Clean old incremental backup codes.

2 files changed, 83 insertions, 0 deletions

diff --git a/src/main/java/com/keuin/kbackupfabric/util/backup/name/BackupFileNameEncoder.java b/src/main/java/com/keuin/kbackupfabric/util/backup/name/BackupFileNameEncoder.java
new file mode 100644
index 0000000..83967b7
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/util/backup/name/BackupFileNameEncoder.java
@@ -0,0 +1,49 @@
+package com.keuin.kbackupfabric.util.backup.name;
+
+import java.time.LocalDateTime;
+
+/**
+ * Encode and decode backup file name for a specific backup type.
+ */
+public interface BackupFileNameEncoder {
+
+    /**
+     * Construct full backup file name from custom name and creation time.
+     * @param customName the custom name. If the custom name contains invalid chars, an exception will be thrown.
+     * @param time the creation time.
+     * @return the file name.
+     */
+    String encode(String customName, LocalDateTime time);
+
+    /**
+     * Extract custom and backup time from backup file name.
+     * @param fileName the backup file name.
+     * @return the information. If the given file name is invalid, return null.
+     */
+    BackupBasicInformation decode(String fileName);
+
+    /**
+     * Check if the given string is a valid custom backup name.
+     * @param customName the custom backup name.
+     * @return if the name is valid.
+     */
+    default boolean isValidCustomName(String customName) {
+        final char[] ILLEGAL_CHARACTERS = {'/', '\n', '\r', '\t', '\0', '\f', '`', '?', '*', '\\', '<', '>', '|', '\"', ':'};
+        for (char c : ILLEGAL_CHARACTERS) {
+            if (customName.contains(String.valueOf(c))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    class BackupBasicInformation {
+        public final String customName;
+        public final LocalDateTime time;
+
+        BackupBasicInformation(String customName, LocalDateTime time) {
+            this.customName = customName;
+            this.time = time;
+        }
+    }
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/util/backup/name/PrimitiveBackupFileNameEncoder.java b/src/main/java/com/keuin/kbackupfabric/util/backup/name/PrimitiveBackupFileNameEncoder.java
new file mode 100644
index 0000000..39c2403
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/util/backup/name/PrimitiveBackupFileNameEncoder.java
@@ -0,0 +1,34 @@
+package com.keuin.kbackupfabric.util.backup.name;
+
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class PrimitiveBackupFileNameEncoder implements BackupFileNameEncoder {
+
+    private static final String backupFileNamePrefix = "kbackup";
+    private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd_HH-mm-ss");
+
+    @Override
+    public String encode(String customName, LocalDateTime time) {
+        if (!isValidCustomName(customName))
+            throw new IllegalArgumentException("Invalid custom name");
+        String timeString = time.format(formatter);
+        return backupFileNamePrefix + "-" + timeString + "_" + customName + ".zip";
+    }
+
+    @Override
+    public BackupBasicInformation decode(String fileName) {
+        Pattern pattern = Pattern.compile(
+                backupFileNamePrefix + "-" + "([0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{2}-[0-9]{2}-[0-9]{2})_(.+)\\.zip"
+        );
+        Matcher matcher = pattern.matcher(fileName);
+        if (matcher.find()) {
+            String timeString = matcher.group(1);
+            String customName = matcher.group(2);
+            return new BackupBasicInformation(customName, LocalDateTime.parse(timeString, formatter));
+        }
+        return null;
+    }
+}