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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.
There is a newer version: 9.1.6
/*
 * ProGuardCORE -- library to process Java bytecode.
 *
 * Copyright (c) 2002-2023 Guardsquare NV
 *
 * 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 proguard.evaluation;

import static proguard.classfile.AccessConstants.STATIC;

import proguard.classfile.ClassConstants;
import proguard.classfile.Clazz;
import proguard.classfile.LibraryClass;
import proguard.classfile.LibraryField;
import proguard.classfile.LibraryMethod;
import proguard.classfile.Method;
import proguard.classfile.ProgramClass;
import proguard.classfile.ProgramField;
import proguard.classfile.ProgramMethod;
import proguard.classfile.constant.AnyMethodrefConstant;
import proguard.classfile.constant.ClassConstant;
import proguard.classfile.constant.FieldrefConstant;
import proguard.classfile.constant.InvokeDynamicConstant;
import proguard.classfile.util.ClassUtil;
import proguard.classfile.visitor.MemberVisitor;
import proguard.evaluation.value.ReferenceValue;
import proguard.evaluation.value.Value;
import proguard.evaluation.value.ValueFactory;

/**
 * This {@link InvocationUnit} sets up the variables for entering a method, and it updates the stack
 * for the invocation of a class member, using simple values.
 *
 * @author Eric Lafortune
 */
public class BasicInvocationUnit extends SimplifiedInvocationUnit
    implements InvocationUnit, MemberVisitor {
  protected final ValueFactory valueFactory;

  // Field acting as parameter between the visitor methods.
  private Clazz returnTypeClass;

  /** Creates a new BasicInvocationUnit with the given value factory. */
  public BasicInvocationUnit(ValueFactory valueFactory) {
    this.valueFactory = valueFactory;
  }

  // Implementations for SimplifiedInvocationUnit.

  public Value getExceptionValue(Clazz clazz, ClassConstant catchClassConstant) {
    String catchClassName =
        catchClassConstant != null
            ? catchClassConstant.getName(clazz)
            : ClassConstants.NAME_JAVA_LANG_THROWABLE;

    Clazz catchClass = catchClassConstant != null ? catchClassConstant.referencedClass : null;

    return valueFactory.createReferenceValue(
        ClassUtil.internalTypeFromClassName(catchClassName),
        catchClass,
        ClassUtil.isExtendable(catchClass),
        false);
  }

  public void setFieldClassValue(
      Clazz clazz, FieldrefConstant fieldrefConstant, ReferenceValue value) {
    // We don't care about the new value.
  }

  public Value getFieldClassValue(Clazz clazz, FieldrefConstant fieldrefConstant, String type) {
    // Try to figure out the class of the return type.
    returnTypeClass = null;
    fieldrefConstant.referencedFieldAccept(this);

    return valueFactory.createValue(
        type, returnTypeClass, ClassUtil.isExtendable(returnTypeClass), true);
  }

  public void setFieldValue(Clazz clazz, FieldrefConstant fieldrefConstant, Value value) {
    // We don't care about the new field value.
  }

  public Value getFieldValue(Clazz clazz, FieldrefConstant fieldrefConstant, String type) {
    // Try to figure out the class of the return type.
    returnTypeClass = null;
    fieldrefConstant.referencedFieldAccept(this);

    return valueFactory.createValue(
        type, returnTypeClass, ClassUtil.isExtendable(returnTypeClass), true);
  }

  public void setMethodParameterValue(
      Clazz clazz, AnyMethodrefConstant anyMethodrefConstant, int parameterIndex, Value value) {
    // We don't care about the parameter value.
  }

  public Value getMethodParameterValue(
      Clazz clazz, Method method, int parameterIndex, String type, Clazz referencedClass) {
    // A "this" parameter can never be null.
    boolean isThis = parameterIndex == 0 && (method.getAccessFlags() & STATIC) == 0;

    return valueFactory.createValue(
        type, referencedClass, ClassUtil.isExtendable(referencedClass), !isThis);
  }

  public void setMethodReturnValue(Clazz clazz, Method method, Value value) {
    // We don't care about the return value.
  }

  public Value getMethodReturnValue(
      Clazz clazz, AnyMethodrefConstant anyMethodrefConstant, String type) {
    // Try to figure out the class of the return type.
    returnTypeClass = null;
    anyMethodrefConstant.referencedMethodAccept(this);

    return valueFactory.createValue(
        type, returnTypeClass, ClassUtil.isExtendable(returnTypeClass), true);
  }

  /** Returns the return value of the specified method. */
  public Value getMethodReturnValue(
      Clazz clazz, InvokeDynamicConstant invokeDynamicConstant, String type) {
    // Try to figure out the class of the return type.
    Clazz[] referencedClasses = invokeDynamicConstant.referencedClasses;

    Clazz referencedClass =
        referencedClasses != null && ClassUtil.isInternalClassType(type)
            ? referencedClasses[referencedClasses.length - 1]
            : null;

    return valueFactory.createValue(
        type, referencedClass, ClassUtil.isExtendable(referencedClass), true);
  }

  // Implementations for MemberVisitor.

  public void visitProgramField(ProgramClass programClass, ProgramField programField) {
    returnTypeClass = programField.referencedClass;
  }

  public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) {
    Clazz[] referencedClasses = programMethod.referencedClasses;
    if (referencedClasses != null
        && ClassUtil.isInternalClassType(programMethod.getDescriptor(programClass))) {
      returnTypeClass = referencedClasses[referencedClasses.length - 1];
    }
  }

  public void visitLibraryField(LibraryClass programClass, LibraryField libraryField) {
    returnTypeClass = libraryField.referencedClass;
  }

  public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod) {
    Clazz[] referencedClasses = libraryMethod.referencedClasses;
    if (referencedClasses != null
        && ClassUtil.isInternalClassType(libraryMethod.getDescriptor(libraryClass))) {
      returnTypeClass = referencedClasses[referencedClasses.length - 1];
    }
  }
}