| // Copyright 2023 The Bazel Authors. All rights reserved. |
| // |
| // 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 net.starlark.java.eval; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.ImmutableList; |
| import java.util.Arrays; |
| |
| /** A specific implementation of a Tuple that has exactly 1 element. */ |
| final class SingletonTuple extends Tuple { |
| final Object elem; |
| |
| SingletonTuple(Object elem) { |
| this.elem = elem; |
| } |
| |
| @Override |
| public boolean isImmutable() { |
| return Starlark.isImmutable(elem); |
| } |
| |
| @Override |
| public void checkHashable() throws EvalException { |
| Starlark.checkHashable(elem); |
| } |
| |
| @Override |
| public int hashCode() { |
| // This produces the same results as RegularTuple.hashCode(), |
| return 9857 + 8167 * (31 + elem.hashCode()); |
| } |
| |
| @Override |
| public Object get(int i) { |
| Preconditions.checkElementIndex(i, 1); |
| return elem; |
| } |
| |
| @Override |
| public int size() { |
| return 1; |
| } |
| |
| @Override |
| public boolean contains(Object o) { |
| // Tuple contains only valid Starlark objects (which are non-null) |
| if (o == null) { |
| return false; |
| } |
| return o.equals(elem); |
| } |
| |
| @Override |
| public Tuple subList(int from, int to) { |
| Preconditions.checkPositionIndexes(from, to, 1); |
| return from <= 0 && to >= 1 ? this : empty(); |
| } |
| |
| /** Returns a new array of class Object[] containing the tuple elements. */ |
| @Override |
| public Object[] toArray() { |
| return new Object[] {elem}; |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public <T> T[] toArray(T[] a) { |
| if (a.length < 1) { |
| return (T[]) new Object[] {elem}; |
| } else { |
| a[0] = (T) elem; |
| Arrays.fill(a, 1, a.length, null); |
| return a; |
| } |
| } |
| |
| @Override |
| public void repr(Printer printer) { |
| printer.append('(').repr(elem).append(",)"); |
| } |
| |
| @Override |
| public ImmutableList<Object> getImmutableList() { |
| return ImmutableList.of(elem); |
| } |
| |
| @Override |
| public Tuple getSlice(Mutability mu, int start, int stop, int step) throws EvalException { |
| RangeList indices = new RangeList(start, stop, step); |
| return indices.isEmpty() ? Tuple.empty() : this; |
| } |
| |
| @Override |
| Tuple repeat(StarlarkInt n) throws EvalException { |
| if (n.signum() <= 0) { |
| return empty(); |
| } |
| |
| int ni = n.toInt("repeat"); |
| if (ni > StarlarkList.MAX_ALLOC) { |
| throw Starlark.errorf("excessive repeat (%d * %d elements)", 1, ni); |
| } |
| Object[] res = new Object[ni]; |
| Arrays.fill(res, 0, ni, elem); |
| return wrap(res); |
| } |
| } |