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/* -*- Mode: java; tab-width: 4; indent-tabs-mode: 1; c-basic-offset: 4 -*-
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* The contents of this file are subject to the Netscape Public
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* License Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.mozilla.org/NPL/
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* Software distributed under the License is distributed on an "AS
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* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express oqr
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* implied. See the License for the specific language governing
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* rights and limitations under the License.
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* The Original Code is Rhino code, released
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* The Initial Developer of the Original Code is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1997-1999 Netscape Communications Corporation. All
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* Alternatively, the contents of this file may be used under the
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* terms of the GNU Public License (the "GPL"), in which case the
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* provisions of the GPL are applicable instead of those above.
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* If you wish to allow use of your version of this file only
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* under the terms of the GPL and not to allow others to use your
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* version of this file under the NPL, indicate your decision by
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* deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL. If you do not delete
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* the provisions above, a recipient may use your version of this
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* file under either the NPL or the GPL.
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package org.mozilla.javascript;
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Base class for native object implementation that uses IdFunction to export its methods to script via <class-name>.prototype object.
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Any descendant should implement at least the following methods:
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To define non-function properties, the descendant should customize
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getIdDefaultAttributes
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to get/set property value and provide its default attributes.
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To customize initializition of constructor and protype objects, descendant
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may override scopeInit or fillConstructorProperties methods.
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public abstract class IdScriptable extends ScriptableObject
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implements IdFunctionMaster
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/** NULL_TAG can be used to distinguish between uninitialized and null
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protected static final Object NULL_TAG = new Object();
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public IdScriptable() {
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activateIdMap(maxInstanceId());
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public boolean has(String name, Scriptable start) {
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int id = mapNameToId(name);
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return super.has(name, start);
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public Object get(String name, Scriptable start) {
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int maxId = this.maxId;
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Object[] data = idMapData;
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int id = mapNameToId(name);
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return getIdValue(id);
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if (data[id - 1 + maxId] != name) {
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id = mapNameToId(name);
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if (id == 0) { break L; }
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data[id - 1 + maxId] = name;
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Object value = data[id - 1];
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value = getIdValue(id);
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else if (value == NULL_TAG) {
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int id = mapNameToId(name);
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Object[] data = idMapData;
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return getIdValue(id);
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Object value = data[id - 1];
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value = getIdValue(id);
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else if (value == NULL_TAG) {
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return super.get(name, start);
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public void put(String name, Scriptable start, Object value) {
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int id = mapNameToId(name);
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int attr = getAttributes(id);
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if ((attr & READONLY) == 0) {
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setIdValue(id, value);
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start.put(name, start, value);
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super.put(name, start, value);
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public void delete(String name) {
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int id = mapNameToId(name);
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// Let the super class to throw exceptions for sealed objects
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int attr = getAttributes(id);
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if ((attr & PERMANENT) == 0) {
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public int getAttributes(String name, Scriptable start)
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throws PropertyException
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int id = mapNameToId(name);
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return getAttributes(id);
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// For ids with deleted values super will throw exceptions
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return super.getAttributes(name, start);
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public void setAttributes(String name, Scriptable start,
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throws PropertyException
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int id = mapNameToId(name);
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synchronized (this) {
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setAttributes(id, attributes);
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// For ids with deleted values super will throw exceptions
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super.setAttributes(name, start, attributes);
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synchronized void addPropertyAttribute(int attribute) {
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extraIdAttributes |= (byte)attribute;
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super.addPropertyAttribute(attribute);
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* Redefine ScriptableObject.defineProperty to allow changing
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* values/attributes of id-based properties unless
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* getIdDefaultAttributes contains the READONLY attribute.
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* @see #getIdDefaultAttributes
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* @see org.mozilla.javascript.ScriptableObject#defineProperty
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public void defineProperty(String propertyName, Object value,
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int id = mapNameToId(propertyName);
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int default_attributes = getIdDefaultAttributes(id);
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if ((default_attributes & READONLY) != 0) {
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// It is a bug to redefine id with readonly attributes
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throw new RuntimeException
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("Attempt to redefine read-only id " + propertyName);
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setAttributes(id, attributes);
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setIdValue(id, value);
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super.defineProperty(propertyName, value, attributes);
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Object[] getIds(boolean getAll) {
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Object[] result = super.getIds(getAll);
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for (int id = maxId; id != 0; --id) {
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if (getAll || (getAttributes(id) & DONTENUM) == 0) {
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// Need extra room for nor more then [1..id] names
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ids = new Object[id];
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ids[count++] = getIdName(id);
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if (result.length == 0 && ids.length == count) {
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Object[] tmp = new Object[result.length + count];
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System.arraycopy(result, 0, tmp, 0, result.length);
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System.arraycopy(ids, 0, tmp, result.length, count);
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/** Return maximum id number that should be present in each instance. */
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protected int maxInstanceId() { return 0; }
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* Map name to id of prototype or instance property.
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* Should return 0 if not found
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protected abstract int mapNameToId(String name);
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/** Map id back to property name it defines.
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protected abstract String getIdName(int id);
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/** Get default attributes for id.
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** Default implementation return DONTENUM that is the standard attribute
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** for core EcmaScript function. Typically descendants need to overwrite
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** this for non-function attributes like length to return
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** DONTENUM | READONLY | PERMANENT or DONTENUM | PERMANENT
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protected int getIdDefaultAttributes(int id) {
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/** Check if id value exists.
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** Default implementation always returns true */
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protected boolean hasIdValue(int id) {
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** If id value is constant, descendant can call cacheIdValue to store
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** value in the permanent cache.
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** Default implementation creates IdFunction instance for given id
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** and cache its value
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protected Object getIdValue(int id) {
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IdFunction f = newIdFunction(id);
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f.setParentScope(getParentScope());
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return cacheIdValue(id, f);
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* IdScriptable never calls this method if result of
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* <code>getIdDefaultAttributes(id)</code> contains READONLY attribute.
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* Descendants can overwrite this method to provide custom handler for
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* property assignments.
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protected void setIdValue(int id, Object value) {
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synchronized (this) {
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ensureIdData()[id - 1] = (value != null) ? value : NULL_TAG;
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* Store value in permanent cache unless value was already assigned to id.
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* After this call IdScriptable never calls hasIdValue and getIdValue
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protected Object cacheIdValue(int id, Object value) {
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synchronized (this) {
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Object[] data = ensureIdData();
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Object curValue = data[id - 1];
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if (curValue == null) {
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data[id - 1] = (value != null) ? value : NULL_TAG;
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* Delete value represented by id so hasIdValue return false.
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* IdScriptable never calls this method if result of
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* <code>getIdDefaultAttributes(id)</code> contains PERMANENT attribute.
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* Descendants can overwrite this method to provide custom handler for
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protected void deleteIdValue(int id) {
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synchronized (this) {
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ensureIdData()[id - 1] = NOT_FOUND;
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/** 'thisObj' will be null if invoked as constructor, in which case
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** instance of Scriptable should be returned. */
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public Object execMethod(int methodId, IdFunction function,
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Context cx, Scriptable scope,
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Scriptable thisObj, Object[] args)
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throws JavaScriptException
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throw IdFunction.onBadMethodId(this, methodId);
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/** Get arity or defined argument count for method with given id.
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** Should return -1 if methodId is not known or can not be used
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** with execMethod call. */
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public int methodArity(int methodId) {
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/** Activate id support with the given maximum id */
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protected void activateIdMap(int maxId) {
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/** Sets whether newly constructed function objects should be sealed */
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protected void setSealFunctionsFlag(boolean sealed) {
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setSetupFlag(SEAL_FUNCTIONS_FLAG, sealed);
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* Set parameters of function properties.
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* Currently only determines whether functions should use dynamic scope.
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* @param cx context to read function parameters.
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* @see org.mozilla.javascript.Context#hasCompileFunctionsWithDynamicScope
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protected void setFunctionParametrs(Context cx) {
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setSetupFlag(USE_DYNAMIC_SCOPE_FLAG,
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cx.hasCompileFunctionsWithDynamicScope());
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private void setSetupFlag(int flag, boolean value) {
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setupFlags = (byte)(value ? setupFlags | flag : setupFlags & ~flag);
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* Prepare this object to serve as the prototype property of constructor
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* object with name <code>getClassName()<code> defined in
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* <code>scope</code>.
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* @param maxId maximum id available in prototype object
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* @param cx current context
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* @param scope object to define constructor in.
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* @param sealed indicates whether object and all its properties should
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public void addAsPrototype(int maxId, Context cx, Scriptable scope,
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activateIdMap(maxId);
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setSealFunctionsFlag(sealed);
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setFunctionParametrs(cx);
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int constructorId = mapNameToId("constructor");
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if (constructorId == 0) {
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// It is a bug to call this function without id for constructor
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throw new RuntimeException("No id for constructor property");
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IdFunction ctor = newIdFunction(constructorId);
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ctor.initAsConstructor(scope, this);
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fillConstructorProperties(cx, ctor, sealed);
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ctor.addPropertyAttribute(READONLY);
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setParentScope(ctor);
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setPrototype(getObjectPrototype(scope));
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cacheIdValue(constructorId, ctor);
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defineProperty(scope, getClassName(), ctor, ScriptableObject.DONTENUM);
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protected void fillConstructorProperties
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(Context cx, IdFunction ctor, boolean sealed)
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protected void addIdFunctionProperty
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(Scriptable obj, int id, boolean sealed)
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IdFunction f = newIdFunction(id);
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if (sealed) { f.sealObject(); }
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defineProperty(obj, getIdName(id), f, DONTENUM);
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* Utility method for converting target object into native this.
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* Possible usage would be to have a private function like realThis:
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private NativeSomething realThis(Scriptable thisObj,
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IdFunction f, boolean readOnly)
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while (!(thisObj instanceof NativeSomething)) {
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thisObj = nextInstanceCheck(thisObj, f, readOnly);
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return (NativeSomething)thisObj;
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* Note that although such function can be implemented universally via
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* java.lang.Class.isInstance(), it would be much more slower.
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* @param readOnly specify if the function f does not change state of object.
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* @return Scriptable object suitable for a check by the instanceof operator.
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* @throws RuntimeException if no more instanceof target can be found
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protected Scriptable nextInstanceCheck(Scriptable thisObj,
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if (readOnly && 0 != (setupFlags & USE_DYNAMIC_SCOPE_FLAG)) {
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// for read only functions under dynamic scope look prototype chain
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thisObj = thisObj.getPrototype();
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if (thisObj != null) { return thisObj; }
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throw NativeGlobal.typeError1("msg.incompat.call",
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f.getFunctionName(), f);
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protected IdFunction newIdFunction(int id) {
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IdFunction f = new IdFunction(this, getIdName(id), id);
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if (0 != (setupFlags & SEAL_FUNCTIONS_FLAG)) { f.sealObject(); }
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protected final Object wrap_double(double x) {
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return (x == x) ? new Double(x) : ScriptRuntime.NaNobj;
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protected final Object wrap_int(int x) {
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if (b == x) { return new Byte(b); }
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return new Integer(x);
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protected final Object wrap_long(long x) {
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if (i == x) { return wrap_int(i); }
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protected final Object wrap_boolean(boolean x) {
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return x ? Boolean.TRUE : Boolean.FALSE;
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private boolean hasValue(int id) {
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Object[] data = idMapData;
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if (data == null || (value = data[id - 1]) == null) {
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return hasIdValue(id);
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return value != NOT_FOUND;
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// Must be called only from synchronized (this)
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private Object[] ensureIdData() {
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Object[] data = idMapData;
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idMapData = data = new Object[CACHE_NAMES ? maxId * 2 : maxId];
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private int getAttributes(int id) {
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int attributes = getIdDefaultAttributes(id) | extraIdAttributes;
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byte[] array = attributesArray;
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attributes |= 0xFF & array[id - 1];
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private void setAttributes(int id, int attributes) {
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int defaultAttrs = getIdDefaultAttributes(id);
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if ((attributes & defaultAttrs) != defaultAttrs) {
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// It is a bug to set attributes to less restrictive values
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// then given by defaultAttrs
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throw new RuntimeException("Attempt to unset default attributes");
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// Store only additional bits
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attributes &= ~defaultAttrs;
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byte[] array = attributesArray;
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if (array == null && attributes != 0) {
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synchronized (this) {
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array = attributesArray;
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attributesArray = array = new byte[maxId];
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array[id - 1] = (byte)attributes;
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private Object[] idMapData;
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private byte[] attributesArray;
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private static final boolean CACHE_NAMES = true;
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private int lastIdCache;
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private static final int USE_DYNAMIC_SCOPE_FLAG = 1 << 0;
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private static final int SEAL_FUNCTIONS_FLAG = 1 << 1;
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private byte setupFlags;
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private byte extraIdAttributes;
added
removed
src/org/mozilla/javascript/IdScriptable.java
