org.glowroot.weaving.WeavingClassFileTransformer Maven / Gradle / Ivy
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/*
* Copyright 2012-2015 the original author or authors.
*
* 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 org.glowroot.weaving;
import java.lang.instrument.ClassFileTransformer;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.util.List;
import javax.annotation.Nullable;
import org.glowroot.shaded.google.common.base.Supplier;
import org.glowroot.shaded.slf4j.Logger;
import org.glowroot.shaded.slf4j.LoggerFactory;
public class WeavingClassFileTransformer implements ClassFileTransformer {
private static final Logger logger = LoggerFactory.getLogger(WeavingClassFileTransformer.class);
private final Weaver weaver;
private final boolean weaveBootstrapClassLoader;
// because of the crazy pre-initialization of javaagent classes (see
// org.glowroot.core.weaving.PreInitializeClasses), all inputs into this class should be
// concrete, non-subclassed types so that the correct set of used classes can be computed (see
// calculation in the test class org.glowroot.weaving.preinit.GlobalCollector, and
// hard-coded results in org.glowroot.weaving.PreInitializeWeavingClassesTest)
// note: an exception is made for WeavingTimerService, see PreInitializeWeavingClassesTest for
// explanation
public WeavingClassFileTransformer(List shimTypes, List mixinTypes,
Supplier> advisors, AnalyzedWorld analyzedWorld,
WeavingTimerService weavingTimerService, boolean timerWrapperMethods) {
weaver = new Weaver(advisors, shimTypes, mixinTypes, analyzedWorld, weavingTimerService,
timerWrapperMethods);
// can only weave classes in bootstrap class loader if glowroot is in bootstrap class
// loader, otherwise woven bootstrap classes will generate NoClassDefFoundError since
// the woven code will not be able to see glowroot classes
// (e.g. woven code will not be able to see org.glowroot.plugin.api.Plugin)
weaveBootstrapClassLoader = isInBootstrapClassLoader();
}
// From the javadoc on ClassFileTransformer.transform():
// "throwing an exception has the same effect as returning null"
//
// so all exceptions must be caught and logged here or they will be lost
@Override
public byte /*@Nullable*/[] transform(@Nullable ClassLoader loader, @Nullable String className,
@Nullable Class classBeingRedefined, @Nullable ProtectionDomain protectionDomain,
byte[] bytes) {
if (className == null) {
// internal subclasses of MethodHandle are passed in with null className
// (see integration test MethodHandleWeavingTest for more detail)
return null;
}
try {
return transformInternal(loader, className, protectionDomain, bytes);
} catch (Throwable t) {
// see method-level comment
logger.error("error weaving {}: {}", className, t.getMessage(), t);
return null;
}
}
private byte /*@Nullable*/[] transformInternal(@Nullable ClassLoader loader, String className,
@Nullable ProtectionDomain protectionDomain, byte[] bytes) {
if (ignoreClass(className)) {
return null;
}
if (loader == null && !weaveBootstrapClassLoader) {
// can only weave classes in bootstrap class loader if glowroot is in bootstrap class
// loader, otherwise woven bootstrap classes will generate NoClassDefFoundError since
// the woven code will not be able to see glowroot classes
// (e.g. woven code will not be able to see org.glowroot.plugin.api.Plugin)
return null;
}
logger.trace("transform(): className={}", className);
CodeSource codeSource = protectionDomain == null ? null : protectionDomain.getCodeSource();
byte[] transformedBytes = weaver.weave(bytes, className, codeSource, loader);
if (transformedBytes != null) {
logger.debug("transform(): transformed {}", className);
}
return transformedBytes;
}
private static boolean ignoreClass(String className) {
if (isGlowrootCoreClass(className)) {
// don't weave glowroot core classes, including shaded classes like h2 jdbc driver
return true;
}
if (className.startsWith("sun/reflect/Generated")) {
// optimization, no need to try to weave the many classes generated for reflection:
// sun/reflect/GeneratedSerializationConstructorAccessor..
// sun/reflect/GeneratedConstructorAccessor..
// sun/reflect/GeneratedMethodAccessor..
return true;
}
if (className.startsWith("com/sun/proxy/$Proxy")) {
// optimization, especially for jdbc plugin to avoid weaving proxy wrappers when dealing
// with connection pools
return true;
}
return false;
}
private static boolean isGlowrootCoreClass(String className) {
// can't just match "org/glowroot/" since that would match glowroot plugins
// (and integration test classes)
return className.startsWith("org/glowroot/plugin/api/")
|| className.startsWith("org/glowroot/advicegen/")
|| className.startsWith("org/glowroot/collector/")
|| className.startsWith("org/glowroot/common/")
|| className.startsWith("org/glowroot/config/")
|| className.startsWith("org/glowroot/jvm/")
|| className.startsWith("org/glowroot/local/")
|| className.startsWith("org/glowroot/shaded/")
|| className.startsWith("org/glowroot/transaction/")
|| className.startsWith("org/glowroot/weaving/");
}
private static boolean isInBootstrapClassLoader() {
return WeavingClassFileTransformer.class.getClassLoader() == null;
}
}