| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 java.io; |
| |
| import dalvik.system.CloseGuard; |
| |
| import java.nio.NioUtils; |
| import java.nio.channels.FileChannel; |
| import java.util.Arrays; |
| import libcore.io.ErrnoException; |
| import libcore.io.IoBridge; |
| import libcore.io.IoUtils; |
| import libcore.io.Libcore; |
| import libcore.io.Streams; |
| import static libcore.io.OsConstants.*; |
| |
| /** |
| * An input stream that reads bytes from a file. |
| * <pre> {@code |
| * File file = ... |
| * InputStream in = null; |
| * try { |
| * in = new BufferedInputStream(new FileInputStream(file)); |
| * ... |
| * } finally { |
| * if (in != null) { |
| * in.close(); |
| * } |
| * } |
| * }</pre> |
| * |
| * <p>This stream is <strong>not buffered</strong>. Most callers should wrap |
| * this stream with a {@link BufferedInputStream}. |
| * |
| * <p>Use {@link FileReader} to read characters, as opposed to bytes, from a |
| * file. |
| * |
| * @see BufferedInputStream |
| * @see FileOutputStream |
| */ |
| public class FileInputStream extends InputStream implements Closeable { |
| |
| private FileDescriptor fd; |
| private final boolean shouldClose; |
| |
| /** The unique file channel. Lazily initialized because it's rarely needed. */ |
| private FileChannel channel; |
| |
| private final CloseGuard guard = CloseGuard.get(); |
| |
| /** |
| * Constructs a new {@code FileInputStream} that reads from {@code file}. |
| * |
| * @param file |
| * the file from which this stream reads. |
| * @throws FileNotFoundException |
| * if {@code file} does not exist. |
| */ |
| public FileInputStream(File file) throws FileNotFoundException { |
| if (file == null) { |
| throw new NullPointerException("file == null"); |
| } |
| this.fd = IoBridge.open(file.getAbsolutePath(), O_RDONLY); |
| this.shouldClose = true; |
| guard.open("close"); |
| } |
| |
| /** |
| * Constructs a new {@code FileInputStream} that reads from {@code fd}. |
| * |
| * @param fd |
| * the FileDescriptor from which this stream reads. |
| * @throws NullPointerException |
| * if {@code fd} is {@code null}. |
| */ |
| public FileInputStream(FileDescriptor fd) { |
| if (fd == null) { |
| throw new NullPointerException("fd == null"); |
| } |
| this.fd = fd; |
| this.shouldClose = false; |
| // Note that we do not call guard.open here because the |
| // FileDescriptor is not owned by the stream. |
| } |
| |
| /** |
| * Equivalent to {@code new FileInputStream(new File(path))}. |
| */ |
| public FileInputStream(String path) throws FileNotFoundException { |
| this(new File(path)); |
| } |
| |
| @Override |
| public int available() throws IOException { |
| return IoBridge.available(fd); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| guard.close(); |
| synchronized (this) { |
| if (channel != null) { |
| channel.close(); |
| } |
| if (shouldClose) { |
| IoUtils.close(fd); |
| } else { |
| // An owned fd has been invalidated by IoUtils.close, but |
| // we need to explicitly stop using an unowned fd (http://b/4361076). |
| fd = new FileDescriptor(); |
| } |
| } |
| } |
| |
| /** |
| * Ensures that all resources for this stream are released when it is about |
| * to be garbage collected. |
| * |
| * @throws IOException |
| * if an error occurs attempting to finalize this stream. |
| */ |
| @Override protected void finalize() throws IOException { |
| try { |
| if (guard != null) { |
| guard.warnIfOpen(); |
| } |
| close(); |
| } finally { |
| try { |
| super.finalize(); |
| } catch (Throwable t) { |
| // for consistency with the RI, we must override Object.finalize() to |
| // remove the 'throws Throwable' clause. |
| throw new AssertionError(t); |
| } |
| } |
| } |
| |
| /** |
| * Returns a read-only {@link FileChannel} that shares its position with |
| * this stream. |
| */ |
| public FileChannel getChannel() { |
| synchronized (this) { |
| if (channel == null) { |
| channel = NioUtils.newFileChannel(this, fd, O_RDONLY); |
| } |
| return channel; |
| } |
| } |
| |
| /** |
| * Returns the underlying file descriptor. |
| */ |
| public final FileDescriptor getFD() throws IOException { |
| return fd; |
| } |
| |
| @Override public int read() throws IOException { |
| return Streams.readSingleByte(this); |
| } |
| |
| @Override public int read(byte[] buffer, int byteOffset, int byteCount) throws IOException { |
| return IoBridge.read(fd, buffer, byteOffset, byteCount); |
| } |
| |
| @Override |
| public long skip(long byteCount) throws IOException { |
| if (byteCount < 0) { |
| throw new IOException("byteCount < 0: " + byteCount); |
| } |
| try { |
| // Try lseek(2). That returns the new offset, but we'll throw an |
| // exception if it couldn't perform exactly the seek we asked for. |
| Libcore.os.lseek(fd, byteCount, SEEK_CUR); |
| return byteCount; |
| } catch (ErrnoException errnoException) { |
| if (errnoException.errno == ESPIPE) { |
| // You can't seek on a pipe, so fall back to the superclass' implementation. |
| return super.skip(byteCount); |
| } |
| throw errnoException.rethrowAsIOException(); |
| } |
| } |
| } |