/*
* Copyright (c) 2002-2010 Gargoyle Software Inc.
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.gargoylesoftware.htmlunit.javascript;
import net.sourceforge.htmlunit.corejs.javascript.Callable;
import net.sourceforge.htmlunit.corejs.javascript.Context;
import net.sourceforge.htmlunit.corejs.javascript.ContextFactory;
import net.sourceforge.htmlunit.corejs.javascript.ErrorReporter;
import net.sourceforge.htmlunit.corejs.javascript.Evaluator;
import net.sourceforge.htmlunit.corejs.javascript.Script;
import net.sourceforge.htmlunit.corejs.javascript.ScriptRuntime;
import net.sourceforge.htmlunit.corejs.javascript.Scriptable;
import net.sourceforge.htmlunit.corejs.javascript.WrapFactory;
import net.sourceforge.htmlunit.corejs.javascript.debug.Debugger;
import com.gargoylesoftware.htmlunit.BrowserVersion;
import com.gargoylesoftware.htmlunit.BrowserVersionFeatures;
import com.gargoylesoftware.htmlunit.ScriptPreProcessor;
import com.gargoylesoftware.htmlunit.WebAssert;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlElement;
import com.gargoylesoftware.htmlunit.html.HtmlPage;
import com.gargoylesoftware.htmlunit.javascript.regexp.HtmlUnitRegExpProxy;
/**
* ContextFactory that supports termination of scripts if they exceed a timeout. Based on example from
* <a href="http://www.mozilla.org/rhino/apidocs/org/mozilla/javascript/ContextFactory.html">ContextFactory</a>.
*
* @version $Revision: 5408 $
* @author Andre Soereng
* @author Ahmed Ashour
* @author Marc Guillemot
*/
public class HtmlUnitContextFactory extends ContextFactory {
private static final long serialVersionUID = -1282169475857079041L;
private static final int INSTRUCTION_COUNT_THRESHOLD = 10000;
private final BrowserVersion browserVersion_;
private final WebClient webClient_;
private long timeout_;
private Debugger debugger_;
private final ErrorReporter errorReporter_;
private final WrapFactory wrapFactory_ = new HtmlUnitWrapFactory();
/**
* Creates a new instance of HtmlUnitContextFactory.
*
* @param webClient the web client using this factory
*/
public HtmlUnitContextFactory(final WebClient webClient) {
WebAssert.notNull("webClient", webClient);
webClient_ = webClient;
browserVersion_ = webClient.getBrowserVersion();
errorReporter_ = new StrictErrorReporter();
}
/**
* Sets the number of milliseconds a script is allowed to execute before
* being terminated. A value of 0 or less means no timeout.
*
* @param timeout the timeout value
*/
public void setTimeout(final long timeout) {
timeout_ = timeout;
}
/**
* Returns the number of milliseconds a script is allowed to execute before
* being terminated. A value of 0 or less means no timeout.
*
* @return the timeout value (default value is <tt>0</tt>)
*/
public long getTimeout() {
return timeout_;
}
/**
* Sets the JavaScript debugger to use to receive JavaScript execution debugging information.
* The HtmlUnit default implementation ({@link DebuggerImpl}, {@link DebugFrameImpl}) may be
* used, or a custom debugger may be used instead. By default, no debugger is used.
*
* @param debugger the JavaScript debugger to use (may be <tt>null</tt>)
*/
public void setDebugger(final Debugger debugger) {
debugger_ = debugger;
}
/**
* Returns the JavaScript debugger to use to receive JavaScript execution debugging information.
* By default, no debugger is used, and this method returns <tt>null</tt>.
*
* @return the JavaScript debugger to use to receive JavaScript execution debugging information
*/
public Debugger getDebugger() {
return debugger_;
}
/**
* Custom context to store execution time and handle timeouts.
*/
private class TimeoutContext extends Context {
private long startTime_;
protected TimeoutContext(final ContextFactory factory) {
super(factory);
}
public void startClock() {
startTime_ = System.currentTimeMillis();
}
public void terminateScriptIfNecessary() {
if (timeout_ > 0) {
final long currentTime = System.currentTimeMillis();
if (currentTime - startTime_ > timeout_) {
// Terminate script by throwing an Error instance to ensure that the
// script will never get control back through catch or finally.
throw new TimeoutError(timeout_, currentTime - startTime_);
}
}
}
@Override
protected Script compileString(String source, final Evaluator compiler,
final ErrorReporter compilationErrorReporter, final String sourceName,
final int lineno, final Object securityDomain) {
// this method gets called by Context.compileString and by ScriptRuntime.evalSpecial
// which is used for window.eval. We have to take care in which case we are.
final boolean isWindowEval = (compiler != null);
// Remove HTML comments around the source if needed
if (!isWindowEval) {
final String sourceCodeTrimmed = source.trim();
if (sourceCodeTrimmed.startsWith("<!--")) {
source = source.replaceFirst("<!--", "// <!--");
}
// IE ignores the last line containing uncommented -->
if (browserVersion_.isIE() && sourceCodeTrimmed.endsWith("-->")) {
final int lastDoubleSlash = source.lastIndexOf("//");
final int lastNewLine = Math.max(source.lastIndexOf('\n'), source.lastIndexOf('\r'));
if (lastNewLine > lastDoubleSlash) {
source = source.substring(0, lastNewLine);
}
}
}
// Pre process the source code
final HtmlPage page = (HtmlPage) Context.getCurrentContext()
.getThreadLocal(JavaScriptEngine.KEY_STARTING_PAGE);
source = preProcess(page, source, sourceName, null);
source = new StringScriptPreProcessor(HtmlUnitContextFactory.this, lineno)
.preProcess(page, source, sourceName, null);
// PreProcess IE Conditional Compilation if needed
if (browserVersion_.isIE()) {
final ScriptPreProcessor ieCCPreProcessor = new IEConditionalCompilationScriptPreProcessor();
source = ieCCPreProcessor.preProcess(page, source, sourceName, null);
// sourceCode = IEWeirdSyntaxScriptPreProcessor.getInstance()
// .preProcess(htmlPage, sourceCode, sourceName, null);
}
return super.compileString(source, compiler, compilationErrorReporter,
sourceName, lineno, securityDomain);
}
}
/**
* Pre process the specified source code in the context of the given page using the processor specified
* in the webclient. This method delegates to the pre processor handler specified in the
* <code>WebClient</code>. If no pre processor handler is defined, the original source code is returned
* unchanged.
* @param htmlPage the page
* @param sourceCode the code to process
* @param sourceName a name for the chunk of code (used in error messages)
* @param htmlElement the HTML element that will act as the context
* @return the source code after being pre processed
* @see com.gargoylesoftware.htmlunit.ScriptPreProcessor
*/
protected String preProcess(
final HtmlPage htmlPage, final String sourceCode, final String sourceName, final HtmlElement htmlElement) {
String newSourceCode = sourceCode;
final ScriptPreProcessor preProcessor = webClient_.getScriptPreProcessor();
if (preProcessor != null) {
newSourceCode = preProcessor.preProcess(htmlPage, sourceCode, sourceName, htmlElement);
if (newSourceCode == null) {
newSourceCode = "";
}
}
return newSourceCode;
}
/**
* {@inheritDoc}
*/
@Override
protected Context makeContext() {
final TimeoutContext cx = new TimeoutContext(this);
// Use pure interpreter mode to get observeInstructionCount() callbacks.
cx.setOptimizationLevel(-1);
// Set threshold on how often we want to receive the callbacks
cx.setInstructionObserverThreshold(INSTRUCTION_COUNT_THRESHOLD);
configureErrorReporter(cx);
cx.setWrapFactory(wrapFactory_);
if (debugger_ != null) {
cx.setDebugger(debugger_, null);
}
// register custom RegExp processing
ScriptRuntime.setRegExpProxy(cx, new HtmlUnitRegExpProxy(ScriptRuntime.getRegExpProxy(cx)));
return cx;
}
/**
* Configures the {@link ErrorReporter} on the context.
* @param context the context to configure
* @see {@link Context#setErrorReporter(ErrorReporter)}
*/
protected void configureErrorReporter(final Context context) {
context.setErrorReporter(errorReporter_);
}
/**
* Run-time calls this when instruction counting is enabled and the counter
* reaches limit set by setInstructionObserverThreshold(). A script can be
* terminated by throwing an Error instance here.
*
* @param cx the context calling us
* @param instructionCount amount of script instruction executed since last call to observeInstructionCount
*/
@Override
protected void observeInstructionCount(final Context cx, final int instructionCount) {
final TimeoutContext tcx = (TimeoutContext) cx;
tcx.terminateScriptIfNecessary();
}
/**
* {@inheritDoc}
*/
@Override
protected Object doTopCall(final Callable callable,
final Context cx, final Scriptable scope,
final Scriptable thisObj, final Object[] args) {
final TimeoutContext tcx = (TimeoutContext) cx;
tcx.startClock();
return super.doTopCall(callable, cx, scope, thisObj, args);
}
/**
* {@inheritDoc}
*/
@Override
protected boolean hasFeature(final Context cx, final int featureIndex) {
switch (featureIndex) {
case Context.FEATURE_RESERVED_KEYWORD_AS_IDENTIFIER:
return true;
case Context.FEATURE_PARENT_PROTO_PROPERTIES:
return !browserVersion_.isIE();
case Context.FEATURE_NON_ECMA_GET_YEAR:
return browserVersion_.isIE();
case Context.FEATURE_HTMLUNIT_WRITE_READONLY_PROPERTIES:
return browserVersion_.hasFeature(BrowserVersionFeatures.SET_READONLY_PROPERTIES);
case Context.FEATURE_HTMLUNIT_JS_CATCH_JAVA_EXCEPTION:
return false;
default:
return super.hasFeature(cx, featureIndex);
}
}
}