gecko-dev/js/narcissus/jsexec.js

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JavaScript

/* ***** BEGIN LICENSE BLOCK *****
* vim: set ts=4 sw=4 et tw=80:
*
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the Narcissus JavaScript engine.
*
* The Initial Developer of the Original Code is
* Brendan Eich <brendan@mozilla.org>.
* Portions created by the Initial Developer are Copyright (C) 2004
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* Narcissus - JS implemented in JS.
*
* Execution of parse trees.
*
* Standard classes except for eval, Function, Array, and String are borrowed
* from the host JS environment. Function is metacircular. Array and String
* are reflected via wrapping the corresponding native constructor and adding
* an extra level of prototype-based delegation.
*/
const GLOBAL_CODE = 0, EVAL_CODE = 1, FUNCTION_CODE = 2;
function ExecutionContext(type) {
this.type = type;
}
var global = {
// Value properties.
NaN: NaN, Infinity: Infinity, undefined: undefined,
// Function properties.
eval: function eval(s) {
if (typeof s != "string")
return s;
var x = ExecutionContext.current;
var x2 = new ExecutionContext(EVAL_CODE);
x2.thisObject = x.thisObject;
x2.caller = x.caller;
x2.callee = x.callee;
x2.scope = x.scope;
ExecutionContext.current = x2;
try {
execute(parse(s), x2);
} catch (e if e == THROW) {
x.result = x2.result;
throw e;
} finally {
ExecutionContext.current = x;
}
return x2.result;
},
parseInt: parseInt, parseFloat: parseFloat,
isNaN: isNaN, isFinite: isFinite,
decodeURI: decodeURI, encodeURI: encodeURI,
decodeURIComponent: decodeURIComponent,
encodeURIComponent: encodeURIComponent,
// Class constructors. Where ECMA-262 requires C.length == 1, we declare
// a dummy formal parameter.
Object: Object,
Function: function Function(dummy) {
var p = "", b = "", n = arguments.length;
if (n) {
var m = n - 1;
if (m) {
p += arguments[0];
for (var k = 1; k < m; k++)
p += "," + arguments[k];
}
b += arguments[m];
}
// XXX We want to pass a good file and line to the tokenizer.
// Note the anonymous name to maintain parity with Spidermonkey.
var t = new Tokenizer("anonymous(" + p + ") {" + b + "}");
// NB: Use the STATEMENT_FORM constant since we don't want to push this
// function onto the null compilation context.
var f = FunctionDefinition(t, null, false, STATEMENT_FORM);
var s = {object: global, parent: null};
return new FunctionObject(f, s);
},
Array: function Array(dummy) {
// Array when called as a function acts as a constructor.
return GLOBAL.Array.apply(this, arguments);
},
String: function String(s) {
// Called as function or constructor: convert argument to string type.
s = arguments.length ? "" + s : "";
if (this instanceof String) {
// Called as constructor: save the argument as the string value
// of this String object and return this object.
this.value = s;
return this;
}
return s;
},
Boolean: Boolean, Number: Number, Date: Date, RegExp: RegExp,
Error: Error, EvalError: EvalError, RangeError: RangeError,
ReferenceError: ReferenceError, SyntaxError: SyntaxError,
TypeError: TypeError, URIError: URIError,
// Other properties.
Math: Math,
// Extensions to ECMA.
snarf: snarf, evaluate: evaluate,
load: function load(s) {
if (typeof s != "string")
return s;
evaluate(snarf(s), s, 1)
},
print: print, version: null
};
// Helper to avoid Object.prototype.hasOwnProperty polluting scope objects.
function hasDirectProperty(o, p) {
return Object.prototype.hasOwnProperty.call(o, p);
}
// Reflect a host class into the target global environment by delegation.
function reflectClass(name, proto) {
var gctor = global[name];
gctor.__defineProperty__('prototype', proto, true, true, true);
proto.__defineProperty__('constructor', gctor, false, false, true);
return proto;
}
// Reflect Array -- note that all Array methods are generic.
reflectClass('Array', new Array);
// Reflect String, overriding non-generic methods.
var gSp = reflectClass('String', new String);
gSp.toSource = function () { return this.value.toSource(); };
gSp.toString = function () { return this.value; };
gSp.valueOf = function () { return this.value; };
global.String.fromCharCode = String.fromCharCode;
var XCp = ExecutionContext.prototype;
ExecutionContext.current = XCp.caller = XCp.callee = null;
XCp.scope = {object: global, parent: null};
XCp.thisObject = global;
XCp.result = undefined;
XCp.target = null;
XCp.ecmaStrictMode = false;
function Reference(base, propertyName, node) {
this.base = base;
this.propertyName = propertyName;
this.node = node;
}
Reference.prototype.toString = function () { return this.node.getSource(); }
function getValue(v) {
if (v instanceof Reference) {
if (!v.base) {
throw new ReferenceError(v.propertyName + " is not defined",
v.node.filename, v.node.lineno);
}
return v.base[v.propertyName];
}
return v;
}
function putValue(v, w, vn) {
if (v instanceof Reference)
return (v.base || global)[v.propertyName] = w;
throw new ReferenceError("Invalid assignment left-hand side",
vn.filename, vn.lineno);
}
function isPrimitive(v) {
var t = typeof v;
return (t == "object") ? v === null : t != "function";
}
function isObject(v) {
var t = typeof v;
return (t == "object") ? v !== null : t == "function";
}
// If r instanceof Reference, v == getValue(r); else v === r. If passed, rn
// is the node whose execute result was r.
function toObject(v, r, rn) {
switch (typeof v) {
case "boolean":
return new global.Boolean(v);
case "number":
return new global.Number(v);
case "string":
return new global.String(v);
case "function":
return v;
case "object":
if (v !== null)
return v;
}
var message = r + " (type " + (typeof v) + ") has no properties";
throw rn ? new TypeError(message, rn.filename, rn.lineno)
: new TypeError(message);
}
function execute(n, x) {
var a, f, i, j, r, s, t, u, v;
switch (n.type) {
case FUNCTION:
if (n.functionForm != DECLARED_FORM) {
if (!n.name || n.functionForm == STATEMENT_FORM) {
v = new FunctionObject(n, x.scope);
if (n.functionForm == STATEMENT_FORM)
x.scope.object.__defineProperty__(n.name, v, true);
} else {
t = new Object;
x.scope = {object: t, parent: x.scope};
try {
v = new FunctionObject(n, x.scope);
t.__defineProperty__(n.name, v, true, true);
} finally {
x.scope = x.scope.parent;
}
}
}
break;
case SCRIPT:
t = x.scope.object;
a = n.funDecls;
for (i = 0, j = a.length; i < j; i++) {
s = a[i].name;
f = new FunctionObject(a[i], x.scope);
t.__defineProperty__(s, f, x.type != EVAL_CODE);
}
a = n.varDecls;
for (i = 0, j = a.length; i < j; i++) {
u = a[i];
s = u.name;
if (u.readOnly && hasDirectProperty(t, s)) {
throw new TypeError("Redeclaration of const " + s,
u.filename, u.lineno);
}
if (u.readOnly || !hasDirectProperty(t, s)) {
t.__defineProperty__(s, undefined, x.type != EVAL_CODE,
u.readOnly);
}
}
// FALL THROUGH
case BLOCK:
for (i = 0, j = n.length; i < j; i++)
execute(n[i], x);
break;
case IF:
if (getValue(execute(n.condition, x)))
execute(n.thenPart, x);
else if (n.elsePart)
execute(n.elsePart, x);
break;
case SWITCH:
s = getValue(execute(n.discriminant, x));
a = n.cases;
var matchDefault = false;
switch_loop:
for (i = 0, j = a.length; ; i++) {
if (i == j) {
if (n.defaultIndex >= 0) {
i = n.defaultIndex - 1; // no case matched, do default
matchDefault = true;
continue;
}
break; // no default, exit switch_loop
}
t = a[i]; // next case (might be default!)
if (t.type == CASE) {
u = getValue(execute(t.caseLabel, x));
} else {
if (!matchDefault) // not defaulting, skip for now
continue;
u = s; // force match to do default
}
if (u === s) {
for (;;) { // this loop exits switch_loop
if (t.statements.length) {
try {
execute(t.statements, x);
} catch (e if e == BREAK && x.target == n) {
break switch_loop;
}
}
if (++i == j)
break switch_loop;
t = a[i];
}
// NOT REACHED
}
}
break;
case FOR:
n.setup && getValue(execute(n.setup, x));
// FALL THROUGH
case WHILE:
while (!n.condition || getValue(execute(n.condition, x))) {
try {
execute(n.body, x);
} catch (e if e == BREAK && x.target == n) {
break;
} catch (e if e == CONTINUE && x.target == n) {
// Must run the update expression.
}
n.update && getValue(execute(n.update, x));
}
break;
case FOR_IN:
u = n.varDecl;
if (u)
execute(u, x);
r = n.iterator;
s = execute(n.object, x);
v = getValue(s);
// ECMA deviation to track extant browser JS implementation behavior.
t = (v == null && !x.ecmaStrictMode) ? v : toObject(v, s, n.object);
a = [];
for (i in t)
a.push(i);
for (i = 0, j = a.length; i < j; i++) {
putValue(execute(r, x), a[i], r);
try {
execute(n.body, x);
} catch (e if e == BREAK && x.target == n) {
break;
} catch (e if e == CONTINUE && x.target == n) {
continue;
}
}
break;
case DO:
do {
try {
execute(n.body, x);
} catch (e if e == BREAK && x.target == n) {
break;
} catch (e if e == CONTINUE && x.target == n) {
continue;
}
} while (getValue(execute(n.condition, x)));
break;
case BREAK:
case CONTINUE:
x.target = n.target;
throw n.type;
case TRY:
try {
execute(n.tryBlock, x);
} catch (e if e == THROW && (j = n.catchClauses.length)) {
e = x.result;
x.result = undefined;
for (i = 0; ; i++) {
if (i == j) {
x.result = e;
throw THROW;
}
t = n.catchClauses[i];
x.scope = {object: {}, parent: x.scope};
x.scope.object.__defineProperty__(t.varName, e, true);
try {
if (t.guard && !getValue(execute(t.guard, x)))
continue;
execute(t.block, x);
break;
} finally {
x.scope = x.scope.parent;
}
}
} finally {
if (n.finallyBlock)
execute(n.finallyBlock, x);
}
break;
case THROW:
x.result = getValue(execute(n.exception, x));
throw THROW;
case RETURN:
x.result = getValue(execute(n.value, x));
throw RETURN;
case WITH:
r = execute(n.object, x);
t = toObject(getValue(r), r, n.object);
x.scope = {object: t, parent: x.scope};
try {
execute(n.body, x);
} finally {
x.scope = x.scope.parent;
}
break;
case VAR:
case CONST:
for (i = 0, j = n.length; i < j; i++) {
u = n[i].initializer;
if (!u)
continue;
t = n[i].name;
for (s = x.scope; s; s = s.parent) {
if (hasDirectProperty(s.object, t))
break;
}
u = getValue(execute(u, x));
if (n.type == CONST)
s.object.__defineProperty__(t, u, x.type != EVAL_CODE, true);
else
s.object[t] = u;
}
break;
case DEBUGGER:
throw "NYI: " + tokens[n.type];
case SEMICOLON:
if (n.expression)
x.result = getValue(execute(n.expression, x));
break;
case LABEL:
try {
execute(n.statement, x);
} catch (e if e == BREAK && x.target == n) {
}
break;
case COMMA:
for (i = 0, j = n.length; i < j; i++)
v = getValue(execute(n[i], x));
break;
case ASSIGN:
r = execute(n[0], x);
t = n[0].assignOp;
if (t)
u = getValue(r);
v = getValue(execute(n[1], x));
if (t) {
switch (t) {
case BITWISE_OR: v = u | v; break;
case BITWISE_XOR: v = u ^ v; break;
case BITWISE_AND: v = u & v; break;
case LSH: v = u << v; break;
case RSH: v = u >> v; break;
case URSH: v = u >>> v; break;
case PLUS: v = u + v; break;
case MINUS: v = u - v; break;
case MUL: v = u * v; break;
case DIV: v = u / v; break;
case MOD: v = u % v; break;
}
}
putValue(r, v, n[0]);
break;
case HOOK:
v = getValue(execute(n[0], x)) ? getValue(execute(n[1], x))
: getValue(execute(n[2], x));
break;
case OR:
v = getValue(execute(n[0], x)) || getValue(execute(n[1], x));
break;
case AND:
v = getValue(execute(n[0], x)) && getValue(execute(n[1], x));
break;
case BITWISE_OR:
v = getValue(execute(n[0], x)) | getValue(execute(n[1], x));
break;
case BITWISE_XOR:
v = getValue(execute(n[0], x)) ^ getValue(execute(n[1], x));
break;
case BITWISE_AND:
v = getValue(execute(n[0], x)) & getValue(execute(n[1], x));
break;
case EQ:
v = getValue(execute(n[0], x)) == getValue(execute(n[1], x));
break;
case NE:
v = getValue(execute(n[0], x)) != getValue(execute(n[1], x));
break;
case STRICT_EQ:
v = getValue(execute(n[0], x)) === getValue(execute(n[1], x));
break;
case STRICT_NE:
v = getValue(execute(n[0], x)) !== getValue(execute(n[1], x));
break;
case LT:
v = getValue(execute(n[0], x)) < getValue(execute(n[1], x));
break;
case LE:
v = getValue(execute(n[0], x)) <= getValue(execute(n[1], x));
break;
case GE:
v = getValue(execute(n[0], x)) >= getValue(execute(n[1], x));
break;
case GT:
v = getValue(execute(n[0], x)) > getValue(execute(n[1], x));
break;
case IN:
v = getValue(execute(n[0], x)) in getValue(execute(n[1], x));
break;
case INSTANCEOF:
t = getValue(execute(n[0], x));
u = getValue(execute(n[1], x));
if (isObject(u) && typeof u.__hasInstance__ == "function")
v = u.__hasInstance__(t);
else
v = t instanceof u;
break;
case LSH:
v = getValue(execute(n[0], x)) << getValue(execute(n[1], x));
break;
case RSH:
v = getValue(execute(n[0], x)) >> getValue(execute(n[1], x));
break;
case URSH:
v = getValue(execute(n[0], x)) >>> getValue(execute(n[1], x));
break;
case PLUS:
v = getValue(execute(n[0], x)) + getValue(execute(n[1], x));
break;
case MINUS:
v = getValue(execute(n[0], x)) - getValue(execute(n[1], x));
break;
case MUL:
v = getValue(execute(n[0], x)) * getValue(execute(n[1], x));
break;
case DIV:
v = getValue(execute(n[0], x)) / getValue(execute(n[1], x));
break;
case MOD:
v = getValue(execute(n[0], x)) % getValue(execute(n[1], x));
break;
case DELETE:
t = execute(n[0], x);
v = !(t instanceof Reference) || delete t.base[t.propertyName];
break;
case VOID:
getValue(execute(n[0], x));
break;
case TYPEOF:
t = execute(n[0], x);
if (t instanceof Reference)
t = t.base ? t.base[t.propertyName] : undefined;
v = typeof t;
break;
case NOT:
v = !getValue(execute(n[0], x));
break;
case BITWISE_NOT:
v = ~getValue(execute(n[0], x));
break;
case UNARY_PLUS:
v = +getValue(execute(n[0], x));
break;
case UNARY_MINUS:
v = -getValue(execute(n[0], x));
break;
case INCREMENT:
case DECREMENT:
t = execute(n[0], x);
u = Number(getValue(t));
if (n.postfix)
v = u;
putValue(t, (n.type == INCREMENT) ? ++u : --u, n[0]);
if (!n.postfix)
v = u;
break;
case DOT:
r = execute(n[0], x);
t = getValue(r);
u = n[1].value;
v = new Reference(toObject(t, r, n[0]), u, n);
break;
case INDEX:
r = execute(n[0], x);
t = getValue(r);
u = getValue(execute(n[1], x));
v = new Reference(toObject(t, r, n[0]), String(u), n);
break;
case LIST:
// Curse ECMA for specifying that arguments is not an Array object!
v = {};
for (i = 0, j = n.length; i < j; i++) {
u = getValue(execute(n[i], x));
v.__defineProperty__(i, u, false, false, true);
}
v.__defineProperty__('length', i, false, false, true);
break;
case CALL:
r = execute(n[0], x);
a = execute(n[1], x);
f = getValue(r);
if (isPrimitive(f) || typeof f.__call__ != "function") {
throw new TypeError(r + " is not callable",
n[0].filename, n[0].lineno);
}
t = (r instanceof Reference) ? r.base : null;
if (t instanceof Activation)
t = null;
v = f.__call__(t, a, x);
break;
case NEW:
case NEW_WITH_ARGS:
r = execute(n[0], x);
f = getValue(r);
if (n.type == NEW) {
a = {};
a.__defineProperty__('length', 0, false, false, true);
} else {
a = execute(n[1], x);
}
if (isPrimitive(f) || typeof f.__construct__ != "function") {
throw new TypeError(r + " is not a constructor",
n[0].filename, n[0].lineno);
}
v = f.__construct__(a, x);
break;
case ARRAY_INIT:
v = [];
for (i = 0, j = n.length; i < j; i++) {
if (n[i])
v[i] = getValue(execute(n[i], x));
}
v.length = j;
break;
case OBJECT_INIT:
v = {};
for (i = 0, j = n.length; i < j; i++) {
t = n[i];
if (t.type == PROPERTY_INIT) {
v[t[0].value] = getValue(execute(t[1], x));
} else {
f = new FunctionObject(t, x.scope);
u = (t.type == GETTER) ? '__defineGetter__'
: '__defineSetter__';
v[u](t.name, thunk(f, x));
}
}
break;
case NULL:
v = null;
break;
case THIS:
v = x.thisObject;
break;
case TRUE:
v = true;
break;
case FALSE:
v = false;
break;
case IDENTIFIER:
for (s = x.scope; s; s = s.parent) {
if (n.value in s.object)
break;
}
v = new Reference(s && s.object, n.value, n);
break;
case NUMBER:
case STRING:
case REGEXP:
v = n.value;
break;
case GROUP:
v = execute(n[0], x);
break;
default:
throw "PANIC: unknown operation " + n.type + ": " + uneval(n);
}
return v;
}
function Activation(f, a) {
for (var i = 0, j = f.params.length; i < j; i++)
this.__defineProperty__(f.params[i], a[i], true);
this.__defineProperty__('arguments', a, true);
}
// Null Activation.prototype's proto slot so that Object.prototype.* does not
// pollute the scope of heavyweight functions. Also delete its 'constructor'
// property so that it doesn't pollute function scopes. But first, we must
// copy __defineProperty__ down from Object.prototype.
Activation.prototype.__defineProperty__ = Object.prototype.__defineProperty__;
Activation.prototype.__proto__ = null;
delete Activation.prototype.constructor;
function FunctionObject(node, scope) {
this.node = node;
this.scope = scope;
this.__defineProperty__('length', node.params.length, true, true, true);
var proto = {};
this.__defineProperty__('prototype', proto, true);
proto.__defineProperty__('constructor', this, false, false, true);
}
var FOp = FunctionObject.prototype = {
// Internal methods.
__call__: function (t, a, x) {
var x2 = new ExecutionContext(FUNCTION_CODE);
x2.thisObject = t || global;
x2.caller = x;
x2.callee = this;
a.__defineProperty__('callee', this, false, false, true);
var f = this.node;
x2.scope = {object: new Activation(f, a), parent: this.scope};
ExecutionContext.current = x2;
try {
execute(f.body, x2);
} catch (e if e == RETURN) {
return x2.result;
} catch (e if e == THROW) {
x.result = x2.result;
throw THROW;
} finally {
ExecutionContext.current = x;
}
return undefined;
},
__construct__: function (a, x) {
var o = new Object;
var p = this.prototype;
if (isObject(p))
o.__proto__ = p;
// else o.__proto__ defaulted to Object.prototype
var v = this.__call__(o, a, x);
if (isObject(v))
return v;
return o;
},
__hasInstance__: function (v) {
if (isPrimitive(v))
return false;
var p = this.prototype;
if (isPrimitive(p)) {
throw new TypeError("'prototype' property is not an object",
this.node.filename, this.node.lineno);
}
var o;
while ((o = v.__proto__)) {
if (o == p)
return true;
v = o;
}
return false;
},
// Standard methods.
toString: function () {
return this.node.getSource();
},
apply: function (t, a) {
// Curse ECMA again!
if (typeof this.__call__ != "function") {
throw new TypeError("Function.prototype.apply called on" +
" uncallable object");
}
if (t === undefined || t === null)
t = global;
else if (typeof t != "object")
t = toObject(t, t);
if (a === undefined || a === null) {
a = {};
a.__defineProperty__('length', 0, false, false, true);
} else if (a instanceof Array) {
var v = {};
for (var i = 0, j = a.length; i < j; i++)
v.__defineProperty__(i, a[i], false, false, true);
v.__defineProperty__('length', i, false, false, true);
a = v;
} else if (!(a instanceof Object)) {
// XXX check for a non-arguments object
throw new TypeError("Second argument to Function.prototype.apply" +
" must be an array or arguments object",
this.node.filename, this.node.lineno);
}
return this.__call__(t, a, ExecutionContext.current);
},
call: function (t) {
// Curse ECMA a third time!
var a = Array.prototype.splice.call(arguments, 1);
return this.apply(t, a);
}
};
// Connect Function.prototype and Function.prototype.constructor in global.
reflectClass('Function', FOp);
// Help native and host-scripted functions be like FunctionObjects.
var Fp = Function.prototype;
var REp = RegExp.prototype;
if (!('__call__' in Fp)) {
Fp.__defineProperty__('__call__', function (t, a, x) {
// Curse ECMA yet again!
a = Array.prototype.splice.call(a, 0, a.length);
return this.apply(t, a);
}, true, true, true);
REp.__defineProperty__('__call__', function (t, a, x) {
a = Array.prototype.splice.call(a, 0, a.length);
return this.exec.apply(this, a);
}, true, true, true);
Fp.__defineProperty__('__construct__', function (a, x) {
a = Array.prototype.splice.call(a, 0, a.length);
return this.__applyConstructor__(a);
}, true, true, true);
// Since we use native functions such as Date along with host ones such
// as global.eval, we want both to be considered instances of the native
// Function constructor.
Fp.__defineProperty__('__hasInstance__', function (v) {
return v instanceof Function || v instanceof global.Function;
}, true, true, true);
}
function thunk(f, x) {
return function () { return f.__call__(this, arguments, x); };
}
function evaluate(s, f, l) {
if (typeof s != "string")
return s;
var x = ExecutionContext.current;
var x2 = new ExecutionContext(GLOBAL_CODE);
ExecutionContext.current = x2;
try {
execute(parse(s, f, l), x2);
} catch (e if e == THROW) {
if (x) {
x.result = x2.result;
throw THROW;
}
throw x2.result;
} finally {
ExecutionContext.current = x;
}
return x2.result;
}