1 files changed, 69 insertions, 0 deletions
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/processors/checksum/MessageDigestProcessingStep.java b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/processors/checksum/MessageDigestProcessingStep.java
new file mode 100644
index 000000000..3fef57d03
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/processors/checksum/MessageDigestProcessingStep.java
@@ -0,0 +1,69 @@
+/*******************************************************************************
+ * Copyright (c) 2018, 2018 Mykola Nikishov.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Mykola Nikishov - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.internal.p2.artifact.processors.checksum;
+
+import java.io.IOException;
+import java.nio.BufferOverflowException;
+import java.nio.ByteBuffer;
+import java.security.MessageDigest;
+import org.eclipse.equinox.internal.p2.repository.helpers.ChecksumHelper;
+import org.eclipse.equinox.internal.provisional.p2.artifact.repository.processing.ProcessingStep;
+
+/**
+ * @noreference This class is not intended to be referenced by clients.
+ */
+public abstract class MessageDigestProcessingStep extends ProcessingStep {
+
+	protected MessageDigest messageDigest;
+	private static final int BUFFER_SIZE = 16 * 1024;
+	private ByteBuffer buffer = ByteBuffer.allocate(BUFFER_SIZE);
+
+	@Override
+	// TODO template method, should be final but MD5Verifier prevents this
+	public void write(int b) throws IOException {
+		getDestination().write(b);
+
+		// TODO exceptions are expensive
+		try {
+			buffer.put((byte) b);
+		} catch (BufferOverflowException e) {
+			processBufferredBytes();
+			buffer.put((byte) b);
+		}
+	}
+
+	private void processBufferredBytes() {
+		buffer.flip();
+		updateDigest();
+		buffer.clear();
+	}
+
+	private void updateDigest() {
+		messageDigest.update(buffer);
+	}
+
+	@Override
+	// TODO should be final but MD5Verifier prevents this
+	public void close() throws IOException {
+		processBufferredBytes();
+		String digestString = digest();
+		onClose(digestString);
+		super.close();
+	}
+
+	private String digest() {
+		byte[] digestBytes = messageDigest.digest();
+		return ChecksumHelper.toHexString(digestBytes);
+	}
+
+	protected abstract void onClose(String digestString);
+
+}