/*
* Copyright 2016 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.gradle.api.internal.tasks.compile.incremental.asm;
import com.google.common.base.Predicate;
import com.google.common.collect.Sets;
import org.gradle.api.internal.tasks.compile.incremental.deps.ClassAnalysis;
import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.TypePath;
import org.objectweb.asm.commons.InstructionAdapter;
import java.lang.annotation.RetentionPolicy;
import java.util.Set;
public class ClassDependenciesVisitor extends ClassVisitor {
private final static int API = Opcodes.ASM5;
private static final MethodVisitor EMPTY_VISITOR = new MethodVisitor(API, null) {
};
private final LiteralAdapter literalAdapter;
private final AnnotationVisitor annotationVisitor;
private final Set<Integer> constants;
private final Set<Integer> literals;
private final Set<String> superTypes;
private final Set<String> types;
private final Predicate<String> typeFilter;
private boolean isAnnotationType;
private boolean dependencyToAll;
public ClassDependenciesVisitor(Set<Integer> constantsCollector) {
this(constantsCollector, null, null, null, null);
}
private ClassDependenciesVisitor(Set<Integer> constantsCollector, Set<Integer> literalsCollector, Set<String> types, Predicate<String> typeFilter, ClassReader reader) {
super(API);
this.constants = constantsCollector;
this.literals = literalsCollector;
this.types = types;
this.superTypes = types == null ? null : Sets.<String>newHashSet();
this.annotationVisitor = literals == null ? null : new LiteralRecordingAnnotationVisitor();
this.literalAdapter = literals == null ? null : new LiteralAdapter();
this.typeFilter = typeFilter;
if (reader != null) {
collectClassDependencies(reader);
}
}
public static ClassAnalysis analyze(String className, ClassReader reader) {
Set<Integer> constants = Sets.newHashSet();
Set<Integer> literals = Sets.newHashSet();
Set<String> classDependencies = Sets.newHashSet();
ClassDependenciesVisitor visitor = new ClassDependenciesVisitor(constants, literals, classDependencies, new ClassRelevancyFilter(className), reader);
reader.accept(visitor, ClassReader.SKIP_DEBUG | ClassReader.SKIP_FRAMES);
return new ClassAnalysis(className, classDependencies, visitor.isDependencyToAll(), constants, literals, visitor.getSuperTypes());
}
public static Set<Integer> retrieveConstants(ClassReader reader) {
Set<Integer> constants = Sets.newHashSet();
ClassDependenciesVisitor visitor = new ClassDependenciesVisitor(constants);
reader.accept(visitor, ClassReader.SKIP_DEBUG | ClassReader.SKIP_FRAMES);
return constants;
}
@Override
public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
isAnnotationType = isAnnotationType(interfaces);
if (superName != null) {
// superName can be null if what we are analyzing is `java.lang.Object`
// which can happen when a custom Java SDK is on classpath (typically, android.jar)
String type = typeOfFromSlashyString(superName);
maybeAddSuperType(type);
maybeAddDependentType(type);
}
for (String s : interfaces) {
String interfaceType = typeOfFromSlashyString(s);
maybeAddDependentType(interfaceType);
maybeAddSuperType(interfaceType);
}
}
// performs a fast analysis of classes referenced in bytecode (method bodies)
// avoiding us to implement a costly visitor and potentially missing edge cases
private void collectClassDependencies(ClassReader reader) {
char[] charBuffer = new char[reader.getMaxStringLength()];
for (int i = 1; i < reader.getItemCount(); i++) {
int itemOffset = reader.getItem(i);
if (itemOffset > 0 && reader.readByte(itemOffset - 1) == 7) {
// A CONSTANT_Class entry, read the class descriptor
String classDescriptor = reader.readUTF8(itemOffset, charBuffer);
Type type = Type.getObjectType(classDescriptor);
while (type.getSort() == Type.ARRAY) {
type = type.getElementType();
}
if (type.getSort() != Type.OBJECT) {
// A primitive type
continue;
}
String name = type.getClassName();
maybeAddDependentType(name);
}
}
}
protected void maybeAddSuperType(String type) {
if (superTypes != null && typeFilter.apply(type)) {
superTypes.add(type);
}
}
protected void maybeAddDependentType(String type) {
if (types != null && typeFilter.apply(type)) {
types.add(type);
}
}
protected String typeOfFromSlashyString(String slashyStyleDesc) {
return Type.getObjectType(slashyStyleDesc).getClassName();
}
public Set<String> getSuperTypes() {
return superTypes;
}
private boolean isAnnotationType(String[] interfaces) {
return interfaces.length == 1 && interfaces[0].equals("java/lang/annotation/Annotation");
}
@Override
public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) {
maybeAddDependentType(descTypeOf(desc));
if (isAccessibleConstant(access, value) && constants != null) {
// we need to compute a hash for a constant, which is based on the name of the constant + its value
// otherwise we miss the case where a class defines several constants with the same value, or when
// two values are switched
constants.add((name + '|' + value).hashCode()); //non-private const
}
return null;
}
private static boolean isAccessibleConstant(int access, Object value) {
return isConstant(access) && !isPrivate(access) && value != null;
}
protected String descTypeOf(String desc) {
Type type = Type.getType(desc);
if (type.getSort() == Type.ARRAY && type.getDimensions() > 0) {
type = type.getElementType();
}
return type.getClassName();
}
@Override
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
if (literals == null) {
return null;
}
Type methodType = Type.getMethodType(desc);
maybeAddDependentType(methodType.getReturnType().getClassName());
for (Type argType : methodType.getArgumentTypes()) {
maybeAddDependentType(argType.getClassName());
}
return literalAdapter;
}
@Override
public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
if (isAnnotationType && "Ljava/lang/annotation/Retention;".equals(desc)) {
return new RetentionPolicyAnalyzer();
}
return annotationVisitor;
}
@Override
public AnnotationVisitor visitTypeAnnotation(int typeRef, TypePath typePath, String desc, boolean visible) {
return annotationVisitor;
}
private static boolean isPrivate(int access) {
return (access & Opcodes.ACC_PRIVATE) != 0;
}
private static boolean isConstant(int access) {
return (access & Opcodes.ACC_FINAL) != 0 && (access & Opcodes.ACC_STATIC) != 0;
}
public boolean isDependencyToAll() {
return dependencyToAll;
}
private class LiteralAdapter extends InstructionAdapter {
protected LiteralAdapter() {
super(API, EMPTY_VISITOR);
}
@Override
public void visitLocalVariable(String name, String desc, String signature, Label start, Label end, int index) {
maybeAddDependentType(descTypeOf(desc));
super.visitLocalVariable(name, desc, signature, start, end, index);
}
@Override
public AnnotationVisitor visitAnnotationDefault() {
return annotationVisitor;
}
@Override
public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
return annotationVisitor;
}
@Override
public AnnotationVisitor visitTypeAnnotation(int typeRef, TypePath typePath, String desc, boolean visible) {
return annotationVisitor;
}
@Override
public AnnotationVisitor visitParameterAnnotation(int parameter, String desc, boolean visible) {
return annotationVisitor;
}
@Override
public AnnotationVisitor visitInsnAnnotation(int typeRef, TypePath typePath, String desc, boolean visible) {
return annotationVisitor;
}
@Override
public AnnotationVisitor visitTryCatchAnnotation(int typeRef, TypePath typePath, String desc, boolean visible) {
return annotationVisitor;
}
@Override
public AnnotationVisitor visitLocalVariableAnnotation(int typeRef, TypePath typePath, Label[] start, Label[] end, int[] index, String desc, boolean visible) {
return annotationVisitor;
}
@Override
public void iconst(int cst) {
literals.add(cst);
super.iconst(cst);
}
@Override
public void fconst(float cst) {
literals.add(Float.valueOf(cst).hashCode());
super.fconst(cst);
}
@Override
public void dconst(double cst) {
literals.add(Double.valueOf(cst).hashCode());
super.dconst(cst);
}
@Override
public void lconst(long cst) {
literals.add(Long.valueOf(cst).hashCode());
super.lconst(cst);
}
@Override
public void visitLdcInsn(Object cst) {
recordConstant(cst);
super.visitLdcInsn(cst);
}
}
protected void recordConstant(Object cst) {
if (cst != null && !(cst instanceof Class)) {
literals.add(cst.hashCode());
}
}
private class LiteralRecordingAnnotationVisitor extends AnnotationVisitor {
public LiteralRecordingAnnotationVisitor() {
super(ClassDependenciesVisitor.API, null);
}
@Override
public void visit(String name, Object value) {
recordConstant(value);
}
@Override
public AnnotationVisitor visitAnnotation(String name, String desc) {
return this;
}
}
private class RetentionPolicyAnalyzer extends AnnotationVisitor {
public RetentionPolicyAnalyzer() {
super(ClassDependenciesVisitor.API);
}
@Override
public void visitEnum(String name, String desc, String value) {
if ("Ljava/lang/annotation/RetentionPolicy;".equals(desc)) {
RetentionPolicy policy = RetentionPolicy.valueOf(value);
if (policy == RetentionPolicy.SOURCE) {
dependencyToAll = true;
}
}
}
}
}