| // Copyright 2018 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.android.dexer; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static com.google.common.base.Preconditions.checkState; |
| import static java.util.concurrent.TimeUnit.MINUTES; |
| |
| import java.io.BufferedOutputStream; |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.nio.file.Files; |
| import java.nio.file.OpenOption; |
| import java.nio.file.Path; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.atomic.AtomicReference; |
| import java.util.zip.ZipEntry; |
| import java.util.zip.ZipOutputStream; |
| |
| /** |
| * {@link ZipOutputStream} wrapper that {@link #writeAsync writes} zip entries asynchronously in the |
| * given order. It's essential to eventually {@link #close} to block until writing is finished. |
| */ |
| public class AsyncZipOut implements Closeable { |
| /** A single thread used to write zip entries sequentially in the given order. */ |
| private final ExecutorService writerThread = Executors.newSingleThreadExecutor(); |
| /** The first exception writing to {@link #out}, if any. */ |
| private final AtomicReference<Throwable> exception = new AtomicReference<>(null); |
| |
| private final Path dest; // for exception messages |
| /** |
| * The underlying zip output. This field must be exclusively accessed through tasks enqueued in |
| * {@link #writerThread}. |
| */ |
| private final ZipOutputStream out; |
| |
| AsyncZipOut(Path dest, OpenOption... options) throws IOException { |
| this(dest, new ZipOutputStream(new BufferedOutputStream(Files.newOutputStream(dest, options)))); |
| } |
| |
| private AsyncZipOut(Path dest, ZipOutputStream out) { |
| this.dest = dest; |
| this.out = out; |
| } |
| |
| /** |
| * Enqueues a zip entry to write after any already enqueued entries, unless errors have occurred |
| * or {@link #finishAsync} or {@link #close} have been called. |
| * |
| * @throws IOException exceptions that occurred writing any previously enqueued entries |
| */ |
| void writeAsync(ZipEntry entry, byte[] content) throws IOException { |
| checkPendingException(); // fail fast |
| checkArgument(entry.getMethod() == ZipEntry.STORED); |
| checkArgument(entry.getSize() == content.length); |
| writerThread.execute( |
| () -> { |
| try { |
| out.putNextEntry(entry); |
| out.write(content); |
| out.closeEntry(); |
| } catch (Throwable e) { |
| exception.compareAndSet(null, e); |
| } |
| }); |
| } |
| |
| /** |
| * After any pending writes are done, this closes the underlying {@link ZipOutputStream}, which |
| * appends the zip file's central directory to the end of the file. |
| */ |
| void finishAsync() { |
| if (writerThread.isShutdown()) { |
| return; |
| } |
| writerThread.execute( |
| () -> { |
| try { |
| out.close(); |
| } catch (Throwable e) { |
| exception.compareAndSet(null, e); |
| } |
| }); |
| writerThread.shutdown(); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| finishAsync(); |
| try { |
| checkState(writerThread.awaitTermination(1, MINUTES), "Didn't finish writing in time"); |
| } catch (InterruptedException e) { |
| Thread.currentThread().interrupt(); |
| throw new IOException(e); |
| } |
| checkPendingException(); |
| } |
| |
| private void checkPendingException() throws IOException { |
| Throwable e = exception.get(); |
| if (e != null) { |
| writerThread.shutdownNow(); // abort pending writes, since we're failed anyways |
| throw new IOException("Asynchronous exception writing " + dest, e); |
| } |
| } |
| |
| @Override |
| protected void finalize() throws Throwable { |
| close(); // Call close() so we get any exceptions, but note this may block |
| } |
| } |