| /* |
| * 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.storage.dht; |
| |
| import java.io.IOException; |
| |
| import org.eclipse.jgit.lib.AnyObjectId; |
| import org.eclipse.jgit.lib.ObjectLoader; |
| import org.eclipse.jgit.storage.dht.DhtReader.ChunkAndOffset; |
| import org.eclipse.jgit.storage.dht.RefDataUtil.IdWithChunk; |
| |
| final class RecentChunks { |
| private final DhtReader reader; |
| |
| private final DhtReader.Statistics stats; |
| |
| private final int maxSize; |
| |
| private int curSize; |
| |
| private Node lruHead; |
| |
| private Node lruTail; |
| |
| RecentChunks(DhtReader reader) { |
| this.reader = reader; |
| this.stats = reader.getStatistics(); |
| this.maxSize = reader.getOptions().getRecentChunkCacheSize(); |
| } |
| |
| PackChunk get(ChunkKey key) { |
| for (Node n = lruHead; n != null; n = n.next) { |
| if (key.equals(n.chunk.getChunkKey())) { |
| hit(n); |
| stats.recentChunks_Hits++; |
| return n.chunk; |
| } |
| } |
| stats.recentChunks_Miss++; |
| return null; |
| } |
| |
| void put(PackChunk chunk) { |
| for (Node n = lruHead; n != null; n = n.next) { |
| if (n.chunk == chunk) { |
| hit(n); |
| return; |
| } |
| } |
| |
| Node n; |
| if (curSize < maxSize) { |
| n = new Node(); |
| curSize++; |
| } else { |
| n = lruTail; |
| } |
| n.chunk = chunk; |
| hit(n); |
| } |
| |
| ObjectLoader open(RepositoryKey repo, AnyObjectId objId, int typeHint) |
| throws IOException { |
| if (objId instanceof IdWithChunk) { |
| PackChunk chunk = get(((IdWithChunk) objId).getChunkKey()); |
| if (chunk != null) { |
| int pos = chunk.findOffset(repo, objId); |
| if (0 <= pos) |
| return PackChunk.read(chunk, pos, reader, typeHint); |
| } |
| |
| // IdWithChunk is only a hint, and can be wrong. Locally |
| // searching is faster than looking in the Database. |
| } |
| |
| for (Node n = lruHead; n != null; n = n.next) { |
| int pos = n.chunk.findOffset(repo, objId); |
| if (0 <= pos) { |
| hit(n); |
| stats.recentChunks_Hits++; |
| return PackChunk.read(n.chunk, pos, reader, typeHint); |
| } |
| } |
| |
| return null; |
| } |
| |
| ChunkAndOffset find(RepositoryKey repo, AnyObjectId objId) { |
| if (objId instanceof IdWithChunk) { |
| PackChunk chunk = get(((IdWithChunk) objId).getChunkKey()); |
| if (chunk != null) { |
| int pos = chunk.findOffset(repo, objId); |
| if (0 <= pos) |
| return new ChunkAndOffset(chunk, pos); |
| } |
| |
| // IdWithChunk is only a hint, and can be wrong. Locally |
| // searching is faster than looking in the Database. |
| } |
| |
| for (Node n = lruHead; n != null; n = n.next) { |
| int pos = n.chunk.findOffset(repo, objId); |
| if (0 <= pos) { |
| hit(n); |
| stats.recentChunks_Hits++; |
| return new ChunkAndOffset(n.chunk, pos); |
| } |
| } |
| |
| return null; |
| } |
| |
| boolean has(RepositoryKey repo, AnyObjectId objId) { |
| for (Node n = lruHead; n != null; n = n.next) { |
| int pos = n.chunk.findOffset(repo, objId); |
| if (0 <= pos) { |
| hit(n); |
| stats.recentChunks_Hits++; |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| void clear() { |
| curSize = 0; |
| lruHead = null; |
| lruTail = null; |
| } |
| |
| private void hit(Node n) { |
| if (lruHead != n) { |
| remove(n); |
| first(n); |
| } |
| } |
| |
| private void remove(Node node) { |
| Node p = node.prev; |
| Node n = node.next; |
| |
| if (p != null) |
| p.next = n; |
| if (n != null) |
| n.prev = p; |
| |
| if (lruHead == node) |
| lruHead = n; |
| if (lruTail == node) |
| lruTail = p; |
| } |
| |
| private void first(Node node) { |
| Node h = lruHead; |
| |
| node.prev = null; |
| node.next = h; |
| |
| if (h != null) |
| h.prev = node; |
| else |
| lruTail = node; |
| |
| lruHead = node; |
| } |
| |
| private static class Node { |
| PackChunk chunk; |
| |
| Node prev; |
| |
| Node next; |
| } |
| } |