| // Copyright (c) 2020, 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.errors.Unreachable; |
| import java.util.function.Function; |
| |
| /** Two value continuation value to indicate the continuation of a loop/traversal. */ |
| /* This class is used for building up api class member traversals. */ |
| public abstract class TraversalContinuation<TB, TC> { |
| |
| public boolean isBreak() { |
| return false; |
| } |
| |
| public Break<TB, TC> asBreak() { |
| return null; |
| } |
| |
| public boolean isContinue() { |
| return false; |
| } |
| |
| public Continue<TB, TC> asContinue() { |
| return null; |
| } |
| |
| public <TBx, TCx> TraversalContinuation<TBx, TCx> map( |
| Function<TB, TBx> mapBreak, Function<TC, TCx> mapContinue) { |
| if (isBreak()) { |
| return new Break<>(mapBreak.apply(asBreak().getValue())); |
| } else { |
| assert isContinue(); |
| return new Continue<>(mapContinue.apply(asContinue().getValue())); |
| } |
| } |
| |
| public static class Continue<TB, TC> extends TraversalContinuation<TB, TC> { |
| private static final TraversalContinuation.Continue<?, ?> CONTINUE_NO_VALUE = |
| new Continue<Object, Object>(null) { |
| @Override |
| public Object getValue() { |
| return new Unreachable( |
| "Invalid attempt at getting a value from a no-value continue state."); |
| } |
| |
| @Override |
| public Object getValueOrDefault(Object defaultValue) { |
| return defaultValue; |
| } |
| }; |
| |
| private final TC value; |
| |
| private Continue(TC value) { |
| this.value = value; |
| } |
| |
| public TC getValue() { |
| return value; |
| } |
| |
| public TC getValueOrDefault(TC defaultValue) { |
| return value; |
| } |
| |
| @Override |
| public boolean isContinue() { |
| return true; |
| } |
| |
| @Override |
| public Continue<TB, TC> asContinue() { |
| return this; |
| } |
| } |
| |
| public static class Break<TB, TC> extends TraversalContinuation<TB, TC> { |
| private static final TraversalContinuation.Break<?, ?> BREAK_NO_VALUE = |
| new Break<Object, Object>(null) { |
| @Override |
| public Object getValue() { |
| return new Unreachable( |
| "Invalid attempt at getting a value from a no-value break state."); |
| } |
| |
| @Override |
| public Object getValueOrDefault(Object defaultValue) { |
| return defaultValue; |
| } |
| }; |
| |
| private final TB value; |
| |
| private Break(TB value) { |
| this.value = value; |
| } |
| |
| public TB getValue() { |
| return value; |
| } |
| |
| public TB getValueOrDefault(TB defaultValue) { |
| return value; |
| } |
| |
| @Override |
| public boolean isBreak() { |
| return true; |
| } |
| |
| @Override |
| public Break<TB, TC> asBreak() { |
| return this; |
| } |
| } |
| |
| public static <TB, TC> TraversalContinuation<TB, TC> breakIf(boolean condition) { |
| return continueIf(!condition); |
| } |
| |
| public static <TB, TC> TraversalContinuation<TB, TC> continueIf(boolean condition) { |
| return condition ? doContinue() : doBreak(); |
| } |
| |
| public TraversalContinuation<TB, TC> ifContinueThen( |
| Function<TraversalContinuation.Continue<TB, TC>, TraversalContinuation<TB, TC>> fn) { |
| return isContinue() ? fn.apply(asContinue()) : this; |
| } |
| |
| @SuppressWarnings("unchecked") |
| public static <TB, TC> TraversalContinuation.Continue<TB, TC> doContinue() { |
| return (TraversalContinuation.Continue<TB, TC>) Continue.CONTINUE_NO_VALUE; |
| } |
| |
| public static <TB, TC> TraversalContinuation.Continue<TB, TC> doContinue(TC value) { |
| return new Continue<>(value); |
| } |
| |
| @SuppressWarnings("unchecked") |
| public static <TB, TC> TraversalContinuation.Break<TB, TC> doBreak() { |
| return (TraversalContinuation.Break<TB, TC>) Break.BREAK_NO_VALUE; |
| } |
| |
| public static <TB, TC> TraversalContinuation.Break<TB, TC> doBreak(TB value) { |
| return new Break<>(value); |
| } |
| |
| public final boolean shouldBreak() { |
| return isBreak(); |
| } |
| |
| public final boolean shouldContinue() { |
| return isContinue(); |
| } |
| } |