| // Copyright 2019 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.vfs.inmemoryfs; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.io.ByteStreams; |
| import com.google.devtools.build.lib.clock.Clock; |
| import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe; |
| import java.io.ByteArrayInputStream; |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| import java.nio.ByteBuffer; |
| import java.nio.channels.ReadableByteChannel; |
| |
| /** |
| * InMemoryFileInfo manages file contents by storing them entirely in memory. |
| */ |
| @ThreadSafe |
| public class InMemoryFileInfo extends FileInfo { |
| |
| /** |
| * Updates to the content must atomically update the lastModifiedTime. So all |
| * accesses to this field must be synchronized. |
| */ |
| protected byte[] content; |
| |
| public InMemoryFileInfo(Clock clock) { |
| super(clock); |
| content = new byte[0]; // New files start out empty. |
| } |
| |
| @Override |
| public synchronized long getSize() { |
| return content.length; |
| } |
| |
| @Override |
| public byte[] getxattr(String name) { |
| return null; |
| } |
| |
| @Override |
| public byte[] getFastDigest() { |
| return null; |
| } |
| |
| private synchronized void setContent(byte[] newContent) { |
| content = newContent; |
| markModificationTime(); |
| } |
| |
| @Override |
| public synchronized InputStream getInputStream() { |
| return new ByteArrayInputStream(content); |
| } |
| |
| @Override |
| public ReadableByteChannel createReadableByteChannel() { |
| return new ReadableByteChannel() { |
| private int offset = 0; |
| |
| @Override |
| public int read(ByteBuffer dst) { |
| if (offset >= content.length) { |
| return -1; |
| } |
| int length = Math.min(dst.remaining(), content.length - offset); |
| dst.put(content, offset, length); |
| offset += length; |
| return length; |
| } |
| |
| @Override |
| public boolean isOpen() { |
| return true; |
| } |
| |
| @Override |
| public void close() {} |
| }; |
| } |
| |
| @Override |
| public synchronized OutputStream getOutputStream(boolean append) { |
| OutputStream out = new InMemoryOutputStream(this::setContent); |
| if (append) { |
| try (InputStream in = getInputStream()) { |
| ByteStreams.copy(in, out); |
| } catch (IOException e) { |
| throw new IllegalStateException(e); |
| } |
| } |
| return out; |
| } |
| |
| /** |
| * A {@link ByteArrayOutputStream} which notifiers a callback when it has flushed its data. |
| */ |
| public static class InMemoryOutputStream extends ByteArrayOutputStream { |
| private final IOByteReceiver receiver; |
| private boolean closed = false; |
| |
| public InMemoryOutputStream(IOByteReceiver receiver) { |
| this.receiver = receiver; |
| } |
| |
| @Override |
| public void write(byte[] data) throws IOException { |
| Preconditions.checkState(!closed); |
| super.write(data); |
| } |
| |
| @Override |
| public synchronized void write(int dataByte) { |
| Preconditions.checkState(!closed); |
| super.write(dataByte); |
| } |
| |
| @Override |
| public synchronized void write(byte[] data, int offset, int length) { |
| Preconditions.checkState(!closed); |
| super.write(data, offset, length); |
| } |
| |
| @Override |
| public synchronized void close() throws IOException { |
| flush(); |
| closed = true; |
| } |
| |
| @Override |
| public synchronized void flush() throws IOException { |
| receiver.accept(toByteArray().clone()); |
| } |
| } |
| |
| /** |
| * Similar to {@link com.google.common.base.Receiver}, but allows implementations to throw |
| * {@link IOException}. |
| */ |
| public interface IOByteReceiver { |
| void accept(byte[] bytes) throws IOException; |
| } |
| } |