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ASM, a very small and fast Java bytecode manipulation framework
// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holders nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
// THE POSSIBILITY OF SUCH DAMAGE.
package org.objectweb.asm;
/**
* A visitor to visit a Java class. The methods of this class must be called in the following order:
* {@code visit} [ {@code visitSource} ] [ {@code visitModule} ][ {@code visitNestHost} ][ {@code
* visitOuterClass} ] ( {@code visitAnnotation} | {@code visitTypeAnnotation} | {@code
* visitAttribute} )* ( {@code visitNestMember} | [ {@code * visitPermittedSubclass} ] | {@code
* visitInnerClass} | {@code visitRecordComponent} | {@code visitField} | {@code visitMethod} )*
* {@code visitEnd}.
*
* @author Eric Bruneton
*/
public abstract class ClassVisitor {
/**
* The ASM API version implemented by this visitor. The value of this field must be one of the
* {@code ASM}x values in {@link Opcodes}.
*/
protected final int api;
/** The class visitor to which this visitor must delegate method calls. May be {@literal null}. */
protected ClassVisitor cv;
/**
* Constructs a new {@link ClassVisitor}.
*
* @param api the ASM API version implemented by this visitor. Must be one of the {@code
* ASM}x values in {@link Opcodes}.
*/
protected ClassVisitor(final int api) {
this(api, null);
}
/**
* Constructs a new {@link ClassVisitor}.
*
* @param api the ASM API version implemented by this visitor. Must be one of the {@code
* ASM}x values in {@link Opcodes}.
* @param classVisitor the class visitor to which this visitor must delegate method calls. May be
* null.
*/
protected ClassVisitor(final int api, final ClassVisitor classVisitor) {
if (api != Opcodes.ASM9
&& api != Opcodes.ASM8
&& api != Opcodes.ASM7
&& api != Opcodes.ASM6
&& api != Opcodes.ASM5
&& api != Opcodes.ASM4
&& api != Opcodes.ASM10_EXPERIMENTAL) {
throw new IllegalArgumentException("Unsupported api " + api);
}
if (api == Opcodes.ASM10_EXPERIMENTAL) {
Constants.checkAsmExperimental(this);
}
this.api = api;
this.cv = classVisitor;
}
/**
* The class visitor to which this visitor must delegate method calls. May be {@literal null}.
*
* @return the class visitor to which this visitor must delegate method calls, or {@literal null}.
*/
public ClassVisitor getDelegate() {
return cv;
}
/**
* Visits the header of the class.
*
* @param version the class version. The minor version is stored in the 16 most significant bits,
* and the major version in the 16 least significant bits.
* @param access the class's access flags (see {@link Opcodes}). This parameter also indicates if
* the class is deprecated {@link Opcodes#ACC_DEPRECATED} or a record {@link
* Opcodes#ACC_RECORD}.
* @param name the internal name of the class (see {@link Type#getInternalName()}).
* @param signature the signature of this class. May be {@literal null} if the class is not a
* generic one, and does not extend or implement generic classes or interfaces.
* @param superName the internal of name of the super class (see {@link Type#getInternalName()}).
* For interfaces, the super class is {@link Object}. May be {@literal null}, but only for the
* {@link Object} class.
* @param interfaces the internal names of the class's interfaces (see {@link
* Type#getInternalName()}). May be {@literal null}.
*/
public void visit(
final int version,
final int access,
final String name,
final String signature,
final String superName,
final String[] interfaces) {
if (api < Opcodes.ASM8 && (access & Opcodes.ACC_RECORD) != 0) {
throw new UnsupportedOperationException("Records requires ASM8");
}
if (cv != null) {
cv.visit(version, access, name, signature, superName, interfaces);
}
}
/**
* Visits the source of the class.
*
* @param source the name of the source file from which the class was compiled. May be {@literal
* null}.
* @param debug additional debug information to compute the correspondence between source and
* compiled elements of the class. May be {@literal null}.
*/
public void visitSource(final String source, final String debug) {
if (cv != null) {
cv.visitSource(source, debug);
}
}
/**
* Visit the module corresponding to the class.
*
* @param name the fully qualified name (using dots) of the module.
* @param access the module access flags, among {@code ACC_OPEN}, {@code ACC_SYNTHETIC} and {@code
* ACC_MANDATED}.
* @param version the module version, or {@literal null}.
* @return a visitor to visit the module values, or {@literal null} if this visitor is not
* interested in visiting this module.
*/
public ModuleVisitor visitModule(final String name, final int access, final String version) {
if (api < Opcodes.ASM6) {
throw new UnsupportedOperationException("Module requires ASM6");
}
if (cv != null) {
return cv.visitModule(name, access, version);
}
return null;
}
/**
* Visits the nest host class of the class. A nest is a set of classes of the same package that
* share access to their private members. One of these classes, called the host, lists the other
* members of the nest, which in turn should link to the host of their nest. This method must be
* called only once and only if the visited class is a non-host member of a nest. A class is
* implicitly its own nest, so it's invalid to call this method with the visited class name as
* argument.
*
* @param nestHost the internal name of the host class of the nest (see {@link
* Type#getInternalName()}).
*/
public void visitNestHost(final String nestHost) {
if (api < Opcodes.ASM7) {
throw new UnsupportedOperationException("NestHost requires ASM7");
}
if (cv != null) {
cv.visitNestHost(nestHost);
}
}
/**
* Visits the enclosing class of the class. This method must be called only if this class is a
* local or anonymous class. See the JVMS 4.7.7 section for more details.
*
* @param owner internal name of the enclosing class of the class (see {@link
* Type#getInternalName()}).
* @param name the name of the method that contains the class, or {@literal null} if the class is
* not enclosed in a method or constructor of its enclosing class (e.g. if it is enclosed in
* an instance initializer, static initializer, instance variable initializer, or class
* variable initializer).
* @param descriptor the descriptor of the method that contains the class, or {@literal null} if
* the class is not enclosed in a method or constructor of its enclosing class (e.g. if it is
* enclosed in an instance initializer, static initializer, instance variable initializer, or
* class variable initializer).
*/
public void visitOuterClass(final String owner, final String name, final String descriptor) {
if (cv != null) {
cv.visitOuterClass(owner, name, descriptor);
}
}
/**
* Visits an annotation of the class.
*
* @param descriptor the class descriptor of the annotation class.
* @param visible {@literal true} if the annotation is visible at runtime.
* @return a visitor to visit the annotation values, or {@literal null} if this visitor is not
* interested in visiting this annotation.
*/
public AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) {
if (cv != null) {
return cv.visitAnnotation(descriptor, visible);
}
return null;
}
/**
* Visits an annotation on a type in the class signature.
*
* @param typeRef a reference to the annotated type. The sort of this type reference must be
* {@link TypeReference#CLASS_TYPE_PARAMETER}, {@link
* TypeReference#CLASS_TYPE_PARAMETER_BOUND} or {@link TypeReference#CLASS_EXTENDS}. See
* {@link TypeReference}.
* @param typePath the path to the annotated type argument, wildcard bound, array element type, or
* static inner type within 'typeRef'. May be {@literal null} if the annotation targets
* 'typeRef' as a whole.
* @param descriptor the class descriptor of the annotation class.
* @param visible {@literal true} if the annotation is visible at runtime.
* @return a visitor to visit the annotation values, or {@literal null} if this visitor is not
* interested in visiting this annotation.
*/
public AnnotationVisitor visitTypeAnnotation(
final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
if (api < Opcodes.ASM5) {
throw new UnsupportedOperationException("TypeAnnotation requires ASM5");
}
if (cv != null) {
return cv.visitTypeAnnotation(typeRef, typePath, descriptor, visible);
}
return null;
}
/**
* Visits a non standard attribute of the class.
*
* @param attribute an attribute.
*/
public void visitAttribute(final Attribute attribute) {
if (cv != null) {
cv.visitAttribute(attribute);
}
}
/**
* Visits a member of the nest. A nest is a set of classes of the same package that share access
* to their private members. One of these classes, called the host, lists the other members of the
* nest, which in turn should link to the host of their nest. This method must be called only if
* the visited class is the host of a nest. A nest host is implicitly a member of its own nest, so
* it's invalid to call this method with the visited class name as argument.
*
* @param nestMember the internal name of a nest member (see {@link Type#getInternalName()}).
*/
public void visitNestMember(final String nestMember) {
if (api < Opcodes.ASM7) {
throw new UnsupportedOperationException("NestMember requires ASM7");
}
if (cv != null) {
cv.visitNestMember(nestMember);
}
}
/**
* Visits a permitted subclasses. A permitted subclass is one of the allowed subclasses of the
* current class.
*
* @param permittedSubclass the internal name of a permitted subclass (see {@link
* Type#getInternalName()}).
*/
public void visitPermittedSubclass(final String permittedSubclass) {
if (api < Opcodes.ASM9) {
throw new UnsupportedOperationException("PermittedSubclasses requires ASM9");
}
if (cv != null) {
cv.visitPermittedSubclass(permittedSubclass);
}
}
/**
* Visits information about an inner class. This inner class is not necessarily a member of the
* class being visited. More precisely, every class or interface C which is referenced by this
* class and which is not a package member must be visited with this method. This class must
* reference its nested class or interface members, and its enclosing class, if any. See the JVMS
* 4.7.6 section for more details.
*
* @param name the internal name of C (see {@link Type#getInternalName()}).
* @param outerName the internal name of the class or interface C is a member of (see {@link
* Type#getInternalName()}). Must be {@literal null} if C is not the member of a class or
* interface (e.g. for local or anonymous classes).
* @param innerName the (simple) name of C. Must be {@literal null} for anonymous inner classes.
* @param access the access flags of C originally declared in the source code from which this
* class was compiled.
*/
public void visitInnerClass(
final String name, final String outerName, final String innerName, final int access) {
if (cv != null) {
cv.visitInnerClass(name, outerName, innerName, access);
}
}
/**
* Visits a record component of the class.
*
* @param name the record component name.
* @param descriptor the record component descriptor (see {@link Type}).
* @param signature the record component signature. May be {@literal null} if the record component
* type does not use generic types.
* @return a visitor to visit this record component annotations and attributes, or {@literal null}
* if this class visitor is not interested in visiting these annotations and attributes.
*/
public RecordComponentVisitor visitRecordComponent(
final String name, final String descriptor, final String signature) {
if (api < Opcodes.ASM8) {
throw new UnsupportedOperationException("Record requires ASM8");
}
if (cv != null) {
return cv.visitRecordComponent(name, descriptor, signature);
}
return null;
}
/**
* Visits a field of the class.
*
* @param access the field's access flags (see {@link Opcodes}). This parameter also indicates if
* the field is synthetic and/or deprecated.
* @param name the field's name.
* @param descriptor the field's descriptor (see {@link Type}).
* @param signature the field's signature. May be {@literal null} if the field's type does not use
* generic types.
* @param value the field's initial value. This parameter, which may be {@literal null} if the
* field does not have an initial value, must be an {@link Integer}, a {@link Float}, a {@link
* Long}, a {@link Double} or a {@link String} (for {@code int}, {@code float}, {@code long}
* or {@code String} fields respectively). This parameter is only used for static
* fields. Its value is ignored for non static fields, which must be initialized through
* bytecode instructions in constructors or methods.
* @return a visitor to visit field annotations and attributes, or {@literal null} if this class
* visitor is not interested in visiting these annotations and attributes.
*/
public FieldVisitor visitField(
final int access,
final String name,
final String descriptor,
final String signature,
final Object value) {
if (cv != null) {
return cv.visitField(access, name, descriptor, signature, value);
}
return null;
}
/**
* Visits a method of the class. This method must return a new {@link MethodVisitor}
* instance (or {@literal null}) each time it is called, i.e., it should not return a previously
* returned visitor.
*
* @param access the method's access flags (see {@link Opcodes}). This parameter also indicates if
* the method is synthetic and/or deprecated.
* @param name the method's name.
* @param descriptor the method's descriptor (see {@link Type}).
* @param signature the method's signature. May be {@literal null} if the method parameters,
* return type and exceptions do not use generic types.
* @param exceptions the internal names of the method's exception classes (see {@link
* Type#getInternalName()}). May be {@literal null}.
* @return an object to visit the byte code of the method, or {@literal null} if this class
* visitor is not interested in visiting the code of this method.
*/
public MethodVisitor visitMethod(
final int access,
final String name,
final String descriptor,
final String signature,
final String[] exceptions) {
if (cv != null) {
return cv.visitMethod(access, name, descriptor, signature, exceptions);
}
return null;
}
/**
* Visits the end of the class. This method, which is the last one to be called, is used to inform
* the visitor that all the fields and methods of the class have been visited.
*/
public void visitEnd() {
if (cv != null) {
cv.visitEnd();
}
}
}