add support for transactional upload

src/java/JavaFileStorage/app/src/main/java/keepass2android/javafilestorage/WebDavStorage.java

@@ -1,6 +1,7 @@
 package keepass2android.javafilestorage;
 
 import android.content.Context;
+import java.math.BigInteger;
 import android.content.Intent;
 
 import android.net.Uri;
@@ -27,6 +28,7 @@ import java.security.KeyManagementException;
 import java.security.KeyStore;
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Date;
@@ -194,11 +196,73 @@ public class WebDavStorage extends JavaFileStorageBase {
         return client;
     }
 
+    public void renameOrMoveWebDavResource(String sourcePath, String destinationPath, boolean overwrite) throws Exception {
+
+        ConnectionInfo sourceCi = splitStringToConnectionInfo(sourcePath);
+        ConnectionInfo destinationCi = splitStringToConnectionInfo(destinationPath);
+
+        Request.Builder requestBuilder = new Request.Builder()
+                .url(new URL(sourceCi.URL))
+                .method("MOVE", null) // "MOVE" is the HTTP method
+                .header("Destination", destinationCi.URL); // New URI for the resource
+
+        // Add Overwrite header
+        if (overwrite) {
+            requestBuilder.header("Overwrite", "T"); // 'T' for true
+        } else {
+            requestBuilder.header("Overwrite", "F"); // 'F' for false
+        }
+
+        Request request = requestBuilder.build();
+
+        Response response = getClient(sourceCi).newCall(request).execute();
+
+        // Check the status code
+        if (response.isSuccessful()) {
+            // WebDAV MOVE can return 201 (Created) if a new resource was created at dest,
+            // or 204 (No Content) if moved to a pre-existing destination (e.g., just renamed).
+            // A 200 OK might also be returned by some servers, though 201/204 are more common.
+
+        }
+        else
+        {
+            throw new Exception("Rename/Move failed for " + sourceCi.URL + " to " + destinationCi.URL + ": " + response.code() + " " + response.message());
+        }
+    }
+
+    public static String generateRandomHexString(int length) {
+        SecureRandom secureRandom = new SecureRandom();
+        // Generate enough bytes to ensure we can get the desired number of hex characters.
+        // Each byte converts to two hex characters.
+        // For 8 hex characters, we need 4 bytes.
+        int numBytes = (int) Math.ceil(length / 2.0);
+        byte[] randomBytes = new byte[numBytes];
+        secureRandom.nextBytes(randomBytes);
+
+        // Convert the byte array to a hexadecimal string
+        // BigInteger(1, randomBytes) treats the byte array as a positive number.
+        // toString(16) converts it to a hexadecimal string.
+        String hexString = new BigInteger(1, randomBytes).toString(16);
+
+        // Pad with leading zeros if necessary (e.g., if the generated number is small)
+        // and then take the first 'length' characters.
+        // Using String.format to ensure leading zeros if the hexString is shorter.
+        return String.format("%0" + length + "d", new BigInteger(hexString, 16)).substring(0, length);
+    }
 
     @Override
     public void uploadFile(String path, byte[] data, boolean writeTransactional)
             throws Exception {
 
+        if (writeTransactional)
+        {
+            String randomSuffix = ".tmp." + generateRandomHexString(8);
+            uploadFile(path + randomSuffix, data, false);
+            renameOrMoveWebDavResource(path+randomSuffix, path, true);
+            return;
+        }
+
+
         try {
             ConnectionInfo ci = splitStringToConnectionInfo(path);
 
@@ -245,8 +309,6 @@ public class WebDavStorage extends JavaFileStorageBase {
                     .build();
 
 
-            //TODO consider writeTransactional
-            //TODO check for error
 
             Response response = getClient(ci).newCall(request).execute();
             checkStatus(response);

src/java/JavaFileStorageTest-AS/app/src/main/java/com/crocoapps/javafilestoragetest2/MainActivity.java

@@ -548,7 +548,7 @@ public class MainActivity extends Activity implements JavaFileStorage.FileStorag
 
 
 		//storageToTest = new GoogleDriveAppDataFileStorage();
-		/*storageToTest = new WebDavStorage(new ICertificateErrorHandler() {
+		storageToTest = new WebDavStorage(new ICertificateErrorHandler() {
 			@Override
 			public boolean onValidationError(String error) {
 				return false;
@@ -558,12 +558,12 @@ public class MainActivity extends Activity implements JavaFileStorage.FileStorag
 			public boolean alwaysFailOnValidationError() {
 				return false;
 			}
-		});
-*/
+		}, 64*1024);
+
 		//storageToTest =  new DropboxV2Storage(ctx,"4ybka4p4a1027n6", "1z5lv528un9nre8", !simulateRestart);
 		//storageToTest =  new DropboxFileStorage(ctx,"4ybka4p4a1027n6", "1z5lv528un9nre8", !simulateRestart);
 		//storageToTest = new DropboxAppFolderFileStorage(ctx,"ax0268uydp1ya57", "3s86datjhkihwyc", true);
-		storageToTest = new GoogleDriveFullFileStorage();
+		// storageToTest = new GoogleDriveFullFileStorage();
 
 
 		return storageToTest;