package org.eclipse.jgit.storage.dfs;
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicInteger;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Ref.Storage;
import org.eclipse.jgit.util.RefList;
/**
* Git repository stored entirely in the local process memory.
* <p>
* This implementation builds on the DFS repository by storing all reference and
* object data in the local process. It is not very efficient and exists only
* for unit testing and small experiments.
* <p>
* The repository is thread-safe. Memory used is released only when this object
* is garbage collected. Closing the repository has no impact on its memory.
*/
public class InMemoryRepository extends DfsRepository {
private final DfsObjDatabase objdb;
private final DfsRefDatabase refdb;
/**
* Initialize a new in-memory repository.
*
* @param repoDesc
* description of the repository.
*/
public InMemoryRepository(DfsRepository repoDesc) {
super(new DfsRepositoryBuilder<DfsRepositoryBuilder, InMemoryRepository>() {
@Override
public InMemoryRepository build() throws IOException {
throw new UnsupportedOperationException();
}
});
objdb = new MemObjDatabase(this);
refdb = new MemRefDatabase();
}
@Override
public DfsObjDatabase getObjectDatabase() {
return objdb;
}
@Override
public DfsRefDatabase getRefDatabase() {
return refdb;
}
private class MemObjDatabase extends DfsObjDatabase {
private final AtomicInteger packId = new AtomicInteger();
private List<DfsPackDescription> packs = new ArrayList<DfsPackDescription>();
MemObjDatabase(DfsRepository repo) {
super(repo, new DfsReaderOptions());
}
@Override
protected synchronized List<DfsPackDescription> listPacks() {
return packs;
}
@Override
protected DfsPackDescription newPack(PackSource source) {
int id = packId.incrementAndGet();
return new MemPack("pack-" + id + "-" + source.name(),
getRepository().getDescription());
}
@Override
protected synchronized void commitPackImpl(
Collection<DfsPackDescription> desc,
Collection<DfsPackDescription> replace) {
List<DfsPackDescription> n;
n = new ArrayList<DfsPackDescription>(desc.size() + packs.size());
n.addAll(desc);
n.addAll(packs);
if (replace != null)
n.removeAll(replace);
packs = n;
}
@Override
protected void rollbackPack(Collection<DfsPackDescription> desc) {
// Do nothing. Pack is not recorded until commitPack.
}
@Override
protected ReadableChannel openPackFile(DfsPackDescription desc)
throws FileNotFoundException {
MemPack memPack = (MemPack) desc;
if (memPack.packFile == null)
throw new FileNotFoundException(desc.getPackName());
return new ByteArrayReadableChannel(memPack.packFile);
}
@Override
protected ReadableChannel openPackIndex(DfsPackDescription desc)
throws FileNotFoundException {
MemPack memPack = (MemPack) desc;
if (memPack.packIndex == null)
throw new FileNotFoundException(desc.getIndexName());
return new ByteArrayReadableChannel(memPack.packIndex);
}
@Override
protected DfsOutputStream writePackFile(DfsPackDescription desc) {
final MemPack memPack = (MemPack) desc;
return new Out() {
@Override
public void flush() {
memPack.packFile = getData();
}
};
}
@Override
protected DfsOutputStream writePackIndex(DfsPackDescription desc) {
final MemPack memPack = (MemPack) desc;
return new Out() {
@Override
public void flush() {
memPack.packIndex = getData();
}
};
}
}
private static class MemPack extends DfsPackDescription {
private byte[] packFile;
private byte[] packIndex;
MemPack(String name, DfsRepositoryDescription repoDesc) {
super(repoDesc, name);
}
}
private abstract static class Out extends DfsOutputStream {
private final ByteArrayOutputStream dst = new ByteArrayOutputStream();
private byte[] data;
@Override
public void write(byte[] buf, int off, int len) {
data = null;
dst.write(buf, off, len);
}
@Override
public int read(long position, ByteBuffer buf) {
byte[] d = getData();
int n = Math.min(buf.remaining(), d.length - (int) position);
if (n == 0)
return -1;
buf.put(d, (int) position, n);
return n;
}
byte[] getData() {
if (data == null)
data = dst.toByteArray();
return data;
}
@Override
public abstract void flush();
@Override
public void close() {
flush();
}
}
private static class ByteArrayReadableChannel implements ReadableChannel {
private final byte[] data;
private int position;
private boolean open = true;
ByteArrayReadableChannel(byte[] buf) {
data = buf;
}
public int read(ByteBuffer dst) {
int n = Math.min(dst.remaining(), data.length - position);
if (n == 0)
return -1;
dst.put(data, position, n);
position += n;
return n;
}
public void close() {
open = false;
}
public boolean isOpen() {
return open;
}
public long position() {
return position;
}
public void position(long newPosition) {
position = (int) newPosition;
}
public long size() {
return data.length;
}
public int blockSize() {
return 0;
}
}
private class MemRefDatabase extends DfsRefDatabase {
private final ConcurrentMap<String, Ref> refs = new ConcurrentHashMap<String, Ref>();
MemRefDatabase() {
super(InMemoryRepository.this);
}
@Override
protected RefCache scanAllRefs() throws IOException {
RefList.Builder<Ref> ids = new RefList.Builder<Ref>();
RefList.Builder<Ref> sym = new RefList.Builder<Ref>();
for (Ref ref : refs.values()) {
if (ref.isSymbolic())
sym.add(ref);
ids.add(ref);
}
ids.sort();
sym.sort();
return new RefCache(ids.toRefList(), sym.toRefList());
}
@Override
protected boolean compareAndPut(Ref oldRef, Ref newRef)
throws IOException {
String name = newRef.getName();
if (oldRef == null || oldRef.getStorage() == Storage.NEW)
return refs.putIfAbsent(name, newRef) == null;
Ref cur = refs.get(name);
if (cur != null && eq(cur, oldRef))
return refs.replace(name, cur, newRef);
else
return false;
}
@Override
protected boolean compareAndRemove(Ref oldRef) throws IOException {
String name = oldRef.getName();
Ref cur = refs.get(name);
if (cur != null && eq(cur, oldRef))
return refs.remove(name, cur);
else
return false;
}
private boolean eq(Ref a, Ref b) {
if (a.getObjectId() == null && b.getObjectId() == null)
return true;
if (a.getObjectId() != null)
return a.getObjectId().equals(b.getObjectId());
return false;
}
}
}