval = 0;
	int reference = LUA_NOREF;

	if(lua_gettop(interpreter) != 2){
		LOGPF("Interval function called with %d arguments, expected 2 (function, number)", lua_gettop(interpreter));
		return 0;
	}

	//get instance pointer from registry
	lua_pushstring(interpreter, LUA_REGISTRY_KEY);
	lua_gettable(interpreter, LUA_REGISTRYINDEX);

	//fetch and round the interval
	interval = luaL_checkinteger(interpreter, 2);
	if(interval % 10 < 5){
		interval -= interval % 10;
	}
	else{
		interval += (10 - (interval % 10));
	}

	//push the function again
	lua_pushvalue(interpreter, 1);
	if(lua_gettable(interpreter, LUA_REGISTRYINDEX) == LUA_TNUMBER){
		//already interval'd
		reference = luaL_checkinteger(interpreter, 4);
		DBGPF("Updating interval to %" PRIu64 " msec", interval);
	}
	else if(interval){
		//get a reference to the function
		lua_pushvalue(interpreter, 1);
		reference = luaL_ref(interpreter, LUA_REGISTRYINDEX);

		//the function indexes the reference
		lua_pushvalue(interpreter, 1);
		lua_pushinteger(interpreter, reference);
		lua_settable(interpreter, LUA_REGISTRYINDEX);

		DBGPF("Registered interval with %" PRIu64 " msec", interval);
	}

	//find matching timer
	for(n = 0; n < timers; n++){
		if(timer[n].reference == reference && timer[n].interpreter == interpreter){
			break;
		}
	}

	if(n < timers){
		//set new interval
		timer[n].interval = interval;
		timer[n].delta = 0;
	}
	else if(interval){
		//append new timer
		timer = realloc(timer, (timers + 1) * sizeof(lua_timer));
		if(!timer){
			LOG("Failed to allocate memory");
			timers = 0;
			return 0;
		}
		timer[timers].interval = interval;
		timer[timers].delta = 0;
		timer[timers].interpreter = interpreter;
		timer[timers].reference = reference;
		timers++;
	}

	//recalculate timerspec
	lua_update_timerfd();
	return 0;
}

static int lua_callback_value(lua_State* interpreter, uint8_t input){
	size_t n = 0;
	instance* inst = NULL;
	lua_instance_data* data = NULL;
	const char* channel_name = NULL;

	if(lua_gettop(interpreter) != 1){
		LOGPF("get_value function called with %d arguments, expected 1 (string)", lua_gettop(interpreter));
		return 0;
	}

	//get instance pointer from registry
	lua_pushstring(interpreter, LUA_REGISTRY_KEY);
	lua_gettable(interpreter, LUA_REGISTRYINDEX);
	inst = (instance*) lua_touserdata(interpreter, -1);
	data = (lua_instance_data*) inst->impl;

	//fetch argument
	channel_name = lua_tostring(interpreter, 1);

	//find correct channel & return value
	for(n = 0; n < data->channels; n++){
		if(!strcmp(channel_name, data->channel_name[n])){
			lua_pushnumber(interpreter, (input) ? data->input[n] : data->output[n]);
			return 1;
		}
	}

	LOGPF("Tried to get unknown channel %s.%s", inst->name, channel_name);
	return 0;
}

static int lua_callback_input_value(lua_State* interpreter){
	return lua_callback_value(interpreter, 1);
}

static int lua_callback_output_value(lua_State* interpreter){
	return lua_callback_value(interpreter, 0);
}

static int lua_callback_input_channel(lua_State* interpreter){
	lua_pushstring(interpreter, LUA_REGISTRY_CURRENT_CHANNEL);
	lua_gettable(interpreter, LUA_REGISTRYINDEX);
	return 1;
}

static int lua_callback_timestamp(lua_State* interpreter){
	lua_pushnumber(interpreter, mm_timestamp());
	return 1;
}

static int lua_configure(char* option, char* value){
	LOG("No backend configuration possible");
	return 1;
}

static int lua_configure_instance(instance* inst, char* option, char* value){
	lua_instance_data* data = (lua_instance_data*) inst->impl;

	//load a lua file into the interpreter
	if(!strcmp(option, "script") || !strcmp(option, "source")){
		if(luaL_dofile(data->interpreter, value)){
			LOGPF("Failed to load source file %s for instance %s: %s", value, inst->name, lua_tostring(data->interpreter, -1));
			return 1;
		}
		return 0;
	}

	LOGPF("Unknown instance configuration parameter %s for instance %s", option, inst->name);
	return 1;
}

static int lua_instance(instance* inst){
	lua_instance_data* data = calloc(1, sizeof(lua_instance_data));
	if(!data){
		LOG("Failed to allocate memory");
		return 1;
	}

	//load the interpreter
	data->interpreter = luaL_newstate();
	if(!data->interpreter){
		LOG("Failed to initialize interpreter");
		free(data);
		return 1;
	}
	luaL_openlibs(data->interpreter);

	//register lua interface functions
	lua_register(data->interpreter, "output", lua_callback_output);
	lua_register(data->interpreter, "interval", lua_callback_interval);
	lua_register(data->interpreter, "input_value", lua_callback_input_value);
	lua_register(data->interpreter, "output_value", lua_callback_output_value);
	lua_register(data->interpreter, "input_channel", lua_callback_input_channel);
	lua_register(data->interpreter, "timestamp", lua_callback_timestamp);

	//store instance pointer to the lua state
	lua_pushstring(data->interpreter, LUA_REGISTRY_KEY);
	lua_pushlightuserdata(data->interpreter, (void *) inst);
	lua_settable(data->interpreter, LUA_REGISTRYINDEX);

	inst->impl = data;
	return 0;
}

static channel* lua_channel(instance* inst, char* spec, uint8_t flags){
	size_t u;
	lua_instance_data* data = (lua_instance_data*) inst->impl;

	//find matching channel
	for(u = 0; u < data->channels; u++){
		if(!strcmp(spec, data->channel_name[u])){
			break;
		}
	}

	//allocate new channel
	if(u == data->channels){
		data->channel_name = realloc(data->channel_name, (u + 1) * sizeof(char*));
		data->reference = realloc(data->reference, (u + 1) * sizeof(int));
		data->input = realloc(data->input, (u + 1) * sizeof(double));
		data->output = realloc(data->output, (u + 1) * sizeof(double));
		if(!data->channel_name || !data->reference || !data->input || !data->output){
			LOG("Failed to allocate memory");
			return NULL;
		}

		data->reference[u] = LUA_NOREF;
		data->input[u] = data->output[u] = 0.0;
		data->channel_name[u] = strdup(spec);
		if(!data->channel_name[u]){
			LOG("Failed to allocate memory");
			return NULL;
		}
		data->channels++;
	}

	return mm_channel(inst, u, 1);
}

static int lua_set(instance* inst, size_t num, channel** c, channel_value* v){
	size_t n = 0;
	lua_instance_data* data = (lua_instance_data*) inst->impl;

	//handle all incoming events
	for(n = 0; n < num; n++){
		data->input[c[n]->ident] = v[n].normalised;
		//call lua channel handlers if present
		if(data->reference[c[n]->ident] != LUA_NOREF){
			//push the channel name
			lua_pushstring(data->interpreter, LUA_REGISTRY_CURRENT_CHANNEL);
			lua_pushstring(data->interpreter, data->channel_name[c[n]->ident]);
			lua_settable(data->interpreter, LUA_REGISTRYINDEX);

			lua_rawgeti(data->interpreter, LUA_REGISTRYINDEX, data->reference[c[n]->ident]);
			lua_pushnumber(data->interpreter, v[n].normalised);
			if(lua_pcall(data->interpreter, 1, 0, 0) != LUA_OK){
				LOGPF("Failed to call handler for %s.%s: %s", inst->name, data->channel_name[c[n]->ident], lua_tostring(data->interpreter, -1));
				lua_pop(data->interpreter, 1);
			}
		}
	}

	//clear the channel name
	lua_pushstring(data->interpreter, LUA_REGISTRY_CURRENT_CHANNEL);
	lua_pushnil(data->interpreter);
	lua_settable(data->interpreter, LUA_REGISTRYINDEX);
	return 0;
}

static int lua_handle(size_t num, managed_fd* fds){
	uint64_t delta = timer_interval;
	size_t n;

	#ifdef MMBACKEND_LUA_TIMERFD
	uint8_t read_buffer[100];
	if(!num){
		return 0;
	}

	//read the timer iteration to acknowledge the fd
	if(read(timer_fd, read_buffer, sizeof(read_buffer)) < 0){
		LOGPF("Failed to read timer: %s", strerror(errno));
		return 1;
	}
	#else
	delta = mm_timestamp() - last_timestamp;
	last_timestamp = mm_timestamp();
	#endif

	//no timers active
	if(!timer_interval){
		return 0;
	}

	//add delta to all active timers
	for(n = 0; n < timers; n++){
		if(timer[n].interval){
			timer[n].delta += delta;
			//call lua function if timer expired
			if(timer[n].delta >= timer[n].interval){
				timer[n].delta %= timer[n].interval;
				lua_rawgeti(timer[n].interpreter, LUA_REGISTRYINDEX, timer[n].reference);
				lua_pcall(timer[n].interpreter, 0, 0, 0);
				DBGPF("Calling interval timer function %" PRIsize_t, n);
			}
		}
	}
	return 0;
}

static int lua_start(size_t n, instance** inst){
	size_t u, p;
	lua_instance_data* data = NULL;

	//resolve channels to their handler functions
	for(u = 0; u < n; u++){
		data = (lua_instance_data*) inst[u]->impl;
		for(p = 0; p < data->channels; p++){
			//exclude reserved names
			if(strcmp(data->channel_name[p], "output")
					&& strcmp(data->channel_name[p], "input_value")
					&& strcmp(data->channel_name[p], "output_value")
					&& strcmp(data->channel_name[p], "input_channel")
					&& strcmp(data->channel_name[p], "timestamp")
					&& strcmp(data->channel_name[p], "interval")){
				lua_getglobal(data->interpreter, data->channel_name[p]);
				data->reference[p] = luaL_ref(data->interpreter, LUA_REGISTRYINDEX);
				if(data->reference[p] == LUA_REFNIL){
					data->reference[p] = LUA_NOREF;
				}
			}
		}
	}

	#ifdef MMBACKEND_LUA_TIMERFD
	//register the timer with the core
	LOG("Registering 1 descriptor to core");
	if(mm_manage_fd(timer_fd, BACKEND_NAME, 1, NULL)){
		return 1;
	}
	#else
	last_timestamp = mm_timestamp();
	#endif
	return 0;
}

static int lua_shutdown(size_t n, instance** inst){
	size_t u, p;
	lua_instance_data* data = NULL;

	for(u = 0; u < n; u++){
		data = (lua_instance_data*) inst[u]->impl;
		//stop the interpreter
		lua_close(data->interpreter);
		//cleanup channel data
		for(p = 0; p < data->channels; p++){
			free(data->channel_name[p]);
		}
		free(data->channel_name);
		free(data->reference);
		free(data->input);
		free(data->output);
		free(inst[u]->impl);
	}

	//free module-global data
	free(timer);
	timer = NULL;
	timers = 0;
	#ifdef MMBACKEND_LUA_TIMERFD
	close(timer_fd);
	timer_fd = -1;
	#endif

	LOG("Backend shut down");
	return 0;
}