Fix #327 save to previous database version when conditions are required

app/src/main/java/com/kunzisoft/keepass/database/element/PwDatabase.kt

@@ -296,6 +296,8 @@ abstract class PwDatabase<Group : PwGroup<*, Group, Entry>, Entry : PwEntry<Grou
 
     abstract fun rootCanContainsEntry(): Boolean
 
+    abstract fun containsCustomData(): Boolean
+
     fun addGroupTo(newGroup: Group, parent: Group?) {
         // Add tree to parent tree
         parent?.addChildGroup(newGroup)

app/src/main/java/com/kunzisoft/keepass/database/element/PwDatabaseV3.kt

@@ -154,6 +154,10 @@ class PwDatabaseV3 : PwDatabase<PwGroupV3, PwEntryV3>() {
         return false
     }
 
+    override fun containsCustomData(): Boolean {
+        return false
+    }
+
     override fun isBackup(group: PwGroupV3): Boolean {
         var currentGroup: PwGroupV3? = group
         while (currentGroup != null) {

app/src/main/java/com/kunzisoft/keepass/database/element/PwDatabaseV4.kt

@@ -196,6 +196,10 @@ class PwDatabaseV4 : PwDatabase<PwGroupV4, PwEntryV4> {
         this.customData[label] = value
     }
 
+    override fun containsCustomData(): Boolean {
+        return getCustomData().isNotEmpty()
+    }
+
     @Throws(InvalidKeyFileException::class, IOException::class)
     public override fun getMasterKey(key: String?, keyInputStream: InputStream?): ByteArray {
 

app/src/main/java/com/kunzisoft/keepass/database/element/PwEntryV4.kt

@@ -26,7 +26,7 @@ import com.kunzisoft.keepass.database.element.security.ProtectedString
 import com.kunzisoft.keepass.utils.MemoryUtil
 import java.util.*
 
-class PwEntryV4 : PwEntry<PwGroupV4, PwEntryV4>, NodeV4Interface {
+class PwEntryV4 : PwEntry<PwGroupV4, PwEntryV4>, PwNodeV4Interface {
 
     // To decode each field not parcelable
     @Transient
@@ -275,12 +275,12 @@ class PwEntryV4 : PwEntry<PwGroupV4, PwEntryV4>, NodeV4Interface {
         return history.size
     }
 
-    fun putCustomData(key: String, value: String) {
+    override fun putCustomData(key: String, value: String) {
         customData[key] = value
     }
 
-    fun containsCustomData(): Boolean {
+    override fun containsCustomData(): Boolean {
-        return customData.size > 0
+        return customData.isNotEmpty()
     }
 
     fun addEntryToHistory(entry: PwEntryV4) {

app/src/main/java/com/kunzisoft/keepass/database/element/PwGroupV4.kt

@@ -25,7 +25,7 @@ import android.os.Parcelable
 import java.util.HashMap
 import java.util.UUID
 
-class PwGroupV4 : PwGroup<UUID, PwGroupV4, PwEntryV4>, NodeV4Interface {
+class PwGroupV4 : PwGroup<UUID, PwGroupV4, PwEntryV4>, PwNodeV4Interface {
 
     // TODO Encapsulate
     override var icon: PwIcon
@@ -123,12 +123,12 @@ class PwGroupV4 : PwGroup<UUID, PwGroupV4, PwEntryV4>, NodeV4Interface {
         locationChanged = PwDate()
     }
 
-    fun putCustomData(key: String, value: String) {
+    override fun putCustomData(key: String, value: String) {
         customData[key] = value
     }
 
-    fun containsCustomData(): Boolean {
+    override fun containsCustomData(): Boolean {
-        return customData.size > 0
+        return customData.isNotEmpty()
     }
 
     override fun allowAddEntryIfIsRoot(): Boolean {

app/src/main/java/com/kunzisoft/keepass/database/element/PwNodeV4Interface.kt

@@ -19,10 +19,14 @@
  */
 package com.kunzisoft.keepass.database.element
 
-interface NodeV4Interface : NodeTimeInterface {
+interface PwNodeV4Interface : NodeTimeInterface {
 
     var usageCount: Long
 
     var locationChanged: PwDate
 
+    fun putCustomData(key: String, value: String)
+
+    fun containsCustomData(): Boolean
+
 }

app/src/main/java/com/kunzisoft/keepass/database/file/PwDbHeaderV4.kt

@@ -23,7 +23,11 @@ import com.kunzisoft.keepass.crypto.CrsAlgorithm
 import com.kunzisoft.keepass.crypto.keyDerivation.AesKdf
 import com.kunzisoft.keepass.crypto.keyDerivation.KdfFactory
 import com.kunzisoft.keepass.crypto.keyDerivation.KdfParameters
+import com.kunzisoft.keepass.database.NodeHandler
+import com.kunzisoft.keepass.database.element.PwNodeV4Interface
 import com.kunzisoft.keepass.database.element.PwDatabaseV4
+import com.kunzisoft.keepass.database.element.PwEntryV4
+import com.kunzisoft.keepass.database.element.PwGroupV4
 import com.kunzisoft.keepass.database.exception.InvalidDBVersionException
 import com.kunzisoft.keepass.stream.CopyInputStream
 import com.kunzisoft.keepass.stream.HmacBlockStream
@@ -88,18 +92,42 @@ class PwDbHeaderV4(private val databaseV4: PwDatabaseV4) : PwDbHeader() {
         this.masterSeed = ByteArray(32)
     }
 
+    private inner class NodeHasCustomData<T:PwNodeV4Interface> : NodeHandler<T>() {
+
+        internal var containsCustomData = false
+
+        override fun operate(node: T): Boolean {
+            if (node.containsCustomData()) {
+                containsCustomData = true
+                return false
+            }
+            return true
+        }
+    }
+
     private fun getMinKdbxVersion(databaseV4: PwDatabaseV4): Long {
+        // https://keepass.info/help/kb/kdbx_4.html
+
+        // Return v4 if AES is not use
+        if (databaseV4.kdfParameters != null
+                && databaseV4.kdfParameters!!.uuid != AesKdf.CIPHER_UUID) {
+            return FILE_VERSION_32_4
+        }
+
         if (databaseV4.rootGroup == null) {
             return FILE_VERSION_32_3
         }
 
-        // Return v4 if AES is not use
+        val entryHandler = NodeHasCustomData<PwEntryV4>()
-        if (databaseV4.kdfParameters != null && databaseV4.kdfParameters!!.uuid != AesKdf.CIPHER_UUID) {
+        val groupHandler = NodeHasCustomData<PwGroupV4>()
-            return FILE_VERSION_32_4
+        databaseV4.rootGroup?.doForEachChildAndForIt(entryHandler, groupHandler)
+        return if (databaseV4.containsCustomData()
+                    || entryHandler.containsCustomData
+                    || groupHandler.containsCustomData) {
+            FILE_VERSION_32_4
+        } else {
+            FILE_VERSION_32_3
         }
-
-        // Return V4 by default
-        return FILE_VERSION_32_4
     }
 
     /** Assumes the input stream is at the beginning of the .kdbx file

app/src/main/java/com/kunzisoft/keepass/database/file/load/ImporterV4.kt

@@ -577,12 +577,12 @@ class ImporterV4(private val streamDir: File) : Importer<PwDatabaseV4>() {
             }
 
             KdbContext.GroupTimes, KdbContext.EntryTimes -> {
-                val tl: NodeV4Interface?
+                val tl: PwNodeV4Interface? =
-                if (ctx == KdbContext.GroupTimes) {
+                        if (ctx == KdbContext.GroupTimes) {
-                    tl = ctxGroup
+                            ctxGroup
-                } else {
+                        } else {
-                    tl = ctxEntry
+                            ctxEntry
-                }
+                        }
 
                 when {
                     name.equals(PwDatabaseV4XML.ElemLastModTime, ignoreCase = true) -> tl?.lastModificationTime = readPwTime(xpp)

app/src/main/java/com/kunzisoft/keepass/database/file/save/PwDbV4Output.kt

@@ -653,7 +653,7 @@ class PwDbV4Output(private val mDatabaseV4: PwDatabaseV4, outputStream: OutputSt
     }
 
     @Throws(IllegalArgumentException::class, IllegalStateException::class, IOException::class)
-    private fun writeList(name: String?, it: NodeV4Interface) {
+    private fun writeList(name: String?, it: PwNodeV4Interface) {
         assert(name != null)
 
         xml.startTag(null, name)