| /* |
| * Copyright (C) 2017, Google Inc. 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.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.internal.storage.reftable.ReftableWriter.Stats; |
| import org.eclipse.jgit.lib.PersonIdent; |
| 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 #setReflogExpireMinUpdateIndex(long)} and {@link #setReflogExpireMaxUpdateIndex(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 #setReflogExpireOldestReflogTimeMillis(long)}, or disable the log altogether with |
| * {@code setOldestReflogTimeMillis(Long.MAX_VALUE)}. |
| */ |
| public class ReftableCompactor { |
| private final ReftableWriter writer; |
| private final ArrayDeque<ReftableReader> tables = new ArrayDeque<>(); |
| |
| private boolean includeDeletes; |
| private long reflogExpireMinUpdateIndex = 0; |
| private long reflogExpireMaxUpdateIndex = Long.MAX_VALUE; |
| private long reflogExpireOldestReflogTimeMillis; |
| private Stats stats; |
| |
| /** |
| * Creates a new compactor. |
| * |
| * @param out |
| * stream to write the compacted tables to. Caller is responsible |
| * for closing {@code out}. |
| */ |
| public ReftableCompactor(OutputStream out) { |
| writer = new ReftableWriter(out); |
| } |
| |
| /** |
| * Set configuration for the reftable. |
| * |
| * @param cfg |
| * configuration for the reftable. |
| * @return {@code this} |
| */ |
| public ReftableCompactor setConfig(ReftableConfig cfg) { |
| writer.setConfig(cfg); |
| return this; |
| } |
| |
| /** |
| * Whether to include deletions in the output, which may be necessary for |
| * partial compaction. |
| * |
| * @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; |
| } |
| |
| /** |
| * Set the minimum update index for log entries that appear in the compacted |
| * reftable. |
| * |
| * @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 setReflogExpireMinUpdateIndex(long min) { |
| reflogExpireMinUpdateIndex = min; |
| return this; |
| } |
| |
| /** |
| * Set the maximum update index for log entries that appear in the compacted |
| * reftable. |
| * |
| * @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 setReflogExpireMaxUpdateIndex(long max) { |
| reflogExpireMaxUpdateIndex = max; |
| return this; |
| } |
| |
| /** |
| * Set oldest reflog time to preserve. |
| * |
| * @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 setReflogExpireOldestReflogTimeMillis(long timeMillis) { |
| reflogExpireOldestReflogTimeMillis = timeMillis; |
| return this; |
| } |
| |
| /** |
| * Add all of the tables, in the specified order. |
| * |
| * @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. |
| * @throws java.io.IOException |
| * update indexes of a reader cannot be accessed. |
| */ |
| public void addAll(List<ReftableReader> readers) throws IOException { |
| for (ReftableReader r : readers) { |
| tables.add(r); |
| } |
| } |
| |
| /** |
| * Write a compaction to {@code out}. |
| * |
| * @throws java.io.IOException |
| * if tables cannot be read, or cannot be written. |
| */ |
| public void compact() throws IOException { |
| MergedReftable mr = new MergedReftable(new ArrayList<>(tables)); |
| mr.setIncludeDeletes(includeDeletes); |
| |
| writer.setMaxUpdateIndex(mr.maxUpdateIndex()); |
| writer.setMinUpdateIndex(mr.minUpdateIndex()); |
| |
| writer.begin(); |
| mergeRefs(mr); |
| mergeLogs(mr); |
| writer.finish(); |
| stats = writer.getStats(); |
| } |
| |
| /** |
| * Get statistics of the last written reftable. |
| * |
| * @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(), rc.getRef().getUpdateIndex()); |
| } |
| } |
| } |
| |
| private void mergeLogs(MergedReftable mr) throws IOException { |
| if (reflogExpireOldestReflogTimeMillis == Long.MAX_VALUE) { |
| return; |
| } |
| |
| try (LogCursor lc = mr.allLogs()) { |
| while (lc.next()) { |
| long updateIndex = lc.getUpdateIndex(); |
| if (updateIndex > reflogExpireMaxUpdateIndex || updateIndex < reflogExpireMinUpdateIndex) { |
| 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() >= reflogExpireOldestReflogTimeMillis) { |
| writer.writeLog( |
| refName, |
| updateIndex, |
| who, |
| log.getOldId(), |
| log.getNewId(), |
| log.getComment()); |
| } |
| } |
| } |
| } |
| } |