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XLT (Xceptance LoadTest) is an extensive load and performance test tool developed and maintained by Xceptance.
/*
* Copyright (c) 2005-2022 Xceptance Software Technologies GmbH
*
* 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.xceptance.xlt.engine;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.gargoylesoftware.htmlunit.Cache;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlPage;
import com.gargoylesoftware.htmlunit.javascript.HtmlUnitContextFactory;
import com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine;
import com.gargoylesoftware.htmlunit.javascript.background.BackgroundJavaScriptFactory;
import com.xceptance.xlt.api.engine.CustomData;
import com.xceptance.xlt.api.engine.Session;
import net.sourceforge.htmlunit.corejs.javascript.Function;
import net.sourceforge.htmlunit.corejs.javascript.NativeFunction;
import net.sourceforge.htmlunit.corejs.javascript.Script;
import net.sourceforge.htmlunit.corejs.javascript.Scriptable;
import net.sourceforge.htmlunit.corejs.javascript.debug.DebuggableScript;
/**
* The {@link XltJavaScriptEngine} class is a specialization of HtmlUnit's {@link JavaScriptEngine}, which allows for
* setting the optimization level to use when compiling JS snippets. Additionally, it measures the time taken to compile
* and execute JS code.
*
* @author Jörg Werner (Xceptance Software Technologies GmbH)
*/
public final class XltJavaScriptEngine extends JavaScriptEngine
{
/**
* Class logger.
*/
private static final Logger LOG = LoggerFactory.getLogger(XltJavaScriptEngine.class);
/**
* The context factory to use.
*/
private final HtmlUnitContextFactory contextFactory;
/**
* Whether or not to take measurements.
*/
private final boolean takeMeasurements;
static
{
BackgroundJavaScriptFactory.setFactory(new XltBackgroundJavaScriptFactory());
}
/**
* Constructor.
*
* @param webClient
* the web client
* @param optimizationLevel
* the optimization level to use when compiling JS snippets
* @param takeMeasurements
* whether or not to take measurements
*/
public XltJavaScriptEngine(final WebClient webClient, final int optimizationLevel, final boolean takeMeasurements)
{
super(webClient);
contextFactory = new XltContextFactory(webClient, optimizationLevel);
this.takeMeasurements = takeMeasurements;
}
/**
* {@inheritDoc}
*/
@Override
public Object callFunction(final HtmlPage htmlPage, final Function function, final Scriptable scope, final Scriptable thisObject,
final Object[] args)
{
final Object result;
if (takeMeasurements)
{
final String functionName = getFunctionName(function);
final CustomData customData = new CustomData("Executing function " + functionName);
final long start = System.nanoTime();
try
{
result = super.callFunction(htmlPage, function, scope, thisObject, args);
}
finally
{
final long runTimeInNS = System.nanoTime() - start;
customData.setRunTime(runTimeInNS / 1000000L);
Session.getCurrent().getDataManager().logDataRecord(customData);
if (LOG.isDebugEnabled())
{
LOG.debug(String.format("Execution of function '%s' took %.2f ms", functionName, runTimeInNS / 1000000.0));
}
}
}
else
{
result = super.callFunction(htmlPage, function, scope, thisObject, args);
}
return result;
}
/**
* {@inheritDoc}
*/
@Override
public Script compile(final HtmlPage htmlPage, final String sourceCode, final String sourceName, final int startLine)
{
Script script;
final Cache cache = getWebClient().getCache();
if (cache instanceof XltCache)
{
final XltCache xltCache = (XltCache) cache;
script = xltCache.getCachedScript(sourceCode);
if (script == null)
{
final String sourceFileName = getSourceFileName(sourceName, sourceCode);
script = compileScript(htmlPage, sourceCode, sourceName, startLine, sourceFileName);
// script can be null
if (script != null)
{
// wrap the script and attach more information
script = new XltScript(script, sourceFileName);
// finally put it in the cache
xltCache.cache(sourceCode, script);
}
}
}
else
{
// someone messed around with our XltCache so we have to compile the script each time
final String sourceFileName = getSourceFileName(sourceName, sourceCode);
script = compileScript(htmlPage, sourceCode, sourceName, startLine, sourceFileName);
}
return script;
}
/**
* {@inheritDoc}
*/
@Override
public Object execute(final HtmlPage htmlPage, final Script script)
{
final Object result;
if (takeMeasurements)
{
final String sourceFileName = getSourceFileName(script);
final CustomData customData = new CustomData("Executing " + sourceFileName);
final long start = System.nanoTime();
try
{
result = super.execute(htmlPage, script);
}
finally
{
final long runTimeInNS = System.nanoTime() - start;
customData.setRunTime(runTimeInNS / 1000000L);
Session.getCurrent().getDataManager().logDataRecord(customData);
if (LOG.isDebugEnabled())
{
LOG.debug(String.format("Execution of script '%s' took %.2f ms", sourceFileName, runTimeInNS / 1000000.0));
}
}
}
else
{
result = super.execute(htmlPage, script);
}
return result;
}
/**
* {@inheritDoc}
*/
@Override
public HtmlUnitContextFactory getContextFactory()
{
return contextFactory;
}
/**
* Compiles the given source code to a script.
*
* @param htmlPage
* the page that the code will execute within
* @param sourceCode
* the JavaScript code to execute
* @param sourceName
* the name that will be displayed on error conditions
* @param startLine
* the line at which the script source starts
* @param sourceFileName
* the source file name to use for logging
* @return the generated script
*/
private Script compileScript(final HtmlPage htmlPage, final String sourceCode, final String sourceName, final int startLine,
final String sourceFileName)
{
final Script script;
if (takeMeasurements)
{
final CustomData customData = new CustomData();
final long start = System.nanoTime();
try
{
script = super.compile(htmlPage, sourceCode, sourceName, startLine);
}
catch (final RuntimeException e)
{
customData.setFailed(true);
throw e;
}
finally
{
final long runTimeInNS = System.nanoTime() - start;
customData.setName("Compiling " + sourceFileName);
customData.setRunTime(runTimeInNS / 1000000L);
Session.getCurrent().getDataManager().logDataRecord(customData);
if (LOG.isDebugEnabled())
{
LOG.debug(String.format("Compilation of script '%s' took %.2f ms", sourceFileName, runTimeInNS / 1000000.0));
}
}
}
else
{
script = super.compile(htmlPage, sourceCode, sourceName, startLine);
}
return script;
}
/**
* Determines the name of the passed function.
*
* @param function
* the function
* @return the function name
*/
private String getFunctionName(final Function function)
{
String functionName;
if (function instanceof NativeFunction)
{
// will come to this point both in interpreted and compiled mode
functionName = ((NativeFunction) function).getFunctionName();
// handle anonymous functions
if (functionName == null || functionName.isEmpty())
{
// try to tell one anonymous function from another
final int hashCode;
final DebuggableScript debuggableScript = ((NativeFunction) function).getDebuggableView();
if (debuggableScript == null)
{
// TODO: Is this safe for multiple JVMs?
// compiled mode -> get the hash from the name of the generated class
hashCode = function.getClass().getName().hashCode();
}
else
{
// Using the hash of the source code Would be perfect but is expensive as the source will be
// generated each time.
// hashCode = function.toString().hashCode();
// TODO: Definitely not safe for multiple JVMs!
// interpreted mode -> get the hash from the debugging info
hashCode = debuggableScript.hashCode();
}
// qualify the function name with the hash
functionName = "anonymous@" + hashCode;
}
}
else
{
// last try
functionName = "unknown@0";
}
return functionName;
}
/**
* Determines the name of the JS source file from the passed script object.
*
* @param script
* the script
* @return the source file name
*/
private String getSourceFileName(final Script script)
{
String sourceFileName;
if (script instanceof XltScript)
{
// return the name as given during compilation
sourceFileName = ((XltScript) script).getSourceName();
}
else
{
// various fall-backs
if (script instanceof NativeFunction)
{
// will come to this point both in interpreted and compiled mode
final DebuggableScript debuggableScript = ((NativeFunction) script).getDebuggableView();
if (debuggableScript == null)
{
// compiled mode -> get the source file name from the name of the generated class
sourceFileName = script.getClass().getSimpleName();
sourceFileName = StringUtils.substringBeforeLast(sourceFileName, "_");
}
else
{
// interpreted mode -> get the source file name from the debugging info
sourceFileName = debuggableScript.getSourceName();
sourceFileName = StringUtils.substringAfterLast(sourceFileName, "/");
sourceFileName = StringUtils.substringBefore(sourceFileName, "?");
}
}
else
{
// last try
sourceFileName = "unknown_script@" + script.toString().hashCode();
}
}
return sourceFileName;
}
/**
* Determines the name of the JS source file from the passed script object.
*
* @param sourceName
* the source name
* @param sourceCode
* @return the source file name
*/
private String getSourceFileName(final String sourceName, final String sourceCode)
{
final String sourceFileName;
if (sourceName.equals("injected script"))
{
// for injected scripts qualify the source file name with the source's hash
sourceFileName = sourceName + "@" + sourceCode.hashCode();
}
else
{
sourceFileName = sourceName;
}
return sourceFileName;
}
}