jdk/src/java.base/share/classes/sun/nio/ch/ChannelInputStream.java

275 lines
8.7 KiB
Java

/*
* Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.nio.ch;
import java.io.InputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.IllegalBlockingModeException;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.SeekableByteChannel;
import java.nio.channels.SelectableChannel;
import java.nio.channels.WritableByteChannel;
import java.util.Arrays;
import java.util.Objects;
import jdk.internal.util.ArraysSupport;
/**
* This class is defined here rather than in java.nio.channels.Channels
* so that code can be shared with SocketAdaptor.
*
* @author Mike McCloskey
* @author Mark Reinhold
* @since 1.4
*/
public class ChannelInputStream
extends InputStream
{
private static final int DEFAULT_BUFFER_SIZE = 8192;
public static int read(ReadableByteChannel ch, ByteBuffer bb,
boolean block)
throws IOException
{
if (ch instanceof SelectableChannel sc) {
synchronized (sc.blockingLock()) {
boolean bm = sc.isBlocking();
if (!bm)
throw new IllegalBlockingModeException();
if (bm != block)
sc.configureBlocking(block);
int n = ch.read(bb);
if (bm != block)
sc.configureBlocking(bm);
return n;
}
} else {
return ch.read(bb);
}
}
protected final ReadableByteChannel ch;
private ByteBuffer bb = null;
private byte[] bs = null; // Invoker's previous array
private byte[] b1 = null;
public ChannelInputStream(ReadableByteChannel ch) {
this.ch = ch;
}
public synchronized int read() throws IOException {
if (b1 == null)
b1 = new byte[1];
int n = this.read(b1);
if (n == 1)
return b1[0] & 0xff;
return -1;
}
public synchronized int read(byte[] bs, int off, int len)
throws IOException
{
Objects.checkFromIndexSize(off, len, bs.length);
if (len == 0)
return 0;
ByteBuffer bb = ((this.bs == bs)
? this.bb
: ByteBuffer.wrap(bs));
bb.limit(Math.min(off + len, bb.capacity()));
bb.position(off);
this.bb = bb;
this.bs = bs;
return read(bb);
}
protected int read(ByteBuffer bb)
throws IOException
{
return ChannelInputStream.read(ch, bb, true);
}
@Override
public byte[] readAllBytes() throws IOException {
if (!(ch instanceof SeekableByteChannel sbc))
return super.readAllBytes();
long length = sbc.size();
long position = sbc.position();
long size = length - position;
if (length <= 0 || size <= 0)
return super.readAllBytes();
if (size > (long) Integer.MAX_VALUE) {
String msg =
String.format("Required array size too large: %d = %d - %d",
size, length, position);
throw new OutOfMemoryError(msg);
}
int capacity = (int)size;
byte[] buf = new byte[capacity];
int nread = 0;
int n;
for (;;) {
// read to EOF which may read more or less than initial size, e.g.,
// file is truncated while we are reading
while ((n = read(buf, nread, capacity - nread)) > 0)
nread += n;
// if last call to read() returned -1, we are done; otherwise,
// try to read one more byte and if that fails we're done too
if (n < 0 || (n = read()) < 0)
break;
// one more byte was read; need to allocate a larger buffer
capacity = Math.max(ArraysSupport.newLength(capacity,
1, // min growth
capacity), // pref growth
DEFAULT_BUFFER_SIZE);
buf = Arrays.copyOf(buf, capacity);
buf[nread++] = (byte)n;
}
return (capacity == nread) ? buf : Arrays.copyOf(buf, nread);
}
@Override
public byte[] readNBytes(int len) throws IOException {
if (len < 0)
throw new IllegalArgumentException("len < 0");
if (len == 0)
return new byte[0];
if (!(ch instanceof SeekableByteChannel sbc))
return super.readNBytes(len);
long length = sbc.size();
long position = sbc.position();
long size = length - position;
if (length <= 0 || size <= 0)
return super.readNBytes(len);
int capacity = (int)Math.min(len, size);
byte[] buf = new byte[capacity];
int remaining = capacity;
int nread = 0;
int n;
do {
n = read(buf, nread, remaining);
if (n > 0) {
nread += n;
remaining -= n;
} else if (n == 0) {
// Block until a byte is read or EOF is detected
byte b = (byte)read();
if (b == -1 )
break;
buf[nread++] = b;
remaining--;
}
} while (n >= 0 && remaining > 0);
return (capacity == nread) ? buf : Arrays.copyOf(buf, nread);
}
public int available() throws IOException {
// special case where the channel is to a file
if (ch instanceof SeekableByteChannel sbc) {
long rem = Math.max(0, sbc.size() - sbc.position());
return (rem > Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int)rem;
}
return 0;
}
public synchronized long skip(long n) throws IOException {
// special case where the channel is to a file
if (ch instanceof SeekableByteChannel sbc) {
long pos = sbc.position();
long newPos;
if (n > 0) {
newPos = pos + n;
long size = sbc.size();
if (newPos < 0 || newPos > size) {
newPos = size;
}
} else {
newPos = Long.max(pos + n, 0);
}
sbc.position(newPos);
return newPos - pos;
}
return super.skip(n);
}
public void close() throws IOException {
ch.close();
}
@Override
public long transferTo(OutputStream out) throws IOException {
Objects.requireNonNull(out, "out");
if (out instanceof ChannelOutputStream cos
&& ch instanceof FileChannel fc) {
WritableByteChannel wbc = cos.channel();
if (wbc instanceof FileChannel dst) {
return transfer(fc, dst);
}
if (wbc instanceof SelectableChannel sc) {
synchronized (sc.blockingLock()) {
if (!sc.isBlocking())
throw new IllegalBlockingModeException();
return transfer(fc, wbc);
}
}
return transfer(fc, wbc);
}
return super.transferTo(out);
}
private static long transfer(FileChannel src, WritableByteChannel dst) throws IOException {
long initialPos = src.position();
long pos = initialPos;
try {
while (pos < src.size()) {
pos += src.transferTo(pos, Long.MAX_VALUE, dst);
}
} finally {
src.position(pos);
}
return pos - initialPos;
}
}