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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) 2002-2020 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.classfile.constant;

import proguard.classfile.*;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.visitor.*;
import proguard.resources.file.ResourceFile;
import proguard.resources.file.visitor.ResourceFileVisitor;

/**
 * This {@link Constant} represents a string constant in the constant pool.
 *
 * @author Eric Lafortune
 */
public class StringConstant extends Constant {
  public int u2stringIndex;

  /**
   * An extra field pointing to the referenced Clazz object, if this string is being used in
   * Class.forName(), .class, or Class.getDeclaredField/Method constructs. This field is typically
   * filled out by the {@link
   * proguard.classfile.util.DynamicClassReferenceInitializer
   * DynamicClassReferenceInitializer} or by the {@link
   * proguard.classfile.util.DynamicMemberReferenceInitializer
   * DynamicMemberReferenceInitializer}.
   */
  public Clazz referencedClass;

  /**
   * An extra field pointing to the referenced Member object, if this string is being used in
   * Class.getDeclaredField/Method constructs. This field is typically filled out by the 
   * {@link
   * proguard.classfile.util.DynamicMemberReferenceInitializer
   * DynamicMemberReferenceInitializer}.
   */
  public Member referencedMember;

  /**
   * An extra field pointing to the java.lang.String Clazz object. This field is typically filled
   * out by the {@link
   * proguard.classfile.util.ClassReferenceInitializer
   * ClassReferenceInitializer}..
   */
  public Clazz javaLangStringClass;

  /**
   * An extra field pointing to the referenced resource ID, if this string references an Android
   * resource. Limitation: a String may point to multiple resources with the same name but a
   * different type - only one can be cached.
   */
  public int referencedResourceId;

  /** An extra field pointing to the referenced resource file, if this string references one. */
  public ResourceFile referencedResourceFile;

  /** Creates an uninitialized StringConstant. */
  public StringConstant() {}

  /**
   * Creates a new StringConstant with the given string index.
   *
   * @param u2stringIndex the index of the string in the constant pool.
   * @param referencedClass the referenced class, if any.
   * @param referencedMember the referenced class member, if any.
   */
  public StringConstant(int u2stringIndex, Clazz referencedClass, Member referencedMember) {
    this(u2stringIndex, referencedClass, referencedMember, 0, null);
  }

  /**
   * Creates a new StringConstant with the given string index.
   *
   * @param u2stringIndex the index of the string in the constant pool.
   * @param referencedResourceFile the referenced resource filename, if any.
   */
  public StringConstant(int u2stringIndex, ResourceFile referencedResourceFile) {
    this(u2stringIndex, null, null, 0, referencedResourceFile);
  }

  /**
   * Creates a new StringConstant with the given string index.
   *
   * @param u2stringIndex the index of the string in the constant pool.
   * @param referencedClass the referenced class, if any.
   * @param referencedMember the referenced class member, if any.
   * @param referencedResourceId the referenced resource id, if any, 0 otherwise.
   * @param referencedResourceFile the referenced resource filename, if any.
   */
  public StringConstant(
      int u2stringIndex,
      Clazz referencedClass,
      Member referencedMember,
      int referencedResourceId,
      ResourceFile referencedResourceFile) {
    this.u2stringIndex = u2stringIndex;
    this.referencedClass = referencedClass;
    this.referencedMember = referencedMember;
    this.referencedResourceId = referencedResourceId;
    this.referencedResourceFile = referencedResourceFile;
  }

  /** Returns the string value. */
  public String getString(Clazz clazz) {
    return clazz.getString(u2stringIndex);
  }

  // Implementations for Constant.

  @Override
  public int getTag() {
    return Constant.STRING;
  }

  @Override
  public boolean isCategory2() {
    return false;
  }

  @Override
  public void accept(Clazz clazz, ConstantVisitor constantVisitor) {
    constantVisitor.visitStringConstant(clazz, this);
  }

  /** Lets the referenced class accept the given visitor. */
  public void referencedClassAccept(ClassVisitor classVisitor) {
    if (referencedClass != null && referencedMember == null) {
      referencedClass.accept(classVisitor);
    }
  }

  /** Lets the referenced member accept the given visitor. */
  public void referencedMemberAccept(MemberVisitor memberVisitor) {
    if (referencedMember != null) {
      referencedMember.accept(referencedClass, memberVisitor);
    }
  }

  /** Lets the referenced resource file accept the given visitor. */
  public void referencedResourceFileAccept(ResourceFileVisitor resourceFileVisitor) {
    if (referencedResourceFile != null) {
      referencedResourceFile.accept(resourceFileVisitor);
    }
  }

  // Implementations for Object.

  @Override
  public boolean equals(Object object) {
    if (object == null || !this.getClass().equals(object.getClass())) {
      return false;
    }

    if (this == object) {
      return true;
    }

    StringConstant other = (StringConstant) object;

    // We're also taking into account the references here, so similar
    // constants can still be manipulated in different ways.
    return this.u2stringIndex == other.u2stringIndex
        && this.referencedClass == other.referencedClass
        && this.referencedMember == other.referencedMember
        && this.referencedResourceId == other.referencedResourceId
        && this.referencedResourceFile == other.referencedResourceFile;
  }

  @Override
  public int hashCode() {
    return Constant.STRING ^ (u2stringIndex << 5);
  }

  @Override
  public String toString() {
    return "String(" + u2stringIndex + ")";
  }
}