diff options
Diffstat (limited to 'backends')
| -rw-r--r-- | backends/Makefile | 4 | ||||
| -rw-r--r-- | backends/lua.c | 202 | ||||
| -rw-r--r-- | backends/lua.h | 21 | ||||
| -rw-r--r-- | backends/lua.md | 49 |
4 files changed, 275 insertions, 1 deletions
diff --git a/backends/Makefile b/backends/Makefile index c11de56..fe88669 100644 --- a/backends/Makefile +++ b/backends/Makefile @@ -1,7 +1,7 @@ .PHONY: all clean full OPTIONAL_BACKENDS = ola.so LINUX_BACKENDS = midi.so evdev.so -BACKENDS = artnet.so osc.so loopback.so sacn.so +BACKENDS = artnet.so osc.so loopback.so sacn.so lua.so BACKEND_LIB = libmmbackend.o SYSTEM := $(shell uname -s) @@ -27,6 +27,8 @@ evdev.so: CFLAGS += $(shell pkg-config --cflags libevdev) evdev.so: LDLIBS = $(shell pkg-config --libs libevdev) ola.so: LDLIBS = -lola ola.so: CPPFLAGS += -Wno-write-strings +lua.so: CFLAGS += $(shell pkg-config --cflags lua5.3) +lua.so: LDLIBS += $(shell pkg-config --libs lua5.3) %.so :: %.c %.h $(BACKEND_LIB) $(CC) $(CFLAGS) $(LDLIBS) $< $(ADDITIONAL_OBJS) -o $@ $(LDFLAGS) diff --git a/backends/lua.c b/backends/lua.c new file mode 100644 index 0000000..ae2d460 --- /dev/null +++ b/backends/lua.c @@ -0,0 +1,202 @@ +#include <string.h> +#include "lua.h" + +#define BACKEND_NAME "lua" +#define LUA_REGISTRY_KEY "_midimonster_lua_instance" + +//TODO instance identification for callvacks + +int init(){ + backend lua = { + .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; + } + return 0; +} + +static int lua_callback_output(lua_State* interpreter){ + int arguments = lua_gettop(interpreter); + size_t n; + channel_value val; + const char* channel_name = NULL; + channel* channel = NULL; + instance* inst = NULL; + lua_instance_data* data = NULL; + + if(arguments != 2){ + fprintf(stderr, "Lua output function called with %d arguments, expected 2\n", arguments); + return 0; + } + + channel_name = lua_tostring(interpreter, 1); + val.normalised = clamp(lua_tonumber(interpreter, 2), 1.0, 0.0); + + lua_pushstring(interpreter, LUA_REGISTRY_KEY); + lua_gettable(interpreter, LUA_REGISTRYINDEX); + inst = (instance *) lua_touserdata(interpreter, -1); + data = (lua_instance_data*) inst->impl; + + 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); + return 0; + } + } + + fprintf(stderr, "Tried to set unknown channel %s.%s\n", inst->name, channel_name); + return 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; + + if(!strcmp(option, "script")){ + 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 backend\n", option); + 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 api functions + lua_register(data->interpreter, "output", lua_callback_output); + + //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){ + 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*)); + if(!data->channel_name){ + fprintf(stderr, "Failed to allocate memory\n"); + return NULL; + } + + 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; + + for(n = 0; n < num; n++){ + //call lua channel handlers + lua_getglobal(data->interpreter, data->channel_name[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){ + //TODO call timer callbacks + return 0; +} + +static int lua_start(){ + //TODO start timers / register fds + return 0; +} + +static int lua_shutdown(){ + size_t n, u, p; + instance** inst = NULL; + lua_instance_data* data = NULL; + + 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(inst[u]->impl); + } + + free(inst); + + fprintf(stderr, "Lua backend shut down\n"); + return 0; +} diff --git a/backends/lua.h b/backends/lua.h new file mode 100644 index 0000000..27e1afd --- /dev/null +++ b/backends/lua.h @@ -0,0 +1,21 @@ +#include "midimonster.h" + +#include <lua.h> +#include <lualib.h> +#include <lauxlib.h> + +int init(); +static int lua_configure(char* option, char* value); +static int lua_configure_instance(instance* inst, char* option, char* value); +static instance* lua_instance(); +static channel* lua_channel(instance* inst, char* spec); +static int lua_set(instance* inst, size_t num, channel** c, channel_value* v); +static int lua_handle(size_t num, managed_fd* fds); +static int lua_start(); +static int lua_shutdown(); + +typedef struct /*_lua_instance_data*/ { + size_t channels; + char** channel_name; + lua_State* interpreter; +} lua_instance_data; diff --git a/backends/lua.md b/backends/lua.md new file mode 100644 index 0000000..91e8fe2 --- /dev/null +++ b/backends/lua.md @@ -0,0 +1,49 @@ +### The `lua` backend + +The `lua` backend provides a flexible programming environment, allowing users to route and manipulate +events using the Lua programming language. + +Every instance has it's own interpreter state which can be loaded with custom handler scripts. + +To process incoming channel events, the MIDIMonster calls corresponding Lua functions with +the value (as a Lua `number` type) as parameter. To send output on a channel, the Lua environment +provides the function `output(channel-name, value)`. + +Example script: +``` +function bar(value) + output("foo", value / 2) +end +``` + +Input values range between 0.0 and 1.0, output values are clamped to the same range. + +#### Global configuration + +The backend does not take any global configuration. + +#### Instance configuration + +| Option | Example value | Default value | Description | +|---------------|-----------------------|-----------------------|-----------------------| +| `source` | `script.lua` | none | Lua source file | + +A single instance may have multiple `source` options specified, which will all be read cumulatively. + +#### Channel specification + +Channel names may be any valid Lua function name. + +Example mapping: +``` +lua1.foo > lua2.bar +``` + +#### Known bugs / problems + +Using `output` as an input channel name to a Lua instance does not work, as the interpreter has +`output` globally assigned to the event output function. Using `output` as an output channel name +via `output("output", value)` works as intended. + +The path to the Lua source files is relative to the current working directory. This may lead +to problems when copying configuration between installations. |