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- /*
- * Copyright (C) 2021, Tencent.
- *
- * 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.internal.storage.commitgraph;
-
- import static org.eclipse.jgit.internal.storage.commitgraph.CommitGraphConstants.COMMIT_GRAPH_MAGIC;
-
- import java.io.IOException;
- import java.io.OutputStream;
- import java.security.MessageDigest;
-
- import org.eclipse.jgit.internal.JGitText;
- import org.eclipse.jgit.lib.Constants;
- import org.eclipse.jgit.lib.ProgressMonitor;
- import org.eclipse.jgit.util.NB;
-
- /**
- * Custom output stream to support
- * {@link org.eclipse.jgit.internal.storage.commitgraph.CommitGraphWriter}.
- */
- public class CommitGraphOutPutStream extends OutputStream {
-
- private static final int BYTES_TO_WRITE_BEFORE_CANCEL_CHECK = 128 * 1024;
-
- private final ProgressMonitor writeMonitor;
-
- private final OutputStream out;
-
- private final MessageDigest md = Constants.newMessageDigest();
-
- private long count;
-
- private long checkCancelAt;
-
- private final byte[] headerBuffer = new byte[16];
-
- /**
- * Initialize a commit-graph output stream.
- *
- * @param writeMonitor
- * monitor to update on output progress.
- * @param out
- * target stream to receive all contents.
- */
- public CommitGraphOutPutStream(ProgressMonitor writeMonitor,
- OutputStream out) {
- this.writeMonitor = writeMonitor;
- this.out = out;
- this.checkCancelAt = BYTES_TO_WRITE_BEFORE_CANCEL_CHECK;
- }
-
- /** {@inheritDoc} */
- @Override
- public final void write(int b) throws IOException {
- count++;
- out.write(b);
- md.update((byte) b);
- }
-
- /** {@inheritDoc} */
- @Override
- public final void write(byte[] b, int off, int len) throws IOException {
- while (0 < len) {
- int n = Math.min(len, BYTES_TO_WRITE_BEFORE_CANCEL_CHECK);
- count += n;
-
- if (checkCancelAt <= count) {
- if (writeMonitor.isCancelled()) {
- throw new IOException(JGitText
- .get().commitGraphGeneratingCancelledDuringWriting);
- }
- checkCancelAt = count + BYTES_TO_WRITE_BEFORE_CANCEL_CHECK;
- }
-
- out.write(b, off, n);
- md.update(b, off, n);
-
- off += n;
- len -= n;
- }
- }
-
- /** {@inheritDoc} */
- @Override
- public void flush() throws IOException {
- out.flush();
- }
-
- void writeFileHeader(int version, int hashVersion, int chunksNumber)
- throws IOException {
- NB.encodeInt32(headerBuffer, 0, COMMIT_GRAPH_MAGIC);
- byte[] buff = { (byte) version, (byte) hashVersion, (byte) chunksNumber,
- (byte) 0 };
- System.arraycopy(buff, 0, headerBuffer, 4, 4);
- write(headerBuffer, 0, 8);
- }
-
- /** @return obtain the current SHA-1 digest. */
- byte[] getDigest() {
- return md.digest();
- }
-
- void updateMonitor() {
- writeMonitor.update(1);
- }
- }
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