StoredObjectRepresentation.java

/*
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 * 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
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 * without modification, are permitted provided that the following
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 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
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package org.eclipse.jgit.internal.storage.pack;

import org.eclipse.jgit.lib.ObjectId;

/**
 * An object representation
 * {@link org.eclipse.jgit.internal.storage.pack.PackWriter} can consider for
 * packing.
 */
public class StoredObjectRepresentation {
    /** Special unknown value for {@link #getWeight()}. */
    public static final int WEIGHT_UNKNOWN = Integer.MAX_VALUE;

    /** Stored in pack format, as a delta to another object. */
    public static final int PACK_DELTA = 0;

    /** Stored in pack format, without delta. */
    public static final int PACK_WHOLE = 1;

    /** Only available after inflating to canonical format. */
    public static final int FORMAT_OTHER = 2;

    /**
     * Get relative size of this object's packed form.
     *
     * @return relative size of this object's packed form. The special value
     *         {@link #WEIGHT_UNKNOWN} can be returned to indicate the
     *         implementation doesn't know, or cannot supply the weight up
     *         front.
     */
    public int getWeight() {
        return WEIGHT_UNKNOWN;
    }

    /**
     * Get the storage format type
     *
     * @return the storage format type, which must be one of
     *         {@link #PACK_DELTA}, {@link #PACK_WHOLE}, or
     *         {@link #FORMAT_OTHER}.
     */
    public int getFormat() {
        return FORMAT_OTHER;
    }

    /**
     * Get identity of the object this delta applies to in order to recover the
     * original object content.
     *
     * @return identity of the object this delta applies to in order to recover
     *         the original object content. This method should only be called if
     *         {@link #getFormat()} returned {@link #PACK_DELTA}.
     */
    public ObjectId getDeltaBase() {
        return null;
    }

    /**
     * Whether the current representation of the object has had delta
     * compression attempted on it.
     *
     * @return whether the current representation of the object has had delta
     *         compression attempted on it.
     */
    public boolean wasDeltaAttempted() {
        int fmt = getFormat();
        return fmt == PACK_DELTA || fmt == PACK_WHOLE;
    }
}