/*
* 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
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*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
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* - 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.
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package org.eclipse.jgit.storage.dht;
import java.io.IOException;
import java.text.MessageFormat;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.eclipse.jgit.generated.storage.dht.proto.GitStore.CachedPackInfo;
import org.eclipse.jgit.generated.storage.dht.proto.GitStore.CachedPackInfo.ChunkList;
import org.eclipse.jgit.generated.storage.dht.proto.GitStore.ChunkMeta;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.storage.pack.CachedPack;
import org.eclipse.jgit.storage.pack.ObjectToPack;
import org.eclipse.jgit.storage.pack.PackOutputStream;
import org.eclipse.jgit.storage.pack.StoredObjectRepresentation;
/** A cached pack stored by the DHT. */
public class DhtCachedPack extends CachedPack {
private final CachedPackInfo info;
private Set<ObjectId> tips;
private Set<ChunkKey> keySet;
private ChunkKey[] keyList;
DhtCachedPack(CachedPackInfo info) {
this.info = info;
}
@Override
public Set<ObjectId> getTips() {
if (tips == null) {
tips = new HashSet<ObjectId>();
for (String idString : info.getTipList().getObjectNameList())
tips.add(ObjectId.fromString(idString));
tips = Collections.unmodifiableSet(tips);
}
return tips;
}
@Override
public long getObjectCount() {
return info.getObjectsTotal();
}
@Override
public long getDeltaCount() throws IOException {
return info.getObjectsDelta();
}
/** @return information describing this cached pack. */
public CachedPackInfo getCachedPackInfo() {
return info;
}
@Override
public boolean hasObject(ObjectToPack obj, StoredObjectRepresentation rep) {
DhtObjectRepresentation objrep = (DhtObjectRepresentation) rep;
if (keySet == null)
init();
return keySet.contains(objrep.getChunkKey());
}
private void init() {
ChunkList chunkList = info.getChunkList();
int cnt = chunkList.getChunkKeyCount();
keySet = new HashSet<ChunkKey>();
keyList = new ChunkKey[cnt];
for (int i = 0; i < cnt; i++) {
ChunkKey key = ChunkKey.fromString(chunkList.getChunkKey(i));
keySet.add(key);
keyList[i] = key;
}
}
void copyAsIs(PackOutputStream out, boolean validate, DhtReader ctx)
throws IOException {
if (keyList == null)
init();
// Clear the recent chunks because all of the reader's
// chunk limit should be made available for prefetch.
int cacheLimit = ctx.getOptions().getChunkLimit();
ctx.getRecentChunks().setMaxBytes(0);
try {
Prefetcher p = new Prefetcher(ctx, 0, cacheLimit);
p.push(Arrays.asList(keyList));
copyPack(out, p, validate);
} finally {
ctx.getRecentChunks().setMaxBytes(cacheLimit);
}
}
private void copyPack(PackOutputStream out, Prefetcher prefetcher,
boolean validate) throws DhtException, DhtMissingChunkException,
IOException {
Map<String, Long> startsAt = new HashMap<String, Long>();
for (ChunkKey key : keyList) {
PackChunk chunk = prefetcher.get(key);
// The prefetcher should always produce the chunk for us, if not
// there is something seriously wrong with the ordering or
// within the prefetcher code and aborting is more sane than
// using slow synchronous lookups.
//
if (chunk == null)
throw new DhtMissingChunkException(key);
// Verify each long OFS_DELTA chunk appears at the right offset.
// This is a cheap validation that the cached pack hasn't been
// incorrectly created and would confuse the client.
//
long position = out.length();
ChunkMeta meta = chunk.getMeta();
if (meta != null && meta.getBaseChunkCount() != 0) {
for (ChunkMeta.BaseChunk base : meta.getBaseChunkList()) {
Long act = startsAt.get(base.getChunkKey());
long exp = position - base.getRelativeStart();
if (act == null) {
throw new DhtException(MessageFormat.format(DhtText
.get().wrongChunkPositionInCachedPack,
rowKey(), base.getChunkKey(),
"[not written]", key, Long.valueOf(exp)));
}
if (act.longValue() != exp) {
throw new DhtException(MessageFormat.format(DhtText
.get().wrongChunkPositionInCachedPack,
rowKey(), base.getChunkKey(),
act, key, Long.valueOf(exp)));
}
}
}
startsAt.put(key.asString(), Long.valueOf(position));
chunk.copyEntireChunkAsIs(out, null, validate);
}
}
private String rowKey() {
return info.getName() + "." + info.getVersion();
}
}