Examples with ClassVisitor org.eclipse.persistence.internal.libraries.asm.ClassVisitor used on opensource projects

Example 1 with ClassVisitor

use of org.eclipse.persistence.internal.libraries.asm.ClassVisitor in project eclipselink by eclipse-ee4j.

the class PersistenceWeaver method transform.

/**
 * INTERNAL:
 * Perform dynamic byte code weaving of class.
 * @param loader              The defining loader of the class to be transformed, may be {@code null}
 *                            if the bootstrap loader.
 * @param className           The name of the class in the internal form of fully qualified class and interface
 *                            names.
 * @param classBeingRedefined If this is a redefine, the class being redefined, otherwise {@code null}.
 * @param protectionDomain    The protection domain of the class being defined or redefined.
 * @param classfileBuffer     The input byte buffer in class file format (must not be modified).
 * @return  A well-formed class file buffer (the result of the transform), or {@code null} if no transform
 *          is performed.
 */
@Override
public byte[] transform(final ClassLoader loader, final String className, final Class<?> classBeingRedefined, final ProtectionDomain protectionDomain, final byte[] classfileBuffer) throws TransformerException {
    final SessionLog log = AbstractSessionLog.getLog();
    // PERF: Is finest logging on weaving turned on?
    final boolean shouldLogFinest = log.shouldLog(SessionLog.FINEST, SessionLog.WEAVER);
    final Map<String, ClassDetails> classDetailsMap = this.classDetailsMap;
    // Check if cleared already.
    if (classDetailsMap == null) {
        return null;
    }
    try {
        /*
             * The ClassFileTransformer callback - when called by the JVM's
             * Instrumentation implementation - is invoked for every class loaded.
             * Thus, we must check the classDetailsMap to see if we are 'interested'
             * in the class.
             */
        final ClassDetails classDetails = classDetailsMap.get(Helper.toSlashedClassName(className));
        if (classDetails != null) {
            if (shouldLogFinest) {
                log.log(SessionLog.FINEST, SessionLog.WEAVER, "begin_weaving_class", className);
            }
            ClassReader classReader = null;
            try {
                classReader = new ClassReader(classfileBuffer);
            } catch (IllegalArgumentException iae) {
                // in such case log a warning and try to re-read the class without class version check
                if (log.shouldLog(SessionLog.FINE, SessionLog.WEAVER)) {
                    SessionLogEntry entry = new SessionLogEntry(null, SessionLog.FINE, SessionLog.WEAVER, iae);
                    entry.setMessage(ExceptionLocalization.buildMessage("unsupported_classfile_version", new Object[] { className }));
                    log.log(entry);
                }
                classReader = new EclipseLinkClassReader(classfileBuffer);
            }
            final String reflectiveIntrospectionProperty = PrivilegedAccessHelper.getSystemProperty(SystemProperties.WEAVING_REFLECTIVE_INTROSPECTION);
            final ClassWriter classWriter = reflectiveIntrospectionProperty != null ? new ClassWriter(ClassWriter.COMPUTE_FRAMES) : new ComputeClassWriter(loader, ClassWriter.COMPUTE_FRAMES);
            final ClassWeaver classWeaver = new ClassWeaver(classWriter, classDetails);
            final ClassVisitor sv = new SerialVersionUIDAdder(classWeaver);
            classReader.accept(sv, 0);
            if (classWeaver.alreadyWeaved) {
                if (shouldLogFinest) {
                    log.log(SessionLog.FINEST, SessionLog.WEAVER, "end_weaving_class", className);
                }
                return null;
            }
            if (classWeaver.weaved) {
                final byte[] bytes = classWriter.toByteArray();
                final String outputPath = PrivilegedAccessHelper.getSystemProperty(SystemProperties.WEAVING_OUTPUT_PATH, "");
                if (!outputPath.equals("")) {
                    Helper.outputClassFile(className, bytes, outputPath);
                }
                // PERF: Don't execute this set of if statements with logging turned off.
                if (shouldLogFinest) {
                    if (classWeaver.weavedPersistenceEntity) {
                        log.log(SessionLog.FINEST, SessionLog.WEAVER, "weaved_persistenceentity", className);
                    }
                    if (classWeaver.weavedChangeTracker) {
                        log.log(SessionLog.FINEST, SessionLog.WEAVER, "weaved_changetracker", className);
                    }
                    if (classWeaver.weavedLazy) {
                        log.log(SessionLog.FINEST, SessionLog.WEAVER, "weaved_lazy", className);
                    }
                    if (classWeaver.weavedFetchGroups) {
                        log.log(SessionLog.FINEST, SessionLog.WEAVER, "weaved_fetchgroups", className);
                    }
                    if (classWeaver.weavedRest) {
                        log.log(SessionLog.FINEST, SessionLog.WEAVER, "weaved_rest", className);
                    }
                    log.log(SessionLog.FINEST, SessionLog.WEAVER, "end_weaving_class", className);
                }
                return bytes;
            }
            if (shouldLogFinest) {
                log.log(SessionLog.FINEST, SessionLog.WEAVER, "end_weaving_class", className);
            }
        } else {
            if (shouldLogFinest) {
                log.log(SessionLog.FINEST, SessionLog.WEAVER, "transform_missing_class_details", className);
            }
        }
    } catch (Throwable exception) {
        if (log.shouldLog(SessionLog.WARNING, SessionLog.WEAVER)) {
            log.log(SessionLog.WARNING, SessionLog.WEAVER, "exception_while_weaving", new Object[] { className, exception.getLocalizedMessage() });
            if (shouldLogFinest) {
                log.logThrowable(SessionLog.FINEST, SessionLog.WEAVER, exception);
            }
        }
    }
    if (shouldLogFinest) {
        log.log(SessionLog.FINEST, SessionLog.WEAVER, "transform_existing_class_bytes", className);
    }
    // Returning null means 'use existing class bytes'.
    return null;
}