diff options
Diffstat (limited to 'backends/lua.c')
-rw-r--r-- | backends/lua.c | 510 |
1 files changed, 510 insertions, 0 deletions
diff --git a/backends/lua.c b/backends/lua.c new file mode 100644 index 0000000..40e6613 --- /dev/null +++ b/backends/lua.c @@ -0,0 +1,510 @@ +#include "lua.h" + +#include <string.h> +#include <unistd.h> +#include <errno.h> +#ifdef MMBACKEND_LUA_TIMERFD +#include <sys/timerfd.h> +#endif + +#define BACKEND_NAME "lua" +#define LUA_REGISTRY_KEY "_midimonster_lua_instance" + +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)){ + fprintf(stderr, "Failed to register lua backend\n"); + return 1; + } + + #ifdef MMBACKEND_LUA_TIMERFD + //create the timer to expire intervals + timer_fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK); + if(timer_fd < 0){ + fprintf(stderr, "Failed to create timer for Lua backend\n"); + 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){ + fprintf(stderr, "Lua output function called with %d arguments, expected 2 (string, number)\n", 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; + } + } + + fprintf(stderr, "Tried to set unknown channel %s.%s\n", 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){ + fprintf(stderr, "Lua output function called with %d arguments, expected 2 (string, number)\n", 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); + } + 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); + } + + //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){ + fprintf(stderr, "Failed to allocate memory\n"); + 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){ + fprintf(stderr, "Lua get_value function called with %d arguments, expected 1 (string)\n", 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(data->interpreter, (input) ? data->input[n] : data->output[n]); + return 1; + } + } + + fprintf(stderr, "Tried to get unknown channel %s.%s\n", 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_configure(char* option, char* value){ + fprintf(stderr, "The lua backend does not take any global configuration\n"); + 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)){ + fprintf(stderr, "Failed to load lua source file %s for instance %s: %s\n", value, inst->name, lua_tostring(data->interpreter, -1)); + return 1; + } + return 0; + } + + fprintf(stderr, "Unknown configuration parameter %s for lua instance %s\n", option, inst->name); + return 1; +} + +static instance* lua_instance(){ + instance* inst = mm_instance(); + if(!inst){ + return NULL; + } + + lua_instance_data* data = calloc(1, sizeof(lua_instance_data)); + if(!data){ + fprintf(stderr, "Failed to allocate memory\n"); + return NULL; + } + + //load the interpreter + data->interpreter = luaL_newstate(); + if(!data->interpreter){ + fprintf(stderr, "Failed to initialize LUA\n"); + free(data); + return NULL; + } + 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); + + //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 inst; +} + +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){ + fprintf(stderr, "Failed to allocate memory\n"); + 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]){ + fprintf(stderr, "Failed to allocate memory\n"); + 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){ + 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){ + fprintf(stderr, "Failed to call handler for %s.%s: %s\n", inst->name, data->channel_name[c[n]->ident], lua_tostring(data->interpreter, -1)); + lua_pop(data->interpreter, 1); + } + } + } + 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){ + fprintf(stderr, "Failed to read from Lua timer: %s\n", strerror(errno)); + return 1; + } + #else + if(!last_timestamp){ + last_timestamp = mm_timestamp(); + } + 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); + } + } + } + return 0; +} + +static int lua_start(){ + size_t n, u, p; + instance** inst = NULL; + lua_instance_data* data = NULL; + + //fetch all defined instances + if(mm_backend_instances(BACKEND_NAME, &n, &inst)){ + fprintf(stderr, "Failed to fetch instance list\n"); + return 1; + } + + //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], "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; + } + } + } + } + + free(inst); + + #ifdef MMBACKEND_LUA_TIMERFD + //register the timer with the core + fprintf(stderr, "Lua backend registering 1 descriptor to core\n"); + if(mm_manage_fd(timer_fd, BACKEND_NAME, 1, NULL)){ + return 1; + } + #endif + return 0; +} + +static int lua_shutdown(){ + size_t n, u, p; + instance** inst = NULL; + lua_instance_data* data = NULL; + + //fetch all instances + if(mm_backend_instances(BACKEND_NAME, &n, &inst)){ + fprintf(stderr, "Failed to fetch instance list\n"); + return 1; + } + + 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(inst); + //free module-global data + free(timer); + timer = NULL; + timers = 0; + #ifdef MMBACKEND_LUA_TIMERFD + close(timer_fd); + timer_fd = -1; + #endif + + fprintf(stderr, "Lua backend shut down\n"); + return 0; +} |