Bug 561086: [Resources] add method to calculate a hash over a file
added getChecksum()
Change-Id: Ic360708f687427394de6c62cbd59e5190406f58f
diff --git a/plugins/org.eclipse.ease.modules.platform/src/org/eclipse/ease/modules/platform/ResourcesModule.java b/plugins/org.eclipse.ease.modules.platform/src/org/eclipse/ease/modules/platform/ResourcesModule.java
index b6db65f..ae3257e 100644
--- a/plugins/org.eclipse.ease.modules.platform/src/org/eclipse/ease/modules/platform/ResourcesModule.java
+++ b/plugins/org.eclipse.ease.modules.platform/src/org/eclipse/ease/modules/platform/ResourcesModule.java
@@ -22,6 +22,9 @@
import java.nio.file.SimpleFileVisitor;
import java.nio.file.StandardCopyOption;
import java.nio.file.attribute.BasicFileAttributes;
+import java.security.DigestInputStream;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
@@ -1078,4 +1081,50 @@
return targetDirectory;
}
+
+ /**
+ * Get an MD5 checksum over a readable resource.
+ *
+ * @param location
+ * location of resource to create checksum for
+ * @return file hash as hex encoded string
+ * @throws NoSuchAlgorithmException
+ * when MD5 digest cannot be found
+ * @throws IOException
+ * when resource cannot be read
+ */
+ @WrapToScript
+ public String getChecksum(Object location) throws NoSuchAlgorithmException, IOException {
+ final Object resolvedLocation = ResourceTools.resolve(location, getScriptEngine().getExecutedFile());
+ try (InputStream input = ResourceTools.getInputStream(resolvedLocation)) {
+ if (input != null) {
+ final MessageDigest digest = MessageDigest.getInstance("MD5");
+ final DigestInputStream digestInputStream = new DigestInputStream(input, digest);
+
+ final byte[] buffer = new byte[8 * 1024];
+ int readBytes;
+ do {
+ readBytes = digestInputStream.read(buffer);
+ } while (readBytes > 0);
+
+ return byteArrayToHexString(digest.digest());
+ }
+
+ throw new IOException("Location \"" + location + "\" cannot be accessed.");
+ }
+ }
+
+ private String byteArrayToHexString(byte[] bytes) {
+ final StringBuilder builder = new StringBuilder();
+
+ for (final byte b : bytes) {
+ final String token = Integer.toHexString(b);
+ if (token.length() == 1)
+ builder.append('0');
+
+ builder.append(token.substring(Math.max(token.length() - 2, 0)));
+ }
+
+ return builder.toString();
+ }
}
