Bug 490028 - Extract MD5 checksum calculation into a separate class

MD5 checksum is calculated in (almost) the same way in two places:
org.eclipse.equinox.p2.internal.repository.tools.RepositoryUtilities and
org.eclipse.equinox.spi.p2.publisher.PublisherHelper.

The latter uses 4K byte buffer instead of byte-by-byte update which
makes MD5 calculation for a 300k jar file 5x faster, see bug #405716 for
more details. Due to the duplication, this has been fixed in
PublisherHelper only but not in RepositoryUtilities.

Eliminate code duplication by extracting MD5 checksum calculation into a
separate class, ChecksumProducer. To make it consimable by
org.eclipse.equinox.p2.publisher and
org.eclipse.equinox.p2.repository.tools bundles but not exposing too
much internals, move it to the x-friend'ed
org.eclipse.equinox.internal.p2.repository.helpers package of
org.eclipse.equinox.p2.repository bundle.

Change-Id: Ic8b45a47700f35af1fb69f534dec7b32a2f7714a
Signed-off-by: Mykola Nikishov <mn@mn.com.ua>

5 files changed, 76 insertions, 86 deletions

diff --git a/bundles/org.eclipse.equinox.p2.publisher/META-INF/MANIFEST.MF b/bundles/org.eclipse.equinox.p2.publisher/META-INF/MANIFEST.MF
index 7de84a73f..521ac95cc 100644
--- a/bundles/org.eclipse.equinox.p2.publisher/META-INF/MANIFEST.MF
+++ b/bundles/org.eclipse.equinox.p2.publisher/META-INF/MANIFEST.MF
@@ -36,6 +36,7 @@ Import-Package: org.eclipse.equinox.app;version="1.0.0";resolution:=optional,
  org.eclipse.equinox.internal.p2.metadata.expression,
  org.eclipse.equinox.internal.p2.metadata.index,
  org.eclipse.equinox.internal.p2.metadata.repository,
+ org.eclipse.equinox.internal.p2.repository.helpers,
  org.eclipse.equinox.p2.core;version="[2.0.0,3.0.0)",
  org.eclipse.equinox.p2.metadata;version="[2.0.0,3.0.0)",
  org.eclipse.equinox.p2.metadata.expression;version="[2.0.0,3.0.0)",
diff --git a/bundles/org.eclipse.equinox.p2.publisher/src/org/eclipse/equinox/spi/p2/publisher/PublisherHelper.java b/bundles/org.eclipse.equinox.p2.publisher/src/org/eclipse/equinox/spi/p2/publisher/PublisherHelper.java
index c7da22884..96d9ff973 100644
--- a/bundles/org.eclipse.equinox.p2.publisher/src/org/eclipse/equinox/spi/p2/publisher/PublisherHelper.java
+++ b/bundles/org.eclipse.equinox.p2.publisher/src/org/eclipse/equinox/spi/p2/publisher/PublisherHelper.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- *  Copyright (c) 2007, 2011 IBM Corporation and others.
+ *  Copyright (c) 2007, 2016 IBM Corporation and others.
  *  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
@@ -9,16 +9,16 @@
  *     IBM Corporation - initial API and implementation
  *     Genuitec, LLC - added license support
  *     Code 9 - Ongoing development
-#      SAP AG - consolidation of publishers for PDE formats
+ *     SAP AG - consolidation of publishers for PDE formats
+ *     Mykola Nikishov - extract MD5 checksum calculation
  *******************************************************************************/
 package org.eclipse.equinox.spi.p2.publisher;
 
-import java.io.*;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
+import java.io.File;
 import java.util.*;
 import org.eclipse.equinox.internal.p2.metadata.ArtifactKey;
 import org.eclipse.equinox.internal.p2.metadata.BasicVersion;
+import org.eclipse.equinox.internal.p2.repository.helpers.ChecksumProducer;
 import org.eclipse.equinox.p2.metadata.*;
 import org.eclipse.equinox.p2.metadata.MetadataFactory.InstallableUnitDescription;
 import org.eclipse.equinox.p2.metadata.MetadataFactory.InstallableUnitFragmentDescription;
@@ -108,7 +108,7 @@ public class PublisherHelper {
 				descriptor.setProperty(IArtifactDescriptor.DOWNLOAD_SIZE, Long.toString(pathOnDisk.length()));
 			}
 			if (info == null || (info.getArtifactOptions() & IPublisherInfo.A_NO_MD5) == 0) {
-				String md5 = computeMD5(pathOnDisk);
+				String md5 = ChecksumProducer.computeMD5(pathOnDisk);
 				if (md5 != null)
 					descriptor.setProperty(IArtifactDescriptor.DOWNLOAD_MD5, md5);
 			}
@@ -116,46 +116,6 @@ public class PublisherHelper {
 		return result;
 	}
 
-	private static String computeMD5(File file) {
-		if (file == null || file.isDirectory() || !file.exists())
-			return null;
-		MessageDigest md5Checker;
-		try {
-			md5Checker = MessageDigest.getInstance("MD5"); //$NON-NLS-1$
-		} catch (NoSuchAlgorithmException e) {
-			return null;
-		}
-		InputStream fis = null;
-		try {
-			fis = new BufferedInputStream(new FileInputStream(file));
-			int read = -1;
-			final int bufferSize = 4 * 1024;
-			byte[] buffer = new byte[bufferSize];
-			while ((read = fis.read(buffer, 0, bufferSize)) != -1) {
-				md5Checker.update(buffer, 0, read);
-			}
-			byte[] digest = md5Checker.digest();
-			StringBuffer buf = new StringBuffer();
-			for (int i = 0; i < digest.length; i++) {
-				if ((digest[i] & 0xFF) < 0x10)
-					buf.append('0');
-				buf.append(Integer.toHexString(digest[i] & 0xFF));
-			}
-			return buf.toString();
-		} catch (FileNotFoundException e) {
-			return null;
-		} catch (IOException e) {
-			return null;
-		} finally {
-			if (fis != null)
-				try {
-					fis.close();
-				} catch (IOException e) {
-					// ignore
-				}
-		}
-	}
-
 	public static IProvidedCapability makeTranslationCapability(String hostId, Locale locale) {
 		return MetadataFactory.createProvidedCapability(NAMESPACE_IU_LOCALIZATION, locale.toString(), Version.createOSGi(1, 0, 0));
 	}
diff --git a/bundles/org.eclipse.equinox.p2.repository.tools/src/org/eclipse/equinox/p2/internal/repository/tools/RepositoryUtilities.java b/bundles/org.eclipse.equinox.p2.repository.tools/src/org/eclipse/equinox/p2/internal/repository/tools/RepositoryUtilities.java
index 11e3e32c6..01d89a2ca 100644
--- a/bundles/org.eclipse.equinox.p2.repository.tools/src/org/eclipse/equinox/p2/internal/repository/tools/RepositoryUtilities.java
+++ b/bundles/org.eclipse.equinox.p2.repository.tools/src/org/eclipse/equinox/p2/internal/repository/tools/RepositoryUtilities.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2009 IBM Corporation and others.
+ * Copyright (c) 2009, 2016 IBM Corporation and others.
  * 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
@@ -7,51 +7,17 @@
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
+ *     Mykola Nikishov - extract MD5 checksum calculation
  *******************************************************************************/
 
 package org.eclipse.equinox.p2.internal.repository.tools;
 
-import java.io.*;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
+import java.io.File;
+import org.eclipse.equinox.internal.p2.repository.helpers.ChecksumProducer;
 
 public class RepositoryUtilities {
 
 	public static String computeMD5(File file) {
-		if (file == null || file.isDirectory() || !file.exists())
-			return null;
-		MessageDigest md5Checker;
-		try {
-			md5Checker = MessageDigest.getInstance("MD5"); //$NON-NLS-1$
-		} catch (NoSuchAlgorithmException e) {
-			return null;
-		}
-		InputStream fis = null;
-		try {
-			fis = new BufferedInputStream(new FileInputStream(file));
-			int read = -1;
-			while ((read = fis.read()) != -1) {
-				md5Checker.update((byte) read);
-			}
-			byte[] digest = md5Checker.digest();
-			StringBuffer buf = new StringBuffer();
-			for (int i = 0; i < digest.length; i++) {
-				if ((digest[i] & 0xFF) < 0x10)
-					buf.append('0');
-				buf.append(Integer.toHexString(digest[i] & 0xFF));
-			}
-			return buf.toString();
-		} catch (FileNotFoundException e) {
-			return null;
-		} catch (IOException e) {
-			return null;
-		} finally {
-			if (fis != null)
-				try {
-					fis.close();
-				} catch (IOException e) {
-					// ignore
-				}
-		}
+		return ChecksumProducer.computeMD5(file);
 	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.repository/META-INF/MANIFEST.MF b/bundles/org.eclipse.equinox.p2.repository/META-INF/MANIFEST.MF
index 8abfa281f..b513e4936 100644
--- a/bundles/org.eclipse.equinox.p2.repository/META-INF/MANIFEST.MF
+++ b/bundles/org.eclipse.equinox.p2.repository/META-INF/MANIFEST.MF
@@ -19,12 +19,14 @@ Export-Package: org.eclipse.equinox.internal.p2.persistence;
    org.eclipse.equinox.p2.repository.tools,
    org.eclipse.equinox.p2.transport.ecf,
    org.eclipse.equinox.p2.engine,
-   org.eclipse.equinox.p2.discovery.compatibility",
+   org.eclipse.equinox.p2.discovery.compatibility,
+   org.eclipse.equinox.p2.publisher",
  org.eclipse.equinox.internal.p2.repository.helpers;
   x-friends:="org.eclipse.equinox.p2.artifact.repository,
    org.eclipse.equinox.p2.exemplarysetup,
    org.eclipse.equinox.p2.metadata.repository,
    org.eclipse.equinox.p2.operations,
+   org.eclipse.equinox.p2.publisher,
    org.eclipse.equinox.p2.repository.tools,
    org.eclipse.equinox.p2.ui,
    org.eclipse.equinox.p2.updatesite",
diff --git a/bundles/org.eclipse.equinox.p2.repository/src/org/eclipse/equinox/internal/p2/repository/helpers/ChecksumProducer.java b/bundles/org.eclipse.equinox.p2.repository/src/org/eclipse/equinox/internal/p2/repository/helpers/ChecksumProducer.java
new file mode 100644
index 000000000..a9c1c5a9f
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.repository/src/org/eclipse/equinox/internal/p2/repository/helpers/ChecksumProducer.java
@@ -0,0 +1,61 @@
+/*******************************************************************************
+ * Copyright (c) 2009, 2016 IBM Corporation and others.
+ * 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:
+ *     IBM Corporation - initial API and implementation
+ *     Mykola Nikishov - extract MD5 checksum calculation
+ *******************************************************************************/
+
+package org.eclipse.equinox.internal.p2.repository.helpers;
+
+import java.io.*;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+public class ChecksumProducer {
+
+	public static String computeMD5(File file) {
+		if (file == null || file.isDirectory() || !file.exists())
+			return null;
+		MessageDigest md5Checker;
+		try {
+			md5Checker = MessageDigest.getInstance("MD5"); //$NON-NLS-1$
+		} catch (NoSuchAlgorithmException e) {
+			return null;
+		}
+		InputStream fis = null;
+		try {
+			fis = new BufferedInputStream(new FileInputStream(file));
+			int read = -1;
+			final int bufferSize = 4 * 1024;
+			byte[] buffer = new byte[bufferSize];
+			while ((read = fis.read(buffer, 0, bufferSize)) != -1) {
+				md5Checker.update(buffer, 0, read);
+			}
+			byte[] digest = md5Checker.digest();
+			StringBuffer buf = new StringBuffer();
+			for (int i = 0; i < digest.length; i++) {
+				if ((digest[i] & 0xFF) < 0x10)
+					buf.append('0');
+				buf.append(Integer.toHexString(digest[i] & 0xFF));
+			}
+			return buf.toString();
+		} catch (FileNotFoundException e) {
+			return null;
+		} catch (IOException e) {
+			return null;
+		} finally {
+			if (fis != null)
+				try {
+					fis.close();
+				} catch (IOException e) {
+					// ignore
+				}
+		}
+	}
+
+}