function_object.cpp

// krazy:excludeall=doublequote_chars (UStrings aren't QStrings)
/*
 *  This file is part of the KDE libraries
 *  Copyright (C) 1999-2001 Harri Porten ([email protected])
 *  Copyright (C) 2003, 2004, 2005, 2006 Apple Computer, Inc.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */
 
#include "function_object.h"
#include "internal.h"
#include "scriptfunction.h"
#include "array_object.h"
#include "nodes.h"
#include "lexer.h"
#include "debugger.h"
#include "object.h"
 
#include <assert.h>
#include <stdio.h>
#include <string.h>
 
using namespace KJS;
 
// ------------------------------ FunctionPrototype -------------------------
 
FunctionPrototype::FunctionPrototype(ExecState *exec)
{
    static const Identifier *applyPropertyName = new Identifier("apply");
    static const Identifier *callPropertyName = new Identifier("call");
    static const Identifier *bindPropertyName = new Identifier("bind");
 
    putDirect(exec->propertyNames().length, jsNumber(0), DontDelete | ReadOnly | DontEnum);
    putDirectFunction(new FunctionProtoFunc(exec, this, FunctionProtoFunc::ToString, 0, exec->propertyNames().toString), DontEnum);
    putDirectFunction(new FunctionProtoFunc(exec, this, FunctionProtoFunc::Apply, 2, *applyPropertyName), DontEnum);
    putDirectFunction(new FunctionProtoFunc(exec, this, FunctionProtoFunc::Call, 1, *callPropertyName), DontEnum);
    putDirectFunction(new FunctionProtoFunc(exec, this, FunctionProtoFunc::Bind, 1, *bindPropertyName), DontEnum);
}
 
FunctionPrototype::~FunctionPrototype()
{
}
 
// ECMA 15.3.4
JSValue *FunctionPrototype::callAsFunction(ExecState * /*exec*/, JSObject * /*thisObj*/, const List &/*args*/)
{
    return jsUndefined();
}
 
// ------------------------------ FunctionProtoFunc -------------------------
 
FunctionProtoFunc::FunctionProtoFunc(ExecState *exec, FunctionPrototype *funcProto, int i, int len, const Identifier &name)
    : InternalFunctionImp(funcProto, name)
    , id(i)
{
    putDirect(exec->propertyNames().length, len, DontDelete | ReadOnly | DontEnum);
}
 
JSValue *FunctionProtoFunc::callAsFunction(ExecState *exec, JSObject *thisObj, const List &args)
{
    JSValue *result = nullptr;
 
    switch (id) {
    case ToString:
        if (!thisObj || !thisObj->inherits(&InternalFunctionImp::info)) {
#ifndef NDEBUG
            fprintf(stderr, "attempted toString() call on null or non-function object\n");
#endif
            return throwError(exec, TypeError);
        }
        if (thisObj->inherits(&FunctionImp::info)) {
            return jsString(static_cast<FunctionImp *>(thisObj)->toSource());
        } else if (thisObj->inherits(&InternalFunctionImp::info) &&
                   !static_cast<InternalFunctionImp *>(thisObj)->functionName().isNull()) {
            result = jsString("\nfunction " + static_cast<InternalFunctionImp *>(thisObj)->functionName().ustring() + "() {\n"
                              "    [native code]\n}\n");
        } else {
            result = jsString("[function]");
        }
        break;
    case Apply: {
        JSValue *thisArg = args[0];
        JSValue *argArray = args[1];
        JSObject *func = thisObj;
 
        if (!func->implementsCall()) {
            return throwError(exec, TypeError);
        }
 
        JSObject *applyThis;
        if (JSValue::isUndefinedOrNull(thisArg)) {
            applyThis = exec->dynamicInterpreter()->globalObject();
        } else {
            applyThis = JSValue::toObject(thisArg, exec);
        }
 
        List applyArgs;
        if (!JSValue::isUndefinedOrNull(argArray)) {
            if (JSValue::isObject(argArray) &&
                    (static_cast<JSObject *>(argArray)->inherits(&ArrayInstance::info) ||
                     static_cast<JSObject *>(argArray)->inherits(&Arguments::info))) {
 
                JSObject *argArrayObj = static_cast<JSObject *>(argArray);
                unsigned int length = JSValue::toUInt32(argArrayObj->get(exec, exec->propertyNames().length), exec);
                for (unsigned int i = 0; i < length; i++) {
                    applyArgs.append(argArrayObj->get(exec, i));
                }
            } else {
                return throwError(exec, TypeError);
            }
        }
        result = func->call(exec, applyThis, applyArgs);
    }
    break;
    case Call: {
        JSValue *thisArg = args[0];
        JSObject *func = thisObj;
 
        if (!func->implementsCall()) {
            return throwError(exec, TypeError);
        }
 
        JSObject *callThis;
        if (JSValue::isUndefinedOrNull(thisArg)) {
            callThis = exec->dynamicInterpreter()->globalObject();
        } else {
            callThis = JSValue::toObject(thisArg, exec);
        }
 
        result = func->call(exec, callThis, args.copyTail());
    }
    break;
    case Bind: { //ECMA Edition 5.1r6 - 15.3.4.5
        JSObject *target(thisObj);
        if (!target->implementsCall()) {
            return throwError(exec, TypeError, "object is not callable");
        }
 
        List newArgs;
        for (int i = 1; i < args.size(); ++i) {
            newArgs.append(args[i]);
        }
 
        JSObject *boundThis = nullptr;
 
        // As call does not accept JSValue(undefined/null),
        // do it like in call and use the global object
        if (JSValue::isUndefinedOrNull(args[0])) {
            boundThis = exec->dynamicInterpreter()->globalObject();
        } else {
            boundThis = JSValue::toObject(args[0], exec);
        }
 
        BoundFunction *bfunc = new BoundFunction(exec, target, boundThis, newArgs);
 
        unsigned length;
        if (target->inherits(&FunctionImp::info)) {
            double L = JSValue::getNumber(target->get(exec, exec->propertyNames().length)) - newArgs.size();
            length = (unsigned)std::max<int>((int)L, 0);
        } else {
            length = 0;
        }
        bfunc->put(exec, exec->propertyNames().length, jsNumber(length), ReadOnly | DontEnum | DontDelete);
 
        JSObject *thrower = new Thrower(TypeError);
        PropertyDescriptor callerDesc;
 
        GetterSetterImp *gs = new GetterSetterImp();
        gs->setGetter(thrower);
        gs->setSetter(thrower);
 
        callerDesc.setPropertyDescriptorValues(exec, gs, DontEnum | DontDelete);
        bfunc->defineOwnProperty(exec, exec->propertyNames().caller, callerDesc, false);
 
        PropertyDescriptor argumentsDesc;
        argumentsDesc.setPropertyDescriptorValues(exec, gs, DontEnum | DontDelete);
        bfunc->defineOwnProperty(exec, exec->propertyNames().arguments, argumentsDesc, false);
 
        return bfunc;
    }
    break;
    }
 
    return result;
}
 
// ------------------------------ FunctionObjectImp ----------------------------
 
FunctionObjectImp::FunctionObjectImp(ExecState *exec, FunctionPrototype *funcProto)
    : InternalFunctionImp(funcProto)
{
    putDirect(exec->propertyNames().prototype, funcProto, DontEnum | DontDelete | ReadOnly);
 
    // no. of arguments for constructor
    putDirect(exec->propertyNames().length, jsNumber(1), ReadOnly | DontDelete | DontEnum);
}
 
FunctionObjectImp::~FunctionObjectImp()
{
}
 
bool FunctionObjectImp::implementsConstruct() const
{
    return true;
}
 
// ECMA 15.3.2 The Function Constructor
JSObject *FunctionObjectImp::construct(ExecState *exec, const List &args, const Identifier &functionName, const UString &sourceURL, int lineNumber)
{
    UString p("");
    UString body;
    int argsSize = args.size();
    if (argsSize == 0) {
        body = "";
    } else if (argsSize == 1) {
        body = JSValue::toString(args[0], exec);
    } else {
        p = JSValue::toString(args[0], exec);
        for (int k = 1; k < argsSize - 1; k++) {
            p += "," + JSValue::toString(args[k], exec);
        }
        body = JSValue::toString(args[argsSize - 1], exec);
    }
 
    // parse the source code
    int sourceId;
    int errLine;
    UString errMsg;
    RefPtr<FunctionBodyNode> functionBody = parser().parseFunctionBody(sourceURL, lineNumber, body.data(), body.size(), &sourceId, &errLine, &errMsg);
 
    // notify debugger that source has been parsed
    Debugger *dbg = exec->dynamicInterpreter()->debugger();
    if (dbg) {
        // make sure to pass in sourceURL, since it's useful for lazy event listeners, and empty for actual function ctor
        dbg->reportSourceParsed(exec, functionBody.get(), sourceId, sourceURL, body, lineNumber, errLine, errMsg);
    }
 
    // no program node == syntax error - throw a syntax error
    if (!functionBody)
        // we can't return a Completion(Throw) here, so just set the exception
        // and return it
    {
        return throwError(exec, SyntaxError, errMsg, errLine, sourceId, sourceURL);
    }
 
    ScopeChain scopeChain;
    scopeChain.push(exec->lexicalInterpreter()->globalObject());
 
    FunctionImp *fimp = new FunctionImp(exec, functionName, functionBody.get(), scopeChain);
 
    // parse parameter list. throw syntax error on illegal identifiers
    int len = p.size();
    const UChar *c = p.data();
    int i = 0, params = 0;
    UString param;
    while (i < len) {
        while (*c == ' ' && i < len) {
            c++, i++;
        }
        if (Lexer::isIdentStart(c->uc)) {  // else error
            param = UString(c, 1);
            c++, i++;
            while (i < len && (Lexer::isIdentPart(c->uc))) {
                param += UString(c, 1);
                c++, i++;
            }
            while (i < len && *c == ' ') {
                c++, i++;
            }
            if (i == len) {
                functionBody->addParam(Identifier(param));
                params++;
                break;
            } else if (*c == ',') {
                functionBody->addParam(Identifier(param));
                params++;
                c++, i++;
                continue;
            } // else error
        }
        return throwError(exec, SyntaxError, "Syntax error in parameter list");
    }
 
    List consArgs;
 
    JSObject *objCons = exec->lexicalInterpreter()->builtinObject();
    JSObject *prototype = objCons->construct(exec, List::empty());
    prototype->put(exec, exec->propertyNames().constructor, fimp, DontEnum | DontDelete | ReadOnly);
    // ECMA Edition 5.1r6 - 15.3.5.2 - [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: false
    fimp->put(exec, exec->propertyNames().prototype, prototype, Internal | DontDelete | DontEnum);
    return fimp;
}
 
// ECMA 15.3.2 The Function Constructor
JSObject *FunctionObjectImp::construct(ExecState *exec, const List &args)
{
    return construct(exec, args, "anonymous", UString(), 0);
}
 
// ECMA 15.3.1 The Function Constructor Called as a Function
JSValue *FunctionObjectImp::callAsFunction(ExecState *exec, JSObject * /*thisObj*/, const List &args)
{
    return construct(exec, args);
}