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nodemcu-firmware/app/lua53/lua.c

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/*
** NodeMCU Lua 5.1 and 5.3 main initiator and comand interpreter
** See Copyright Notice in lua.h
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "user_version.h"
#include "driver/input.h"
#define lua_c
#define LUA_CORE
#ifndef LUA_VERSION_51 /* LUA_VERSION_NUM == 503 */
#define LUA_VERSION_53
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
#include "lprefix.h"
#include "lgc.h"
#include "lnodemcu.h"
#endif
#include "platform.h"
#if !defined(LUA_PROMPT)
#define LUA_PROMPT "> "
#define LUA_PROMPT2 ">> "
#endif
#ifndef LUA_INIT_STRING
#define LUA_INIT_STRING "@init.lua"
#endif
/*
** The NodeMCU version of lua.c is structurally different for standard lua.c
** as a result of architectural drivers arising from its context and being
** initiated within the startup sequence of an IoT SoC embedded runtime.
**
** 1) Processing is based on a single threaded event loop model (somewhat akin
** to Node.js), so access to most system services is asyncronous and uses
** a callback mechanism. The Lua interactive mode processes input lines
** that are provided by the firmware on a line by line basis and indeed
** other Lua tasks might interleave any multiline processing, so the
** standard doREPL approach won't work.
**
** 2) Most OS services and enviroment processing are supported so much of the
** standard functionality is irrelevant and is stripped out for simplicity.
**
** 3) stderr and stdout redirection aren't offered as an OS service, so this
** is handled in the baselib print function and errors are sent to print.
*/
lua_State *globalL = NULL;
static int pmain (lua_State *L);
void lua_input_string (const char *line, int len);
/*
** Prints (calling the Lua 'print' function) to print n values on the stack
*/
static void l_print (lua_State *L, int n) {
if (n > 0) { /* any result to be printed? */
luaL_checkstack(L, LUA_MINSTACK, "too many results to print");
lua_getglobal(L, "print");
lua_insert(L, -n-1);
if (lua_pcall(L, n, 0, 0) != LUA_OK) {
lua_writestringerror("error calling 'print' (%s)\n", lua_tostring(L, -1));
lua_settop(L, -n-1);
}
}
}
/*
** Message handler is used with all chunks calls. Returns the traceback on ToS
*/
static int msghandler (lua_State *L) {
lua_getglobal(L, "debug");
lua_getfield(L, -1, "traceback");
if (lua_isfunction(L, -1)) {
lua_insert(L, 1); /* insert tracback function above error */
lua_pop(L, 1); /* dump the debug table entry */
lua_pushinteger(L, 2); /* skip this function and traceback */
lua_call(L, 2, 1); /* call debug.traceback and return it as a string */
}
return 1; /* return the traceback */
}
/*
** Interface to 'lua_pcall', which sets appropriate message function and error
** handler. Used to run all chunks. Results or error traceback left on stack.
** This function is interactive so unlike lua_pcallx(), the error is sent direct
** to the print function and erroring does not trigger an on error restart.
*/
static int docall (lua_State *L, int narg) {
int status;
int base = lua_gettop(L) - narg; /* function index */
lua_pushcfunction(L, msghandler); /* push message handler */
lua_insert(L, base); /* put it under chunk and args */
status = lua_pcall(L, narg, LUA_MULTRET, base);
lua_remove(L, base); /* remove message handler from the stack */
/* force a complete garbage collection in case of errors */
if (status != 0) lua_gc(L, LUA_GCCOLLECT, 0);
return status;
}
#ifndef DISABLE_STARTUP_BANNER
static void print_version (lua_State *L) {
lua_writestringerror( "\n" NODE_VERSION " build " BUILD_DATE
" powered by " LUA_RELEASE " on SDK %s\n", SDK_VERSION);
}
#endif
/*
** Returns the string to be used as a prompt by the interpreter.
*/
static const char *get_prompt (lua_State *L, int firstline) {
const char *p;
lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2");
p = lua_tostring(L, -1);
if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
lua_pop(L, 1); /* remove global */
return p;
}
/*
** Check whether 'status' signals a syntax error and the error
** message at the top of the stack ends with the above mark for
** incomplete statements.
*/
#ifdef LUA_VERSION_51
#define EOFMARK LUA_QL("<eof>")
#else
#define EOFMARK "<eof>"
#endif
#define MARKLEN (sizeof(EOFMARK)/sizeof(char) - 1)
static int incomplete (lua_State *L, int status) {
if (status == LUA_ERRSYNTAX) {
size_t lmsg;
const char *msg = lua_tolstring(L, -1, &lmsg);
if (lmsg >= MARKLEN && !strcmp(msg + lmsg - MARKLEN, EOFMARK)) {
lua_pop(L, 1);
return 1;
}
}
return 0;
}
static void l_create_stdin (lua_State *L);
/*
** Note that the Lua stack can't be used to stash part-line components as
** other C API and Lua functions might be executed as tasks between lines in
** a multiline, so a standard luaL_ref() registry entry is used instead.
*/
static void dojob (lua_State *L) {
static int MLref = LUA_NOREF; /* Lua Reg entry for cached multi-line */
int status;
const char *prompt;
size_t l;
const char *b = lua_tostring(L, -1); /* ToS contains next input line */
if (MLref != LUA_NOREF) {
/* processing multiline */
lua_rawgeti(L, LUA_REGISTRYINDEX, MLref); /* insert prev lines(s) */
lua_pushliteral(L, "\n"); /* insert CR */
lua_pushvalue(L, -3); /* dup new line */
lua_concat(L, 3); /* concat all 3 */
lua_remove(L,-2); /* and shift down to ToS */
} else if (b[0] == '=') { /* If firstline and of the format =<expression> */
lua_pushfstring(L, "return %s", b+1);
lua_remove(L, -2);
}
/*
* ToS is at S[2] which contains the putative chunk to be compiled
*/
b = lua_tolstring(L, -1, &l);
status = luaL_loadbuffer(L, b, l, "=stdin");
if (incomplete(L, status)) {
/* Store line back in the Reg mlref sot */
if (MLref == LUA_NOREF) {
MLref = luaL_ref(L, LUA_REGISTRYINDEX);
} else {
lua_rawseti(L, LUA_REGISTRYINDEX, MLref);
}
} else {
/* compile finished OK or with hard error */
lua_remove(L, -2); /* remove line because now redundant */
if (MLref != LUA_NOREF) { /* also remove multiline if it exists */
luaL_unref(L, LUA_REGISTRYINDEX, MLref);
MLref = LUA_NOREF;
}
/* Execute the compiled chunk of successful */
if (status == 0)
status = docall(L, 0);
/* print any returned results or error message */
if (status && !lua_isnil(L, -1)) {
lua_pushliteral(L, "Lua error: ");
lua_insert(L , -2);
}
l_print(L, lua_gettop(L) - 1); /* print error or results one stack */
}
prompt = get_prompt(L, MLref!= LUA_NOREF ? 0 : 1);
input_setprompt(prompt);
lua_writestring(prompt,strlen(prompt));
}
/*
** Main body of standalone interpreter.
*/
static int pmain (lua_State *L) {
const char *init = LUA_INIT_STRING;
int status;
STARTUP_COUNT;
lua_gc(L, LUA_GCSTOP, 0); /* stop GC during initialization */
luaL_openlibs(L); /* Nodemcu open will throw to signal an LFS reload */
#ifdef LUA_VERSION_51
lua_setegcmode( L, EGC_ALWAYS, 4096 );
#else
lua_gc( L, LUA_GCSETMEMLIMIT, 4096 );
#endif
lua_gc(L, LUA_GCRESTART, 0); /* restart GC and set EGC mode */
lua_settop(L, 0);
l_create_stdin(L);
input_setup(LUA_MAXINPUT, get_prompt(L, 1));
lua_input_string(" \n", 2); /* queue CR to issue first prompt */
#ifndef DISABLE_STARTUP_BANNER
if ((platform_rcr_get_startup_option() & STARTUP_OPTION_NO_BANNER) == 0) {
print_version(L);
}
#endif
/*
* And last of all, kick off application initialisation. Note that if
* LUA_INIT_STRING is a file reference and the file system is uninitialised
* then attempting the open will trigger a file system format.
*/
platform_rcr_read(PLATFORM_RCR_INITSTR, (void**) &init);
STARTUP_COUNT;
if (init[0] == '!') { /* !module is a compile-free way of executing LFS module */
luaL_pushlfsmodule(L);
lua_pushstring(L, init+1);
lua_call(L, 1, 1); /* return LFS.module or nil */
status = LUA_OK;
if (!lua_isfunction(L, -1)) {
lua_pushfstring(L, "cannot load LFS.%s", init+1);
status = LUA_ERRRUN;
}
} else {
status = (init[0] == '@') ?
luaL_loadfile(L, init+1) :
luaL_loadbuffer(L, init, strlen(init), "=INIT");
}
STARTUP_COUNT;
if (status == LUA_OK)
status = docall(L, 0);
if (status != LUA_OK)
l_print (L, 1);
STARTUP_COUNT;
return 0;
}
/*
** The system initialisation CB nodemcu_init() calls lua_main() to startup the
** Lua environment by calling luaL_newstate() which initiates the core Lua VM.
** The initialisation of the libraries, etc. can potentially throw errors and
** so is wrapped in a protected call which also kicks off the user application
** through the LUA_INIT_STRING hook.
*/
int lua_main (void) {
lua_State *L = luaL_newstate();
if (L == NULL) {
lua_writestringerror( "cannot create state: %s", "not enough memory");
return 0;
}
globalL = L;
lua_pushcfunction(L, pmain);
if (docall(L, 0) != LUA_OK) {
if (strstr(lua_tostring(L, -1),"!LFSrestart!")) {
lua_close(L);
return 1; /* non-zero return to flag LFS reload */
}
l_print(L, 1);
}
return 0;
}
lua_State *lua_getstate(void) {
return globalL;
}
/*
** The Lua interpreter is event-driven and task-oriented in NodeMCU rather than
** based on a readline poll loop as in the standard implementation. Input lines
** can come from one of two sources: the application can "push" lines for the
** interpreter to compile and execute, or they can come from the UART. To
** minimise application blocking, the lines are queued in a pipe when received,
** with the Lua interpreter task attached to the pipe as its reader task. This
** CB processes one line of input per task execution.
**
** Even though lines can be emitted from independent sources (the UART and the
** node API), and they could in theory get interleaved, the strategy here is
** "let the programmer beware": interactive input will normally only occur in
** development and injected input occur in telnet type applications. If there
** is a need for interlocks, then the application should handle this.
*/
void lua_input_string (const char *line, int len) {
lua_State *L = globalL;
lua_getfield(L, LUA_REGISTRYINDEX, "stdin");
lua_rawgeti(L, -1, 1); /* get the pipe_write from stdin[1] */
lua_insert(L, -2); /* stick above the pipe */
lua_pushlstring(L, line, len);
lua_call(L, 2, 0); /* stdin:write(line) */
}
/*
** CB reader for the stdin pipe, and follows the calling conventions for a
** pipe readers; it has one argument, the stdin pipe that it is reading.
*/
static int l_read_stdin (lua_State *L) {
size_t l;
lua_settop(L, 1); /* pipe obj at S[1] */
lua_getfield(L, 1, "read"); /* pobj:read at S[2] */
lua_pushvalue(L, 1); /* dup pobj to S[3] */
lua_pushliteral(L, "\n+"); /* S[4] = "\n+" */
lua_call(L, 2, 1); /* S[2] = pobj:read("\n+") */
const char* b = lua_tolstring(L, 2, &l); /* b = NULL if S[2] is nil */
/*
* If the pipe is empty, or the line not CR terminated, return false to
* suppress automatic reposting
*/
lua_pushboolean(L, false);
if ((lua_isnil(L, 2) || l == 0))
return 1; /* return false if pipe empty */
if (b[l-1] != '\n') {
/* likewise if not CR terminated, then unread and ditto */
lua_insert(L, 1); /* insert false return above the pipe */
lua_getfield(L, 2, "unread");
lua_insert(L, 2); /* insert pipe.unread above the pipe */
lua_call(L, 2, 0); /* pobj:unread(line) */
return 1; /* return false */
}
lua_pop(L, 1); /* dump false value at ToS */
/*
* Now we can process a proper CR terminated line
*/
lua_pushlstring(L, b, --l); /* remove end CR */
lua_remove(L, 2);
dojob(L);
return 0;
}
/*
** Create and initialise the stdin pipe
*/
static void l_create_stdin (lua_State *L) {
lua_pushliteral(L, "stdin");
lua_getglobal(L, "pipe");
lua_getfield(L, -1, "create");
lua_remove(L, -2);
lua_pushcfunction(L, l_read_stdin);
lua_pushinteger(L, LUA_TASK_LOW);
lua_call(L, 2, 1); /* ToS = pipe.create(dojob, low_priority) */
lua_rawset(L, LUA_REGISTRYINDEX); /* and stash input pipe in Reg["stdin"] */
}
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