com.yahoo.jdisc.handler.UnsafeContentInputStream Maven / Gradle / Ivy
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.jdisc.handler;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.Objects;
/**
* This class provides an adapter from a {@link ReadableContentChannel} to an InputStream. This class supports all
* regular InputStream operations, and can be combined with any other InputStream API.
*
* Because this class encapsulates the reference-counted {@link ContentChannel} operations, one must be sure to
* always call {@link #close()} before discarding it. Failure to do so will prevent the Container from ever shutting
* down.
*
* @author Simon Thoresen Hult
*/
public class UnsafeContentInputStream extends InputStream {
private final ReadableContentChannel content;
private ByteBuffer currBuf = ByteBuffer.allocate(0);
private byte [] marked;
private int readSinceMarked;
/**
* Constructs a new ContentInputStream that reads from the given {@link ReadableContentChannel}.
*
* @param content The content to read the stream from.
*/
public UnsafeContentInputStream(ReadableContentChannel content) {
this.content = content;
}
@Override
public int read() {
fetchNonEmptyBuffer();
if (currBuf == null) return -1;
byte b = currBuf.get();
if (marked != null) {
if (readSinceMarked < marked.length) {
marked[readSinceMarked++] = b;
} else {
marked = null;
}
}
return ((int)b) & 0xFF;
}
private boolean fetchNonEmptyBuffer() {
while (currBuf != null && currBuf.remaining() == 0) {
currBuf = content.read();
}
return (currBuf != null && currBuf.hasRemaining());
}
@Override
public int read(byte buf[], int off, int len) {
Objects.requireNonNull(buf, "buf");
if (off < 0 || len < 0 || len > buf.length - off) {
throw new IndexOutOfBoundsException();
}
if (len == 0) return 0;
if ( ! fetchNonEmptyBuffer() ) return -1;
int read = 0;
while ((available() > 0) && fetchNonEmptyBuffer() && ((len - read) > 0)) {
int toRead = Math.min(currBuf.remaining(), (len - read));
currBuf.get(buf, off + read, toRead);
read += toRead;
}
if (marked != null) {
if (readSinceMarked + read <= marked.length) {
System.arraycopy(buf, off, marked, readSinceMarked, read);
readSinceMarked += read;
} else {
marked = null;
}
}
return read;
}
@Override
public int available() {
if (currBuf != null && currBuf.remaining() > 0) {
return currBuf.remaining();
}
return content.available();
}
@Override
public void close() {
// noinspection StatementWithEmptyBody
while (content.read() != null) {
}
}
@Override
public synchronized void mark(int readlimit) {
marked = new byte[readlimit];
readSinceMarked = 0;
}
@Override
public synchronized void reset() throws IOException {
if (marked == null) {
throw new IOException("mark has not been called, or too much has been read since marked.");
}
var remainingInCurrent = currBuf == null ? 0 : currBuf.remaining();
ByteBuffer newBuf = ByteBuffer.allocate(readSinceMarked + remainingInCurrent);
newBuf.put(marked, 0, readSinceMarked);
if (remainingInCurrent > 0) newBuf.put(currBuf);
newBuf.flip();
currBuf = newBuf;
marked = null;
}
@Override
public boolean markSupported() {
return true;
}
}