1 files changed, 65 insertions, 0 deletions
diff --git a/src/main/java/com/keuin/kbackupfabric/backup/incremental/serializer/IncBackupInfoSerializer.java b/src/main/java/com/keuin/kbackupfabric/backup/incremental/serializer/IncBackupInfoSerializer.java
new file mode 100644
index 0000000..45590ba
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/backup/incremental/serializer/IncBackupInfoSerializer.java
@@ -0,0 +1,65 @@
+package com.keuin.kbackupfabric.backup.incremental.serializer;
+
+import com.keuin.kbackupfabric.backup.incremental.ObjectCollection2;
+import com.keuin.kbackupfabric.backup.incremental.ObjectCollectionConverter;
+import com.keuin.kbackupfabric.backup.name.BackupFileNameEncoder;
+import com.keuin.kbackupfabric.backup.name.IncrementalBackupFileNameEncoder;
+import com.keuin.kbackupfabric.util.backup.incremental.ObjectCollection;
+
+import java.io.*;
+import java.util.Objects;
+
+public class IncBackupInfoSerializer {
+    /**
+     * Load incremental backup index file into object, no matter what version it is.
+     *
+     * @param file a valid incremental backup file. (with a valid file name)
+     * @return the object. Not null.
+     * @throws IOException when failed due to an I/O error.
+     */
+    public static SavedIncrementalBackup fromFile(File file) throws IOException {
+        Objects.requireNonNull(file);
+        try (FileInputStream fileInputStream = new FileInputStream(file)) {
+            try (ObjectInputStream objectInputStream = new ObjectInputStream(fileInputStream)) {
+                Object o = objectInputStream.readObject();
+                if (o instanceof SavedIncrementalBackup) {
+                    return (SavedIncrementalBackup) o;
+                } else if (o instanceof ObjectCollection) {
+                    // backward compatibility with old-style (v0) incremental backup
+                    BackupFileNameEncoder.BackupBasicInformation info = new IncrementalBackupFileNameEncoder().decode(file.getName());
+                    if (info == null)
+                        throw new IOException("Invalid backup file name.");
+                    return new SavedIncBackupV0(ObjectCollectionConverter.convert((ObjectCollection) o), info);
+                } else if (o instanceof ObjectCollection2) {
+                    // compatible with 1.4.6 implementation
+                    BackupFileNameEncoder.BackupBasicInformation info = new IncrementalBackupFileNameEncoder().decode(file.getName());
+                    if (info == null)
+                        throw new IOException("Invalid backup file name.");
+                    return new SavedIncBackupV0((ObjectCollection2) o, info);
+                } else {
+                    throw new RuntimeException("Unrecognized backup file format: unknown class " + o.getClass().getCanonicalName());
+                }
+            } catch (ClassNotFoundException e) {
+                // this should not happen
+                throw new RuntimeException(e);
+            }
+        }
+    }
+
+    /**
+     * Save incremental backup index and metadata into file.
+     *
+     * @param file   the file.
+     * @param backup the backup.
+     * @throws IOException when failed due to an I/O error.
+     */
+    public static void toFile(File file, SavedIncrementalBackup backup) throws IOException {
+        Objects.requireNonNull(file);
+        Objects.requireNonNull(backup);
+        try (FileOutputStream fileOutputStream = new FileOutputStream(file)) {
+            try (ObjectOutputStream objectOutputStream = new ObjectOutputStream(fileOutputStream)) {
+                objectOutputStream.writeObject(backup);
+            }
+        }
+    }
+}