]> source.dussan.org Git - jgit.git/commitdiff
ObjectIdSubclassMap: Support duplicate additions 61/2361/2
authorShawn O. Pearce <spearce@spearce.org>
Fri, 28 Jan 2011 01:20:36 +0000 (17:20 -0800)
committerShawn O. Pearce <spearce@spearce.org>
Fri, 28 Jan 2011 16:17:20 +0000 (08:17 -0800)
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 <spearce@spearce.org>
org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectIdSubclassMapTest.java [new file with mode: 0644]
org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectIdSubclassMap.java
org.eclipse.jgit/src/org/eclipse/jgit/storage/file/CachedObjectDirectory.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 (file)
index 0000000..07561de
--- /dev/null
@@ -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<SubId> m = new ObjectIdSubclassMap<SubId>();
+               assertTrue(m.isEmpty());
+               assertEquals(0, m.size());
+
+               Iterator<SubId> i = m.iterator();
+               assertNotNull(i);
+               assertFalse(i.hasNext());
+
+               assertFalse(m.contains(id(1)));
+       }
+
+       @Test
+       public void testAddGetAndContains() {
+               ObjectIdSubclassMap<SubId> m = new ObjectIdSubclassMap<SubId>();
+               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<SubId> m = new ObjectIdSubclassMap<SubId>();
+
+               m.add(id_1);
+               assertSame(id_1, m.get(id_1));
+
+               m.clear();
+               assertTrue(m.isEmpty());
+               assertEquals(0, m.size());
+
+               Iterator<SubId> i = m.iterator();
+               assertNotNull(i);
+               assertFalse(i.hasNext());
+
+               assertFalse(m.contains(id(1)));
+       }
+
+       @Test
+       public void testAddIfAbsent() {
+               ObjectIdSubclassMap<SubId> m = new ObjectIdSubclassMap<SubId>();
+               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<SubId> m = new ObjectIdSubclassMap<SubId>();
+               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<SubId> m = new ObjectIdSubclassMap<SubId>();
+               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<SubId> m = new ObjectIdSubclassMap<SubId>();
+               m.add(id_1);
+               m.add(id_2);
+               m.add(id_3);
+
+               Iterator<SubId> 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);
+               }
+       }
+}
index 612e00ea25ab941b9c395b6ddb02777261ba8d78..ad78acdb8e8d75d73f01cbf7e8a0e3201d70b5f7 100644 (file)
@@ -114,12 +114,12 @@ public class ObjectIdSubclassMap<V extends ObjectId> implements Iterable<V> {
         * <p>
         * An existing mapping for <b>must not</b> 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
-        *            <Q>
+        * @param <Q>
         *            type of instance to store.
         */
        public <Q extends V> void add(final Q newValue) {
@@ -129,6 +129,47 @@ public class ObjectIdSubclassMap<V extends ObjectId> implements Iterable<V> {
                size++;
        }
 
+       /**
+        * Store an object for future lookup.
+        * <p>
+        * 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:
+        *
+        * <pre>
+        * V obj = ...;
+        * boolean wasNew = map.addIfAbsent(obj) == obj;
+        * </pre>
+        *
+        * @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 <Q>
+        *            type of instance to store.
+        */
+       public <Q extends V> 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
         */
index 001ae288a1d7bc9991930a63deeabd3ca9bc495e..d5f2ac53cb9537adbe6c5176cd34028f81e20986 100644 (file)
@@ -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: