From 17dc6bdafd6399a94f2b64357ea48873f6b71b2a Mon Sep 17 00:00:00 2001 From: "Shawn O. Pearce" Date: Thu, 27 Jan 2011 17:20:36 -0800 Subject: [PATCH] ObjectIdSubclassMap: Support duplicate additions The new addIfAbsent() method combines get() with add(), but does it in a single step so that the common case of get() returning null for a new object can immediately insert the object into the map. Change-Id: Ib599ab4de13ad67665ccfccf3ece52ba3222bcba Signed-off-by: Shawn O. Pearce --- .../jgit/lib/ObjectIdSubclassMapTest.java | 221 ++++++++++++++++++ .../eclipse/jgit/lib/ObjectIdSubclassMap.java | 47 +++- .../storage/file/CachedObjectDirectory.java | 3 +- 3 files changed, 266 insertions(+), 5 deletions(-) create mode 100644 org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdSubclassMapTest.java diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdSubclassMapTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdSubclassMapTest.java new file mode 100644 index 000000000..07561deac --- /dev/null +++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdSubclassMapTest.java @@ -0,0 +1,221 @@ +/* + * Copyright (C) 2011, 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.lib; + +import static org.junit.Assert.assertEquals; +import static org.junit.Assert.assertFalse; +import static org.junit.Assert.assertNotNull; +import static org.junit.Assert.assertSame; +import static org.junit.Assert.assertTrue; +import static org.junit.Assert.fail; + +import java.util.Iterator; +import java.util.NoSuchElementException; + +import org.junit.Before; +import org.junit.Test; + +public class ObjectIdSubclassMapTest { + private MutableObjectId idBuf; + + private SubId id_1, id_2, id_3, id_a31, id_b31; + + @Before + public void init() { + idBuf = new MutableObjectId(); + id_1 = new SubId(id(1)); + id_2 = new SubId(id(2)); + id_3 = new SubId(id(3)); + id_a31 = new SubId(id(31)); + id_b31 = new SubId(id((1 << 8) + 31)); + } + + @Test + public void testEmptyMap() { + ObjectIdSubclassMap m = new ObjectIdSubclassMap(); + assertTrue(m.isEmpty()); + assertEquals(0, m.size()); + + Iterator i = m.iterator(); + assertNotNull(i); + assertFalse(i.hasNext()); + + assertFalse(m.contains(id(1))); + } + + @Test + public void testAddGetAndContains() { + ObjectIdSubclassMap m = new ObjectIdSubclassMap(); + m.add(id_1); + m.add(id_2); + m.add(id_3); + m.add(id_a31); + m.add(id_b31); + assertFalse(m.isEmpty()); + assertEquals(5, m.size()); + + assertSame(id_1, m.get(id_1)); + assertSame(id_1, m.get(id(1))); + assertSame(id_1, m.get(id(1).copy())); + assertSame(id_2, m.get(id(2).copy())); + assertSame(id_3, m.get(id(3).copy())); + assertSame(id_a31, m.get(id(31).copy())); + assertSame(id_b31, m.get(id_b31.copy())); + + assertTrue(m.contains(id_1)); + } + + @Test + public void testClear() { + ObjectIdSubclassMap m = new ObjectIdSubclassMap(); + + m.add(id_1); + assertSame(id_1, m.get(id_1)); + + m.clear(); + assertTrue(m.isEmpty()); + assertEquals(0, m.size()); + + Iterator i = m.iterator(); + assertNotNull(i); + assertFalse(i.hasNext()); + + assertFalse(m.contains(id(1))); + } + + @Test + public void testAddIfAbsent() { + ObjectIdSubclassMap m = new ObjectIdSubclassMap(); + m.add(id_1); + + assertSame(id_1, m.addIfAbsent(new SubId(id_1))); + assertEquals(1, m.size()); + + assertSame(id_2, m.addIfAbsent(id_2)); + assertEquals(2, m.size()); + assertSame(id_a31, m.addIfAbsent(id_a31)); + assertSame(id_b31, m.addIfAbsent(id_b31)); + + assertSame(id_a31, m.addIfAbsent(new SubId(id_a31))); + assertSame(id_b31, m.addIfAbsent(new SubId(id_b31))); + assertEquals(4, m.size()); + } + + @Test + public void testAddGrowsWithObjects() { + ObjectIdSubclassMap m = new ObjectIdSubclassMap(); + m.add(id_1); + for (int i = 32; i < 8000; i++) + m.add(new SubId(id(i))); + assertEquals(8000 - 32 + 1, m.size()); + + assertSame(id_1, m.get(id_1.copy())); + for (int i = 32; i < 8000; i++) + assertTrue(m.contains(id(i))); + } + + @Test + public void testAddIfAbsentGrowsWithObjects() { + ObjectIdSubclassMap m = new ObjectIdSubclassMap(); + m.add(id_1); + for (int i = 32; i < 8000; i++) + m.addIfAbsent(new SubId(id(i))); + assertEquals(8000 - 32 + 1, m.size()); + + assertSame(id_1, m.get(id_1.copy())); + for (int i = 32; i < 8000; i++) + assertTrue(m.contains(id(i))); + } + + @Test + public void testIterator() { + ObjectIdSubclassMap m = new ObjectIdSubclassMap(); + m.add(id_1); + m.add(id_2); + m.add(id_3); + + Iterator i = m.iterator(); + assertTrue(i.hasNext()); + assertSame(id_1, i.next()); + assertTrue(i.hasNext()); + assertSame(id_2, i.next()); + assertTrue(i.hasNext()); + assertSame(id_3, i.next()); + + assertFalse(i.hasNext()); + try { + i.next(); + fail("did not fail on next with no next"); + } catch (NoSuchElementException expected) { + // OK + } + + i = m.iterator(); + assertSame(id_1, i.next()); + try { + i.remove(); + fail("did not fail on remove"); + } catch (UnsupportedOperationException expected) { + // OK + } + } + + private AnyObjectId id(int val) { + // Using bytes 2 and 3 positions our value at the low end of idBuf.w1, + // which is what ObjectIdSubclassMap uses for hashing. This makes + // collisions likely, making collision testing easier. + + val <<= 1; + + idBuf.setByte(2, (val >>> 8) & 0xff); + idBuf.setByte(3, val & 0xff); + return idBuf; + } + + private static class SubId extends ObjectId { + SubId(AnyObjectId id) { + super(id); + } + } +} diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectIdSubclassMap.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectIdSubclassMap.java index 612e00ea2..ad78acdb8 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectIdSubclassMap.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectIdSubclassMap.java @@ -114,12 +114,12 @@ public class ObjectIdSubclassMap implements Iterable { *

* An existing mapping for must not be in this map. Callers must * first call {@link #get(AnyObjectId)} to verify there is no current - * mapping prior to adding a new mapping. + * mapping prior to adding a new mapping, or use + * {@link #addIfAbsent(ObjectId)}. * * @param newValue * the object to store. - * @param - * + * @param * type of instance to store. */ public void add(final Q newValue) { @@ -129,6 +129,47 @@ public class ObjectIdSubclassMap implements Iterable { size++; } + /** + * Store an object for future lookup. + *

+ * Stores {@code newValue}, but only if there is not already an object for + * the same object name. Callers can tell if the value is new by checking + * the return value with reference equality: + * + * 

+	 * V obj = ...;
+	 * boolean wasNew = map.addIfAbsent(obj) == obj;
+	 *
+ * + * @param newValue + * the object to store. + * @return {@code newValue} if stored, or the prior value already stored and + * that would have been returned had the caller used + * {@code get(newValue)} first. + * @param + * type of instance to store. + */ + public V addIfAbsent(final Q newValue) { + int i = index(newValue); + V obj; + + while ((obj = obj_hash[i]) != null) { + if (AnyObjectId.equals(obj, newValue)) + return obj; + if (++i == obj_hash.length) + i = 0; + } + + if (obj_hash.length - 1 <= size * 2) { + grow(); + insert(newValue); + } else { + obj_hash[i] = newValue; + } + size++; + return newValue; + } + /** * @return number of objects in map */ diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/CachedObjectDirectory.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/CachedObjectDirectory.java index 001ae288a..d5f2ac53c 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/CachedObjectDirectory.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/CachedObjectDirectory.java @@ -228,8 +228,7 @@ class CachedObjectDirectory extends FileObjectDatabase { switch (result) { case INSERTED: case EXISTS_LOOSE: - if (!unpackedObjects.contains(objectId)) - unpackedObjects.add(objectId); + unpackedObjects.addIfAbsent(objectId); break; case EXISTS_PACKED: