fengari
Version:
A Lua VM written in JS ES6 targeting the browser
516 lines (475 loc) • 15.7 kB
JavaScript
;
const {
LUA_MASKCALL,
LUA_MASKCOUNT,
LUA_MASKLINE,
LUA_MASKRET,
LUA_REGISTRYINDEX,
LUA_TFUNCTION,
LUA_TNIL,
LUA_TTABLE,
LUA_TUSERDATA,
lua_Debug,
lua_call,
lua_checkstack,
lua_gethook,
lua_gethookcount,
lua_gethookmask,
lua_getinfo,
lua_getlocal,
lua_getmetatable,
lua_getstack,
lua_getupvalue,
lua_getuservalue,
lua_insert,
lua_iscfunction,
lua_isfunction,
lua_isnoneornil,
lua_isthread,
lua_newtable,
lua_pcall,
lua_pop,
lua_pushboolean,
lua_pushfstring,
lua_pushinteger,
lua_pushlightuserdata,
lua_pushliteral,
lua_pushnil,
lua_pushstring,
lua_pushvalue,
lua_rawgetp,
lua_rawsetp,
lua_rotate,
lua_setfield,
lua_sethook,
lua_setlocal,
lua_setmetatable,
lua_settop,
lua_setupvalue,
lua_setuservalue,
lua_tojsstring,
lua_toproxy,
lua_tostring,
lua_tothread,
lua_touserdata,
lua_type,
lua_upvalueid,
lua_upvaluejoin,
lua_xmove
} = require('./lua.js');
const {
luaL_argcheck,
luaL_argerror,
luaL_checkany,
luaL_checkinteger,
luaL_checkstring,
luaL_checktype,
luaL_error,
luaL_loadbuffer,
luaL_newlib,
luaL_optinteger,
luaL_optstring,
luaL_traceback,
lua_writestringerror
} = require('./lauxlib.js');
const lualib = require('./lualib.js');
const {
luastring_indexOf,
to_luastring
} = require("./fengaricore.js");
/*
** If L1 != L, L1 can be in any state, and therefore there are no
** guarantees about its stack space; any push in L1 must be
** checked.
*/
const checkstack = function(L, L1, n) {
if (L !== L1 && !lua_checkstack(L1, n))
luaL_error(L, to_luastring("stack overflow", true));
};
const db_getregistry = function(L) {
lua_pushvalue(L, LUA_REGISTRYINDEX);
return 1;
};
const db_getmetatable = function(L) {
luaL_checkany(L, 1);
if (!lua_getmetatable(L, 1)) {
lua_pushnil(L); /* no metatable */
}
return 1;
};
const db_setmetatable = function(L) {
const t = lua_type(L, 2);
luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2, "nil or table expected");
lua_settop(L, 2);
lua_setmetatable(L, 1);
return 1; /* return 1st argument */
};
const db_getuservalue = function(L) {
if (lua_type(L, 1) !== LUA_TUSERDATA)
lua_pushnil(L);
else
lua_getuservalue(L, 1);
return 1;
};
const db_setuservalue = function(L) {
luaL_checktype(L, 1, LUA_TUSERDATA);
luaL_checkany(L, 2);
lua_settop(L, 2);
lua_setuservalue(L, 1);
return 1;
};
/*
** Auxiliary function used by several library functions: check for
** an optional thread as function's first argument and set 'arg' with
** 1 if this argument is present (so that functions can skip it to
** access their other arguments)
*/
const getthread = function(L) {
if (lua_isthread(L, 1)) {
return {
arg: 1,
thread: lua_tothread(L, 1)
};
} else {
return {
arg: 0,
thread: L
}; /* function will operate over current thread */
}
};
/*
** Variations of 'lua_settable', used by 'db_getinfo' to put results
** from 'lua_getinfo' into result table. Key is always a string;
** value can be a string, an int, or a boolean.
*/
const settabss = function(L, k, v) {
lua_pushstring(L, v);
lua_setfield(L, -2, k);
};
const settabsi = function(L, k, v) {
lua_pushinteger(L, v);
lua_setfield(L, -2, k);
};
const settabsb = function(L, k, v) {
lua_pushboolean(L, v);
lua_setfield(L, -2, k);
};
/*
** In function 'db_getinfo', the call to 'lua_getinfo' may push
** results on the stack; later it creates the result table to put
** these objects. Function 'treatstackoption' puts the result from
** 'lua_getinfo' on top of the result table so that it can call
** 'lua_setfield'.
*/
const treatstackoption = function(L, L1, fname) {
if (L == L1)
lua_rotate(L, -2, 1); /* exchange object and table */
else
lua_xmove(L1, L, 1); /* move object to the "main" stack */
lua_setfield(L, -2, fname); /* put object into table */
};
/*
** Calls 'lua_getinfo' and collects all results in a new table.
** L1 needs stack space for an optional input (function) plus
** two optional outputs (function and line table) from function
** 'lua_getinfo'.
*/
const db_getinfo = function(L) {
let ar = new lua_Debug();
let thread = getthread(L);
let arg = thread.arg;
let L1 = thread.thread;
let options = luaL_optstring(L, arg + 2, "flnStu");
checkstack(L, L1, 3);
if (lua_isfunction(L, arg + 1)) { /* info about a function? */
options = lua_pushfstring(L, to_luastring(">%s"), options); /* add '>' to 'options' */
lua_pushvalue(L, arg + 1); /* move function to 'L1' stack */
lua_xmove(L, L1, 1);
} else { /* stack level */
if (!lua_getstack(L1, luaL_checkinteger(L, arg + 1), ar)) {
lua_pushnil(L); /* level out of range */
return 1;
}
}
if (!lua_getinfo(L1, options, ar))
luaL_argerror(L, arg + 2, "invalid option");
lua_newtable(L); /* table to collect results */
if (luastring_indexOf(options, 83 /* 'S'.charCodeAt(0) */) > -1) {
settabss(L, to_luastring("source", true), ar.source);
settabss(L, to_luastring("short_src", true), ar.short_src);
settabsi(L, to_luastring("linedefined", true), ar.linedefined);
settabsi(L, to_luastring("lastlinedefined", true), ar.lastlinedefined);
settabss(L, to_luastring("what", true), ar.what);
}
if (luastring_indexOf(options, 108 /* 'l'.charCodeAt(0) */) > -1)
settabsi(L, to_luastring("currentline", true), ar.currentline);
if (luastring_indexOf(options, 117 /* 'u'.charCodeAt(0) */) > -1) {
settabsi(L, to_luastring("nups", true), ar.nups);
settabsi(L, to_luastring("nparams", true), ar.nparams);
settabsb(L, to_luastring("isvararg", true), ar.isvararg);
}
if (luastring_indexOf(options, 110 /* 'n'.charCodeAt(0) */) > -1) {
settabss(L, to_luastring("name", true), ar.name);
settabss(L, to_luastring("namewhat", true), ar.namewhat);
}
if (luastring_indexOf(options, 116 /* 't'.charCodeAt(0) */) > -1)
settabsb(L, to_luastring("istailcall", true), ar.istailcall);
if (luastring_indexOf(options, 76 /* 'L'.charCodeAt(0) */) > -1)
treatstackoption(L, L1, to_luastring("activelines", true));
if (luastring_indexOf(options, 102 /* 'f'.charCodeAt(0) */) > -1)
treatstackoption(L, L1, to_luastring("func", true));
return 1; /* return table */
};
const db_getlocal = function(L) {
let thread = getthread(L);
let L1 = thread.thread;
let arg = thread.arg;
let ar = new lua_Debug();
let nvar = luaL_checkinteger(L, arg + 2); /* local-variable index */
if (lua_isfunction(L, arg + 1)) {
lua_pushvalue(L, arg + 1); /* push function */
lua_pushstring(L, lua_getlocal(L, null, nvar)); /* push local name */
return 1; /* return only name (there is no value) */
} else { /* stack-level argument */
let level = luaL_checkinteger(L, arg + 1);
if (!lua_getstack(L1, level, ar)) /* out of range? */
return luaL_argerror(L, arg+1, "level out of range");
checkstack(L, L1, 1);
let name = lua_getlocal(L1, ar, nvar);
if (name) {
lua_xmove(L1, L, 1); /* move local value */
lua_pushstring(L, name); /* push name */
lua_rotate(L, -2, 1); /* re-order */
return 2;
}
else {
lua_pushnil(L); /* no name (nor value) */
return 1;
}
}
};
const db_setlocal = function(L) {
let thread = getthread(L);
let L1 = thread.thread;
let arg = thread.arg;
let ar = new lua_Debug();
let level = luaL_checkinteger(L, arg + 1);
let nvar = luaL_checkinteger(L, arg + 2);
if (!lua_getstack(L1, level, ar)) /* out of range? */
return luaL_argerror(L, arg + 1, "level out of range");
luaL_checkany(L, arg + 3);
lua_settop(L, arg + 3);
checkstack(L, L1, 1);
lua_xmove(L, L1, 1);
let name = lua_setlocal(L1, ar, nvar);
if (name === null)
lua_pop(L1, 1); /* pop value (if not popped by 'lua_setlocal') */
lua_pushstring(L, name);
return 1;
};
/*
** get (if 'get' is true) or set an upvalue from a closure
*/
const auxupvalue = function(L, get) {
let n = luaL_checkinteger(L, 2); /* upvalue index */
luaL_checktype(L, 1, LUA_TFUNCTION); /* closure */
let name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
if (name === null) return 0;
lua_pushstring(L, name);
lua_insert(L, -(get+1)); /* no-op if get is false */
return get + 1;
};
const db_getupvalue = function(L) {
return auxupvalue(L, 1);
};
const db_setupvalue = function(L) {
luaL_checkany(L, 3);
return auxupvalue(L, 0);
};
/*
** Check whether a given upvalue from a given closure exists and
** returns its index
*/
const checkupval = function(L, argf, argnup) {
let nup = luaL_checkinteger(L, argnup); /* upvalue index */
luaL_checktype(L, argf, LUA_TFUNCTION); /* closure */
luaL_argcheck(L, (lua_getupvalue(L, argf, nup) !== null), argnup, "invalid upvalue index");
return nup;
};
const db_upvalueid = function(L) {
let n = checkupval(L, 1, 2);
lua_pushlightuserdata(L, lua_upvalueid(L, 1, n));
return 1;
};
const db_upvaluejoin = function(L) {
let n1 = checkupval(L, 1, 2);
let n2 = checkupval(L, 3, 4);
luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");
luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");
lua_upvaluejoin(L, 1, n1, 3, n2);
return 0;
};
/*
** The hook table at registry[HOOKKEY] maps threads to their current
** hook function. (We only need the unique address of 'HOOKKEY'.)
*/
const HOOKKEY = to_luastring("__hooks__", true);
const hooknames = ["call", "return", "line", "count", "tail call"].map(e => to_luastring(e));
/*
** Call hook function registered at hook table for the current
** thread (if there is one)
*/
const hookf = function(L, ar) {
lua_rawgetp(L, LUA_REGISTRYINDEX, HOOKKEY);
let hooktable = lua_touserdata(L, -1);
let proxy = hooktable.get(L);
if (proxy) { /* is there a hook function? */
proxy(L);
lua_pushstring(L, hooknames[ar.event]); /* push event name */
if (ar.currentline >= 0)
lua_pushinteger(L, ar.currentline); /* push current line */
else lua_pushnil(L);
lualib.lua_assert(lua_getinfo(L, to_luastring("lS"), ar));
lua_call(L, 2, 0); /* call hook function */
}
};
/*
** Convert a string mask (for 'sethook') into a bit mask
*/
const makemask = function(smask, count) {
let mask = 0;
if (luastring_indexOf(smask, 99 /* 'c'.charCodeAt(0) */) > -1) mask |= LUA_MASKCALL;
if (luastring_indexOf(smask, 114 /* 'r'.charCodeAt(0) */) > -1) mask |= LUA_MASKRET;
if (luastring_indexOf(smask, 108 /* 'l'.charCodeAt(0) */) > -1) mask |= LUA_MASKLINE;
if (count > 0) mask |= LUA_MASKCOUNT;
return mask;
};
/*
** Convert a bit mask (for 'gethook') into a string mask
*/
const unmakemask = function(mask, smask) {
let i = 0;
if (mask & LUA_MASKCALL) smask[i++] = 99 /* 'c'.charCodeAt(0) */;
if (mask & LUA_MASKRET) smask[i++] = 114 /* 'r'.charCodeAt(0) */;
if (mask & LUA_MASKLINE) smask[i++] = 108 /* 'l'.charCodeAt(0) */;
return smask.subarray(0, i);
};
const db_sethook = function(L) {
let mask, count, func;
let thread = getthread(L);
let L1 = thread.thread;
let arg = thread.arg;
if (lua_isnoneornil(L, arg+1)) { /* no hook? */
lua_settop(L, arg+1);
func = null; mask = 0; count = 0; /* turn off hooks */
}
else {
const smask = luaL_checkstring(L, arg + 2);
luaL_checktype(L, arg+1, LUA_TFUNCTION);
count = luaL_optinteger(L, arg + 3, 0);
func = hookf; mask = makemask(smask, count);
}
/* as weak tables are not supported; use a JS weak-map */
let hooktable;
if (lua_rawgetp(L, LUA_REGISTRYINDEX, HOOKKEY) === LUA_TNIL) {
hooktable = new WeakMap();
lua_pushlightuserdata(L, hooktable);
lua_rawsetp(L, LUA_REGISTRYINDEX, HOOKKEY); /* set it in position */
} else {
hooktable = lua_touserdata(L, -1);
}
let proxy = lua_toproxy(L, arg + 1); /* value (hook function) */
hooktable.set(L1, proxy);
lua_sethook(L1, func, mask, count);
return 0;
};
const db_gethook = function(L) {
let thread = getthread(L);
let L1 = thread.thread;
let buff = new Uint8Array(5);
let mask = lua_gethookmask(L1);
let hook = lua_gethook(L1);
if (hook === null) /* no hook? */
lua_pushnil(L);
else if (hook !== hookf) /* external hook? */
lua_pushliteral(L, "external hook");
else { /* hook table must exist */
lua_rawgetp(L, LUA_REGISTRYINDEX, HOOKKEY);
let hooktable = lua_touserdata(L, -1);
let proxy = hooktable.get(L1);
proxy(L);
}
lua_pushstring(L, unmakemask(mask, buff)); /* 2nd result = mask */
lua_pushinteger(L, lua_gethookcount(L1)); /* 3rd result = count */
return 3;
};
const db_traceback = function(L) {
let thread = getthread(L);
let L1 = thread.thread;
let arg = thread.arg;
let msg = lua_tostring(L, arg + 1);
if (msg === null && !lua_isnoneornil(L, arg + 1)) /* non-string 'msg'? */
lua_pushvalue(L, arg + 1); /* return it untouched */
else {
let level = luaL_optinteger(L, arg + 2, L === L1 ? 1 : 0);
luaL_traceback(L, L1, msg, level);
}
return 1;
};
const dblib = {
"gethook": db_gethook,
"getinfo": db_getinfo,
"getlocal": db_getlocal,
"getmetatable": db_getmetatable,
"getregistry": db_getregistry,
"getupvalue": db_getupvalue,
"getuservalue": db_getuservalue,
"sethook": db_sethook,
"setlocal": db_setlocal,
"setmetatable": db_setmetatable,
"setupvalue": db_setupvalue,
"setuservalue": db_setuservalue,
"traceback": db_traceback,
"upvalueid": db_upvalueid,
"upvaluejoin": db_upvaluejoin
};
let getinput;
if (typeof process !== "undefined") { // Only with Node
const readlineSync = require('readline-sync');
readlineSync.setDefaultOptions({
prompt: 'lua_debug> '
});
getinput = function() {
return readlineSync.prompt();
};
} else if (typeof window !== "undefined") {
/* if in browser use window.prompt. Doesn't work from web workers.
See https://developer.mozilla.org/en-US/docs/Web/API/Window/prompt
*/
getinput = function() {
let input = prompt("lua_debug>", "");
return (input !== null) ? input : "";
};
}
if (getinput) {
dblib.debug = function(L) {
for (;;) {
let input = getinput();
if (input === "cont")
return 0;
if (input.length === 0)
continue;
let buffer = to_luastring(input);
if (luaL_loadbuffer(L, buffer, buffer.length, to_luastring("=(debug command)", true))
|| lua_pcall(L, 0, 0, 0)) {
lua_writestringerror(lua_tojsstring(L, -1), "\n");
}
lua_settop(L, 0); /* remove eventual returns */
}
};
}
const luaopen_debug = function(L) {
luaL_newlib(L, dblib);
return 1;
};
module.exports.luaopen_debug = luaopen_debug;