LargePackedWholeObject.java

/*
 * Copyright (C) 2010, Google Inc. and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.eclipse.jgit.internal.storage.dfs;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.InflaterInputStream;

import org.eclipse.jgit.errors.LargeObjectException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.ObjectStream;

final class LargePackedWholeObject extends ObjectLoader {
    private final int type;

    private final long size;

    private final long objectOffset;

    private final int headerLength;

    private final DfsPackFile pack;

    private final DfsObjDatabase db;

    LargePackedWholeObject(int type, long size, long objectOffset,
            int headerLength, DfsPackFile pack, DfsObjDatabase db) {
        this.type = type;
        this.size = size;
        this.objectOffset = objectOffset;
        this.headerLength = headerLength;
        this.pack = pack;
        this.db = db;
    }

    /** {@inheritDoc} */
    @Override
    public int getType() {
        return type;
    }

    /** {@inheritDoc} */
    @Override
    public long getSize() {
        return size;
    }

    /** {@inheritDoc} */
    @Override
    public boolean isLarge() {
        return true;
    }

    /** {@inheritDoc} */
    @Override
    public byte[] getCachedBytes() throws LargeObjectException {
        throw new LargeObjectException();
    }

    /** {@inheritDoc} */
    @Override
    public ObjectStream openStream() throws MissingObjectException, IOException {
        PackInputStream packIn;
        // ctx is closed by PackInputStream, or explicitly in the finally block
        DfsReader ctx = db.newReader();
        try {
            try {
                packIn = new PackInputStream(
                        pack, objectOffset + headerLength, ctx);
                ctx = null; // owned by packIn
            } catch (IOException packGone) {
                // If the pack file cannot be pinned into the cursor, it
                // probably was repacked recently. Go find the object
                // again and open the stream from that location instead.
                ObjectId obj = pack.getReverseIdx(ctx).findObject(objectOffset);
                return ctx.open(obj, type).openStream();
            }
        } finally {
            if (ctx != null) {
                ctx.close();
            }
        }

        // Align buffer to inflater size, at a larger than default block.
        // This reduces the number of context switches from the
        // caller down into the pack stream inflation.
        int bufsz = 8192;
        InputStream in = new BufferedInputStream(
                new InflaterInputStream(packIn, packIn.ctx.inflater(), bufsz),
                bufsz);
        return new ObjectStream.Filter(type, size, in);
    }
}