src/main/java/com/android/tools/r8/DexSegments.java

// Copyright (c) 2017, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
package com.android.tools.r8;

import com.android.tools.r8.dex.DexFileReader;
import com.android.tools.r8.dex.Segment;
import com.android.tools.r8.shaking.ProguardRuleParserException;
import com.android.tools.r8.utils.AndroidApp;
import com.android.tools.r8.utils.InternalOptions;
import com.google.common.collect.ImmutableList;
import com.google.common.io.Closer;
import java.io.IOException;
import java.nio.file.Paths;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutionException;

public class DexSegments {
  private static class Command extends BaseCommand {

    public static class Builder
        extends BaseCommand.Builder<Command, Builder> {

      @Override
      Command.Builder self() {
        return this;
      }

      @Override
      public Command build() throws CompilationException, IOException {
        // If printing versions ignore everything else.
        if (isPrintHelp()) {
          return new Command(isPrintHelp());
        }
        validate();
        return new Command(getAppBuilder().build());
      }
    }

    static final String USAGE_MESSAGE = String.join("\n", ImmutableList.of(
        "Usage: dexsegments [options] <input-files>",
        " where <input-files> are dex files",
        "  --version               # Print the version of r8.",
        "  --help                  # Print this message."));

    public static Command.Builder builder() {
      return new Command.Builder();
    }

    public static Command.Builder parse(String[] args)
        throws CompilationException, IOException {
      Command.Builder builder = builder();
      parse(args, builder);
      return builder;
    }

    private static void parse(String[] args, Command.Builder builder)
        throws CompilationException, IOException {
      for (int i = 0; i < args.length; i++) {
        String arg = args[i].trim();
        if (arg.length() == 0) {
          continue;
        } else if (arg.equals("--help")) {
          builder.setPrintHelp(true);
        } else {
          if (arg.startsWith("--")) {
            throw new CompilationException("Unknown option: " + arg);
          }
          builder.addProgramFiles(Paths.get(arg));
        }
      }
    }

    private Command(AndroidApp inputApp) {
      super(inputApp);
    }

    private Command(boolean printHelp) {
      super(printHelp, false);
    }

    @Override
    InternalOptions getInternalOptions() {
      return new InternalOptions();
    }
  }

  public static void main(String[] args)
      throws IOException, ProguardRuleParserException, CompilationException, ExecutionException {
    Command.Builder builder = Command.parse(args);
    Command command = builder.build();
    if (command.isPrintHelp()) {
      System.out.println(Command.USAGE_MESSAGE);
      return;
    }
    AndroidApp app = command.getInputApp();
    Map<String, Integer> result = new HashMap<>();
    try (Closer closer = Closer.create()) {
      for (Resource resource : app.getDexProgramResources()) {
        for (Segment segment: DexFileReader.parseMapFrom(closer.register(resource.getStream()))) {
          int value = result.computeIfAbsent(segment.typeName(), (key) -> 0);
          result.put(segment.typeName(), value + segment.size());
        }
      }
    }
    System.out.println("Segments in dex application (name: size):");
    result.forEach( (key, value) -> System.out.println(" - " + key + ": " + value));
  }
}