| /* |
| * Copyright 2013 Google Inc. |
| * |
| * 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.common.jimfs; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.base.Preconditions.checkPositionIndexes; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| import com.google.common.primitives.Ints; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| import javax.annotation.concurrent.GuardedBy; |
| |
| /** |
| * {@link InputStream} for reading from a file's {@link RegularFile}. |
| * |
| * @author Colin Decker |
| */ |
| final class JimfsInputStream extends InputStream { |
| |
| @GuardedBy("this") |
| @VisibleForTesting |
| RegularFile file; |
| |
| @GuardedBy("this") |
| private long pos; |
| |
| @GuardedBy("this") |
| private boolean finished; |
| |
| private final FileSystemState fileSystemState; |
| |
| public JimfsInputStream(RegularFile file, FileSystemState fileSystemState) { |
| this.file = checkNotNull(file); |
| this.fileSystemState = fileSystemState; |
| fileSystemState.register(this); |
| } |
| |
| @Override |
| public synchronized int read() throws IOException { |
| checkNotClosed(); |
| if (finished) { |
| return -1; |
| } |
| |
| file.readLock().lock(); |
| try { |
| |
| int b = file.read(pos++); // it's ok for pos to go beyond size() |
| if (b == -1) { |
| finished = true; |
| } else { |
| file.updateAccessTime(); |
| } |
| return b; |
| } finally { |
| file.readLock().unlock(); |
| } |
| } |
| |
| @Override |
| public int read(byte[] b) throws IOException { |
| return readInternal(b, 0, b.length); |
| } |
| |
| @Override |
| public int read(byte[] b, int off, int len) throws IOException { |
| checkPositionIndexes(off, off + len, b.length); |
| return readInternal(b, off, len); |
| } |
| |
| private synchronized int readInternal(byte[] b, int off, int len) throws IOException { |
| checkNotClosed(); |
| if (finished) { |
| return -1; |
| } |
| |
| file.readLock().lock(); |
| try { |
| int read = file.read(pos, b, off, len); |
| if (read == -1) { |
| finished = true; |
| } else { |
| pos += read; |
| } |
| |
| file.updateAccessTime(); |
| return read; |
| } finally { |
| file.readLock().unlock(); |
| } |
| } |
| |
| @Override |
| public long skip(long n) throws IOException { |
| if (n <= 0) { |
| return 0; |
| } |
| |
| synchronized (this) { |
| checkNotClosed(); |
| if (finished) { |
| return 0; |
| } |
| |
| // available() must be an int, so the min must be also |
| int skip = (int) Math.min(Math.max(file.size() - pos, 0), n); |
| pos += skip; |
| return skip; |
| } |
| } |
| |
| @Override |
| public synchronized int available() throws IOException { |
| checkNotClosed(); |
| if (finished) { |
| return 0; |
| } |
| long available = Math.max(file.size() - pos, 0); |
| return Ints.saturatedCast(available); |
| } |
| |
| @GuardedBy("this") |
| private void checkNotClosed() throws IOException { |
| if (file == null) { |
| throw new IOException("stream is closed"); |
| } |
| } |
| |
| @Override |
| public synchronized void close() throws IOException { |
| if (isOpen()) { |
| fileSystemState.unregister(this); |
| file.closed(); |
| |
| // file is set to null here and only here |
| file = null; |
| } |
| } |
| |
| @GuardedBy("this") |
| private boolean isOpen() { |
| return file != null; |
| } |
| } |