Add GitIdentifiers helper

src/main/java/org/apache/commons/codec/digest/DigestUtils.java

@@ -18,24 +18,17 @@
 package org.apache.commons.codec.digest;
 
 import java.io.BufferedInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.RandomAccessFile;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
-import java.nio.charset.StandardCharsets;
-import java.nio.file.DirectoryStream;
 import java.nio.file.Files;
 import java.nio.file.OpenOption;
 import java.nio.file.Path;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
-import java.util.TreeSet;
 
 import org.apache.commons.codec.binary.Hex;
 import org.apache.commons.codec.binary.StringUtils;
@@ -191,26 +184,6 @@ public static MessageDigest getDigest(final String algorithm, final MessageDiges
         }
     }
 
-    /**
-     * Returns the {@link GitDirectoryEntry.Type} of a file.
-     *
-     * @param path The file to check.
-     * @return A {@link GitDirectoryEntry.Type}
-     */
-    private static GitDirectoryEntry.Type getGitDirectoryEntryType(final Path path) {
-        // Symbolic links first
-        if (Files.isSymbolicLink(path)) {
-            return GitDirectoryEntry.Type.SYMBOLIC_LINK;
-        }
-        if (Files.isDirectory(path)) {
-            return GitDirectoryEntry.Type.DIRECTORY;
-        }
-        if (Files.isExecutable(path)) {
-            return GitDirectoryEntry.Type.EXECUTABLE;
-        }
-        return GitDirectoryEntry.Type.REGULAR;
-    }
-
     /**
      * Gets an MD2 MessageDigest.
      *
@@ -407,123 +380,6 @@ public static MessageDigest getShake256_512Digest() {
         return getDigest(MessageDigestAlgorithms.SHAKE256_512);
     }
 
-    /**
-     * Reads through a byte array and return a generalized Git blob identifier.
-     *
-     * <p>The identifier is computed in the way described by the
-     * <a href="https://www.swhid.org/swhid-specification/v1.2/5.Core_identifiers/#52-contents">SWHID contents identifier</a>, but it can use any hash
-     * algorithm.</p>
-     *
-     * <p>When the hash algorithm is SHA-1, the identifier is identical to Git blob identifier and SWHID contents identifier.</p>
-     *
-     * @param messageDigest The MessageDigest to use (for example SHA-1).
-     * @param data          Data to digest.
-     * @return A generalized Git blob identifier.
-     * @since 1.22.0
-     */
-    public static byte[] gitBlob(final MessageDigest messageDigest, final byte[] data) {
-        messageDigest.reset();
-        updateDigest(messageDigest, gitBlobPrefix(data.length));
-        return digest(messageDigest, data);
-    }
-
-    /**
-     * Reads through a byte array and return a generalized Git blob identifier.
-     *
-     * <p>The identifier is computed in the way described by the
-     * <a href="https://www.swhid.org/swhid-specification/v1.2/5.Core_identifiers/#52-contents">SWHID contents identifier</a>, but it can use any hash
-     * algorithm.</p>
-     *
-     * <p>When the hash algorithm is SHA-1, the identifier is identical to Git blob identifier and SWHID contents identifier.</p>
-     *
-     * @param messageDigest The MessageDigest to use (for example SHA-1).
-     * @param data          Data to digest.
-     * @param options       Options how to open the file.
-     * @return A generalized Git blob identifier.
-     * @throws IOException On error accessing the file.
-     * @since 1.22.0
-     */
-    public static byte[] gitBlob(final MessageDigest messageDigest, final Path data, final OpenOption... options) throws IOException {
-        messageDigest.reset();
-        if (Files.isSymbolicLink(data)) {
-            final byte[] linkTarget = Files.readSymbolicLink(data).toString().getBytes(StandardCharsets.UTF_8);
-            updateDigest(messageDigest, gitBlobPrefix(linkTarget.length));
-            return digest(messageDigest, linkTarget);
-        }
-        updateDigest(messageDigest, gitBlobPrefix(Files.size(data)));
-        return updateDigest(messageDigest, data, options).digest();
-    }
-
-    private static byte[] gitBlobPrefix(final long dataSize) {
-        return gitPrefix("blob ", dataSize);
-    }
-
-    private static byte[] gitPrefix(final String prefix, final long dataSize) {
-        return (prefix + dataSize + "\0").getBytes(StandardCharsets.UTF_8);
-    }
-
-    /**
-     * Returns a generalized Git tree identifier.
-     *
-     * <p>The identifier is computed in the way described by the
-     * <a href="https://www.swhid.org/swhid-specification/v1.2/5.Core_identifiers/#53-directories">SWHID directory identifier</a>, but it can use any hash
-     * algorithm.</p>
-     *
-     * <p>When the hash algorithm is SHA-1, the identifier is identical to Git tree identifier and SWHID directory identifier.</p>
-     *
-     * @param messageDigest The MessageDigest to use (for example SHA-1).
-     * @param entries       The directory entries.
-     * @return A generalized Git tree identifier.
-     */
-    static byte[] gitTree(final MessageDigest messageDigest, final Collection<GitDirectoryEntry> entries) {
-        final TreeSet<GitDirectoryEntry> treeSet = new TreeSet<>(entries);
-        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        for (final GitDirectoryEntry entry : treeSet) {
-            final byte[] treeEntryBytes = entry.toTreeEntryBytes();
-            baos.write(treeEntryBytes, 0, treeEntryBytes.length);
-        }
-        messageDigest.reset();
-        updateDigest(messageDigest, gitTreePrefix(baos.size()));
-        return updateDigest(messageDigest, baos.toByteArray()).digest();
-    }
-
-    /**
-     * Reads through a byte array and return a generalized Git tree identifier.
-     *
-     * <p>The identifier is computed in the way described by the
-     * <a href="https://www.swhid.org/swhid-specification/v1.2/5.Core_identifiers/#53-directories">SWHID directory identifier</a>, but it can use any hash
-     * algorithm.</p>
-     *
-     * <p>When the hash algorithm is SHA-1, the identifier is identical to Git tree identifier and SWHID directory identifier.</p>
-     *
-     * @param messageDigest The MessageDigest to use (for example SHA-1).
-     * @param data          Data to digest.
-     * @param options       Options how to open the file.
-     * @return A generalized Git tree identifier.
-     * @throws IOException On error accessing the file.
-     * @since 1.22.0
-     */
-    public static byte[] gitTree(final MessageDigest messageDigest, final Path data, final OpenOption... options) throws IOException {
-        final List<GitDirectoryEntry> entries = new ArrayList<>();
-        try (DirectoryStream<Path> files = Files.newDirectoryStream(data)) {
-            for (final Path path : files) {
-                final GitDirectoryEntry.Type type = getGitDirectoryEntryType(path);
-                final byte[] rawObjectId;
-                if (type == GitDirectoryEntry.Type.DIRECTORY) {
-                    rawObjectId = gitTree(messageDigest, path, options);
-                } else {
-                    rawObjectId = gitBlob(messageDigest, path, options);
-                }
-                entries.add(new GitDirectoryEntry(path, type, rawObjectId));
-            }
-        }
-        return gitTree(messageDigest, entries);
-    }
-
-    private static byte[] gitTreePrefix(final long dataSize) {
-        return gitPrefix("tree ", dataSize);
-    }
-
     /**
      * Test whether the algorithm is supported.
      *