RefTreeNames.java

/*
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package org.eclipse.jgit.internal.storage.reftree;

import org.eclipse.jgit.lib.RefDatabase;

/**
 * Magic reference name logic for RefTrees.
 */
public class RefTreeNames {
    /**
     * Suffix used on a {@link RefTreeDatabase#getTxnNamespace()} for user data.
     * <p>
     * A {@link RefTreeDatabase}'s namespace may include a subspace (e.g.
     * {@code "refs/txn/stage/"}) containing commit objects from the usual user
     * portion of the repository (e.g. {@code "refs/heads/"}). These should be
     * packed by the garbage collector alongside other user content rather than
     * with the RefTree.
     */
    private static final String STAGE = "stage/"; //$NON-NLS-1$

    /**
     * Determine if the reference is likely to be a RefTree.
     *
     * @param refdb
     *            database instance.
     * @param ref
     *            reference name.
     * @return {@code true} if the reference is a RefTree.
     */
    public static boolean isRefTree(RefDatabase refdb, String ref) {
        if (refdb instanceof RefTreeDatabase) {
            RefTreeDatabase b = (RefTreeDatabase) refdb;
            if (ref.equals(b.getTxnCommitted())) {
                return true;
            }

            String namespace = b.getTxnNamespace();
            if (namespace != null
                    && ref.startsWith(namespace)
                    && !ref.startsWith(namespace + STAGE)) {
                return true;
            }
        }
        return false;
    }

    private RefTreeNames() {
    }
}