1 files changed, 129 insertions, 0 deletions
diff --git a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/internal/AtomicObjectOutputStream.java b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/internal/AtomicObjectOutputStream.java
new file mode 100644
index 0000000000..009250294e
--- /dev/null
+++ b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/internal/AtomicObjectOutputStream.java
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2015, Matthias Sohn <matthias.sohn@sap.com> 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.lfs.internal;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.file.Path;
+import java.security.DigestOutputStream;
+import java.text.MessageFormat;
+
+import org.eclipse.jgit.annotations.Nullable;
+import org.eclipse.jgit.internal.storage.file.LockFile;
+import org.eclipse.jgit.lfs.errors.CorruptLongObjectException;
+import org.eclipse.jgit.lfs.lib.AnyLongObjectId;
+import org.eclipse.jgit.lfs.lib.Constants;
+import org.eclipse.jgit.lfs.lib.LongObjectId;
+
+/**
+ * Output stream writing content to a
+ * {@link org.eclipse.jgit.internal.storage.file.LockFile} which is committed on
+ * close(). The stream checks if the hash of the stream content matches the id.
+ */
+public class AtomicObjectOutputStream extends OutputStream {
+
+	private LockFile locked;
+
+	private DigestOutputStream out;
+
+	private boolean aborted;
+
+	private AnyLongObjectId id;
+
+	/**
+	 * Constructor for AtomicObjectOutputStream.
+	 *
+	 * @param path
+	 *            a {@link java.nio.file.Path} object.
+	 * @param id
+	 *            a {@link org.eclipse.jgit.lfs.lib.AnyLongObjectId} object.
+	 * @throws java.io.IOException
+	 *             if an IO error occurred
+	 */
+	public AtomicObjectOutputStream(Path path, AnyLongObjectId id)
+			throws IOException {
+		locked = new LockFile(path.toFile());
+		locked.lock();
+		this.id = id;
+		out = new DigestOutputStream(locked.getOutputStream(),
+				Constants.newMessageDigest());
+	}
+
+	/**
+	 * Constructor for AtomicObjectOutputStream.
+	 *
+	 * @param path
+	 *            a {@link java.nio.file.Path} object.
+	 * @throws java.io.IOException
+	 *             if an IO error occurred
+	 */
+	public AtomicObjectOutputStream(Path path) throws IOException {
+		this(path, null);
+	}
+
+	/**
+	 * Get the <code>id</code>.
+	 *
+	 * @return content hash of the object which was streamed through this
+	 *         stream. May return {@code null} if called before closing this
+	 *         stream.
+	 */
+	@Nullable
+	public AnyLongObjectId getId() {
+		return id;
+	}
+
+	@Override
+	public void write(int b) throws IOException {
+		out.write(b);
+	}
+
+	@Override
+	public void write(byte[] b) throws IOException {
+		out.write(b);
+	}
+
+	@Override
+	public void write(byte[] b, int off, int len) throws IOException {
+		out.write(b, off, len);
+	}
+
+	@Override
+	public void close() throws IOException {
+		out.close();
+		if (!aborted) {
+			if (id != null) {
+				verifyHash();
+			} else {
+				id = LongObjectId.fromRaw(out.getMessageDigest().digest());
+			}
+			locked.commit();
+		}
+	}
+
+	private void verifyHash() {
+		AnyLongObjectId contentHash = LongObjectId
+				.fromRaw(out.getMessageDigest().digest());
+		if (!contentHash.equals(id)) {
+			abort();
+			throw new CorruptLongObjectException(id, contentHash,
+					MessageFormat.format(LfsText.get().corruptLongObject,
+							contentHash, id));
+		}
+	}
+
+	/**
+	 * Aborts the stream. Temporary file will be deleted
+	 */
+	public void abort() {
+		locked.unlock();
+		aborted = true;
+	}
+}