| // Copyright (c) 2018, 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.codeinspector; |
| |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| import java.util.function.Predicate; |
| |
| class FilteredInstructionIterator<T extends InstructionSubject> implements Iterator<T> { |
| |
| private final InstructionIterator iterator; |
| private final Predicate<InstructionSubject> predicate; |
| private InstructionSubject pendingNext = null; |
| |
| FilteredInstructionIterator( |
| CodeInspector codeInspector, MethodSubject method, Predicate<InstructionSubject> predicate) { |
| this.iterator = codeInspector.createInstructionIterator(method); |
| this.predicate = predicate; |
| } |
| |
| @Override |
| public boolean hasNext() { |
| if (pendingNext == null) { |
| while (iterator.hasNext()) { |
| pendingNext = iterator.next(); |
| if (predicate.test(pendingNext)) { |
| break; |
| } |
| pendingNext = null; |
| } |
| } |
| return pendingNext != null; |
| } |
| |
| @Override |
| public T next() { |
| hasNext(); |
| if (pendingNext == null) { |
| throw new NoSuchElementException(); |
| } |
| // We cannot tell if the provided predicate will only match instruction subjects of type T. |
| @SuppressWarnings("unchecked") |
| T result = (T) pendingNext; |
| pendingNext = null; |
| return result; |
| } |
| } |