Avoided OutOfMemoryError in MD5 calculation of big files

src/main/java/it/inaf/ia2/transfer/service/PutFileService.java

@@ -12,7 +12,10 @@ import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UncheckedIOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
 import java.nio.file.Files;
+import java.nio.file.StandardOpenOption;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Objects;
@@ -126,14 +129,14 @@ public class PutFileService {
                 LOG.warn("Destination file {} size mismatch with source", destinationFile.toPath().toString());
             }
 
-            if (sourceFileInfo.getContentType() != null && 
-                    !sourceFileInfo.getContentType().equals(destinationFileInfo.getContentType())) {
+            if (sourceFileInfo.getContentType() != null
+                    && !sourceFileInfo.getContentType().equals(destinationFileInfo.getContentType())) {
                 LOG.warn("Destination file {} content type mismatch with source {} {}", destinationFile.toPath().toString(),
                         destinationFileInfo.getContentType(), sourceFileInfo.getContentType());
             }
 
-            if (sourceFileInfo.getContentMd5() != null && 
-                    !sourceFileInfo.getContentMd5().equals(md5Checksum)) {
+            if (sourceFileInfo.getContentMd5() != null
+                    && !sourceFileInfo.getContentMd5().equals(md5Checksum)) {
                 LOG.warn("Destination file {} md5 mismatch with source {} {}", destinationFile.toPath().toString(),
                         destinationFileInfo.getContentMd5(), sourceFileInfo.getContentMd5());
             }
@@ -189,7 +192,27 @@ public class PutFileService {
 
     private String makeMD5Checksum(File file) throws NoSuchAlgorithmException, IOException {
         MessageDigest md = MessageDigest.getInstance("MD5");
-        md.update(Files.readAllBytes(file.toPath()));
+
+        // We can't update the MessageDigest object in a single step using
+        // Files.readAllBytes because we want to handle also big files and that
+        // method loads all the content in memory (OutOfMemoryError has been
+        // noticed for files bigger than 1GB). So multiple updates using
+        // FileChannel and ByteBuffer are used
+        try (FileChannel channel = FileChannel.open(file.toPath(), StandardOpenOption.READ)) {
+            // creating buffer (by default it is in write mode). FileChannel will write into buffer
+            ByteBuffer buffer = ByteBuffer.allocate(1024);
+            int bytesRead;
+            while ((bytesRead = channel.read(buffer)) != -1) {
+                if (bytesRead > 0) {
+                    // switch from write to read mode
+                    buffer.flip();
+                    md.update(buffer);
+                }
+                // using rewind the buffer can be filled again
+                buffer.rewind();
+            }
+        }
+
         byte[] digest = md.digest();
         String checksum = DatatypeConverter.printHexBinary(digest);
         return checksum;

src/test/java/it/inaf/ia2/transfer/controller/PutFileControllerTest.java

@@ -25,6 +25,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.eq;
 import org.mockito.Mockito;
 import static org.mockito.Mockito.mock;
@@ -92,6 +93,9 @@ public class PutFileControllerTest {
 
         assertTrue(file.exists());
         assertEquals("content", Files.contentOf(file, StandardCharsets.UTF_8));
+
+        verify(fileDao, times(1)).updateFileAttributes(anyInt(), eq("text/plain"), any(), eq(7l), eq("9A0364B9E99BB480DD25E1F0284C8555"));
+
         assertTrue(file.delete());
     }