| /* |
| * Copyright (C) 2007 The Guava Authors |
| * Copyright (C) 2014, Sasa Zivkov <sasa.zivkov@sap.com>, SAP AG and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| package org.eclipse.jgit.util.io; |
| |
| import java.io.FilterInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| import org.eclipse.jgit.internal.JGitText; |
| |
| /** |
| * Wraps a {@link java.io.InputStream}, limiting the number of bytes which can |
| * be read. |
| * |
| * This class was copied and modifed from the Google Guava 16.0. Differently |
| * from the original Guava code, when a caller tries to read from this stream |
| * past the given limit and the wrapped stream hasn't yet reached its EOF this |
| * class will call the limitExceeded method instead of returning EOF. |
| * |
| * @since 3.3 |
| */ |
| public abstract class LimitedInputStream extends FilterInputStream { |
| |
| private long left; |
| /** Max number of bytes to be read from the wrapped stream */ |
| protected final long limit; |
| private long mark = -1; |
| |
| /** |
| * Create a new LimitedInputStream |
| * |
| * @param in an InputStream |
| * @param limit max number of bytes to read from the InputStream |
| */ |
| protected LimitedInputStream(InputStream in, long limit) { |
| super(in); |
| left = limit; |
| this.limit = limit; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public int available() throws IOException { |
| return (int) Math.min(in.available(), left); |
| } |
| |
| // it's okay to mark even if mark isn't supported, as reset won't work |
| /** {@inheritDoc} */ |
| @Override |
| public synchronized void mark(int readLimit) { |
| in.mark(readLimit); |
| mark = left; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public int read() throws IOException { |
| if (left == 0) { |
| if (in.available() == 0) { |
| return -1; |
| } |
| limitExceeded(); |
| } |
| |
| int result = in.read(); |
| if (result != -1) { |
| --left; |
| } |
| return result; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public int read(byte[] b, int off, int len) throws IOException { |
| if (left == 0) { |
| if (in.available() == 0) { |
| return -1; |
| } |
| limitExceeded(); |
| } |
| |
| len = (int) Math.min(len, left); |
| int result = in.read(b, off, len); |
| if (result != -1) { |
| left -= result; |
| } |
| return result; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public synchronized void reset() throws IOException { |
| if (!in.markSupported()) |
| throw new IOException(JGitText.get().unsupportedMark); |
| |
| if (mark == -1) |
| throw new IOException(JGitText.get().unsetMark); |
| |
| in.reset(); |
| left = mark; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public long skip(long n) throws IOException { |
| n = Math.min(n, left); |
| long skipped = in.skip(n); |
| left -= skipped; |
| return skipped; |
| } |
| |
| /** |
| * Called when trying to read past the given {@link #limit} and the wrapped |
| * InputStream {@link #in} hasn't yet reached its EOF |
| * |
| * @throws java.io.IOException |
| * subclasses can throw an {@link java.io.IOException} when the |
| * limit is exceeded. The throws java.io.IOException will be |
| * forwarded back to the caller of the read method which read |
| * the stream past the limit. |
| */ |
| protected abstract void limitExceeded() throws IOException; |
| } |