reftable: merge-join reftables
MergedReftable combines multiple reference tables together in a stack, allowing higher/later tables to shadow earlier/lower tables. This forms the basis of a transaction system, where each transaction writes a new reftable containing only the modified references, and readers perform a merge on the fly to get the latest value. Change-Id: Ic2cb750141e8c61a8b2726b2eb95195acb6ddc83
This commit is contained in:
parent
7da2fe6be8
commit
77d8eead6d
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/*
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* Copyright (C) 2017, Google Inc.
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* and other copyright owners as documented in the project's IP log.
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*
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* This program and the accompanying materials are made available
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* under the terms of the Eclipse Distribution License v1.0 which
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* accompanies this distribution, is reproduced below, and is
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* available at http://www.eclipse.org/org/documents/edl-v10.php
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* - Neither the name of the Eclipse Foundation, Inc. nor the
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* names of its contributors may be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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package org.eclipse.jgit.internal.storage.reftable;
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import static org.eclipse.jgit.lib.Constants.HEAD;
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import static org.eclipse.jgit.lib.Constants.OBJECT_ID_LENGTH;
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import static org.eclipse.jgit.lib.Constants.R_HEADS;
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import static org.eclipse.jgit.lib.Ref.Storage.NEW;
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import static org.eclipse.jgit.lib.Ref.Storage.PACKED;
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import static org.junit.Assert.assertEquals;
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import static org.junit.Assert.assertFalse;
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import static org.junit.Assert.assertNull;
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import static org.junit.Assert.assertTrue;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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import org.eclipse.jgit.internal.storage.io.BlockSource;
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import org.eclipse.jgit.lib.ObjectId;
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import org.eclipse.jgit.lib.ObjectIdRef;
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import org.eclipse.jgit.lib.Ref;
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import org.eclipse.jgit.lib.RefComparator;
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import org.junit.Test;
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public class MergedReftableTest {
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@Test
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public void noTables() throws IOException {
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MergedReftable mr = merge(new byte[0][]);
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try (RefCursor rc = mr.allRefs()) {
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assertFalse(rc.next());
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}
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try (RefCursor rc = mr.seekRef(HEAD)) {
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assertFalse(rc.next());
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}
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try (RefCursor rc = mr.seekRef(R_HEADS)) {
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assertFalse(rc.next());
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}
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}
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@Test
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public void oneEmptyTable() throws IOException {
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MergedReftable mr = merge(write());
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try (RefCursor rc = mr.allRefs()) {
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assertFalse(rc.next());
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}
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try (RefCursor rc = mr.seekRef(HEAD)) {
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assertFalse(rc.next());
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}
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try (RefCursor rc = mr.seekRef(R_HEADS)) {
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assertFalse(rc.next());
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}
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}
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@Test
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public void twoEmptyTables() throws IOException {
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MergedReftable mr = merge(write(), write());
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try (RefCursor rc = mr.allRefs()) {
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assertFalse(rc.next());
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}
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try (RefCursor rc = mr.seekRef(HEAD)) {
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assertFalse(rc.next());
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}
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try (RefCursor rc = mr.seekRef(R_HEADS)) {
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assertFalse(rc.next());
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}
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}
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@SuppressWarnings("boxing")
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@Test
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public void oneTableScan() throws IOException {
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List<Ref> refs = new ArrayList<>();
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for (int i = 1; i <= 567; i++) {
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refs.add(ref(String.format("refs/heads/%03d", i), i));
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}
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MergedReftable mr = merge(write(refs));
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try (RefCursor rc = mr.allRefs()) {
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for (Ref exp : refs) {
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assertTrue("has " + exp.getName(), rc.next());
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Ref act = rc.getRef();
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assertEquals(exp.getName(), act.getName());
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assertEquals(exp.getObjectId(), act.getObjectId());
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}
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assertFalse(rc.next());
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}
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}
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@Test
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public void deleteIsHidden() throws IOException {
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List<Ref> delta1 = Arrays.asList(
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ref("refs/heads/apple", 1),
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ref("refs/heads/master", 2));
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List<Ref> delta2 = Arrays.asList(delete("refs/heads/apple"));
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MergedReftable mr = merge(write(delta1), write(delta2));
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try (RefCursor rc = mr.allRefs()) {
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assertTrue(rc.next());
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assertEquals("refs/heads/master", rc.getRef().getName());
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assertEquals(id(2), rc.getRef().getObjectId());
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assertFalse(rc.next());
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}
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}
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@Test
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public void twoTableSeek() throws IOException {
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List<Ref> delta1 = Arrays.asList(
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ref("refs/heads/apple", 1),
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ref("refs/heads/master", 2));
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List<Ref> delta2 = Arrays.asList(ref("refs/heads/banana", 3));
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MergedReftable mr = merge(write(delta1), write(delta2));
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try (RefCursor rc = mr.seekRef("refs/heads/master")) {
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assertTrue(rc.next());
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assertEquals("refs/heads/master", rc.getRef().getName());
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assertEquals(id(2), rc.getRef().getObjectId());
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assertFalse(rc.next());
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}
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}
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@Test
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public void twoTableById() throws IOException {
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List<Ref> delta1 = Arrays.asList(
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ref("refs/heads/apple", 1),
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ref("refs/heads/master", 2));
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List<Ref> delta2 = Arrays.asList(ref("refs/heads/banana", 3));
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MergedReftable mr = merge(write(delta1), write(delta2));
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try (RefCursor rc = mr.byObjectId(id(2))) {
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assertTrue(rc.next());
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assertEquals("refs/heads/master", rc.getRef().getName());
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assertEquals(id(2), rc.getRef().getObjectId());
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assertFalse(rc.next());
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}
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}
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@SuppressWarnings("boxing")
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@Test
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public void fourTableScan() throws IOException {
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List<Ref> base = new ArrayList<>();
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for (int i = 1; i <= 567; i++) {
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base.add(ref(String.format("refs/heads/%03d", i), i));
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}
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List<Ref> delta1 = Arrays.asList(
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ref("refs/heads/next", 4),
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ref(String.format("refs/heads/%03d", 55), 4096));
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List<Ref> delta2 = Arrays.asList(
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delete("refs/heads/next"),
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ref(String.format("refs/heads/%03d", 55), 8192));
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List<Ref> delta3 = Arrays.asList(
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ref("refs/heads/master", 4242),
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ref(String.format("refs/heads/%03d", 42), 5120),
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ref(String.format("refs/heads/%03d", 98), 6120));
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List<Ref> expected = merge(base, delta1, delta2, delta3);
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MergedReftable mr = merge(
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write(base),
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write(delta1),
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write(delta2),
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write(delta3));
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try (RefCursor rc = mr.allRefs()) {
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for (Ref exp : expected) {
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assertTrue("has " + exp.getName(), rc.next());
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Ref act = rc.getRef();
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assertEquals(exp.getName(), act.getName());
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assertEquals(exp.getObjectId(), act.getObjectId());
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}
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assertFalse(rc.next());
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}
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}
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@Test
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public void scanIncludeDeletes() throws IOException {
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List<Ref> delta1 = Arrays.asList(ref("refs/heads/next", 4));
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List<Ref> delta2 = Arrays.asList(delete("refs/heads/next"));
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List<Ref> delta3 = Arrays.asList(ref("refs/heads/master", 8));
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MergedReftable mr = merge(write(delta1), write(delta2), write(delta3));
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mr.setIncludeDeletes(true);
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try (RefCursor rc = mr.allRefs()) {
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assertTrue(rc.next());
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Ref r = rc.getRef();
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assertEquals("refs/heads/master", r.getName());
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assertEquals(id(8), r.getObjectId());
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assertTrue(rc.next());
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r = rc.getRef();
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assertEquals("refs/heads/next", r.getName());
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assertEquals(NEW, r.getStorage());
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assertNull(r.getObjectId());
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assertFalse(rc.next());
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}
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}
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@SuppressWarnings("boxing")
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@Test
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public void oneTableSeek() throws IOException {
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List<Ref> refs = new ArrayList<>();
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for (int i = 1; i <= 567; i++) {
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refs.add(ref(String.format("refs/heads/%03d", i), i));
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}
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MergedReftable mr = merge(write(refs));
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for (Ref exp : refs) {
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try (RefCursor rc = mr.seekRef(exp.getName())) {
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assertTrue("has " + exp.getName(), rc.next());
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Ref act = rc.getRef();
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assertEquals(exp.getName(), act.getName());
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assertEquals(exp.getObjectId(), act.getObjectId());
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assertFalse(rc.next());
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}
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}
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}
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private static MergedReftable merge(byte[]... table) {
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List<Reftable> stack = new ArrayList<>(table.length);
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for (byte[] b : table) {
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stack.add(read(b));
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}
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return new MergedReftable(stack);
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}
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private static ReftableReader read(byte[] table) {
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return new ReftableReader(BlockSource.from(table));
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}
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private static Ref ref(String name, int id) {
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return new ObjectIdRef.PeeledNonTag(PACKED, name, id(id));
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}
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private static Ref delete(String name) {
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return new ObjectIdRef.Unpeeled(NEW, name, null);
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}
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private static ObjectId id(int i) {
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byte[] buf = new byte[OBJECT_ID_LENGTH];
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buf[0] = (byte) (i & 0xff);
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buf[1] = (byte) ((i >>> 8) & 0xff);
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buf[2] = (byte) ((i >>> 16) & 0xff);
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buf[3] = (byte) (i >>> 24);
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return ObjectId.fromRaw(buf);
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}
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private byte[] write(Ref... refs) throws IOException {
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return write(Arrays.asList(refs));
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}
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private byte[] write(Collection<Ref> refs) throws IOException {
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ByteArrayOutputStream buffer = new ByteArrayOutputStream();
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ReftableWriter writer = new ReftableWriter().begin(buffer);
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for (Ref r : RefComparator.sort(refs)) {
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writer.writeRef(r);
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}
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writer.finish();
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return buffer.toByteArray();
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}
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@SafeVarargs
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private static List<Ref> merge(List<Ref>... tables) {
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Map<String, Ref> expect = new HashMap<>();
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for (List<Ref> t : tables) {
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for (Ref r : t) {
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if (r.getStorage() == NEW && r.getObjectId() == null) {
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expect.remove(r.getName());
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} else {
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expect.put(r.getName(), r);
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}
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}
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}
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List<Ref> expected = new ArrayList<>(expect.values());
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Collections.sort(expected, RefComparator.INSTANCE);
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return expected;
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}
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}
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@ -0,0 +1,375 @@
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/*
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* Copyright (C) 2017, Google Inc.
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* and other copyright owners as documented in the project's IP log.
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*
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* This program and the accompanying materials are made available
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* under the terms of the Eclipse Distribution License v1.0 which
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|
* accompanies this distribution, is reproduced below, and is
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|
* available at http://www.eclipse.org/org/documents/edl-v10.php
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
|
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|
* conditions are met:
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|
*
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* - Redistributions of source code must retain the above copyright
|
||||||
|
* notice, this list of conditions and the following disclaimer.
|
||||||
|
*
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|
* - Redistributions in binary form must reproduce the above
|
||||||
|
* copyright notice, this list of conditions and the following
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||||||
|
* disclaimer in the documentation and/or other materials provided
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|
* with the distribution.
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|
*
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* - Neither the name of the Eclipse Foundation, Inc. nor the
|
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* names of its contributors may be used to endorse or promote
|
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|
* products derived from this software without specific prior
|
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|
* written permission.
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|
*
|
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|
* 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.
|
||||||
|
*/
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package org.eclipse.jgit.internal.storage.reftable;
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import java.io.IOException;
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import java.util.List;
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import java.util.PriorityQueue;
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|
import org.eclipse.jgit.lib.AnyObjectId;
|
||||||
|
import org.eclipse.jgit.lib.Ref;
|
||||||
|
import org.eclipse.jgit.lib.ReflogEntry;
|
||||||
|
|
||||||
|
/**
|
||||||
|
* Merges multiple reference tables together.
|
||||||
|
* <p>
|
||||||
|
* A {@link MergedReftable} merge-joins multiple {@link ReftableReader} on the
|
||||||
|
* fly. Tables higher/later in the stack shadow lower/earlier tables, hiding
|
||||||
|
* references that been updated/replaced.
|
||||||
|
* <p>
|
||||||
|
* By default deleted references are skipped and not returned to the caller.
|
||||||
|
* {@link #setIncludeDeletes(boolean)} can be used to modify this behavior if
|
||||||
|
* the caller needs to preserve deletions during partial compaction.
|
||||||
|
* <p>
|
||||||
|
* A {@code MergedReftable} is not thread-safe.
|
||||||
|
*/
|
||||||
|
public class MergedReftable extends Reftable {
|
||||||
|
private final Reftable[] tables;
|
||||||
|
|
||||||
|
/**
|
||||||
|
* Initialize a merged table reader.
|
||||||
|
* <p>
|
||||||
|
* The tables in {@code tableStack} will be closed when this
|
||||||
|
* {@code MergedReftable} is closed.
|
||||||
|
*
|
||||||
|
* @param tableStack
|
||||||
|
* stack of tables to read from. The base of the stack is at
|
||||||
|
* index 0, the most recent should be at the top of the stack at
|
||||||
|
* {@code tableStack.size() - 1}. The top of the stack (higher
|
||||||
|
* index) shadows the base of the stack (lower index).
|
||||||
|
*/
|
||||||
|
public MergedReftable(List<Reftable> tableStack) {
|
||||||
|
tables = tableStack.toArray(new Reftable[0]);
|
||||||
|
|
||||||
|
// Tables must expose deletes to this instance to correctly
|
||||||
|
// shadow references from lower tables.
|
||||||
|
for (Reftable t : tables) {
|
||||||
|
t.setIncludeDeletes(true);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public RefCursor allRefs() throws IOException {
|
||||||
|
MergedRefCursor m = new MergedRefCursor();
|
||||||
|
for (int i = 0; i < tables.length; i++) {
|
||||||
|
m.add(new RefQueueEntry(tables[i].allRefs(), i));
|
||||||
|
}
|
||||||
|
return m;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public RefCursor seekRef(String name) throws IOException {
|
||||||
|
if (name.endsWith("/")) { //$NON-NLS-1$
|
||||||
|
return seekRefPrefix(name);
|
||||||
|
}
|
||||||
|
return seekSingleRef(name);
|
||||||
|
}
|
||||||
|
|
||||||
|
private RefCursor seekRefPrefix(String name) throws IOException {
|
||||||
|
MergedRefCursor m = new MergedRefCursor();
|
||||||
|
for (int i = 0; i < tables.length; i++) {
|
||||||
|
m.add(new RefQueueEntry(tables[i].seekRef(name), i));
|
||||||
|
}
|
||||||
|
return m;
|
||||||
|
}
|
||||||
|
|
||||||
|
private RefCursor seekSingleRef(String name) throws IOException {
|
||||||
|
// Walk the tables from highest priority (end of list) to lowest.
|
||||||
|
// As soon as the reference is found (queue not empty), all lower
|
||||||
|
// priority tables are irrelevant as current table shadows them.
|
||||||
|
MergedRefCursor m = new MergedRefCursor();
|
||||||
|
for (int i = tables.length - 1; i >= 0 && m.queue.isEmpty(); i--) {
|
||||||
|
m.add(new RefQueueEntry(tables[i].seekRef(name), i));
|
||||||
|
}
|
||||||
|
return m;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public RefCursor byObjectId(AnyObjectId name) throws IOException {
|
||||||
|
MergedRefCursor m = new MergedRefCursor();
|
||||||
|
for (int i = 0; i < tables.length; i++) {
|
||||||
|
m.add(new RefQueueEntry(tables[i].byObjectId(name), i));
|
||||||
|
}
|
||||||
|
return m;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public LogCursor allLogs() throws IOException {
|
||||||
|
MergedLogCursor m = new MergedLogCursor();
|
||||||
|
for (int i = 0; i < tables.length; i++) {
|
||||||
|
m.add(new LogQueueEntry(tables[i].allLogs(), i));
|
||||||
|
}
|
||||||
|
return m;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public LogCursor seekLog(String refName, long updateIdx)
|
||||||
|
throws IOException {
|
||||||
|
MergedLogCursor m = new MergedLogCursor();
|
||||||
|
for (int i = 0; i < tables.length; i++) {
|
||||||
|
m.add(new LogQueueEntry(tables[i].seekLog(refName, updateIdx), i));
|
||||||
|
}
|
||||||
|
return m;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public void close() throws IOException {
|
||||||
|
for (Reftable t : tables) {
|
||||||
|
t.close();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
int queueSize() {
|
||||||
|
return Math.max(1, tables.length);
|
||||||
|
}
|
||||||
|
|
||||||
|
private class MergedRefCursor extends RefCursor {
|
||||||
|
private final PriorityQueue<RefQueueEntry> queue;
|
||||||
|
private RefQueueEntry head;
|
||||||
|
private Ref ref;
|
||||||
|
|
||||||
|
MergedRefCursor() {
|
||||||
|
queue = new PriorityQueue<>(queueSize(), RefQueueEntry::compare);
|
||||||
|
}
|
||||||
|
|
||||||
|
void add(RefQueueEntry t) throws IOException {
|
||||||
|
// Common case is many iterations over the same RefQueueEntry
|
||||||
|
// for the bottom of the stack (scanning all refs). Its almost
|
||||||
|
// always less than the top of the queue. Avoid the queue's
|
||||||
|
// O(log N) insertion and removal costs for this common case.
|
||||||
|
if (!t.rc.next()) {
|
||||||
|
t.rc.close();
|
||||||
|
} else if (head == null) {
|
||||||
|
RefQueueEntry p = queue.peek();
|
||||||
|
if (p == null || RefQueueEntry.compare(t, p) < 0) {
|
||||||
|
head = t;
|
||||||
|
} else {
|
||||||
|
head = queue.poll();
|
||||||
|
queue.add(t);
|
||||||
|
}
|
||||||
|
} else if (RefQueueEntry.compare(t, head) > 0) {
|
||||||
|
queue.add(t);
|
||||||
|
} else {
|
||||||
|
queue.add(head);
|
||||||
|
head = t;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public boolean next() throws IOException {
|
||||||
|
for (;;) {
|
||||||
|
RefQueueEntry t = poll();
|
||||||
|
if (t == null) {
|
||||||
|
return false;
|
||||||
|
}
|
||||||
|
|
||||||
|
ref = t.rc.getRef();
|
||||||
|
boolean include = includeDeletes || !t.rc.wasDeleted();
|
||||||
|
skipShadowedRefs(ref.getName());
|
||||||
|
add(t);
|
||||||
|
if (include) {
|
||||||
|
return true;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
private RefQueueEntry poll() {
|
||||||
|
RefQueueEntry e = head;
|
||||||
|
if (e != null) {
|
||||||
|
head = null;
|
||||||
|
return e;
|
||||||
|
}
|
||||||
|
return queue.poll();
|
||||||
|
}
|
||||||
|
|
||||||
|
private void skipShadowedRefs(String name) throws IOException {
|
||||||
|
for (;;) {
|
||||||
|
RefQueueEntry t = head != null ? head : queue.peek();
|
||||||
|
if (t != null && name.equals(t.name())) {
|
||||||
|
add(poll());
|
||||||
|
} else {
|
||||||
|
break;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public Ref getRef() {
|
||||||
|
return ref;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public void close() {
|
||||||
|
while (!queue.isEmpty()) {
|
||||||
|
queue.remove().rc.close();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
private static class RefQueueEntry {
|
||||||
|
static int compare(RefQueueEntry a, RefQueueEntry b) {
|
||||||
|
int cmp = a.name().compareTo(b.name());
|
||||||
|
if (cmp == 0) {
|
||||||
|
// higher index shadows lower index, so higher index first.
|
||||||
|
cmp = b.stackIdx - a.stackIdx;
|
||||||
|
}
|
||||||
|
return cmp;
|
||||||
|
}
|
||||||
|
|
||||||
|
final RefCursor rc;
|
||||||
|
final int stackIdx;
|
||||||
|
|
||||||
|
RefQueueEntry(RefCursor rc, int stackIdx) {
|
||||||
|
this.rc = rc;
|
||||||
|
this.stackIdx = stackIdx;
|
||||||
|
}
|
||||||
|
|
||||||
|
String name() {
|
||||||
|
return rc.getRef().getName();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
private class MergedLogCursor extends LogCursor {
|
||||||
|
private final PriorityQueue<LogQueueEntry> queue;
|
||||||
|
private String refName;
|
||||||
|
private long updateIndex;
|
||||||
|
private ReflogEntry entry;
|
||||||
|
|
||||||
|
MergedLogCursor() {
|
||||||
|
queue = new PriorityQueue<>(queueSize(), LogQueueEntry::compare);
|
||||||
|
}
|
||||||
|
|
||||||
|
void add(LogQueueEntry t) throws IOException {
|
||||||
|
if (t.lc.next()) {
|
||||||
|
queue.add(t);
|
||||||
|
} else {
|
||||||
|
t.lc.close();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public boolean next() throws IOException {
|
||||||
|
for (;;) {
|
||||||
|
LogQueueEntry t = queue.poll();
|
||||||
|
if (t == null) {
|
||||||
|
return false;
|
||||||
|
}
|
||||||
|
|
||||||
|
refName = t.lc.getRefName();
|
||||||
|
updateIndex = t.lc.getUpdateIndex();
|
||||||
|
entry = t.lc.getReflogEntry();
|
||||||
|
boolean include = includeDeletes || entry != null;
|
||||||
|
skipShadowed(refName, updateIndex);
|
||||||
|
add(t);
|
||||||
|
if (include) {
|
||||||
|
return true;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
private void skipShadowed(String name, long index) throws IOException {
|
||||||
|
for (;;) {
|
||||||
|
LogQueueEntry t = queue.peek();
|
||||||
|
if (t != null && name.equals(t.name()) && index == t.index()) {
|
||||||
|
add(queue.remove());
|
||||||
|
} else {
|
||||||
|
break;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public String getRefName() {
|
||||||
|
return refName;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public long getUpdateIndex() {
|
||||||
|
return updateIndex;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public ReflogEntry getReflogEntry() {
|
||||||
|
return entry;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public void close() {
|
||||||
|
while (!queue.isEmpty()) {
|
||||||
|
queue.remove().lc.close();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
private static class LogQueueEntry {
|
||||||
|
static int compare(LogQueueEntry a, LogQueueEntry b) {
|
||||||
|
int cmp = a.name().compareTo(b.name());
|
||||||
|
if (cmp == 0) {
|
||||||
|
// higher update index sorts first.
|
||||||
|
cmp = Long.signum(b.index() - a.index());
|
||||||
|
}
|
||||||
|
if (cmp == 0) {
|
||||||
|
// higher index comes first.
|
||||||
|
cmp = b.stackIdx - a.stackIdx;
|
||||||
|
}
|
||||||
|
return cmp;
|
||||||
|
}
|
||||||
|
|
||||||
|
final LogCursor lc;
|
||||||
|
final int stackIdx;
|
||||||
|
|
||||||
|
LogQueueEntry(LogCursor lc, int stackIdx) {
|
||||||
|
this.lc = lc;
|
||||||
|
this.stackIdx = stackIdx;
|
||||||
|
}
|
||||||
|
|
||||||
|
String name() {
|
||||||
|
return lc.getRefName();
|
||||||
|
}
|
||||||
|
|
||||||
|
long index() {
|
||||||
|
return lc.getUpdateIndex();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
Loading…
Reference in New Issue