|
|
@@ -0,0 +1,149 @@ |
|
|
|
/* |
|
|
|
* Copyright (C) 2010, 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.storage.file; |
|
|
|
|
|
|
|
import java.util.concurrent.atomic.AtomicReferenceArray; |
|
|
|
|
|
|
|
import org.eclipse.jgit.lib.AnyObjectId; |
|
|
|
import org.eclipse.jgit.lib.ObjectId; |
|
|
|
|
|
|
|
/** Remembers objects that are currently unpacked. */ |
|
|
|
class UnpackedObjectCache { |
|
|
|
private static final int INITIAL_BITS = 5; // size = 32 |
|
|
|
|
|
|
|
private static final int MAX_BITS = 11; // size = 2048 |
|
|
|
|
|
|
|
private volatile Table table; |
|
|
|
|
|
|
|
UnpackedObjectCache() { |
|
|
|
table = new Table(INITIAL_BITS); |
|
|
|
} |
|
|
|
|
|
|
|
boolean isUnpacked(AnyObjectId objectId) { |
|
|
|
return table.contains(objectId); |
|
|
|
} |
|
|
|
|
|
|
|
void add(AnyObjectId objectId) { |
|
|
|
Table t = table; |
|
|
|
if (t.add(objectId)) { |
|
|
|
// The object either already exists in the table, or was |
|
|
|
// successfully added. Either way leave the table alone. |
|
|
|
// |
|
|
|
} else { |
|
|
|
// The object won't fit into the table. Implement a crude |
|
|
|
// cache removal by just dropping the table away, but double |
|
|
|
// it in size for the next incarnation. |
|
|
|
// |
|
|
|
Table n = new Table(Math.min(t.bits + 1, MAX_BITS)); |
|
|
|
n.add(objectId); |
|
|
|
table = n; |
|
|
|
} |
|
|
|
} |
|
|
|
|
|
|
|
void remove(AnyObjectId objectId) { |
|
|
|
if (isUnpacked(objectId)) |
|
|
|
clear(); |
|
|
|
} |
|
|
|
|
|
|
|
void clear() { |
|
|
|
table = new Table(INITIAL_BITS); |
|
|
|
} |
|
|
|
|
|
|
|
private static class Table { |
|
|
|
private static final int MAX_CHAIN = 8; |
|
|
|
|
|
|
|
private final AtomicReferenceArray<ObjectId> ids; |
|
|
|
|
|
|
|
private final int shift; |
|
|
|
|
|
|
|
final int bits; |
|
|
|
|
|
|
|
Table(int bits) { |
|
|
|
this.ids = new AtomicReferenceArray<ObjectId>(1 << bits); |
|
|
|
this.shift = 32 - bits; |
|
|
|
this.bits = bits; |
|
|
|
} |
|
|
|
|
|
|
|
boolean contains(AnyObjectId toFind) { |
|
|
|
int i = index(toFind); |
|
|
|
for (int n = 0; n < MAX_CHAIN; n++) { |
|
|
|
ObjectId obj = ids.get(i); |
|
|
|
if (obj == null) |
|
|
|
break; |
|
|
|
|
|
|
|
if (AnyObjectId.equals(obj, toFind)) |
|
|
|
return true; |
|
|
|
|
|
|
|
if (++i == ids.length()) |
|
|
|
i = 0; |
|
|
|
} |
|
|
|
return false; |
|
|
|
} |
|
|
|
|
|
|
|
boolean add(AnyObjectId toAdd) { |
|
|
|
int i = index(toAdd); |
|
|
|
for (int n = 0; n < MAX_CHAIN;) { |
|
|
|
ObjectId obj = ids.get(i); |
|
|
|
if (obj == null) { |
|
|
|
if (ids.compareAndSet(i, null, toAdd.copy())) |
|
|
|
return true; |
|
|
|
else |
|
|
|
continue; |
|
|
|
} |
|
|
|
|
|
|
|
if (AnyObjectId.equals(obj, toAdd)) |
|
|
|
return true; |
|
|
|
|
|
|
|
if (++i == ids.length()) |
|
|
|
i = 0; |
|
|
|
n++; |
|
|
|
} |
|
|
|
return false; |
|
|
|
} |
|
|
|
|
|
|
|
private int index(AnyObjectId id) { |
|
|
|
return id.hashCode() >>> shift; |
|
|
|
} |
|
|
|
} |
|
|
|
} |