DeprecatedGen.java

/*
 * (C) Copyright Uwe Schindler (Generics Policeman) and others.
 *
 * 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 de.thetaphi.forbiddenapis;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.nio.charset.StandardCharsets;
import java.util.Locale;
import java.util.SortedSet;
import java.util.TreeSet;

import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

/** Lists all classes in Java runtime, scans them for deprecated signatures and writes them to a signatures file. */
public abstract class DeprecatedGen<Input> implements Opcodes {
  
  final static String NL = System.getProperty("line.separator", "\n");
  final SortedSet<String> deprecated = new TreeSet<>();
  final String javaVersion, header;
  
  private final Input source;
  private final File output;
  
  public DeprecatedGen(String javaVersion, Input source, File output) {
    this.javaVersion = javaVersion;
    this.source = source;
    this.output = output;
    this.header = new StringBuilder()
      .append("# This file contains API signatures extracted from the rt.jar / jimage file shipped with the class library of Oracle's Java Runtime Environment.").append(NL)
      .append("# It is provided here for reference, but can easily regenerated by executing from the source folder of forbidden-apis:").append(NL)
      .append("# $ ant generate-deprecated").append(NL)
      .append(NL)
      .append("# This file contains all public, deprecated API signatures in Java version ").append(javaVersion)
        .append(" (extracted from build ").append(System.getProperty("java.version")).append(").").append(NL)
      .append(NL)
      .append("@ignoreUnresolvable").append(NL)
      .append("@defaultMessage Deprecated in Java ").append(javaVersion).append(NL)
      .append(NL)
      .toString();
  }
  
  protected boolean isDeprecated(int access) {
   return ((access & (ACC_PUBLIC | ACC_PROTECTED)) != 0 && (access & ACC_DEPRECATED) != 0);
  }
  
  protected void parseClass(InputStream in) throws IOException {
    final ClassReader reader = AsmUtils.readAndPatchClass(in);
    final String className =  Type.getObjectType(reader.getClassName()).getClassName();
    // exclude internal classes like Unsafe,... and non-public classes!
    // Note: reader.getAccess() does no indicate if class is deprecated, as this is a special
    // attribute or annotation (both is handled later), we have to parse the class - this is just early exit!
    if ((reader.getAccess() & ACC_PUBLIC) == 0 || !AsmUtils.isPortableRuntimeClass(className)) {
      return;
    }
    reader.accept(new ClassVisitor(ASM9) {
      boolean classDeprecated = false;
    
      @Override
      public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
        if (isDeprecated(access)) {
          deprecated.add(className);
          classDeprecated = true;
        }
      }

      @Override
      public MethodVisitor visitMethod(final int access, final String name, final String desc, final String signature, final String[] exceptions) {
        if (!classDeprecated && isDeprecated(access)) {
          final Type[] args = Type.getType(desc).getArgumentTypes();
          final StringBuilder sb = new StringBuilder(className).append('#').append(name).append('(');
          boolean comma = false;
          for (final Type t : args) {
            if (comma) sb.append(',');
            sb.append(t.getClassName());
            comma = true;
          }
          sb.append(')');
          deprecated.add(sb.toString());
        }
        return null;
      }
        
      @Override
      public FieldVisitor visitField(final int access, final String name, final String desc, final String signature, final Object value) {
        if (!classDeprecated && isDeprecated(access)) {
          deprecated.add(className + '#' + name);
        }
        return null;
      }
    }, ClassReader.SKIP_CODE | ClassReader.SKIP_DEBUG | ClassReader.SKIP_FRAMES);
  }
  
  protected void writeOutput(OutputStream out) throws IOException {
    BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8));
    writer.write(header);
    for (final String s : deprecated) {
      writer.write(s);
      writer.newLine();
    }
    writer.flush();
  }
  
  protected abstract void collectClasses(Input source) throws IOException;
  
  @SuppressForbidden
  public void run() throws IOException {
    System.err.println(String.format(Locale.ENGLISH, "Reading '%s' and extracting deprecated APIs to signatures file '%s'...", source, output));
    collectClasses(source);
    try (final FileOutputStream out = new FileOutputStream(output)) {
      writeOutput(out);
    }
    System.err.println("Deprecated API signatures for Java version " + javaVersion + " written successfully.");
  }

}