X-Git-Url: https://git.argeo.org/?a=blobdiff_plain;f=org.argeo.cms%2Fsrc%2Forg%2Fargeo%2Fcms%2Futil%2FDirH.java;fp=org.argeo.cms%2Fsrc%2Forg%2Fargeo%2Fcms%2Futil%2FDirH.java;h=2596c61d1ae934220f34cc852e384c00acd61082;hb=54df376a9c2dd458a82eaa09bfbb718fe699dd0d;hp=0000000000000000000000000000000000000000;hpb=3c1cdc594d954520b14646102b366290bdad58c7;p=lgpl%2Fargeo-commons.git

diff --git a/org.argeo.cms/src/org/argeo/cms/util/DirH.java b/org.argeo.cms/src/org/argeo/cms/util/DirH.java
new file mode 100644
index 000000000..2596c61d1
--- /dev/null
+++ b/org.argeo.cms/src/org/argeo/cms/util/DirH.java
@@ -0,0 +1,116 @@
+package org.argeo.cms.util;
+
+import java.io.IOException;
+import java.io.PrintStream;
+import java.nio.charset.Charset;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/** Hashes the hashes of the files in a directory. */
+public class DirH {
+
+	private final static Charset charset = Charset.forName("UTF-16");
+	private final static long bufferSize = 200 * 1024 * 1024;
+	private final static String algorithm = "SHA";
+
+	private final static byte EOL = (byte) '\n';
+	private final static byte SPACE = (byte) ' ';
+
+	private final int hashSize;
+
+	private final byte[][] hashes;
+	private final byte[][] fileNames;
+	private final byte[] digest;
+	private final byte[] dirName;
+
+	/**
+	 * @param dirName can be null or empty
+	 */
+	private DirH(byte[][] hashes, byte[][] fileNames, byte[] dirName) {
+		if (hashes.length != fileNames.length)
+			throw new IllegalArgumentException(hashes.length + " hashes and " + fileNames.length + " file names");
+		this.hashes = hashes;
+		this.fileNames = fileNames;
+		this.dirName = dirName == null ? new byte[0] : dirName;
+		if (hashes.length == 0) {// empty dir
+			hashSize = 20;
+			// FIXME what is the digest of an empty dir?
+			digest = new byte[hashSize];
+			Arrays.fill(digest, SPACE);
+			return;
+		}
+		hashSize = hashes[0].length;
+		for (int i = 0; i < hashes.length; i++) {
+			if (hashes[i].length != hashSize)
+				throw new IllegalArgumentException(
+						"Hash size for " + new String(fileNames[i], charset) + " is " + hashes[i].length);
+		}
+
+		try {
+			MessageDigest md = MessageDigest.getInstance(algorithm);
+			for (int i = 0; i < hashes.length; i++) {
+				md.update(this.hashes[i]);
+				md.update(SPACE);
+				md.update(this.fileNames[i]);
+				md.update(EOL);
+			}
+			digest = md.digest();
+		} catch (NoSuchAlgorithmException e) {
+			throw new IllegalArgumentException("Cannot digest", e);
+		}
+	}
+
+	public void print(PrintStream out) {
+		out.print(DigestUtils.toHexString(digest));
+		if (dirName.length > 0) {
+			out.print(' ');
+			out.print(new String(dirName, charset));
+		}
+		out.print('\n');
+		for (int i = 0; i < hashes.length; i++) {
+			out.print(DigestUtils.toHexString(hashes[i]));
+			out.print(' ');
+			out.print(new String(fileNames[i], charset));
+			out.print('\n');
+		}
+	}
+
+	public static DirH digest(Path dir) {
+		try (DirectoryStream<Path> files = Files.newDirectoryStream(dir)) {
+			List<byte[]> hs = new ArrayList<byte[]>();
+			List<String> fNames = new ArrayList<>();
+			for (Path file : files) {
+				if (!Files.isDirectory(file)) {
+					byte[] digest = DigestUtils.digestAsBytes(algorithm, file, bufferSize);
+					hs.add(digest);
+					fNames.add(file.getFileName().toString());
+				}
+			}
+
+			byte[][] fileNames = new byte[fNames.size()][];
+			for (int i = 0; i < fNames.size(); i++) {
+				fileNames[i] = fNames.get(i).getBytes(charset);
+			}
+			byte[][] hashes = hs.toArray(new byte[hs.size()][]);
+			return new DirH(hashes, fileNames, dir.toString().getBytes(charset));
+		} catch (IOException e) {
+			throw new RuntimeException("Cannot digest " + dir, e);
+		}
+	}
+
+	public static void main(String[] args) {
+		try {
+			DirH dirH = DirH.digest(Paths.get("/home/mbaudier/tmp/"));
+			dirH.print(System.out);
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+}