org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftable/ReftableCompactor.java - sop/jgit - Git at Google

 /*
  * Copyright (C) 2017, 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.internal.storage.reftable;

 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.List;

 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.internal.storage.reftable.ReftableWriter.Stats;
 import org.eclipse.jgit.lib.ReflogEntry;

 /**
  * Merges reftables and compacts them into a single output.
  * <p>
  * For a partial compaction callers should {@link #setIncludeDeletes(boolean)}
  * to {@code true} to ensure the new reftable continues to use a delete marker
  * to shadow any lower reftable that may have the reference present.
  * <p>
  * By default all log entries within the range defined by
  * {@link #setMinUpdateIndex(long)} and {@link #setMaxUpdateIndex(long)} are
  * copied, even if no references in the output file match the log records.
  * Callers may truncate the log to a more recent time horizon with
  * {@link #setOldestReflogTimeMillis(long)}, or disable the log altogether with
  * {@code setOldestReflogTimeMillis(Long.MAX_VALUE)}.
  */
 public class ReftableCompactor {
 	private final ReftableWriter writer = new ReftableWriter();
 	private final ArrayDeque<Reftable> tables = new ArrayDeque<>();

 	private long compactBytesLimit;
 	private long bytesToCompact;
 	private boolean includeDeletes;
 	private long minUpdateIndex;
 	private long maxUpdateIndex;
 	private long oldestReflogTimeMillis;
 	private Stats stats;

 	/**
 	 * @param cfg
 	 *            configuration for the reftable.
 	 * @return {@code this}
 	 */
 	public ReftableCompactor setConfig(ReftableConfig cfg) {
 		writer.setConfig(cfg);
 		return this;
 	}

 	/**
 	 * @param bytes
 	 *            limit on number of bytes from source tables to compact.
 	 * @return {@code this}
 	 */
 	public ReftableCompactor setCompactBytesLimit(long bytes) {
 		compactBytesLimit = bytes;
 		return this;
 	}

 	/**
 	 * @param deletes
 	 *            {@code true} to include deletions in the output, which may be
 	 *            necessary for partial compaction.
 	 * @return {@code this}
 	 */
 	public ReftableCompactor setIncludeDeletes(boolean deletes) {
 		includeDeletes = deletes;
 		return this;
 	}

 	/**
 	 * @param min
 	 *            the minimum update index for log entries that appear in the
 	 *            compacted reftable. This should be 1 higher than the prior
 	 *            reftable's {@code maxUpdateIndex} if this table will be used
 	 *            in a stack.
 	 * @return {@code this}
 	 */
 	public ReftableCompactor setMinUpdateIndex(long min) {
 		minUpdateIndex = min;
 		return this;
 	}

 	/**
 	 * @param max
 	 *            the maximum update index for log entries that appear in the
 	 *            compacted reftable. This should be at least 1 higher than the
 	 *            prior reftable's {@code maxUpdateIndex} if this table will be
 	 *            used in a stack.
 	 * @return {@code this}
 	 */
 	public ReftableCompactor setMaxUpdateIndex(long max) {
 		maxUpdateIndex = max;
 		return this;
 	}

 	/**
 	 * @param timeMillis
 	 *            oldest log time to preserve. Entries whose timestamps are
 	 *            {@code >= timeMillis} will be copied into the output file. Log
 	 *            entries that predate {@code timeMillis} will be discarded.
 	 *            Specified in Java standard milliseconds since the epoch.
 	 * @return {@code this}
 	 */
 	public ReftableCompactor setOldestReflogTimeMillis(long timeMillis) {
 		oldestReflogTimeMillis = timeMillis;
 		return this;
 	}

 	/**
 	 * Add all of the tables, in the specified order.
 	 * <p>
 	 * Unconditionally adds all tables, ignoring the
 	 * {@link #setCompactBytesLimit(long)}.
 	 *
 	 * @param readers
 	 *            tables to compact. Tables should be ordered oldest first/most
 	 *            recent last so that the more recent tables can shadow the
 	 *            older results. Caller is responsible for closing the readers.
 	 */
 	public void addAll(List<? extends Reftable> readers) {
 		tables.addAll(readers);
 	}

 	/**
 	 * Try to add this reader at the bottom of the stack.
 	 * <p>
 	 * A reader may be rejected by returning {@code false} if the compactor is
 	 * already rewriting its {@link #setCompactBytesLimit(long)}. When this
 	 * happens the caller should stop trying to add tables, and execute the
 	 * compaction.
 	 *
 	 * @param reader
 	 *            the reader to insert at the bottom of the stack. Caller is
 	 *            responsible for closing the reader.
 	 * @return {@code true} if the compactor accepted this table; {@code false}
 	 *         if the compactor has reached its limit.
 	 * @throws IOException
 	 *             if size of {@code reader} cannot be read.
 	 */
 	public boolean tryAddFirst(ReftableReader reader) throws IOException {
 		long sz = reader.size();
 		if (compactBytesLimit > 0 && bytesToCompact + sz > compactBytesLimit) {
 			return false;
 		}
 		bytesToCompact += sz;
 		tables.addFirst(reader);
 		return true;
 	}

 	/**
 	 * Write a compaction to {@code out}.
 	 *
 	 * @param out
 	 *            stream to write the compacted tables to. Caller is responsible
 	 *            for closing {@code out}.
 	 * @throws IOException
 	 *             if tables cannot be read, or cannot be written.
 	 */
 	public void compact(OutputStream out) throws IOException {
 		MergedReftable mr = new MergedReftable(new ArrayList<>(tables));
 		mr.setIncludeDeletes(includeDeletes);

 		writer.setMinUpdateIndex(minUpdateIndex);
 		writer.setMaxUpdateIndex(maxUpdateIndex);
 		writer.begin(out);
 		mergeRefs(mr);
 		mergeLogs(mr);
 		writer.finish();
 		stats = writer.getStats();
 	}

 	/** @return statistics of the last written reftable. */
 	public Stats getStats() {
 		return stats;
 	}

 	private void mergeRefs(MergedReftable mr) throws IOException {
 		try (RefCursor rc = mr.allRefs()) {
 			while (rc.next()) {
 				writer.writeRef(rc.getRef());
 			}
 		}
 	}

 	private void mergeLogs(MergedReftable mr) throws IOException {
 		if (oldestReflogTimeMillis == Long.MAX_VALUE) {
 			return;
 		}

 		try (LogCursor lc = mr.allLogs()) {
 			while (lc.next()) {
 				long updateIndex = lc.getUpdateIndex();
 				if (updateIndex < minUpdateIndex
 						|| updateIndex > maxUpdateIndex) {
 					// Cannot merge log records outside the header's range.
 					continue;
 				}

 				String refName = lc.getRefName();
 				ReflogEntry log = lc.getReflogEntry();
 				if (log == null) {
 					if (includeDeletes) {
 						writer.deleteLog(refName, updateIndex);
 					}
 					continue;
 				}

 				PersonIdent who = log.getWho();
 				if (who.getWhen().getTime() >= oldestReflogTimeMillis) {
 					writer.writeLog(
 							refName,
 							updateIndex,
 							who,
 							log.getOldId(),
 							log.getNewId(),
 							log.getComment());
 				}
 			}
 		}
 	}
 }
	/*
	* Copyright (C) 2017, 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.internal.storage.reftable;

	import java.io.IOException;
	import java.io.OutputStream;
	import java.util.ArrayDeque;
	import java.util.ArrayList;
	import java.util.List;

	import org.eclipse.jgit.lib.PersonIdent;
	import org.eclipse.jgit.internal.storage.reftable.ReftableWriter.Stats;
	import org.eclipse.jgit.lib.ReflogEntry;

	/**
	* Merges reftables and compacts them into a single output.
	* <p>
	* For a partial compaction callers should {@link #setIncludeDeletes(boolean)}
	* to {@code true} to ensure the new reftable continues to use a delete marker
	* to shadow any lower reftable that may have the reference present.
	* <p>
	* By default all log entries within the range defined by
	* {@link #setMinUpdateIndex(long)} and {@link #setMaxUpdateIndex(long)} are
	* copied, even if no references in the output file match the log records.
	* Callers may truncate the log to a more recent time horizon with
	* {@link #setOldestReflogTimeMillis(long)}, or disable the log altogether with
	* {@code setOldestReflogTimeMillis(Long.MAX_VALUE)}.
	*/
	public class ReftableCompactor {
	private final ReftableWriter writer = new ReftableWriter();
	private final ArrayDeque<Reftable> tables = new ArrayDeque<>();

	private long compactBytesLimit;
	private long bytesToCompact;
	private boolean includeDeletes;
	private long minUpdateIndex;
	private long maxUpdateIndex;
	private long oldestReflogTimeMillis;
	private Stats stats;

	/**
	* @param cfg
	* configuration for the reftable.
	* @return {@code this}
	*/
	public ReftableCompactor setConfig(ReftableConfig cfg) {
	writer.setConfig(cfg);
	return this;
	}

	/**
	* @param bytes
	* limit on number of bytes from source tables to compact.
	* @return {@code this}
	*/
	public ReftableCompactor setCompactBytesLimit(long bytes) {
	compactBytesLimit = bytes;
	return this;
	}

	/**
	* @param deletes
	* {@code true} to include deletions in the output, which may be
	* necessary for partial compaction.
	* @return {@code this}
	*/
	public ReftableCompactor setIncludeDeletes(boolean deletes) {
	includeDeletes = deletes;
	return this;
	}

	/**
	* @param min
	* the minimum update index for log entries that appear in the
	* compacted reftable. This should be 1 higher than the prior
	* reftable's {@code maxUpdateIndex} if this table will be used
	* in a stack.
	* @return {@code this}
	*/
	public ReftableCompactor setMinUpdateIndex(long min) {
	minUpdateIndex = min;
	return this;
	}

	/**
	* @param max
	* the maximum update index for log entries that appear in the
	* compacted reftable. This should be at least 1 higher than the
	* prior reftable's {@code maxUpdateIndex} if this table will be
	* used in a stack.
	* @return {@code this}
	*/
	public ReftableCompactor setMaxUpdateIndex(long max) {
	maxUpdateIndex = max;
	return this;
	}

	/**
	* @param timeMillis
	* oldest log time to preserve. Entries whose timestamps are
	* {@code >= timeMillis} will be copied into the output file. Log
	* entries that predate {@code timeMillis} will be discarded.
	* Specified in Java standard milliseconds since the epoch.
	* @return {@code this}
	*/
	public ReftableCompactor setOldestReflogTimeMillis(long timeMillis) {
	oldestReflogTimeMillis = timeMillis;
	return this;
	}

	/**
	* Add all of the tables, in the specified order.
	* <p>
	* Unconditionally adds all tables, ignoring the
	* {@link #setCompactBytesLimit(long)}.
	*
	* @param readers
	* tables to compact. Tables should be ordered oldest first/most
	* recent last so that the more recent tables can shadow the
	* older results. Caller is responsible for closing the readers.
	*/
	public void addAll(List<? extends Reftable> readers) {
	tables.addAll(readers);
	}

	/**
	* Try to add this reader at the bottom of the stack.
	* <p>
	* A reader may be rejected by returning {@code false} if the compactor is
	* already rewriting its {@link #setCompactBytesLimit(long)}. When this
	* happens the caller should stop trying to add tables, and execute the
	* compaction.
	*
	* @param reader
	* the reader to insert at the bottom of the stack. Caller is
	* responsible for closing the reader.
	* @return {@code true} if the compactor accepted this table; {@code false}
	* if the compactor has reached its limit.
	* @throws IOException
	* if size of {@code reader} cannot be read.
	*/
	public boolean tryAddFirst(ReftableReader reader) throws IOException {
	long sz = reader.size();
	if (compactBytesLimit > 0 && bytesToCompact + sz > compactBytesLimit) {
	return false;
	}
	bytesToCompact += sz;
	tables.addFirst(reader);
	return true;
	}

	/**
	* Write a compaction to {@code out}.
	*
	* @param out
	* stream to write the compacted tables to. Caller is responsible
	* for closing {@code out}.
	* @throws IOException
	* if tables cannot be read, or cannot be written.
	*/
	public void compact(OutputStream out) throws IOException {
	MergedReftable mr = new MergedReftable(new ArrayList<>(tables));
	mr.setIncludeDeletes(includeDeletes);

	writer.setMinUpdateIndex(minUpdateIndex);
	writer.setMaxUpdateIndex(maxUpdateIndex);
	writer.begin(out);
	mergeRefs(mr);
	mergeLogs(mr);
	writer.finish();
	stats = writer.getStats();
	}

	/** @return statistics of the last written reftable. */
	public Stats getStats() {
	return stats;
	}

	private void mergeRefs(MergedReftable mr) throws IOException {
	try (RefCursor rc = mr.allRefs()) {
	while (rc.next()) {
	writer.writeRef(rc.getRef());
	}
	}
	}

	private void mergeLogs(MergedReftable mr) throws IOException {
	if (oldestReflogTimeMillis == Long.MAX_VALUE) {
	return;
	}

	try (LogCursor lc = mr.allLogs()) {
	while (lc.next()) {
	long updateIndex = lc.getUpdateIndex();
	if (updateIndex < minUpdateIndex
	\|\| updateIndex > maxUpdateIndex) {
	// Cannot merge log records outside the header's range.
	continue;
	}

	String refName = lc.getRefName();
	ReflogEntry log = lc.getReflogEntry();
	if (log == null) {
	if (includeDeletes) {
	writer.deleteLog(refName, updateIndex);
	}
	continue;
	}

	PersonIdent who = log.getWho();
	if (who.getWhen().getTime() >= oldestReflogTimeMillis) {
	writer.writeLog(
	refName,
	updateIndex,
	who,
	log.getOldId(),
	log.getNewId(),
	log.getComment());
	}
	}
	}
	}
	}