| // Copyright 2016 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 com.google.devtools.build.lib.bazel.repository.downloader; |
| |
| import com.google.common.hash.HashCode; |
| import com.google.common.hash.HashFunction; |
| import com.google.common.hash.Hasher; |
| import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadCompatible; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import javax.annotation.Nullable; |
| import javax.annotation.WillCloseWhenClosed; |
| |
| /** |
| * Input stream that guarantees its contents matches a hash code. |
| * |
| * <p>The actual checksum is computed gradually as the input is read. If it doesn't match, then an |
| * {@link IOException} will be thrown when {@link #close()} is called, or when any read method is |
| * called that detects the end of stream. This error will be thrown multiple times if these methods |
| * are called again for some reason. |
| * |
| * <p>This class is not thread safe, but it is safe to message pass this object between threads. |
| */ |
| @ThreadCompatible |
| final class HashInputStream extends InputStream { |
| |
| private final InputStream delegate; |
| private final Hasher hasher; |
| private final HashCode code; |
| @Nullable private volatile HashCode actual; |
| |
| HashInputStream( |
| @WillCloseWhenClosed InputStream delegate, HashFunction function, HashCode code) { |
| this.delegate = delegate; |
| this.hasher = function.newHasher(); |
| this.code = code; |
| } |
| |
| @Override |
| public int read() throws IOException { |
| int result = delegate.read(); |
| if (result == -1) { |
| check(); |
| } else { |
| hasher.putByte((byte) result); |
| } |
| return result; |
| } |
| |
| @Override |
| public int read(byte[] buffer, int offset, int length) throws IOException { |
| int amount = delegate.read(buffer, offset, length); |
| if (amount == -1) { |
| check(); |
| } else { |
| hasher.putBytes(buffer, offset, amount); |
| } |
| return amount; |
| } |
| |
| @Override |
| public int available() throws IOException { |
| return delegate.available(); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| delegate.close(); |
| check(); |
| } |
| |
| private void check() throws IOException { |
| if (actual == null) { |
| actual = hasher.hash(); |
| } |
| if (!code.equals(actual)) { |
| throw new UnrecoverableHttpException( |
| String.format("Checksum was %s but wanted %s", actual, code)); |
| } |
| } |
| } |