package net.bytebuddy.asm;
import lombok.EqualsAndHashCode;
import net.bytebuddy.description.field.FieldDescription;
import net.bytebuddy.description.field.FieldList;
import net.bytebuddy.description.method.MethodDescription;
import net.bytebuddy.description.method.MethodList;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.implementation.Implementation;
import net.bytebuddy.matcher.ElementMatcher;
import net.bytebuddy.pool.TypePool;
import net.bytebuddy.utility.CompoundList;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import java.util.*;
/**
* A class visitor wrapper is used in order to register an intermediate ASM {@link org.objectweb.asm.ClassVisitor} which
* is applied to the main type created by a {@link net.bytebuddy.dynamic.DynamicType.Builder} but not
* to any {@link net.bytebuddy.implementation.auxiliary.AuxiliaryType}s, if any.
*/
public interface AsmVisitorWrapper {
/**
* Indicates that no flags should be set.
*/
int NO_FLAGS = 0;
/**
* Defines the flags that are provided to any {@code ClassWriter} when writing a class. Typically, this gives opportunity to instruct ASM
* to compute stack map frames or the size of the local variables array and the operand stack. If no specific flags are required for
* applying this wrapper, the given value is to be returned.
*
* @param flags The currently set flags. This value should be combined (e.g. {@code flags | foo}) into the value that is returned by this wrapper.
* @return The flags to be provided to the ASM {@code ClassWriter}.
*/
int mergeWriter(int flags);
/**
* Defines the flags that are provided to any {@code ClassReader} when reading a class if applicable. Typically, this gives opportunity to
* instruct ASM to expand or skip frames and to skip code and debug information. If no specific flags are required for applying this
* wrapper, the given value is to be returned.
*
* @param flags The currently set flags. This value should be combined (e.g. {@code flags | foo}) into the value that is returned by this wrapper.
* @return The flags to be provided to the ASM {@code ClassReader}.
*/
int mergeReader(int flags);
/**
* Applies a {@code ClassVisitorWrapper} to the creation of a {@link net.bytebuddy.dynamic.DynamicType}.
*
* @param instrumentedType The instrumented type.
* @param classVisitor A {@code ClassVisitor} to become the new primary class visitor to which the created
* {@link net.bytebuddy.dynamic.DynamicType} is written to.
* @param implementationContext The implementation context of the current instrumentation.
* @param typePool The type pool that was provided for the class creation.
* @param fields The instrumented type's fields.
* @param methods The instrumented type's methods non-ingored declared and virtually inherited methods.
* @param writerFlags The ASM {@link org.objectweb.asm.ClassWriter} flags to consider.
* @param readerFlags The ASM {@link org.objectweb.asm.ClassReader} flags to consider.
* @return A new {@code ClassVisitor} that usually delegates to the {@code ClassVisitor} delivered in the argument.
*/
ClassVisitor wrap(TypeDescription instrumentedType,
ClassVisitor classVisitor,
Implementation.Context implementationContext,
TypePool typePool,
FieldList<FieldDescription.InDefinedShape> fields,
MethodList<?> methods,
int writerFlags,
int readerFlags);
/**
* A class visitor wrapper that does not apply any changes.
*/
enum NoOp implements AsmVisitorWrapper {
/**
* The singleton instance.
*/
INSTANCE;
@Override
public int mergeWriter(int flags) {
return flags;
}
@Override
public int mergeReader(int flags) {
return flags;
}
@Override
public ClassVisitor wrap(TypeDescription instrumentedType,
ClassVisitor classVisitor,
Implementation.Context implementationContext,
TypePool typePool,
FieldList<FieldDescription.InDefinedShape> fields,
MethodList<?> methods,
int writerFlags,
int readerFlags) {
return classVisitor;
}
}
/**
* An abstract base implementation of an ASM visitor wrapper that does not set any flags.
*/
abstract class AbstractBase implements AsmVisitorWrapper {
@Override
public int mergeWriter(int flags) {
return flags;
}
@Override
public int mergeReader(int flags) {
return flags;
}
}
/**
* An ASM visitor wrapper that allows to wrap declared fields of the instrumented type with a {@link FieldVisitorWrapper}.
*/
@EqualsAndHashCode(callSuper = false)
class ForDeclaredFields extends AbstractBase {
/**
* The list of entries that describe matched fields in their application order.
*/
private final List<Entry> entries;
/**
* Creates a new visitor wrapper for declared fields.
*/
public ForDeclaredFields() {
this(Collections.<Entry>emptyList());
}
/**
* Creates a new visitor wrapper for declared fields.
*
* @param entries The list of entries that describe matched fields in their application order.
*/
protected ForDeclaredFields(List<Entry> entries) {
this.entries = entries;
}
/**
* Defines a new field visitor wrapper to be applied if the given field matcher is matched. Previously defined
* entries are applied before the given matcher is applied.
*
* @param matcher The matcher to identify fields to be wrapped.
* @param fieldVisitorWrapper The field visitor wrapper to be applied if the given matcher is matched.
* @return A new ASM visitor wrapper that applied the given field visitor wrapper if the supplied matcher is matched.
*/
public ForDeclaredFields field(ElementMatcher<? super FieldDescription.InDefinedShape> matcher, FieldVisitorWrapper... fieldVisitorWrapper) {
return field(matcher, Arrays.asList(fieldVisitorWrapper));
}
/**
* Defines a new field visitor wrapper to be applied if the given field matcher is matched. Previously defined
* entries are applied before the given matcher is applied.
*
* @param matcher The matcher to identify fields to be wrapped.
* @param fieldVisitorWrappers The field visitor wrapper to be applied if the given matcher is matched.
* @return A new ASM visitor wrapper that applied the given field visitor wrapper if the supplied matcher is matched.
*/
public ForDeclaredFields field(ElementMatcher<? super FieldDescription.InDefinedShape> matcher, List<? extends FieldVisitorWrapper> fieldVisitorWrappers) {
return new ForDeclaredFields(CompoundList.of(entries, new Entry(matcher, fieldVisitorWrappers)));
}
@Override
public ClassVisitor wrap(TypeDescription instrumentedType,
ClassVisitor classVisitor,
Implementation.Context implementationContext,
TypePool typePool,
FieldList<FieldDescription.InDefinedShape> fields,
MethodList<?> methods,
int writerFlags,
int readerFlags) {
Map<String, FieldDescription.InDefinedShape> mapped = new HashMap<String, FieldDescription.InDefinedShape>();
for (FieldDescription.InDefinedShape fieldDescription : fields) {
mapped.put(fieldDescription.getInternalName() + fieldDescription.getDescriptor(), fieldDescription);
}
return new DispatchingVisitor(classVisitor, instrumentedType, mapped);
}
/**
* A field visitor wrapper that allows for wrapping a {@link FieldVisitor} defining a declared field.
*/
public interface FieldVisitorWrapper {
/**
* Wraps a field visitor.
*
* @param instrumentedType The instrumented type.
* @param fieldDescription The field that is currently being defined.
* @param fieldVisitor The original field visitor that defines the given field.
* @return The wrapped field visitor.
*/
FieldVisitor wrap(TypeDescription instrumentedType, FieldDescription.InDefinedShape fieldDescription, FieldVisitor fieldVisitor);
}
/**
* An entry describing a field visitor wrapper paired with a matcher for fields to be wrapped.
*/
@EqualsAndHashCode
protected static class Entry implements ElementMatcher<FieldDescription.InDefinedShape>, FieldVisitorWrapper {
/**
* The matcher to identify fields to be wrapped.
*/
private final ElementMatcher<? super FieldDescription.InDefinedShape> matcher;
/**
* The field visitor wrapper to be applied if the given matcher is matched.
*/
private final List<? extends FieldVisitorWrapper> fieldVisitorWrappers;
/**
* Creates a new entry.
*
* @param matcher The matcher to identify fields to be wrapped.
* @param fieldVisitorWrappers The field visitor wrapper to be applied if the given matcher is matched.
*/
protected Entry(ElementMatcher<? super FieldDescription.InDefinedShape> matcher, List<? extends FieldVisitorWrapper> fieldVisitorWrappers) {
this.matcher = matcher;
this.fieldVisitorWrappers = fieldVisitorWrappers;
}
@Override
public boolean matches(FieldDescription.InDefinedShape target) {
return target != null && matcher.matches(target);
}
@Override
public FieldVisitor wrap(TypeDescription instrumentedType, FieldDescription.InDefinedShape fieldDescription, FieldVisitor fieldVisitor) {
for (FieldVisitorWrapper fieldVisitorWrapper : fieldVisitorWrappers) {
fieldVisitor = fieldVisitorWrapper.wrap(instrumentedType, fieldDescription, fieldVisitor);
}
return fieldVisitor;
}
}
/**
* A class visitor that applies the outer ASM visitor for identifying declared fields.
*/
protected class DispatchingVisitor extends ClassVisitor {
/**
* The instrumented type.
*/
private final TypeDescription instrumentedType;
/**
* A mapping of fields by their name and descriptor key-combination.
*/
private final Map<String, FieldDescription.InDefinedShape> fields;
/**
* Creates a new dispatching visitor.
*
* @param classVisitor The underlying class visitor.
* @param instrumentedType The instrumented type.
* @param fields The instrumented type's declared fields.
*/
protected DispatchingVisitor(ClassVisitor classVisitor, TypeDescription instrumentedType, Map<String, FieldDescription.InDefinedShape> fields) {
super(Opcodes.ASM5, classVisitor);
this.instrumentedType = instrumentedType;
this.fields = fields;
}
@Override
public FieldVisitor visitField(int modifiers, String internalName, String descriptor, String signature, Object defaultValue) {
FieldVisitor fieldVisitor = super.visitField(modifiers, internalName, descriptor, signature, defaultValue);
FieldDescription.InDefinedShape fieldDescription = fields.get(internalName + descriptor);
if (fieldVisitor != null && fieldDescription != null) {
for (Entry entry : entries) {
if (entry.matches(fieldDescription)) {
fieldVisitor = entry.wrap(instrumentedType, fieldDescription, fieldVisitor);
}
}
}
return fieldVisitor;
}
}
}
/**
* <p>
* An ASM visitor wrapper that allows to wrap <b>declared methods</b> of the instrumented type with a {@link MethodVisitorWrapper}.
* </p>
* <p>
* Note: Inherited methods are <b>not</b> matched by this visitor, even if they are intercepted by a normal interception.
* </p>
*/
@EqualsAndHashCode
class ForDeclaredMethods implements AsmVisitorWrapper {
/**
* The list of entries that describe matched methods in their application order.
*/
private final List<Entry> entries;
/**
* The writer flags to set.
*/
private final int writerFlags;
/**
* The reader flags to set.
*/
private final int readerFlags;
/**
* Creates a new visitor wrapper for declared methods.
*/
public ForDeclaredMethods() {
this(Collections.<Entry>emptyList(), NO_FLAGS, NO_FLAGS);
}
/**
* Creates a new visitor wrapper for declared methods.
*
* @param entries The list of entries that describe matched methods in their application order.
* @param readerFlags The reader flags to set.
* @param writerFlags The writer flags to set.
*/
protected ForDeclaredMethods(List<Entry> entries, int writerFlags, int readerFlags) {
this.entries = entries;
this.writerFlags = writerFlags;
this.readerFlags = readerFlags;
}
/**
* Defines a new method visitor wrapper to be applied if the given method matcher is matched. Previously defined
* entries are applied before the given matcher is applied.
*
* @param matcher The matcher to identify methods to be wrapped.
* @param methodVisitorWrapper The method visitor wrapper to be applied if the given matcher is matched.
* @return A new ASM visitor wrapper that applied the given method visitor wrapper if the supplied matcher is matched.
*/
public ForDeclaredMethods method(ElementMatcher<? super MethodDescription> matcher, MethodVisitorWrapper... methodVisitorWrapper) {
return method(matcher, Arrays.asList(methodVisitorWrapper));
}
/**
* Defines a new method visitor wrapper to be applied if the given method matcher is matched. Previously defined
* entries are applied before the given matcher is applied.
*
* @param matcher The matcher to identify methods to be wrapped.
* @param methodVisitorWrappers The method visitor wrapper to be applied if the given matcher is matched.
* @return A new ASM visitor wrapper that applied the given method visitor wrapper if the supplied matcher is matched.
*/
public ForDeclaredMethods method(ElementMatcher<? super MethodDescription> matcher, List<? extends MethodVisitorWrapper> methodVisitorWrappers) {
return new ForDeclaredMethods(CompoundList.of(entries, new Entry(matcher, methodVisitorWrappers)), writerFlags, readerFlags);
}
/**
* Sets flags for the {@link org.objectweb.asm.ClassWriter} this wrapper is applied to.
*
* @param flags The flags to set for the {@link org.objectweb.asm.ClassWriter}.
* @return A new ASM visitor wrapper that sets the supplied writer flags.
*/
public ForDeclaredMethods writerFlags(int flags) {
return new ForDeclaredMethods(entries, writerFlags | flags, readerFlags);
}
/**
* Sets flags for the {@link org.objectweb.asm.ClassReader} this wrapper is applied to.
*
* @param flags The flags to set for the {@link org.objectweb.asm.ClassReader}.
* @return A new ASM visitor wrapper that sets the supplied reader flags.
*/
public ForDeclaredMethods readerFlags(int flags) {
return new ForDeclaredMethods(entries, writerFlags, readerFlags | flags);
}
@Override
public int mergeWriter(int flags) {
return flags | writerFlags;
}
@Override
public int mergeReader(int flags) {
return flags | readerFlags;
}
@Override
public ClassVisitor wrap(TypeDescription instrumentedType,
ClassVisitor classVisitor,
Implementation.Context implementationContext,
TypePool typePool,
FieldList<FieldDescription.InDefinedShape> fields,
MethodList<?> methods,
int writerFlags,
int readerFlags) {
Map<String, MethodDescription> mapped = new HashMap<String, MethodDescription>();
for (MethodDescription methodDescription : CompoundList.<MethodDescription>of(methods, new MethodDescription.Latent.TypeInitializer(instrumentedType))) {
mapped.put(methodDescription.getInternalName() + methodDescription.getDescriptor(), methodDescription);
}
return new DispatchingVisitor(classVisitor,
instrumentedType,
implementationContext,
typePool,
mapped,
writerFlags,
readerFlags);
}
/**
* A method visitor wrapper that allows for wrapping a {@link MethodVisitor} defining a declared method.
*/
public interface MethodVisitorWrapper {
/**
* Wraps a method visitor.
*
* @param instrumentedType The instrumented type.
* @param instrumentedMethod The method that is currently being defined.
* @param methodVisitor The original field visitor that defines the given method.
* @param implementationContext The implementation context to use.
* @param typePool The type pool to use.
* @param writerFlags The ASM {@link org.objectweb.asm.ClassWriter} reader flags to consider.
* @param readerFlags The ASM {@link org.objectweb.asm.ClassReader} reader flags to consider.
* @return The wrapped method visitor.
*/
MethodVisitor wrap(TypeDescription instrumentedType,
MethodDescription instrumentedMethod,
MethodVisitor methodVisitor,
Implementation.Context implementationContext,
TypePool typePool,
int writerFlags,
int readerFlags);
}
/**
* An entry describing a method visitor wrapper paired with a matcher for fields to be wrapped.
*/
@EqualsAndHashCode
protected static class Entry implements ElementMatcher<MethodDescription>, MethodVisitorWrapper {
/**
* The matcher to identify methods to be wrapped.
*/
private final ElementMatcher<? super MethodDescription> matcher;
/**
* The method visitor wrapper to be applied if the given matcher is matched.
*/
private final List<? extends MethodVisitorWrapper> methodVisitorWrappers;
/**
* Creates a new entry.
*
* @param matcher The matcher to identify methods to be wrapped.
* @param methodVisitorWrappers The method visitor wrapper to be applied if the given matcher is matched.
*/
protected Entry(ElementMatcher<? super MethodDescription> matcher, List<? extends MethodVisitorWrapper> methodVisitorWrappers) {
this.matcher = matcher;
this.methodVisitorWrappers = methodVisitorWrappers;
}
@Override
public boolean matches(MethodDescription target) {
return target != null && matcher.matches(target);
}
@Override
public MethodVisitor wrap(TypeDescription instrumentedType,
MethodDescription instrumentedMethod,
MethodVisitor methodVisitor,
Implementation.Context implementationContext,
TypePool typePool,
int writerFlags,
int readerFlags) {
for (MethodVisitorWrapper methodVisitorWrapper : methodVisitorWrappers) {
methodVisitor = methodVisitorWrapper.wrap(instrumentedType,
instrumentedMethod,
methodVisitor,
implementationContext,
typePool,
writerFlags,
readerFlags);
}
return methodVisitor;
}
}
/**
* A class visitor that applies the outer ASM visitor for identifying declared methods.
*/
protected class DispatchingVisitor extends ClassVisitor {
/**
* The instrumented type.
*/
private final TypeDescription instrumentedType;
/**
* The implementation context to use.
*/
private final Implementation.Context implementationContext;
/**
* The type pool to use.
*/
private final TypePool typePool;
/**
* The ASM {@link org.objectweb.asm.ClassWriter} reader flags to consider.
*/
private final int writerFlags;
/**
* The ASM {@link org.objectweb.asm.ClassReader} reader flags to consider.
*/
private final int readerFlags;
/**
* A mapping of fields by their name.
*/
private final Map<String, MethodDescription> methods;
/**
* Creates a new dispatching visitor.
*
* @param classVisitor The underlying class visitor.
* @param instrumentedType The instrumented type.
* @param implementationContext The implementation context to use.
* @param typePool The type pool to use.
* @param methods The methods that are declared by the instrumented type or virtually inherited.
* @param writerFlags The ASM {@link org.objectweb.asm.ClassWriter} flags to consider.
* @param readerFlags The ASM {@link org.objectweb.asm.ClassReader} flags to consider.
*/
protected DispatchingVisitor(ClassVisitor classVisitor,
TypeDescription instrumentedType,
Implementation.Context implementationContext,
TypePool typePool,
Map<String, MethodDescription> methods,
int writerFlags,
int readerFlags) {
super(Opcodes.ASM5, classVisitor);
this.instrumentedType = instrumentedType;
this.implementationContext = implementationContext;
this.typePool = typePool;
this.methods = methods;
this.writerFlags = writerFlags;
this.readerFlags = readerFlags;
}
@Override
public MethodVisitor visitMethod(int modifiers, String internalName, String descriptor, String signature, String[] exceptions) {
MethodVisitor methodVisitor = super.visitMethod(modifiers, internalName, descriptor, signature, exceptions);
MethodDescription methodDescription = methods.get(internalName + descriptor);
if (methodVisitor != null && methodDescription != null) {
for (Entry entry : entries) {
if (entry.matches(methodDescription)) {
methodVisitor = entry.wrap(instrumentedType,
methodDescription,
methodVisitor,
implementationContext,
typePool,
writerFlags,
readerFlags);
}
}
}
return methodVisitor;
}
}
}
/**
* An ordered, immutable chain of {@link AsmVisitorWrapper}s.
*/
@EqualsAndHashCode
class Compound implements AsmVisitorWrapper {
/**
* The class visitor wrappers that are represented by this chain in their order. This list must not be mutated.
*/
private final List<AsmVisitorWrapper> asmVisitorWrappers;
/**
* Creates a new immutable chain based on an existing list of {@link AsmVisitorWrapper}s
* where no copy of the received array is made.
*
* @param asmVisitorWrapper An array of {@link AsmVisitorWrapper}s where elements
* at the beginning of the list are applied first, i.e. will be at the bottom of the generated
* {@link org.objectweb.asm.ClassVisitor}.
*/
public Compound(AsmVisitorWrapper... asmVisitorWrapper) {
this(Arrays.asList(asmVisitorWrapper));
}
/**
* Creates a new immutable chain based on an existing list of {@link AsmVisitorWrapper}s
* where no copy of the received list is made.
*
* @param asmVisitorWrappers A list of {@link AsmVisitorWrapper}s where elements
* at the beginning of the list are applied first, i.e. will be at the bottom of the generated
* {@link org.objectweb.asm.ClassVisitor}.
*/
public Compound(List<? extends AsmVisitorWrapper> asmVisitorWrappers) {
this.asmVisitorWrappers = new ArrayList<AsmVisitorWrapper>();
for (AsmVisitorWrapper asmVisitorWrapper : asmVisitorWrappers) {
if (asmVisitorWrapper instanceof Compound) {
this.asmVisitorWrappers.addAll(((Compound) asmVisitorWrapper).asmVisitorWrappers);
} else if (!(asmVisitorWrapper instanceof NoOp)) {
this.asmVisitorWrappers.add(asmVisitorWrapper);
}
}
}
@Override
public int mergeWriter(int flags) {
for (AsmVisitorWrapper asmVisitorWrapper : asmVisitorWrappers) {
flags = asmVisitorWrapper.mergeWriter(flags);
}
return flags;
}
@Override
public int mergeReader(int flags) {
for (AsmVisitorWrapper asmVisitorWrapper : asmVisitorWrappers) {
flags = asmVisitorWrapper.mergeReader(flags);
}
return flags;
}
@Override
public ClassVisitor wrap(TypeDescription instrumentedType,
ClassVisitor classVisitor,
Implementation.Context implementationContext,
TypePool typePool,
FieldList<FieldDescription.InDefinedShape> fields,
MethodList<?> methods,
int writerFlags,
int readerFlags) {
for (AsmVisitorWrapper asmVisitorWrapper : asmVisitorWrappers) {
classVisitor = asmVisitorWrapper.wrap(instrumentedType,
classVisitor,
implementationContext,
typePool,
fields,
methods,
writerFlags,
readerFlags);
}
return classVisitor;
}
}
}