Add more configuration options to PackWriter

We now at least import other pack settings like pack.window, which
means we can later use these to control how we search for deltas.

The compression level was fixed to use pack.compression rather than
the loose object core.compression setting.

Change-Id: I72ff6d481c936153ceb6a9e485fa731faf075a9a
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackConfig.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2010, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.storage.pack;
+
+import static java.util.zip.Deflater.DEFAULT_COMPRESSION;
+import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.lib.Config.SectionParser;
+
+class PackConfig {
+	/** Key for {@link Config#get(SectionParser)}. */
+	static final Config.SectionParser<PackConfig> KEY = new SectionParser<PackConfig>() {
+		public PackConfig parse(final Config cfg) {
+			return new PackConfig(cfg);
+		}
+	};
+
+	final int deltaWindow;
+
+	final long deltaWindowMemory;
+
+	final int deltaDepth;
+
+	final int compression;
+
+	final int indexVersion;
+
+	private PackConfig(Config rc) {
+		deltaWindow = rc.getInt("pack", "window", PackWriter.DEFAULT_DELTA_SEARCH_WINDOW_SIZE);
+		deltaWindowMemory = rc.getLong("pack", null, "windowmemory", 0);
+		deltaDepth = rc.getInt("pack", "depth", PackWriter.DEFAULT_MAX_DELTA_DEPTH);
+		compression = compression(rc);
+		indexVersion = rc.getInt("pack", "indexversion", 2);
+	}
+
+	private static int compression(Config rc) {
+		if (rc.getString("pack", null, "compression") != null)
+			return rc.getInt("pack", "compression", DEFAULT_COMPRESSION);
+		return rc.getInt("core", "compression", DEFAULT_COMPRESSION);
+	}
+}

org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackWriter.java

@@ -66,7 +66,6 @@ import org.eclipse.jgit.errors.StoredObjectRepresentationNotAvailableException;
 import org.eclipse.jgit.lib.AnyObjectId;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Constants;
-import org.eclipse.jgit.lib.CoreConfig;
 import org.eclipse.jgit.lib.NullProgressMonitor;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectIdSubclassMap;
@@ -166,6 +165,13 @@ public class PackWriter {
 	 */
 	public static final int DEFAULT_MAX_DELTA_DEPTH = 50;
 
+	/**
+	 * Default window size during packing.
+	 *
+	 * @see #setDeltaSearchWindowSize(int)
+	 */
+	public static final int DEFAULT_DELTA_SEARCH_WINDOW_SIZE = 10;
+
 	private static final int PACK_VERSION_GENERATED = 2;
 
 	@SuppressWarnings("unchecked")
@@ -202,9 +208,13 @@ public class PackWriter {
 
 	private boolean deltaBaseAsOffset = DEFAULT_DELTA_BASE_AS_OFFSET;
 
+	private boolean deltaCompress = true;
+
 	private int maxDeltaDepth = DEFAULT_MAX_DELTA_DEPTH;
 
-	private int outputVersion;
+	private int deltaSearchWindowSize = DEFAULT_DELTA_SEARCH_WINDOW_SIZE;
+
+	private int indexVersion;
 
 	private boolean thin;
 
@@ -254,9 +264,11 @@ public class PackWriter {
 		else
 			reuseSupport = null;
 
-		final CoreConfig coreConfig = configOf(repo).get(CoreConfig.KEY);
-		compressionLevel = coreConfig.getCompression();
-		outputVersion = coreConfig.getPackIndexVersion();
+		final PackConfig pc = configOf(repo).get(PackConfig.KEY);
+		deltaSearchWindowSize = pc.deltaWindow;
+		maxDeltaDepth = pc.deltaDepth;
+		compressionLevel = pc.compression;
+		indexVersion = pc.indexVersion;
 	}
 
 	private static Config configOf(final Repository repo) {
@@ -364,6 +376,32 @@ public class PackWriter {
 		this.deltaBaseAsOffset = deltaBaseAsOffset;
 	}
 
+	/**
+	 * Check whether the writer will create new deltas on the fly.
+	 * <p>
+	 * Default setting: true
+	 * </p>
+	 *
+	 * @return true if the writer will create a new delta when either
+	 *         {@link #isReuseDeltas()} is false, or no suitable delta is
+	 *         available for reuse.
+	 */
+	public boolean isDeltaCompress() {
+		return deltaCompress;
+	}
+
+	/**
+	 * Set whether or not the writer will create new deltas on the fly.
+	 *
+	 * @param deltaCompress
+	 *            true to create deltas when {@link #isReuseDeltas()} is false,
+	 *            or when a suitable delta isn't available for reuse. Set to
+	 *            false to write whole objects instead.
+	 */
+	public void setDeltaCompress(boolean deltaCompress) {
+		this.deltaCompress = deltaCompress;
+	}
+
 	/**
 	 * Get maximum depth of delta chain set up for this writer. Generated chains
 	 * are not longer than this value.
@@ -392,6 +430,31 @@ public class PackWriter {
 		this.maxDeltaDepth = maxDeltaDepth;
 	}
 
+	/**
+	 * Get the number of objects to try when looking for a delta base.
+	 *
+	 * @return the object count to be searched.
+	 */
+	public int getDeltaSearchWindowSize() {
+		return deltaSearchWindowSize;
+	}
+
+	/**
+	 * Set the number of objects considered when searching for a delta base.
+	 * <p>
+	 * Default setting: {@value #DEFAULT_DELTA_SEARCH_WINDOW_SIZE}
+	 * </p>
+	 *
+	 * @param objectCount
+	 *            number of objects to search at once.  Must be at least 2.
+	 */
+	public void setDeltaSearchWindowSize(int objectCount) {
+		if (objectCount <= 2)
+			setDeltaCompress(false);
+		else
+			deltaSearchWindowSize = objectCount;
+	}
+
 	/** @return true if this writer is producing a thin pack. */
 	public boolean isThin() {
 		return thin;
@@ -440,7 +503,7 @@ public class PackWriter {
 	 * @see PackIndexWriter
 	 */
 	public void setIndexVersion(final int version) {
-		outputVersion = version;
+		indexVersion = version;
 	}
 
 	/**
@@ -571,10 +634,10 @@ public class PackWriter {
 	public void writeIndex(final OutputStream indexStream) throws IOException {
 		final List<ObjectToPack> list = sortByName();
 		final PackIndexWriter iw;
-		if (outputVersion <= 0)
+		if (indexVersion <= 0)
 			iw = PackIndexWriter.createOldestPossible(indexStream, list);
 		else
-			iw = PackIndexWriter.createVersion(indexStream, outputVersion);
+			iw = PackIndexWriter.createVersion(indexStream, indexVersion);
 		iw.write(list, packcsum);
 	}