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/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.javascript;
/**
* The base class for Function objects. That is one of two purposes. It is also the prototype for
* every "function" defined except those that are used as GeneratorFunctions via the ES6 "function
* *" syntax.
*
* See ECMA 15.3.
*
* @author Norris Boyd
*/
public class BaseFunction extends IdScriptableObject implements Function {
private static final long serialVersionUID = 5311394446546053859L;
private static final Object FUNCTION_TAG = "Function";
private static final String FUNCTION_CLASS = "Function";
static final String GENERATOR_FUNCTION_CLASS = "__GeneratorFunction";
static void init(Scriptable scope, boolean sealed) {
BaseFunction obj = new BaseFunction();
// Function.prototype attributes: see ECMA 15.3.3.1
obj.prototypePropertyAttributes = DONTENUM | READONLY | PERMANENT;
obj.exportAsJSClass(MAX_PROTOTYPE_ID, scope, sealed);
}
static Object initAsGeneratorFunction(Scriptable scope, boolean sealed) {
BaseFunction obj = new BaseFunction(true);
// Function.prototype attributes: see ECMA 15.3.3.1
obj.prototypePropertyAttributes = READONLY | PERMANENT;
obj.exportAsJSClass(MAX_PROTOTYPE_ID, scope, sealed);
// The "GeneratorFunction" name actually never appears in the global scope.
// Return it here so it can be cached as a "builtin"
return ScriptableObject.getProperty(scope, GENERATOR_FUNCTION_CLASS);
}
public BaseFunction() {}
public BaseFunction(boolean isGenerator) {
this.isGeneratorFunction = isGenerator;
}
public BaseFunction(Scriptable scope, Scriptable prototype) {
super(scope, prototype);
}
@Override
public String getClassName() {
return isGeneratorFunction() ? GENERATOR_FUNCTION_CLASS : FUNCTION_CLASS;
}
// Generated code will override this
protected boolean isGeneratorFunction() {
return isGeneratorFunction;
}
/**
* Gets the value returned by calling the typeof operator on this object.
*
* @see org.mozilla.javascript.ScriptableObject#getTypeOf()
* @return "function" or "undefined" if {@link #avoidObjectDetection()} returns true
*
*/
@Override
public String getTypeOf() {
return avoidObjectDetection() ? "undefined" : "function";
}
/**
* Implements the instanceof operator for JavaScript Function objects.
*
*
* foo = new Foo();
* foo instanceof Foo; // true
*
*
* @param instance The value that appeared on the LHS of the instanceof operator
* @return true if the "prototype" property of "this" appears in value's prototype chain
*/
@Override
public boolean hasInstance(Scriptable instance) {
Object protoProp = ScriptableObject.getProperty(this, "prototype");
if (protoProp instanceof Scriptable) {
return ScriptRuntime.jsDelegatesTo(instance, (Scriptable) protoProp);
}
throw ScriptRuntime.typeErrorById("msg.instanceof.bad.prototype", getFunctionName());
}
private static final int Id_length = 1,
Id_arity = 2,
Id_name = 3,
Id_prototype = 4,
Id_arguments = 5,
MAX_INSTANCE_ID = 5;
@Override
protected int getMaxInstanceId() {
return MAX_INSTANCE_ID;
}
@Override
protected int findInstanceIdInfo(String s) {
switch (s) {
case "length":
if (lengthPropertyAttributes >= 0) {
return instanceIdInfo(lengthPropertyAttributes, Id_length);
}
break;
case "arity":
if (arityPropertyAttributes >= 0) {
return instanceIdInfo(arityPropertyAttributes, Id_arity);
}
break;
case "name":
if (namePropertyAttributes >= 0) {
return instanceIdInfo(namePropertyAttributes, Id_name);
}
break;
case "prototype":
if (hasPrototypeProperty()) {
return instanceIdInfo(prototypePropertyAttributes, Id_prototype);
}
break;
case "arguments":
return instanceIdInfo(argumentsAttributes, Id_arguments);
default:
break;
}
return super.findInstanceIdInfo(s);
}
@Override
protected String getInstanceIdName(int id) {
switch (id) {
case Id_length:
return "length";
case Id_arity:
return "arity";
case Id_name:
return "name";
case Id_prototype:
return "prototype";
case Id_arguments:
return "arguments";
}
return super.getInstanceIdName(id);
}
@Override
protected Object getInstanceIdValue(int id) {
switch (id) {
case Id_length:
return lengthPropertyAttributes >= 0 ? getLength() : NOT_FOUND;
case Id_arity:
return arityPropertyAttributes >= 0 ? getArity() : NOT_FOUND;
case Id_name:
return namePropertyAttributes >= 0 ? getFunctionName() : NOT_FOUND;
case Id_prototype:
return getPrototypeProperty();
case Id_arguments:
return getArguments();
}
return super.getInstanceIdValue(id);
}
@Override
protected void setInstanceIdValue(int id, Object value) {
switch (id) {
case Id_prototype:
if ((prototypePropertyAttributes & READONLY) == 0) {
prototypeProperty = (value != null) ? value : UniqueTag.NULL_VALUE;
}
return;
case Id_arguments:
if (value == NOT_FOUND) {
// This should not be called since "arguments" is PERMANENT
Kit.codeBug();
}
if (defaultHas("arguments")) {
defaultPut("arguments", value);
} else if ((argumentsAttributes & READONLY) == 0) {
argumentsObj = value;
}
return;
case Id_name:
if (value == NOT_FOUND) {
namePropertyAttributes = -1;
}
return;
case Id_arity:
if (value == NOT_FOUND) {
arityPropertyAttributes = -1;
}
return;
case Id_length:
if (value == NOT_FOUND) {
lengthPropertyAttributes = -1;
}
return;
}
super.setInstanceIdValue(id, value);
}
@Override
protected void setInstanceIdAttributes(int id, int attr) {
switch (id) {
case Id_prototype:
prototypePropertyAttributes = attr;
return;
case Id_arguments:
argumentsAttributes = attr;
return;
case Id_arity:
arityPropertyAttributes = attr;
return;
case Id_name:
namePropertyAttributes = attr;
return;
case Id_length:
lengthPropertyAttributes = attr;
return;
}
super.setInstanceIdAttributes(id, attr);
}
@Override
protected void fillConstructorProperties(IdFunctionObject ctor) {
// Fix up bootstrapping problem: getPrototype of the IdFunctionObject
// can not return Function.prototype because Function object is not
// yet defined.
ctor.setPrototype(this);
super.fillConstructorProperties(ctor);
}
@Override
protected void initPrototypeId(int id) {
String s;
int arity;
switch (id) {
case Id_constructor:
arity = 1;
s = "constructor";
break;
case Id_toString:
arity = 0;
s = "toString";
break;
case Id_toSource:
arity = 1;
s = "toSource";
break;
case Id_apply:
arity = 2;
s = "apply";
break;
case Id_call:
arity = 1;
s = "call";
break;
case Id_bind:
arity = 1;
s = "bind";
break;
default:
throw new IllegalArgumentException(String.valueOf(id));
}
initPrototypeMethod(FUNCTION_TAG, id, s, arity);
}
static boolean isApply(IdFunctionObject f) {
return f.hasTag(FUNCTION_TAG) && f.methodId() == Id_apply;
}
static boolean isApplyOrCall(IdFunctionObject f) {
if (f.hasTag(FUNCTION_TAG)) {
switch (f.methodId()) {
case Id_apply:
case Id_call:
return true;
}
}
return false;
}
@Override
public Object execIdCall(
IdFunctionObject f, Context cx, Scriptable scope, Scriptable thisObj, Object[] args) {
if (!f.hasTag(FUNCTION_TAG)) {
return super.execIdCall(f, cx, scope, thisObj, args);
}
int id = f.methodId();
switch (id) {
case Id_constructor:
return jsConstructor(cx, scope, args);
case Id_toString:
{
BaseFunction realf = realFunction(thisObj, f);
int indent = ScriptRuntime.toInt32(args, 0);
return realf.decompile(indent, 0);
}
case Id_toSource:
{
BaseFunction realf = realFunction(thisObj, f);
int indent = 0;
int flags = Decompiler.TO_SOURCE_FLAG;
if (args.length != 0) {
indent = ScriptRuntime.toInt32(args[0]);
if (indent >= 0) {
flags = 0;
} else {
indent = 0;
}
}
return realf.decompile(indent, flags);
}
case Id_apply:
case Id_call:
return ScriptRuntime.applyOrCall(id == Id_apply, cx, scope, thisObj, args);
case Id_bind:
if (!(thisObj instanceof Callable)) {
throw ScriptRuntime.notFunctionError(thisObj);
}
Callable targetFunction = (Callable) thisObj;
int argc = args.length;
final Scriptable boundThis;
final Object[] boundArgs;
if (argc > 0) {
boundThis = ScriptRuntime.toObjectOrNull(cx, args[0], scope);
boundArgs = new Object[argc - 1];
System.arraycopy(args, 1, boundArgs, 0, argc - 1);
} else {
boundThis = null;
boundArgs = ScriptRuntime.emptyArgs;
}
return new BoundFunction(cx, scope, targetFunction, boundThis, boundArgs);
}
throw new IllegalArgumentException(String.valueOf(id));
}
private static BaseFunction realFunction(Scriptable thisObj, IdFunctionObject f) {
if (thisObj == null) {
throw ScriptRuntime.notFunctionError(null);
}
Object x = thisObj.getDefaultValue(ScriptRuntime.FunctionClass);
if (x instanceof Delegator) {
x = ((Delegator) x).getDelegee();
}
return ensureType(x, BaseFunction.class, f);
}
/** Make value as DontEnum, DontDelete, ReadOnly prototype property of this Function object */
public void setImmunePrototypeProperty(Object value) {
if ((prototypePropertyAttributes & READONLY) != 0) {
throw new IllegalStateException();
}
prototypeProperty = (value != null) ? value : UniqueTag.NULL_VALUE;
prototypePropertyAttributes = DONTENUM | PERMANENT | READONLY;
}
protected Scriptable getClassPrototype() {
Object protoVal = getPrototypeProperty();
if (protoVal instanceof Scriptable) {
return (Scriptable) protoVal;
}
return ScriptableObject.getObjectPrototype(this);
}
/** Should be overridden. */
@Override
public Object call(Context cx, Scriptable scope, Scriptable thisObj, Object[] args) {
return Undefined.instance;
}
@Override
public Scriptable construct(Context cx, Scriptable scope, Object[] args) {
Scriptable result = createObject(cx, scope);
if (result != null) {
Object val = call(cx, scope, result, args);
if (val instanceof Scriptable) {
result = (Scriptable) val;
}
} else {
Object val = call(cx, scope, null, args);
if (!(val instanceof Scriptable)) {
// It is program error not to return Scriptable from
// the call method if createObject returns null.
throw new IllegalStateException(
"Bad implementation of call as constructor, name="
+ getFunctionName()
+ " in "
+ getClass().getName());
}
result = (Scriptable) val;
if (result.getPrototype() == null) {
Scriptable proto = getClassPrototype();
if (result != proto) {
result.setPrototype(proto);
}
}
if (result.getParentScope() == null) {
Scriptable parent = getParentScope();
if (result != parent) {
result.setParentScope(parent);
}
}
}
return result;
}
/**
* Creates new script object. The default implementation of {@link #construct} uses the method
* to to get the value for thisObj argument when invoking {@link #call}. The methos
* is allowed to return null to indicate that {@link #call} will create a new
* object itself. In this case {@link #construct} will set scope and prototype on the result
* {@link #call} unless they are already set.
*/
public Scriptable createObject(Context cx, Scriptable scope) {
Scriptable newInstance = new NativeObject();
newInstance.setPrototype(getClassPrototype());
newInstance.setParentScope(getParentScope());
return newInstance;
}
/**
* Decompile the source information associated with this js function/script back into a string.
*
* @param indent How much to indent the decompiled result.
* @param flags Flags specifying format of decompilation output.
*/
String decompile(int indent, int flags) {
StringBuilder sb = new StringBuilder();
boolean justbody = (0 != (flags & Decompiler.ONLY_BODY_FLAG));
if (!justbody) {
sb.append("function ");
sb.append(getFunctionName());
sb.append("() {\n\t");
}
sb.append("[native code, arity=");
sb.append(getArity());
sb.append("]\n");
if (!justbody) {
sb.append("}\n");
}
return sb.toString();
}
public int getArity() {
return 0;
}
public int getLength() {
return 0;
}
public String getFunctionName() {
return "";
}
/**
* Sets the attributes of the "name", "length", and "arity" properties, which differ for many
* native objects.
*/
public void setStandardPropertyAttributes(int attributes) {
namePropertyAttributes = attributes;
lengthPropertyAttributes = attributes;
arityPropertyAttributes = attributes;
}
public void setPrototypePropertyAttributes(int attributes) {
prototypePropertyAttributes = attributes;
}
protected boolean hasPrototypeProperty() {
return prototypeProperty != null || this instanceof NativeFunction;
}
protected Object getPrototypeProperty() {
Object result = prototypeProperty;
if (result == null) {
// only create default prototype on native JavaScript functions,
// not on built-in functions, java methods, host objects etc.
if (this instanceof NativeFunction) {
result = setupDefaultPrototype();
} else {
result = Undefined.instance;
}
} else if (result == UniqueTag.NULL_VALUE) {
result = null;
}
return result;
}
protected void setPrototypeProperty(Object prototype) {
this.prototypeProperty = prototype;
}
protected synchronized Object setupDefaultPrototype() {
if (prototypeProperty != null) {
return prototypeProperty;
}
NativeObject obj = new NativeObject();
obj.defineProperty("constructor", this, DONTENUM);
// put the prototype property into the object now, then in the
// wacky case of a user defining a function Object(), we don't
// get an infinite loop trying to find the prototype.
prototypeProperty = obj;
Scriptable proto = getObjectPrototype(this);
if (proto != obj) {
// not the one we just made, it must remain grounded
obj.setPrototype(proto);
}
return obj;
}
private Object getArguments() {
// .arguments is deprecated, so we use a slow
// way of getting it that doesn't add to the invocation cost.
// TODO: add warning, error based on version
Object value = defaultHas("arguments") ? defaultGet("arguments") : argumentsObj;
if (value != NOT_FOUND) {
// Should after changing .arguments its
// activation still be available during Function call?
// This code assumes it should not:
// defaultGet("arguments") != NOT_FOUND
// means assigned arguments
return value;
}
Context cx = Context.getContext();
NativeCall activation = ScriptRuntime.findFunctionActivation(cx, this);
return (activation == null) ? null : activation.get("arguments", activation);
}
private Object jsConstructor(Context cx, Scriptable scope, Object[] args) {
int arglen = args.length;
StringBuilder sourceBuf = new StringBuilder();
sourceBuf.append("function ");
if (isGeneratorFunction()) {
sourceBuf.append("* ");
}
/* version != 1.2 Function constructor behavior -
* print 'anonymous' as the function name if the
* version (under which the function was compiled) is
* less than 1.2... or if it's greater than 1.2, because
* we need to be closer to ECMA.
*/
if (cx.getLanguageVersion() != Context.VERSION_1_2) {
sourceBuf.append("anonymous");
}
sourceBuf.append('(');
// Append arguments as coma separated strings
for (int i = 0; i < arglen - 1; i++) {
if (i > 0) {
sourceBuf.append(',');
}
sourceBuf.append(ScriptRuntime.toString(args[i]));
}
sourceBuf.append(") {");
if (arglen != 0) {
// append function body
String funBody = ScriptRuntime.toString(args[arglen - 1]);
sourceBuf.append(funBody);
}
sourceBuf.append("\n}");
String source = sourceBuf.toString();
int[] linep = new int[1];
String filename = Context.getSourcePositionFromStack(linep);
if (filename == null) {
filename = "";
linep[0] = 1;
}
String sourceURI = ScriptRuntime.makeUrlForGeneratedScript(false, filename, linep[0]);
Scriptable global = ScriptableObject.getTopLevelScope(scope);
ErrorReporter reporter;
reporter = DefaultErrorReporter.forEval(cx.getErrorReporter());
Evaluator evaluator = Context.createInterpreter();
if (evaluator == null) {
throw new JavaScriptException("Interpreter not present", filename, linep[0]);
}
// Compile with explicit interpreter instance to force interpreter
// mode.
return cx.compileFunction(global, source, evaluator, reporter, sourceURI, 1, null);
}
@Override
protected int findPrototypeId(String s) {
int id;
switch (s) {
case "constructor":
id = Id_constructor;
break;
case "toString":
id = Id_toString;
break;
case "toSource":
id = Id_toSource;
break;
case "apply":
id = Id_apply;
break;
case "call":
id = Id_call;
break;
case "bind":
id = Id_bind;
break;
default:
id = 0;
break;
}
return id;
}
private static final int Id_constructor = 1,
Id_toString = 2,
Id_toSource = 3,
Id_apply = 4,
Id_call = 5,
Id_bind = 6,
MAX_PROTOTYPE_ID = Id_bind;
private Object prototypeProperty;
private Object argumentsObj = NOT_FOUND;
private boolean isGeneratorFunction = false;
// For function object instances, attributes are
// {configurable:false, enumerable:false};
// see ECMA 15.3.5.2
private int prototypePropertyAttributes = PERMANENT | DONTENUM;
private int argumentsAttributes = PERMANENT | DONTENUM;
private int arityPropertyAttributes = PERMANENT | READONLY | DONTENUM;
private int namePropertyAttributes = PERMANENT | READONLY | DONTENUM;
private int lengthPropertyAttributes = PERMANENT | READONLY | DONTENUM;
}