src/main/java/com/android/tools/r8/utils/DexVersion.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.utils;

import com.android.tools.r8.dex.Constants;
import com.android.tools.r8.errors.Unreachable;
import com.android.tools.r8.utils.structural.Ordered;
import com.google.common.collect.ImmutableMap;
import java.util.Map;
import java.util.Optional;

/** Android dex version */
public enum DexVersion implements Ordered<DexVersion> {
  V35(35, new byte[] {'0', '3', '5'}, Layout.SINGLE_DEX),
  V37(37, new byte[] {'0', '3', '7'}, Layout.SINGLE_DEX),
  V38(38, new byte[] {'0', '3', '8'}, Layout.SINGLE_DEX),
  V39(39, new byte[] {'0', '3', '9'}, Layout.SINGLE_DEX),
  V40(40, new byte[] {'0', '4', '0'}, Layout.SINGLE_DEX),
  V41(41, new byte[] {'0', '4', '1'}, Layout.CONTAINER_DEX);

  public enum Layout {
    SINGLE_DEX,
    CONTAINER_DEX;

    public boolean isContainer() {
      return this == CONTAINER_DEX;
    }

    @SuppressWarnings("ImmutableEnumChecker")
    public int getHeaderSize() {
      return isContainer() ? Constants.TYPE_HEADER_ITEM_SIZE_V41 : Constants.TYPE_HEADER_ITEM_SIZE;
    }
  }

  private final int dexVersion;

  @SuppressWarnings("ImmutableEnumChecker")
  private final byte[] dexVersionBytes;

  private final Layout layout;

  DexVersion(int dexVersion, byte[] dexVersionBytes, Layout layout) {
    this.dexVersion = dexVersion;
    this.dexVersionBytes = dexVersionBytes;
    this.layout = layout;
  }

  public Layout getLayout() {
    return layout;
  }

  public boolean isContainerDex() {
    return getLayout() == Layout.CONTAINER_DEX;
  }

  public int getIntValue() {
    return dexVersion;
  }

  public byte[] getBytes() {
    return dexVersionBytes;
  }

  public boolean matchesApiLevel(AndroidApiLevel androidApiLevel) {
    if (dexVersion == DexVersion.V40.dexVersion) {
      // getDexVersion does not handle V40. See b/269089718.
      return androidApiLevel.isGreaterThanOrEqualTo(AndroidApiLevel.R);
    }
    return getDexVersion(androidApiLevel).dexVersion >= dexVersion;
  }

  static {
    assert InternalOptions.containerDexApiLevel().isEqualTo(AndroidApiLevel.BAKLAVA);
  }

  static final Map<AndroidApiLevel, DexVersion> apiLevelToDexVersion =
      new ImmutableMap.Builder<AndroidApiLevel, DexVersion>()
          // MAIN is an unknown higher api version we therefore choose the highest known version.
          .put(AndroidApiLevel.MAIN, DexVersion.V41)
          .put(AndroidApiLevel.CINNAMON_BUN, DexVersion.V41)
          .put(AndroidApiLevel.BAKLAVA_1, DexVersion.V41)
          .put(AndroidApiLevel.BAKLAVA, DexVersion.V41)
          .put(AndroidApiLevel.V, DexVersion.V39)
          .put(AndroidApiLevel.U, DexVersion.V39)
          .put(AndroidApiLevel.T, DexVersion.V39)
          .put(AndroidApiLevel.Sv2, DexVersion.V39)
          .put(AndroidApiLevel.S, DexVersion.V39)
          .put(AndroidApiLevel.R, DexVersion.V39)
          // Dex version should have been V40 starting from API level 30, see b/269089718.
          .put(AndroidApiLevel.Q, DexVersion.V39)
          .put(AndroidApiLevel.P, DexVersion.V39)
          .put(AndroidApiLevel.O_MR1, DexVersion.V38)
          .put(AndroidApiLevel.O, DexVersion.V38)
          .put(AndroidApiLevel.N_MR1, DexVersion.V37)
          .put(AndroidApiLevel.N, DexVersion.V37)
          .put(AndroidApiLevel.M, DexVersion.V37)
          .build();

  public static DexVersion getDexVersion(AndroidApiLevel androidApiLevel) {
    if (androidApiLevel.isLessThan(AndroidApiLevel.N)) {
      return DexVersion.V35;
    }
    DexVersion version = apiLevelToDexVersion.get(androidApiLevel);
    if (version == null) {
      throw new Unreachable("Unsupported api level " + androidApiLevel);
    }
    return version;
  }

  public static Optional<DexVersion> getDexVersion(int intValue) {
    switch (intValue) {
      case 35:
        return Optional.of(V35);
      case 37:
        return Optional.of(V37);
      case 38:
        return Optional.of(V38);
      case 39:
        return Optional.of(V39);
      case 40:
        return Optional.of(V40);
      case 41:
        return Optional.of(V41);
      default:
        return Optional.empty();
    }
  }

  public static Optional<DexVersion> getDexVersion(char b0, char b1, char b2) {
    if (b0 != '0') {
      return Optional.empty();
    }
    for (DexVersion candidate : DexVersion.values()) {
      assert candidate.getBytes()[0] == '0';
      if (candidate.getBytes()[2] == b2 && candidate.getBytes()[1] == b1) {
        return Optional.of(candidate);
      }
    }
    return Optional.empty();
  }
}