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+/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0
+ *
+ * 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 Rhino code, released
+ * May 6, 1999.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1997-1999
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ * Igor Bukanov, igor@fastmail.fm
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License Version 2 or later (the "GPL"), in which
+ * case the provisions of the GPL are applicable instead of those above. If
+ * you wish to allow use of your version of this file only under the terms of
+ * the GPL and not to allow others to use your version of this file under the
+ * MPL, indicate your decision by deleting the provisions above and replacing
+ * them with the notice and other provisions required by the GPL. If you do
+ * not delete the provisions above, a recipient may use your version of this
+ * file under either the MPL or the GPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+// API class
+
+package org.mozilla.javascript;
+
+/**
+ * Factory class that Rhino runtime uses to create new {@link Context}
+ * instances. A <code>ContextFactory</code> can also notify listeners
+ * about context creation and release.
+ * <p>
+ * When the Rhino runtime needs to create new {@link Context} instance during
+ * execution of {@link Context#enter()} or {@link Context}, it will call
+ * {@link #makeContext()} of the current global ContextFactory.
+ * See {@link #getGlobal()} and {@link #initGlobal(ContextFactory)}.
+ * <p>
+ * It is also possible to use explicit ContextFactory instances for Context
+ * creation. This is useful to have a set of independent Rhino runtime
+ * instances under single JVM. See {@link #call(ContextAction)}.
+ * <p>
+ * The following example demonstrates Context customization to terminate
+ * scripts running more then 10 seconds and to provide better compatibility
+ * with JavaScript code using MSIE-specific features.
+ * <pre>
+ * import org.mozilla.javascript.*;
+ *
+ * class MyFactory extends ContextFactory
+ * {
+ *
+ * // Custom {@link Context} to store execution time.
+ * private static class MyContext extends Context
+ * {
+ * long startTime;
+ * }
+ *
+ * static {
+ * // Initialize GlobalFactory with custom factory
+ * ContextFactory.initGlobal(new MyFactory());
+ * }
+ *
+ * // Override {@link #makeContext()}
+ * protected Context makeContext()
+ * {
+ * MyContext cx = new MyContext();
+ * // Use pure interpreter mode to allow for
+ * // {@link #observeInstructionCount(Context, int)} to work
+ * cx.setOptimizationLevel(-1);
+ * // Make Rhino runtime to call observeInstructionCount
+ * // each 10000 bytecode instructions
+ * cx.setInstructionObserverThreshold(10000);
+ * return cx;
+ * }
+ *
+ * // Override {@link #hasFeature(Context, int)}
+ * public boolean hasFeature(Context cx, int featureIndex)
+ * {
+ * // Turn on maximum compatibility with MSIE scripts
+ * switch (featureIndex) {
+ * case {@link Context#FEATURE_NON_ECMA_GET_YEAR}:
+ * return true;
+ *
+ * case {@link Context#FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME}:
+ * return true;
+ *
+ * case {@link Context#FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER}:
+ * return true;
+ *
+ * case {@link Context#FEATURE_PARENT_PROTO_PROPERTIES}:
+ * return false;
+ * }
+ * return super.hasFeature(cx, featureIndex);
+ * }
+ *
+ * // Override {@link #observeInstructionCount(Context, int)}
+ * protected void observeInstructionCount(Context cx, int instructionCount)
+ * {
+ * MyContext mcx = (MyContext)cx;
+ * long currentTime = System.currentTimeMillis();
+ * if (currentTime - mcx.startTime > 10*1000) {
+ * // More then 10 seconds from Context creation time:
+ * // it is time to stop the script.
+ * // Throw Error instance to ensure that script will never
+ * // get control back through catch or finally.
+ * throw new Error();
+ * }
+ * }
+ *
+ * // Override {@link #doTopCall(Callable,
+ Context, Scriptable,
+ Scriptable, Object[])}
+ * protected Object doTopCall(Callable callable,
+ * Context cx, Scriptable scope,
+ * Scriptable thisObj, Object[] args)
+ * {
+ * MyContext mcx = (MyContext)cx;
+ * mcx.startTime = System.currentTimeMillis();
+ *
+ * return super.doTopCall(callable, cx, scope, thisObj, args);
+ * }
+ *
+ * }
+ *
+ * </pre>
+ */
+
+public class ContextFactory
+{
+ private static volatile boolean hasCustomGlobal;
+ private static ContextFactory global = new ContextFactory();
+
+ private volatile boolean sealed;
+
+ private final Object listenersLock = new Object();
+ private volatile Object listeners;
+ private boolean disabledListening;
+ private ClassLoader applicationClassLoader;
+
+ /**
+ * Listener of {@link Context} creation and release events.
+ */
+ public interface Listener
+ {
+ /**
+ * Notify about newly created {@link Context} object.
+ */
+ public void contextCreated(Context cx);
+
+ /**
+ * Notify that the specified {@link Context} instance is no longer
+ * associated with the current thread.
+ */
+ public void contextReleased(Context cx);
+ }
+
+ /**
+ * Get global ContextFactory.
+ *
+ * @see #hasExplicitGlobal()
+ * @see #initGlobal(ContextFactory)
+ */
+ public static ContextFactory getGlobal()
+ {
+ return global;
+ }
+
+ /**
+ * Check if global factory was set.
+ * Return true to indicate that {@link #initGlobal(ContextFactory)} was
+ * already called and false to indicate that the global factory was not
+ * explicitly set.
+ *
+ * @see #getGlobal()
+ * @see #initGlobal(ContextFactory)
+ */
+ public static boolean hasExplicitGlobal()
+ {
+ return hasCustomGlobal;
+ }
+
+ /**
+ * Set global ContextFactory.
+ * The method can only be called once.
+ *
+ * @see #getGlobal()
+ * @see #hasExplicitGlobal()
+ */
+ public synchronized static void initGlobal(ContextFactory factory)
+ {
+ if (factory == null) {
+ throw new IllegalArgumentException();
+ }
+ if (hasCustomGlobal) {
+ throw new IllegalStateException();
+ }
+ hasCustomGlobal = true;
+ global = factory;
+ }
+
+ /**
+ * Create new {@link Context} instance to be associated with the current
+ * thread.
+ * This is a callback method used by Rhino to create {@link Context}
+ * instance when it is necessary to associate one with the current
+ * execution thread. <tt>makeContext()</tt> is allowed to call
+ * {@link Context#seal(Object)} on the result to prevent
+ * {@link Context} changes by hostile scripts or applets.
+ */
+ protected Context makeContext()
+ {
+ return new Context(this);
+ }
+
+ /**
+ * Implementation of {@link Context#hasFeature(int featureIndex)}.
+ * This can be used to customize {@link Context} without introducing
+ * additional subclasses.
+ */
+ protected boolean hasFeature(Context cx, int featureIndex)
+ {
+ int version;
+ switch (featureIndex) {
+ case Context.FEATURE_NON_ECMA_GET_YEAR:
+ /*
+ * During the great date rewrite of 1.3, we tried to track the
+ * evolving ECMA standard, which then had a definition of
+ * getYear which always subtracted 1900. Which we
+ * implemented, not realizing that it was incompatible with
+ * the old behavior... now, rather than thrash the behavior
+ * yet again, we've decided to leave it with the - 1900
+ * behavior and point people to the getFullYear method. But
+ * we try to protect existing scripts that have specified a
+ * version...
+ */
+ version = cx.getLanguageVersion();
+ return (version == Context.VERSION_1_0
+ || version == Context.VERSION_1_1
+ || version == Context.VERSION_1_2);
+
+ case Context.FEATURE_MEMBER_EXPR_AS_FUNCTION_NAME:
+ return false;
+
+ case Context.FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER:
+ return false;
+
+ case Context.FEATURE_TO_STRING_AS_SOURCE:
+ version = cx.getLanguageVersion();
+ return version == Context.VERSION_1_2;
+
+ case Context.FEATURE_PARENT_PROTO_PROPERTIES:
+ return true;
+
+ case Context.FEATURE_E4X:
+ version = cx.getLanguageVersion();
+ return (version == Context.VERSION_DEFAULT
+ || version >= Context.VERSION_1_6);
+
+ case Context.FEATURE_DYNAMIC_SCOPE:
+ return false;
+
+ case Context.FEATURE_STRICT_VARS:
+ return false;
+
+ case Context.FEATURE_STRICT_EVAL:
+ return false;
+
+ case Context.FEATURE_LOCATION_INFORMATION_IN_ERROR:
+ return false;
+
+ case Context.FEATURE_STRICT_MODE:
+ return false;
+
+ case Context.FEATURE_WARNING_AS_ERROR:
+ return false;
+
+ case Context.FEATURE_ENHANCED_JAVA_ACCESS:
+ return false;
+ }
+ // It is a bug to call the method with unknown featureIndex
+ throw new IllegalArgumentException(String.valueOf(featureIndex));
+ }
+
+ private boolean isDom3Present() {
+ Class nodeClass = Kit.classOrNull("org.w3c.dom.Node");
+ if (nodeClass == null) return false;
+ // Check to see whether DOM3 is present; use a new method defined in
+ // DOM3 that is vital to our implementation
+ try {
+ nodeClass.getMethod("getUserData", new Class[] { String.class });
+ return true;
+ } catch (NoSuchMethodException e) {
+ return false;
+ }
+ }
+
+ /**
+ * Provides a default
+ * {@link org.mozilla.javascript.xml.XMLLib.Factory XMLLib.Factory}
+ * to be used by the <code>Context</code> instances produced by this
+ * factory. See {@link Context#getE4xImplementationFactory} for details.
+ *
+ * May return null, in which case E4X functionality is not supported in
+ * Rhino.
+ *
+ * The default implementation now prefers the DOM3 E4X implementation.
+ */
+ protected org.mozilla.javascript.xml.XMLLib.Factory
+ getE4xImplementationFactory()
+ {
+ // Must provide default implementation, rather than abstract method,
+ // so that past implementors of ContextFactory do not fail at runtime
+ // upon invocation of this method.
+ // Note that the default implementation returns null if we
+ // neither have XMLBeans nor a DOM3 implementation present.
+
+ if (isDom3Present()) {
+ return org.mozilla.javascript.xml.XMLLib.Factory.create(
+ "org.mozilla.javascript.xmlimpl.XMLLibImpl"
+ );
+ } else if (Kit.classOrNull("org.apache.xmlbeans.XmlCursor") != null) {
+ return org.mozilla.javascript.xml.XMLLib.Factory.create(
+ "org.mozilla.javascript.xml.impl.xmlbeans.XMLLibImpl"
+ );
+ } else {
+ return null;
+ }
+ }
+
+
+ /**
+ * Create class loader for generated classes.
+ * This method creates an instance of the default implementation
+ * of {@link GeneratedClassLoader}. Rhino uses this interface to load
+ * generated JVM classes when no {@link SecurityController}
+ * is installed.
+ * Application can override the method to provide custom class loading.
+ */
+ protected GeneratedClassLoader createClassLoader(ClassLoader parent)
+ {
+ return new DefiningClassLoader(parent);
+ }
+
+ /**
+ * Get ClassLoader to use when searching for Java classes.
+ * Unless it was explicitly initialized with
+ * {@link #initApplicationClassLoader(ClassLoader)} the method returns
+ * null to indicate that Thread.getContextClassLoader() should be used.
+ */
+ public final ClassLoader getApplicationClassLoader()
+ {
+ return applicationClassLoader;
+ }
+
+ /**
+ * Set explicit class loader to use when searching for Java classes.
+ *
+ * @see #getApplicationClassLoader()
+ */
+ public final void initApplicationClassLoader(ClassLoader loader)
+ {
+ if (loader == null)
+ throw new IllegalArgumentException("loader is null");
+ if (!Kit.testIfCanLoadRhinoClasses(loader))
+ throw new IllegalArgumentException(
+ "Loader can not resolve Rhino classes");
+
+ if (this.applicationClassLoader != null)
+ throw new IllegalStateException(
+ "applicationClassLoader can only be set once");
+ checkNotSealed();
+
+ this.applicationClassLoader = loader;
+ }
+
+ /**
+ * Execute top call to script or function.
+ * When the runtime is about to execute a script or function that will
+ * create the first stack frame with scriptable code, it calls this method
+ * to perform the real call. In this way execution of any script
+ * happens inside this function.
+ */
+ protected Object doTopCall(Callable callable,
+ Context cx, Scriptable scope,
+ Scriptable thisObj, Object[] args)
+ {
+ return callable.call(cx, scope, thisObj, args);
+ }
+
+ /**
+ * Implementation of
+ * {@link Context#observeInstructionCount(int instructionCount)}.
+ * This can be used to customize {@link Context} without introducing
+ * additional subclasses.
+ */
+ protected void observeInstructionCount(Context cx, int instructionCount)
+ {
+ }
+
+ protected void onContextCreated(Context cx)
+ {
+ Object listeners = this.listeners;
+ for (int i = 0; ; ++i) {
+ Listener l = (Listener)Kit.getListener(listeners, i);
+ if (l == null)
+ break;
+ l.contextCreated(cx);
+ }
+ }
+
+ protected void onContextReleased(Context cx)
+ {
+ Object listeners = this.listeners;
+ for (int i = 0; ; ++i) {
+ Listener l = (Listener)Kit.getListener(listeners, i);
+ if (l == null)
+ break;
+ l.contextReleased(cx);
+ }
+ }
+
+ public final void addListener(Listener listener)
+ {
+ checkNotSealed();
+ synchronized (listenersLock) {
+ if (disabledListening) {
+ throw new IllegalStateException();
+ }
+ listeners = Kit.addListener(listeners, listener);
+ }
+ }
+
+ public final void removeListener(Listener listener)
+ {
+ checkNotSealed();
+ synchronized (listenersLock) {
+ if (disabledListening) {
+ throw new IllegalStateException();
+ }
+ listeners = Kit.removeListener(listeners, listener);
+ }
+ }
+
+ /**
+ * The method is used only to implement
+ * Context.disableStaticContextListening()
+ */
+ final void disableContextListening()
+ {
+ checkNotSealed();
+ synchronized (listenersLock) {
+ disabledListening = true;
+ listeners = null;
+ }
+ }
+
+ /**
+ * Checks if this is a sealed ContextFactory.
+ * @see #seal()
+ */
+ public final boolean isSealed()
+ {
+ return sealed;
+ }
+
+ /**
+ * Seal this ContextFactory so any attempt to modify it like to add or
+ * remove its listeners will throw an exception.
+ * @see #isSealed()
+ */
+ public final void seal()
+ {
+ checkNotSealed();
+ sealed = true;
+ }
+
+ protected final void checkNotSealed()
+ {
+ if (sealed) throw new IllegalStateException();
+ }
+
+ /**
+ * Call {@link ContextAction#run(Context cx)}
+ * using the {@link Context} instance associated with the current thread.
+ * If no Context is associated with the thread, then
+ * {@link #makeContext()} will be called to construct
+ * new Context instance. The instance will be temporary associated
+ * with the thread during call to {@link ContextAction#run(Context)}.
+ *
+ * @see ContextFactory#call(ContextAction)
+ * @see Context#call(ContextFactory factory, Callable callable,
+ * Scriptable scope, Scriptable thisObj,
+ * Object[] args)
+ */
+ public final Object call(ContextAction action)
+ {
+ return Context.call(this, action);
+ }
+
+ /**
+ * Get a context associated with the current thread, creating one if need
+ * be. The Context stores the execution state of the JavaScript engine, so
+ * it is required that the context be entered before execution may begin.
+ * Once a thread has entered a Context, then getCurrentContext() may be
+ * called to find the context that is associated with the current thread.
+ * <p>
+ * Calling <code>enterContext()</code> will return either the Context
+ * currently associated with the thread, or will create a new context and
+ * associate it with the current thread. Each call to
+ * <code>enterContext()</code> must have a matching call to
+ * {@link Context#exit()}.
+ * <pre>
+ * Context cx = contextFactory.enterContext();
+ * try {
+ * ...
+ * cx.evaluateString(...);
+ * } finally {
+ * Context.exit();
+ * }
+ * </pre>
+ * Instead of using <tt>enterContext()</tt>, <tt>exit()</tt> pair consider
+ * using {@link #call(ContextAction)} which guarantees proper association
+ * of Context instances with the current thread.
+ * With this method the above example becomes:
+ * <pre>
+ * ContextFactory.call(new ContextAction() {
+ * public Object run(Context cx) {
+ * ...
+ * cx.evaluateString(...);
+ * return null;
+ * }
+ * });
+ * </pre>
+ * @return a Context associated with the current thread
+ * @see Context#getCurrentContext()
+ * @see Context#exit()
+ * @see #call(ContextAction)
+ */
+ public Context enterContext()
+ {
+ return enterContext(null);
+ }
+
+ /**
+ * @deprecated use {@link #enterContext()} instead
+ * @return a Context associated with the current thread
+ */
+ public final Context enter()
+ {
+ return enterContext(null);
+ }
+
+ /**
+ * @deprecated Use {@link Context#exit()} instead.
+ */
+ public final void exit()
+ {
+ Context.exit();
+ }
+
+ /**
+ * Get a Context associated with the current thread, using the given
+ * Context if need be.
+ * <p>
+ * The same as <code>enterContext()</code> except that <code>cx</code>
+ * is associated with the current thread and returned if the current thread
+ * has no associated context and <code>cx</code> is not associated with any
+ * other thread.
+ * @param cx a Context to associate with the thread if possible
+ * @return a Context associated with the current thread
+ * @see #enterContext()
+ * @see #call(ContextAction)
+ * @throws IllegalStateException if <code>cx</code> is already associated
+ * with a different thread
+ */
+ public final Context enterContext(Context cx)
+ {
+ return Context.enter(cx, this);
+ }
+} \ No newline at end of file
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