source: webkit/trunk/JavaScriptCore/kjs/internal.cpp@ 10563

/*
 *  This file is part of the KDE libraries
 *  Copyright (C) 1999-2002 Harri Porten ([email protected])
 *  Copyright (C) 2001 Peter Kelly ([email protected])
 *  Copyright (C) 2004 Apple Computer, Inc.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#include <stdio.h>
#include <math.h>
#include <assert.h>

#include "array_object.h"
#include "bool_object.h"
#include "collector.h"
#include "context.h"
#include "date_object.h"
#include "debugger.h"
#include "error_object.h"
#include "function_object.h"
#include "internal.h"
#include "interpreter_map.h"
#include "lexer.h"
#include "math_object.h"
#include "nodes.h"
#include "number_object.h"
#include "object.h"
#include "object_object.h"
#include "operations.h"
#include "regexp_object.h"
#include "string_object.h"

#if WIN32
#include <float.h>
#define copysign(a, b) _copysign(a, b)
#endif

extern int kjsyyparse();

using namespace KXMLCore;

namespace KJS {

#if !APPLE_CHANGES
 
#ifdef WORDS_BIGENDIAN
  const unsigned char NaN_Bytes[] = { 0x7f, 0xf8, 0, 0, 0, 0, 0, 0 };
  const unsigned char Inf_Bytes[] = { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 };
#elif defined(arm)
  const unsigned char NaN_Bytes[] = { 0, 0, 0xf8, 0x7f, 0, 0, 0, 0 };
  const unsigned char Inf_Bytes[] = { 0, 0, 0xf0, 0x7f, 0, 0, 0, 0 };
#else
  const unsigned char NaN_Bytes[] = { 0, 0, 0, 0, 0, 0, 0xf8, 0x7f };
  const unsigned char Inf_Bytes[] = { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f };
#endif
 
  const double NaN = *(const double*) NaN_Bytes;
  const double Inf = *(const double*) Inf_Bytes;
 
#endif // APPLE_CHANGES

#if !KJS_MULTIPLE_THREADS

static inline void initializeInterpreterLock() { }
static inline void lockInterpreter() { }
static inline void unlockInterpreter() { }

const int interpreterLockCount = 1;

#else

static pthread_once_t interpreterLockOnce = PTHREAD_ONCE_INIT;
static pthread_mutex_t interpreterLock;
static int interpreterLockCount = 0;

static void initializeInterpreterLock()
{
  pthread_mutexattr_t attr;

  pthread_mutexattr_init(&attr);
  pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);

  pthread_mutex_init(&interpreterLock, &attr);
}

static inline void lockInterpreter()
{
  pthread_once(&interpreterLockOnce, initializeInterpreterLock);
  pthread_mutex_lock(&interpreterLock);
  interpreterLockCount++;
  Collector::registerThread();
}

static inline void unlockInterpreter()
{
  interpreterLockCount--;
  pthread_mutex_unlock(&interpreterLock);
}

#endif

// ------------------------------ UndefinedImp ---------------------------------

ValueImp *UndefinedImp::toPrimitive(ExecState */*exec*/, Type) const
{
  return const_cast<UndefinedImp *>(this);
}

bool UndefinedImp::toBoolean(ExecState */*exec*/) const
{
  return false;
}

double UndefinedImp::toNumber(ExecState */*exec*/) const
{
  return NaN;
}

UString UndefinedImp::toString(ExecState */*exec*/) const
{
  return "undefined";
}

ObjectImp *UndefinedImp::toObject(ExecState *exec) const
{
  return throwError(exec, TypeError, "Undefined value");
}

// ------------------------------ NullImp --------------------------------------

ValueImp *NullImp::toPrimitive(ExecState */*exec*/, Type) const
{
  return const_cast<NullImp *>(this);
}

bool NullImp::toBoolean(ExecState */*exec*/) const
{
  return false;
}

double NullImp::toNumber(ExecState */*exec*/) const
{
  return 0.0;
}

UString NullImp::toString(ExecState */*exec*/) const
{
  return "null";
}

ObjectImp *NullImp::toObject(ExecState *exec) const
{
  return throwError(exec, TypeError, "Null value");
}

// ------------------------------ BooleanImp -----------------------------------

ValueImp *BooleanImp::toPrimitive(ExecState */*exec*/, Type) const
{
  return const_cast<BooleanImp *>(this);
}

bool BooleanImp::toBoolean(ExecState */*exec*/) const
{
  return val;
}

double BooleanImp::toNumber(ExecState */*exec*/) const
{
  return val ? 1.0 : 0.0;
}

UString BooleanImp::toString(ExecState */*exec*/) const
{
  return val ? "true" : "false";
}

ObjectImp *BooleanImp::toObject(ExecState *exec) const
{
  List args;
  args.append(const_cast<BooleanImp*>(this));
  return static_cast<ObjectImp *>(exec->lexicalInterpreter()->builtinBoolean()->construct(exec,args));
}

// ------------------------------ StringImp ------------------------------------

ValueImp *StringImp::toPrimitive(ExecState */*exec*/, Type) const
{
  return const_cast<StringImp *>(this);
}

bool StringImp::toBoolean(ExecState */*exec*/) const
{
  return (val.size() > 0);
}

double StringImp::toNumber(ExecState */*exec*/) const
{
  return val.toDouble();
}

UString StringImp::toString(ExecState */*exec*/) const
{
  return val;
}

ObjectImp *StringImp::toObject(ExecState *exec) const
{
  List args;
  args.append(const_cast<StringImp*>(this));
  return static_cast<ObjectImp *>(exec->lexicalInterpreter()->builtinString()->construct(exec, args));
}

// ------------------------------ NumberImp ------------------------------------

ValueImp *NumberImp::toPrimitive(ExecState *, Type) const
{
  return const_cast<NumberImp *>(this);
}

bool NumberImp::toBoolean(ExecState *) const
{
  return !((val == 0) /* || (iVal() == N0) */ || isNaN(val));
}

double NumberImp::toNumber(ExecState *) const
{
  return val;
}

UString NumberImp::toString(ExecState *) const
{
  if (val == 0.0) // +0.0 or -0.0
    return "0";
  return UString::from(val);
}

ObjectImp *NumberImp::toObject(ExecState *exec) const
{
  List args;
  args.append(const_cast<NumberImp*>(this));
  return static_cast<ObjectImp *>(exec->lexicalInterpreter()->builtinNumber()->construct(exec,args));
}

bool NumberImp::getUInt32(uint32_t& uint32) const
{
  uint32 = (uint32_t)val;
  return (double)uint32 == val;
}

// ------------------------------ LabelStack -----------------------------------

bool LabelStack::push(const Identifier &id)
{
  if (contains(id))
    return false;

  StackElem *newtos = new StackElem;
  newtos->id = id;
  newtos->prev = tos;
  tos = newtos;
  return true;
}

bool LabelStack::contains(const Identifier &id) const
{
  if (id.isEmpty())
    return true;

  for (StackElem *curr = tos; curr; curr = curr->prev)
    if (curr->id == id)
      return true;

  return false;
}

// ------------------------------ ContextImp -----------------------------------

// ECMA 10.2
ContextImp::ContextImp(ObjectImp *glob, InterpreterImp *interpreter, ObjectImp *thisV, CodeType type,
                       ContextImp *callingCon, FunctionImp *func, const List *args)
    : _interpreter(interpreter), _function(func), _arguments(args)
{
  m_codeType = type;
  _callingContext = callingCon;

  // create and initialize activation object (ECMA 10.1.6)
  if (type == FunctionCode || type == AnonymousCode ) {
    activation = new ActivationImp(func, *args);
    variable = activation;
  } else {
    activation = NULL;
    variable = glob;
  }

  // ECMA 10.2
  switch(type) {
    case EvalCode:
      if (_callingContext) {
        scope = _callingContext->scopeChain();
        variable = _callingContext->variableObject();
        thisVal = _callingContext->thisValue();
        break;
      } // else same as GlobalCode
    case GlobalCode:
      scope.clear();
      scope.push(glob);
      thisVal = static_cast<ObjectImp*>(glob);
      break;
    case FunctionCode:
    case AnonymousCode:
      if (type == FunctionCode) {
        scope = func->scope();
        scope.push(activation);
      } else {
        scope.clear();
        scope.push(glob);
        scope.push(activation);
      }
      variable = activation; // TODO: DontDelete ? (ECMA 10.2.3)
      thisVal = thisV;
      break;
    }

  _interpreter->setContext(this);
}

ContextImp::~ContextImp()
{
  _interpreter->setContext(_callingContext);
}

void ContextImp::mark()
{
  for (ContextImp *context = this; context; context = context->_callingContext) {
    context->scope.mark();
  }
}

// ------------------------------ Parser ---------------------------------------

static SharedPtr<ProgramNode> *progNode;
int Parser::sid = 0;

const int initialCapacity = 64;
const int growthFactor = 2;

static int numNewNodes;
static int newNodesCapacity;
static Node **newNodes;

void Parser::saveNewNode(Node *node)
{
  if (numNewNodes == newNodesCapacity) {
    newNodesCapacity = (newNodesCapacity == 0) ? initialCapacity : newNodesCapacity * growthFactor;
    newNodes = (Node **)realloc(newNodes, sizeof(Node *) * newNodesCapacity);
  }

  newNodes[numNewNodes++] = node;
}

static void clearNewNodes()
{
  for (int i = 0; i < numNewNodes; i++) {
    if (newNodes[i]->refcount() == 0)
      delete newNodes[i];
  }
  delete newNodes;
  newNodes = 0;
  numNewNodes = 0;
  newNodesCapacity = 0;
}

SharedPtr<ProgramNode> Parser::parse(const UString &sourceURL, int startingLineNumber,
                                     const UChar *code, unsigned int length, int *sourceId,
                                     int *errLine, UString *errMsg)
{
  if (errLine)
    *errLine = -1;
  if (errMsg)
    *errMsg = 0;
  if (!progNode)
    progNode = new SharedPtr<ProgramNode>;

  Lexer::curr()->setCode(sourceURL, startingLineNumber, code, length);
  *progNode = 0;
  sid++;
  if (sourceId)
    *sourceId = sid;
  // Enable this (and the #define YYDEBUG in grammar.y) to debug a parse error
  //extern int kjsyydebug;
  //kjsyydebug=1;
  int parseError = kjsyyparse();
  bool lexError = Lexer::curr()->sawError();
  Lexer::curr()->doneParsing();
  SharedPtr<ProgramNode> prog = *progNode;
  *progNode = 0;

  clearNewNodes();

  if (parseError || lexError) {
    int eline = Lexer::curr()->lineNo();
    if (errLine)
      *errLine = eline;
    if (errMsg)
      *errMsg = "Parse error";
    return SharedPtr<ProgramNode>();
  }

  return prog;
}

void Parser::accept(ProgramNode *prog)
{
  *progNode = prog;
}

// ------------------------------ InterpreterImp -------------------------------

InterpreterImp* InterpreterImp::s_hook = 0L;

void InterpreterImp::globalInit()
{
    ConstantValues::init();
}

void InterpreterImp::globalClear()
{
    ConstantValues::clear();
}

InterpreterImp::InterpreterImp(Interpreter *interp, ObjectImp *glob)
    : globExec(interp, 0)
    , _context(0)
{
  // add this interpreter to the global chain
  // as a root set for garbage collection
  InterpreterLock lock;

  m_interpreter = interp;
  if (s_hook) {
    prev = s_hook;
    next = s_hook->next;
    s_hook->next->prev = this;
    s_hook->next = this;
  } else {
    // This is the first interpreter
    s_hook = next = prev = this;
    globalInit();
  }

  InterpreterMap::setInterpreterForGlobalObject(this, glob);

  global = glob;
  dbg = 0;
  m_compatMode = Interpreter::NativeMode;

  // initialize properties of the global object
  initGlobalObject();

  recursion = 0;
}

void InterpreterImp::lock()
{
  lockInterpreter();
}

int InterpreterImp::lockCount()
{
  return interpreterLockCount;
}

void InterpreterImp::unlock()
{
  unlockInterpreter();
}

 void InterpreterImp::initGlobalObject()
{
  Identifier::init();
  
  // Contructor prototype objects (Object.prototype, Array.prototype etc)

  FunctionPrototypeImp *funcProto = new FunctionPrototypeImp(&globExec);
  b_FunctionPrototype = funcProto;
  ObjectPrototypeImp *objProto = new ObjectPrototypeImp(&globExec, funcProto);
  b_ObjectPrototype = objProto;
  funcProto->setPrototype(b_ObjectPrototype);

  ArrayPrototypeImp *arrayProto = new ArrayPrototypeImp(&globExec, objProto);
  b_ArrayPrototype = arrayProto;
  StringPrototypeImp *stringProto = new StringPrototypeImp(&globExec, objProto);
  b_StringPrototype = stringProto;
  BooleanPrototypeImp *booleanProto = new BooleanPrototypeImp(&globExec, objProto, funcProto);
  b_BooleanPrototype = booleanProto;
  NumberPrototypeImp *numberProto = new NumberPrototypeImp(&globExec, objProto, funcProto);
  b_NumberPrototype = numberProto;
  DatePrototypeImp *dateProto = new DatePrototypeImp(&globExec, objProto);
  b_DatePrototype = dateProto;
  RegExpPrototypeImp *regexpProto = new RegExpPrototypeImp(&globExec, objProto, funcProto);
  b_RegExpPrototype = regexpProto;
  ErrorPrototypeImp *errorProto = new ErrorPrototypeImp(&globExec, objProto, funcProto);
  b_ErrorPrototype = errorProto;

  static_cast<ObjectImp*>(global)->setPrototype(b_ObjectPrototype);

  // Constructors (Object, Array, etc.)
  b_Object = new ObjectObjectImp(&globExec, objProto, funcProto);
  b_Function = new FunctionObjectImp(&globExec, funcProto);
  b_Array = new ArrayObjectImp(&globExec, funcProto, arrayProto);
  b_String = new StringObjectImp(&globExec, funcProto, stringProto);
  b_Boolean = new BooleanObjectImp(&globExec, funcProto, booleanProto);
  b_Number = new NumberObjectImp(&globExec, funcProto, numberProto);
  b_Date = new DateObjectImp(&globExec, funcProto, dateProto);
  b_RegExp = new RegExpObjectImp(&globExec, funcProto, regexpProto);
  b_Error = new ErrorObjectImp(&globExec, funcProto, errorProto);

  // Error object prototypes
  b_evalErrorPrototype = new NativeErrorPrototypeImp(&globExec, errorProto, EvalError, "EvalError", "EvalError");
  b_rangeErrorPrototype = new NativeErrorPrototypeImp(&globExec, errorProto, RangeError, "RangeError", "RangeError");
  b_referenceErrorPrototype = new NativeErrorPrototypeImp(&globExec, errorProto, ReferenceError, "ReferenceError", "ReferenceError");
  b_syntaxErrorPrototype = new NativeErrorPrototypeImp(&globExec, errorProto, SyntaxError, "SyntaxError", "SyntaxError");
  b_typeErrorPrototype = new NativeErrorPrototypeImp(&globExec, errorProto, TypeError, "TypeError", "TypeError");
  b_uriErrorPrototype = new NativeErrorPrototypeImp(&globExec, errorProto, URIError, "URIError", "URIError");

  // Error objects
  b_evalError = new NativeErrorImp(&globExec, funcProto, b_evalErrorPrototype);
  b_rangeError = new NativeErrorImp(&globExec, funcProto, b_rangeErrorPrototype);
  b_referenceError = new NativeErrorImp(&globExec, funcProto, b_referenceErrorPrototype);
  b_syntaxError = new NativeErrorImp(&globExec, funcProto, b_syntaxErrorPrototype);
  b_typeError = new NativeErrorImp(&globExec, funcProto, b_typeErrorPrototype);
  b_uriError = new NativeErrorImp(&globExec, funcProto, b_uriErrorPrototype);

  // ECMA 15.3.4.1
  funcProto->put(&globExec, "constructor", b_Function, DontEnum);

  global->put(&globExec, "Object", b_Object, DontEnum);
  global->put(&globExec, "Function", b_Function, DontEnum);
  global->put(&globExec, "Array", b_Array, DontEnum);
  global->put(&globExec, "Boolean", b_Boolean, DontEnum);
  global->put(&globExec, "String", b_String, DontEnum);
  global->put(&globExec, "Number", b_Number, DontEnum);
  global->put(&globExec, "Date", b_Date, DontEnum);
  global->put(&globExec, "RegExp", b_RegExp, DontEnum);
  global->put(&globExec, "Error", b_Error, DontEnum);
  // Using Internal for those to have something != 0
  // (see kjs_window). Maybe DontEnum would be ok too ?
  global->put(&globExec, "EvalError",b_evalError, Internal);
  global->put(&globExec, "RangeError",b_rangeError, Internal);
  global->put(&globExec, "ReferenceError",b_referenceError, Internal);
  global->put(&globExec, "SyntaxError",b_syntaxError, Internal);
  global->put(&globExec, "TypeError",b_typeError, Internal);
  global->put(&globExec, "URIError",b_uriError, Internal);

  // Set the "constructor" property of all builtin constructors
  objProto->put(&globExec, "constructor", b_Object, DontEnum | DontDelete | ReadOnly);
  funcProto->put(&globExec, "constructor", b_Function, DontEnum | DontDelete | ReadOnly);
  arrayProto->put(&globExec, "constructor", b_Array, DontEnum | DontDelete | ReadOnly);
  booleanProto->put(&globExec, "constructor", b_Boolean, DontEnum | DontDelete | ReadOnly);
  stringProto->put(&globExec, "constructor", b_String, DontEnum | DontDelete | ReadOnly);
  numberProto->put(&globExec, "constructor", b_Number, DontEnum | DontDelete | ReadOnly);
  dateProto->put(&globExec, "constructor", b_Date, DontEnum | DontDelete | ReadOnly);
  regexpProto->put(&globExec, "constructor", b_RegExp, DontEnum | DontDelete | ReadOnly);
  errorProto->put(&globExec, "constructor", b_Error, DontEnum | DontDelete | ReadOnly);
  b_evalErrorPrototype->put(&globExec, "constructor", b_evalError, DontEnum | DontDelete | ReadOnly);
  b_rangeErrorPrototype->put(&globExec, "constructor", b_rangeError, DontEnum | DontDelete | ReadOnly);
  b_referenceErrorPrototype->put(&globExec, "constructor", b_referenceError, DontEnum | DontDelete | ReadOnly);
  b_syntaxErrorPrototype->put(&globExec, "constructor", b_syntaxError, DontEnum | DontDelete | ReadOnly);
  b_typeErrorPrototype->put(&globExec, "constructor", b_typeError, DontEnum | DontDelete | ReadOnly);
  b_uriErrorPrototype->put(&globExec, "constructor", b_uriError, DontEnum | DontDelete | ReadOnly);

  // built-in values
  global->put(&globExec, "NaN",        jsNaN(), DontEnum|DontDelete);
  global->put(&globExec, "Infinity",   Number(Inf), DontEnum|DontDelete);
  global->put(&globExec, "undefined",  Undefined(), DontEnum|DontDelete);

  // built-in functions
  global->put(&globExec, "eval",       new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::Eval, 1), DontEnum);
  global->put(&globExec, "parseInt",   new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::ParseInt, 2), DontEnum);
  global->put(&globExec, "parseFloat", new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::ParseFloat, 1), DontEnum);
  global->put(&globExec, "isNaN",      new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::IsNaN, 1), DontEnum);
  global->put(&globExec, "isFinite",   new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::IsFinite, 1), DontEnum);
  global->put(&globExec, "escape",     new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::Escape, 1), DontEnum);
  global->put(&globExec, "unescape",   new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::UnEscape, 1), DontEnum);
  global->put(&globExec, "decodeURI",  new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::DecodeURI, 1), DontEnum);
  global->put(&globExec, "decodeURIComponent", new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::DecodeURIComponent, 1), DontEnum);
  global->put(&globExec, "encodeURI",  new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::EncodeURI, 1), DontEnum);
  global->put(&globExec, "encodeURIComponent", new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::EncodeURIComponent, 1), DontEnum);
#ifndef NDEBUG
  global->put(&globExec, "kjsprint",   new GlobalFuncImp(&globExec, funcProto, GlobalFuncImp::KJSPrint, 1), DontEnum);
#endif

  // built-in objects
  global->put(&globExec, "Math", new MathObjectImp(&globExec, objProto), DontEnum);
}

InterpreterImp::~InterpreterImp()
{
  if (dbg)
    dbg->detach(m_interpreter);
  clear();
}

void InterpreterImp::clear()
{
  //fprintf(stderr,"InterpreterImp::clear\n");
  // remove from global chain (see init())
  InterpreterLock lock;

  next->prev = prev;
  prev->next = next;
  s_hook = next;
  if (s_hook == this)
  {
    // This was the last interpreter
    s_hook = 0L;
    globalClear();
  }
  InterpreterMap::removeInterpreterForGlobalObject(global);
}

void InterpreterImp::mark()
{
  ConstantValues::mark();
  if (m_interpreter)
    m_interpreter->mark();
  if (_context)
    _context->mark();
  if (global)
      global->mark();
  if (globExec._exception)
      globExec._exception->mark();
}

bool InterpreterImp::checkSyntax(const UString &code)
{
  InterpreterLock lock;

  // Parser::parse() returns 0 in a syntax error occurs, so we just check for that
  SharedPtr<ProgramNode> progNode = Parser::parse(UString(), 0, code.data(),code.size(),0,0,0);
  return progNode;
}

Completion InterpreterImp::evaluate(const UString &code, ValueImp *thisV, const UString &sourceURL, int startingLineNumber)
{
  InterpreterLock lock;

  // prevent against infinite recursion
  if (recursion >= 20) {
#if APPLE_CHANGES
    Completion result = Completion(Throw, Error::create(&globExec, GeneralError, "Recursion too deep"));
    return result;
#else
    return Completion(Throw,Error::create(&globExec, GeneralError, "Recursion too deep"));
#endif
  }

  // parse the source code
  int sid;
  int errLine;
  UString errMsg;
  SharedPtr<ProgramNode> progNode = Parser::parse(sourceURL, startingLineNumber, code.data(),code.size(),&sid,&errLine,&errMsg);

  // notify debugger that source has been parsed
  if (dbg) {
    bool cont = dbg->sourceParsed(&globExec, sid, sourceURL, code, errLine);
    if (!cont)
      return Completion(Break);
  }
  
  // no program node means a syntax error occurred
  if (!progNode) {
    ObjectImp *err = Error::create(&globExec, SyntaxError, errMsg, errLine, sid, &sourceURL);
    return Completion(Throw,err);
  }

  globExec.clearException();

  recursion++;

  ObjectImp *globalObj = globalObject();
  ObjectImp *thisObj = globalObject();

  if (thisV) {
    // "this" must be an object... use same rules as Function.prototype.apply()
    if (thisV->isUndefinedOrNull())
      thisObj = globalObject();
    else {
      thisObj = thisV->toObject(&globExec);
    }
  }

  Completion res;
  if (globExec.hadException()) {
    // the thisArg->toObject() conversion above might have thrown an exception - if so,
    // propagate it back
    res = Completion(Throw, globExec.exception());
  }
  else {
    // execute the code
    ContextImp ctx(globalObj, this, thisObj);
    ExecState newExec(m_interpreter, &ctx);
    progNode->processVarDecls(&newExec);
    res = progNode->execute(&newExec);
  }

  recursion--;

  return res;
}

void InterpreterImp::saveBuiltins (SavedBuiltins &builtins) const
{
  if (!builtins._internal) {
    builtins._internal = new SavedBuiltinsInternal;
  }

  builtins._internal->b_Object = b_Object;
  builtins._internal->b_Function = b_Function;
  builtins._internal->b_Array = b_Array;
  builtins._internal->b_Boolean = b_Boolean;
  builtins._internal->b_String = b_String;
  builtins._internal->b_Number = b_Number;
  builtins._internal->b_Date = b_Date;
  builtins._internal->b_RegExp = b_RegExp;
  builtins._internal->b_Error = b_Error;
  
  builtins._internal->b_ObjectPrototype = b_ObjectPrototype;
  builtins._internal->b_FunctionPrototype = b_FunctionPrototype;
  builtins._internal->b_ArrayPrototype = b_ArrayPrototype;
  builtins._internal->b_BooleanPrototype = b_BooleanPrototype;
  builtins._internal->b_StringPrototype = b_StringPrototype;
  builtins._internal->b_NumberPrototype = b_NumberPrototype;
  builtins._internal->b_DatePrototype = b_DatePrototype;
  builtins._internal->b_RegExpPrototype = b_RegExpPrototype;
  builtins._internal->b_ErrorPrototype = b_ErrorPrototype;
  
  builtins._internal->b_evalError = b_evalError;
  builtins._internal->b_rangeError = b_rangeError;
  builtins._internal->b_referenceError = b_referenceError;
  builtins._internal->b_syntaxError = b_syntaxError;
  builtins._internal->b_typeError = b_typeError;
  builtins._internal->b_uriError = b_uriError;
  
  builtins._internal->b_evalErrorPrototype = b_evalErrorPrototype;
  builtins._internal->b_rangeErrorPrototype = b_rangeErrorPrototype;
  builtins._internal->b_referenceErrorPrototype = b_referenceErrorPrototype;
  builtins._internal->b_syntaxErrorPrototype = b_syntaxErrorPrototype;
  builtins._internal->b_typeErrorPrototype = b_typeErrorPrototype;
  builtins._internal->b_uriErrorPrototype = b_uriErrorPrototype;
}

void InterpreterImp::restoreBuiltins (const SavedBuiltins &builtins)
{
  if (!builtins._internal) {
    return;
  }

  b_Object = builtins._internal->b_Object;
  b_Function = builtins._internal->b_Function;
  b_Array = builtins._internal->b_Array;
  b_Boolean = builtins._internal->b_Boolean;
  b_String = builtins._internal->b_String;
  b_Number = builtins._internal->b_Number;
  b_Date = builtins._internal->b_Date;
  b_RegExp = builtins._internal->b_RegExp;
  b_Error = builtins._internal->b_Error;
  
  b_ObjectPrototype = builtins._internal->b_ObjectPrototype;
  b_FunctionPrototype = builtins._internal->b_FunctionPrototype;
  b_ArrayPrototype = builtins._internal->b_ArrayPrototype;
  b_BooleanPrototype = builtins._internal->b_BooleanPrototype;
  b_StringPrototype = builtins._internal->b_StringPrototype;
  b_NumberPrototype = builtins._internal->b_NumberPrototype;
  b_DatePrototype = builtins._internal->b_DatePrototype;
  b_RegExpPrototype = builtins._internal->b_RegExpPrototype;
  b_ErrorPrototype = builtins._internal->b_ErrorPrototype;
  
  b_evalError = builtins._internal->b_evalError;
  b_rangeError = builtins._internal->b_rangeError;
  b_referenceError = builtins._internal->b_referenceError;
  b_syntaxError = builtins._internal->b_syntaxError;
  b_typeError = builtins._internal->b_typeError;
  b_uriError = builtins._internal->b_uriError;
  
  b_evalErrorPrototype = builtins._internal->b_evalErrorPrototype;
  b_rangeErrorPrototype = builtins._internal->b_rangeErrorPrototype;
  b_referenceErrorPrototype = builtins._internal->b_referenceErrorPrototype;
  b_syntaxErrorPrototype = builtins._internal->b_syntaxErrorPrototype;
  b_typeErrorPrototype = builtins._internal->b_typeErrorPrototype;
  b_uriErrorPrototype = builtins._internal->b_uriErrorPrototype;
}

InterpreterImp *InterpreterImp::interpreterWithGlobalObject(ObjectImp *global)
{
  return InterpreterMap::getInterpreterForGlobalObject(global);
}


// ------------------------------ InternalFunctionImp --------------------------

const ClassInfo InternalFunctionImp::info = {"Function", 0, 0, 0};

InternalFunctionImp::InternalFunctionImp()
{
}

InternalFunctionImp::InternalFunctionImp(FunctionPrototypeImp *funcProto)
  : ObjectImp(funcProto)
{
}

bool InternalFunctionImp::implementsHasInstance() const
{
  return true;
}

bool InternalFunctionImp::hasInstance(ExecState *exec, ValueImp *value)
{
  if (!value->isObject())
    return false;

  ValueImp *prot = get(exec,prototypePropertyName);
  if (!prot->isObject() && !prot->isNull()) {
    throwError(exec, TypeError, "Invalid prototype encountered in instanceof operation.");
    return false;
  }

  ObjectImp *v = static_cast<ObjectImp *>(value);
  while ((v = v->prototype()->getObject())) {
    if (v == prot)
      return true;
  }
  return false;
}

// ------------------------------ global functions -----------------------------

double roundValue(ExecState *exec, ValueImp *v)
{
  double d = v->toNumber(exec);
  double ad = fabs(d);
  if (ad == 0 || isNaN(d) || isInf(d))
    return d;
  return copysign(floor(ad), d);
}

#ifndef NDEBUG
#include <stdio.h>
void printInfo(ExecState *exec, const char *s, ValueImp *o, int lineno)
{
  if (!o)
    fprintf(stderr, "KJS: %s: (null)", s);
  else {
    ValueImp *v = o;

    UString name;
    switch (v->type()) {
    case UnspecifiedType:
      name = "Unspecified";
      break;
    case UndefinedType:
      name = "Undefined";
      break;
    case NullType:
      name = "Null";
      break;
    case BooleanType:
      name = "Boolean";
      break;
    case StringType:
      name = "String";
      break;
    case NumberType:
      name = "Number";
      break;
    case ObjectType:
      name = static_cast<ObjectImp *>(v)->className();
      if (name.isNull())
        name = "(unknown class)";
      break;
    }
    UString vString = v->toString(exec);
    if ( vString.size() > 50 )
      vString = vString.substr( 0, 50 ) + "...";
    // Can't use two UString::ascii() in the same fprintf call
    CString tempString( vString.cstring() );

    fprintf(stderr, "KJS: %s: %s : %s (%p)",
            s, tempString.c_str(), name.ascii(), (void*)v);

    if (lineno >= 0)
      fprintf(stderr, ", line %d\n",lineno);
    else
      fprintf(stderr, "\n");
  }
}
#endif

}