Browse Source
* changes: Unpack and cache large deltas as loose objects Remember loose objects and fast-track their lookup Correctly name DeltaBaseCachestable-0.9
Matthias Sohn
15 years ago
committed by
Code Review
10 changed files with 402 additions and 192 deletions
@ -0,0 +1,195 @@
|
||||
/* |
||||
* Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> |
||||
* 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.lang.ref.SoftReference; |
||||
|
||||
class DeltaBaseCache { |
||||
private static final int CACHE_SZ = 1024; |
||||
|
||||
private static final SoftReference<Entry> DEAD; |
||||
|
||||
private static int hash(final long position) { |
||||
return (((int) position) << 22) >>> 22; |
||||
} |
||||
|
||||
private static int maxByteCount; |
||||
|
||||
private static final Slot[] cache; |
||||
|
||||
private static Slot lruHead; |
||||
|
||||
private static Slot lruTail; |
||||
|
||||
private static int openByteCount; |
||||
|
||||
static { |
||||
DEAD = new SoftReference<Entry>(null); |
||||
maxByteCount = new WindowCacheConfig().getDeltaBaseCacheLimit(); |
||||
|
||||
cache = new Slot[CACHE_SZ]; |
||||
for (int i = 0; i < CACHE_SZ; i++) |
||||
cache[i] = new Slot(); |
||||
} |
||||
|
||||
static synchronized void reconfigure(final WindowCacheConfig cfg) { |
||||
final int dbLimit = cfg.getDeltaBaseCacheLimit(); |
||||
if (maxByteCount != dbLimit) { |
||||
maxByteCount = dbLimit; |
||||
releaseMemory(); |
||||
} |
||||
} |
||||
|
||||
static synchronized Entry get(final PackFile pack, final long position) { |
||||
final Slot e = cache[hash(position)]; |
||||
if (e.provider == pack && e.position == position) { |
||||
final Entry buf = e.data.get(); |
||||
if (buf != null) { |
||||
moveToHead(e); |
||||
return buf; |
||||
} |
||||
} |
||||
return null; |
||||
} |
||||
|
||||
static synchronized void store(final PackFile pack, final long position, |
||||
final byte[] data, final int objectType) { |
||||
if (data.length > maxByteCount) |
||||
return; // Too large to cache.
|
||||
|
||||
final Slot e = cache[hash(position)]; |
||||
clearEntry(e); |
||||
|
||||
openByteCount += data.length; |
||||
releaseMemory(); |
||||
|
||||
e.provider = pack; |
||||
e.position = position; |
||||
e.sz = data.length; |
||||
e.data = new SoftReference<Entry>(new Entry(data, objectType)); |
||||
moveToHead(e); |
||||
} |
||||
|
||||
private static void releaseMemory() { |
||||
while (openByteCount > maxByteCount && lruTail != null) { |
||||
final Slot currOldest = lruTail; |
||||
final Slot nextOldest = currOldest.lruPrev; |
||||
|
||||
clearEntry(currOldest); |
||||
currOldest.lruPrev = null; |
||||
currOldest.lruNext = null; |
||||
|
||||
if (nextOldest == null) |
||||
lruHead = null; |
||||
else |
||||
nextOldest.lruNext = null; |
||||
lruTail = nextOldest; |
||||
} |
||||
} |
||||
|
||||
static synchronized void purge(final PackFile file) { |
||||
for (final Slot e : cache) { |
||||
if (e.provider == file) { |
||||
clearEntry(e); |
||||
unlink(e); |
||||
} |
||||
} |
||||
} |
||||
|
||||
private static void moveToHead(final Slot e) { |
||||
unlink(e); |
||||
e.lruPrev = null; |
||||
e.lruNext = lruHead; |
||||
if (lruHead != null) |
||||
lruHead.lruPrev = e; |
||||
else |
||||
lruTail = e; |
||||
lruHead = e; |
||||
} |
||||
|
||||
private static void unlink(final Slot e) { |
||||
final Slot prev = e.lruPrev; |
||||
final Slot next = e.lruNext; |
||||
if (prev != null) |
||||
prev.lruNext = next; |
||||
if (next != null) |
||||
next.lruPrev = prev; |
||||
} |
||||
|
||||
private static void clearEntry(final Slot e) { |
||||
openByteCount -= e.sz; |
||||
e.provider = null; |
||||
e.data = DEAD; |
||||
e.sz = 0; |
||||
} |
||||
|
||||
private DeltaBaseCache() { |
||||
throw new UnsupportedOperationException(); |
||||
} |
||||
|
||||
static class Entry { |
||||
final byte[] data; |
||||
|
||||
final int type; |
||||
|
||||
Entry(final byte[] aData, final int aType) { |
||||
data = aData; |
||||
type = aType; |
||||
} |
||||
} |
||||
|
||||
private static class Slot { |
||||
Slot lruPrev; |
||||
|
||||
Slot lruNext; |
||||
|
||||
PackFile provider; |
||||
|
||||
long position; |
||||
|
||||
int sz; |
||||
|
||||
SoftReference<Entry> data = DEAD; |
||||
} |
||||
} |
||||
Loading…
Reference in new issue