proguard.classfile.MethodDescriptor Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of proguard-core Show documentation
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.classfile;

import static proguard.classfile.util.ClassUtil.externalShortClassName;
import static proguard.classfile.util.ClassUtil.externalType;

import java.lang.ref.WeakReference;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.WeakHashMap;
import java.util.stream.Collectors;
import proguard.classfile.util.ClassUtil;
import proguard.classfile.util.InternalTypeEnumeration;

/**
 * Represents the descriptor that is part of a {@link MethodSignature}. A descriptor consists of
 * parameter types and return type of a method, e.g. "()V" for a void method with no parameters, or
 * "(II)B" for a method that takes two integers and returns a boolean. Read more about this topic in
 * §4.3.3 of
 * the JVM specification.
 *
 * @author Samuel Hopstock
 */
public class MethodDescriptor {
  private static final Map> typeCache = new WeakHashMap<>();

  @Deprecated public final String returnType;
  @Deprecated public final List argumentTypes;

  // Cached hashCode, since computing the hashCode for the list of arguments everytime
  // can be expensive.
  private final int hash;

  public MethodDescriptor(String descriptor) {
    if (descriptor == null) {
      returnType = null;
      argumentTypes = null;
      hash = 0;
    } else {
      returnType = intern(ClassUtil.internalMethodReturnType(descriptor));
      int count = ClassUtil.internalMethodParameterCount(descriptor);
      if (count == 0) {
        this.argumentTypes = Collections.emptyList();
      } else {
        String[] argumentTypes = new String[count];
        InternalTypeEnumeration typeEnum = new InternalTypeEnumeration(descriptor);
        for (int i = 0; i < count; i++) {
          argumentTypes[i] = intern(typeEnum.nextType());
        }
        this.argumentTypes = Arrays.asList(argumentTypes);
      }

      hash = Objects.hash(returnType, argumentTypes);
    }
  }

  public MethodDescriptor(String returnType, List argumentTypes) {
    this.returnType = returnType;
    this.argumentTypes = argumentTypes;
    this.hash = Objects.hash(returnType, argumentTypes);
  }

  /** Check if this descriptor is missing information. */
  public boolean isIncomplete() {
    return returnType == null || argumentTypes == null;
  }

  public String getReturnType() {
    return returnType;
  }

  public List getArgumentTypes() {
    return argumentTypes;
  }

  /**
   * Analogous to {@link MethodSignature.matchesIgnoreNull(MethodSignature, MethodSignature)}.
   *
   * @param descriptor The {@link MethodDescriptor} to be compared
   * @param wildcard The {@link MethodDescriptor} pattern to be matched against
   * @return true if the two objects match
   */
  public static boolean matchesIgnoreNull(MethodDescriptor descriptor, MethodDescriptor wildcard) {
    if (wildcard == null) return true;
    if (descriptor == null) return false;

    return (wildcard.returnType == null
            || Objects.equals(descriptor.returnType, wildcard.returnType))
        && (wildcard.argumentTypes == null
            || Objects.equals(descriptor.argumentTypes, wildcard.argumentTypes));
  }

  /**
   * Analogous to {@link MethodSignature.matchesIgnoreNullAndDollar(MethodSignature,
   * MethodSignature)}.
   *
   * @param descriptor The {@link MethodDescriptor} to be compared
   * @param wildcard The {@link MethodDescriptor} pattern to be matched against
   * @return true if the two objects match
   */
  public static boolean matchesIgnoreNullAndDollar(
      MethodDescriptor descriptor, MethodDescriptor wildcard) {
    if (wildcard == null) return true;
    if (descriptor == null) return false;

    return checkReturnType(descriptor.returnType, wildcard.returnType)
        && checkArguments(wildcard.argumentTypes, descriptor.argumentTypes);
  }

  private static boolean checkReturnType(String returnType, String wildcardReturnType) {
    if (wildcardReturnType == null) return true;
    if (returnType == null) return false;

    return Objects.equals(replaceDollar(returnType), replaceDollar(wildcardReturnType));
  }

  private static boolean checkArguments(
      List wildcardArgumentTypes, List argumentTypes) {
    if (wildcardArgumentTypes == null) return true;
    if (argumentTypes == null) return false;

    if (wildcardArgumentTypes.size() != argumentTypes.size()) return false;

    return Objects.equals(
        argumentTypes.stream().map(MethodDescriptor::replaceDollar).collect(Collectors.toList()),
        wildcardArgumentTypes.stream()
            .map(MethodDescriptor::replaceDollar)
            .collect(Collectors.toList()));
  }

  private static String replaceDollar(String s) {
    return ClassUtil.isInternalClassType(s) ? s.replace('$', '/') : s;
  }

  /**
   * Get the human readable representation of the return type. E.g. "void" for "V" or "?" for an
   * undefined return type.
   *
   * @return The human readable representation of {@link #returnType}
   */
  public String getPrettyReturnType() {
    if (returnType != null) {
      return externalShortClassName(externalType(returnType));
    }
    return "?";
  }

  /**
   * Get the human readable representation of the argument types. E.g. "String,int" for
   * "(Ljava/lang/String;I)".
   *
   * @return The human readable representation of {@link #argumentTypes}
   */
  public String getPrettyArgumentTypes() {
    if (argumentTypes != null) {
      return argumentTypes.stream()
          .map(ClassUtil::externalType)
          .map(ClassUtil::externalShortClassName)
          .collect(Collectors.joining(","));
    }
    return "?";
  }

  @Override
  public String toString() {
    if (returnType != null) {
      if (argumentTypes != null) {
        return ClassUtil.internalMethodDescriptorFromInternalTypes(returnType, argumentTypes);
      } else {
        return "(?)" + returnType;
      }
    } else {
      if (argumentTypes != null) {
        return ClassUtil.internalMethodDescriptorFromInternalTypes("?", argumentTypes);
      } else {
        return "(?)?";
      }
    }
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    MethodDescriptor that = (MethodDescriptor) o;
    return Objects.equals(returnType, that.returnType)
        && Objects.equals(argumentTypes, that.argumentTypes);
  }

  @Override
  public int hashCode() {
    return hash;
  }

  private static synchronized String intern(String item) {
    WeakReference ref = typeCache.get(item);
    if (ref != null) {
      String oldItem = ref.get();
      if (oldItem != null) {
        return oldItem;
      }
    }
    typeCache.put(item, new WeakReference<>(item));
    return item;
  }
}