refactor: Replace MayFail by Result

packages/moxxmpp/lib/moxxmpp.dart

@@ -25,12 +25,12 @@ export 'package:moxxmpp/src/presence.dart';
 export 'package:moxxmpp/src/reconnect.dart';
 export 'package:moxxmpp/src/rfcs/rfc_2782.dart';
 export 'package:moxxmpp/src/rfcs/rfc_4790.dart';
-export 'package:moxxmpp/src/roster.dart';
+export 'package:moxxmpp/src/roster/errors.dart';
+export 'package:moxxmpp/src/roster/roster.dart';
 export 'package:moxxmpp/src/settings.dart';
 export 'package:moxxmpp/src/socket.dart';
 export 'package:moxxmpp/src/stanza.dart';
 export 'package:moxxmpp/src/stringxml.dart';
-export 'package:moxxmpp/src/types/error.dart';
 export 'package:moxxmpp/src/types/result.dart';
 export 'package:moxxmpp/src/xeps/staging/extensible_file_thumbnails.dart';
 export 'package:moxxmpp/src/xeps/staging/file_upload_notification.dart';
@@ -61,7 +61,8 @@ export 'package:moxxmpp/src/xeps/xep_0333.dart';
 export 'package:moxxmpp/src/xeps/xep_0334.dart';
 export 'package:moxxmpp/src/xeps/xep_0352.dart';
 export 'package:moxxmpp/src/xeps/xep_0359.dart';
-export 'package:moxxmpp/src/xeps/xep_0363.dart';
+export 'package:moxxmpp/src/xeps/xep_0363/errors.dart';
+export 'package:moxxmpp/src/xeps/xep_0363/xep_0363.dart';
 export 'package:moxxmpp/src/xeps/xep_0380.dart';
 export 'package:moxxmpp/src/xeps/xep_0384/crypto.dart';
 export 'package:moxxmpp/src/xeps/xep_0384/errors.dart';

packages/moxxmpp/lib/src/connection.dart

@@ -15,7 +15,7 @@ import 'package:moxxmpp/src/negotiators/namespaces.dart';
 import 'package:moxxmpp/src/negotiators/negotiator.dart';
 import 'package:moxxmpp/src/presence.dart';
 import 'package:moxxmpp/src/reconnect.dart';
-import 'package:moxxmpp/src/roster.dart';
+import 'package:moxxmpp/src/roster/roster.dart';
 import 'package:moxxmpp/src/routing.dart';
 import 'package:moxxmpp/src/settings.dart';
 import 'package:moxxmpp/src/socket.dart';

packages/moxxmpp/lib/src/roster/errors.dart

@@ -0,0 +1,7 @@
+abstract class RosterError {}
+
+/// Returned when the server's response did not contain a <query /> element
+class NoQueryError extends RosterError {}
+
+/// Unspecified error
+class UnknownError extends RosterError {}

packages/moxxmpp/lib/src/roster/roster.dart

@@ -7,16 +7,12 @@ import 'package:moxxmpp/src/managers/namespaces.dart';
 import 'package:moxxmpp/src/namespaces.dart';
 import 'package:moxxmpp/src/negotiators/namespaces.dart';
 import 'package:moxxmpp/src/negotiators/negotiator.dart';
+import 'package:moxxmpp/src/roster/errors.dart';
 import 'package:moxxmpp/src/stanza.dart';
 import 'package:moxxmpp/src/stringxml.dart';
-import 'package:moxxmpp/src/types/error.dart';
 import 'package:moxxmpp/src/types/result.dart';
 
-const rosterErrorNoQuery = 1;
-const rosterErrorNonResult = 2;
-
 class XmppRosterItem {
-
   XmppRosterItem({ required this.jid, required this.subscription, this.ask, this.name, this.groups = const [] });
   final String jid;
   final String? name;
@@ -32,14 +28,12 @@ enum RosterRemovalResult {
 }
 
 class RosterRequestResult {
-
   RosterRequestResult({ required this.items, this.ver });
   List<XmppRosterItem> items;
   String? ver;
 }
 
 class RosterPushEvent extends XmppEvent {
-
   RosterPushEvent({ required this.item, this.ver });
   final XmppRosterItem item;
   final String? ver;
@@ -149,7 +143,7 @@ class RosterManager extends XmppManagerBase {
 
   /// Shared code between requesting rosters without and with roster versioning, if
   /// the server deems a regular roster response more efficient than n roster pushes.
-  Future<MayFail<RosterRequestResult>> _handleRosterResponse(XMLNode? query) async {
+  Future<Result<RosterRequestResult, RosterError>> _handleRosterResponse(XMLNode? query) async {
     final List<XmppRosterItem> items;
     if (query != null) {
       items = query.children.map((item) => XmppRosterItem(
@@ -167,7 +161,7 @@ class RosterManager extends XmppManagerBase {
       }
     } else {
       logger.warning('Server response to roster request without roster versioning does not contain a <query /> element, while the type is not error. This violates RFC6121');
-      return MayFail.failure(rosterErrorNoQuery);
+      return Result(NoQueryError());
     }
 
     final ver = query.attributes['ver'] as String?;
@@ -176,7 +170,7 @@ class RosterManager extends XmppManagerBase {
       await commitLastRosterVersion(ver);
     }
     
-    return MayFail.success(
+    return Result(
       RosterRequestResult(
         items: items,
         ver: ver,
@@ -186,7 +180,7 @@ class RosterManager extends XmppManagerBase {
   }
   
   /// Requests the roster following RFC 6121 without using roster versioning.
-  Future<MayFail<RosterRequestResult>> requestRoster() async {
+  Future<Result<RosterRequestResult, RosterError>> requestRoster() async {
     final attrs = getAttributes();
     final response = await attrs.sendStanza(
       Stanza.iq(
@@ -202,7 +196,7 @@ class RosterManager extends XmppManagerBase {
 
     if (response.attributes['type'] != 'result') {
       logger.warning('Error requesting roster without roster versioning: ${response.toXml()}');
-      return MayFail.failure(rosterErrorNonResult);
+      return Result(UnknownError());
     }
 
     final query = response.firstTag('query', xmlns: rosterXmlns);
@@ -211,7 +205,7 @@ class RosterManager extends XmppManagerBase {
 
   /// Requests a series of roster pushes according to RFC6121. Requires that the server
   /// advertises urn:xmpp:features:rosterver in the stream features.
-  Future<MayFail<RosterRequestResult?>> requestRosterPushes() async {
+  Future<Result<RosterRequestResult?, RosterError>> requestRosterPushes() async {
     if (_rosterVersion == null) {
       await loadLastRosterVersion();
     }
@@ -234,7 +228,7 @@ class RosterManager extends XmppManagerBase {
 
     if (result.attributes['type'] != 'result') {
       logger.warning('Requesting roster pushes failed: ${result.toXml()}');
-      return MayFail.failure(rosterErrorNonResult);
+      return Result(UnknownError());
     }
 
     final query = result.firstTag('query', xmlns: rosterXmlns);

packages/moxxmpp/lib/src/types/error.dart

@@ -1,19 +0,0 @@
-/// A wrapper class that can be used to indicate that a function may return a valid
-/// instance of [T] but may also fail.
-/// The way [MayFail] is intended to be used to to have function specific - or application
-/// specific - error codes that can be either handled by code or be translated into a
-/// localised error message for the user.
-class MayFail<T> {
-
-  MayFail({ this.result, this.errorCode });
-  MayFail.success(this.result);
-  MayFail.failure(this.errorCode);
-  T? result;
-  int? errorCode;
-
-  bool isError() => result == null && errorCode != null;
-
-  T getValue() => result!;
-
-  int getErrorCode() => errorCode!;
-}

packages/moxxmpp/lib/src/xeps/xep_0363/errors.dart

@@ -0,0 +1,10 @@
+abstract class HttpFileUploadError {}
+
+/// Returned when we don't know what JID to ask for an upload slot
+class NoEntityKnownError extends HttpFileUploadError {}
+
+/// Returned when the file we want to upload is too big
+class FileTooBigError extends HttpFileUploadError {}
+
+/// Unspecified errors
+class UnknownHttpFileUploadError extends HttpFileUploadError {}

packages/moxxmpp/lib/src/xeps/xep_0363/xep_0363.dart

@@ -7,19 +7,15 @@ import 'package:moxxmpp/src/managers/namespaces.dart';
 import 'package:moxxmpp/src/namespaces.dart';
 import 'package:moxxmpp/src/stanza.dart';
 import 'package:moxxmpp/src/stringxml.dart';
-import 'package:moxxmpp/src/types/error.dart';
+import 'package:moxxmpp/src/types/result.dart';
 import 'package:moxxmpp/src/xeps/xep_0030/errors.dart';
 import 'package:moxxmpp/src/xeps/xep_0030/types.dart';
 import 'package:moxxmpp/src/xeps/xep_0030/xep_0030.dart';
-
-const errorNoUploadServer = 1;
-const errorFileTooBig = 2;
-const errorGeneric = 3;
+import 'package:moxxmpp/src/xeps/xep_0363/errors.dart';
 
 const allowedHTTPHeaders = [ 'authorization', 'cookie', 'expires' ];
 
 class HttpFileUploadSlot {
-
   const HttpFileUploadSlot(this.putUrl, this.getUrl, this.headers);
   final String putUrl;
   final String getUrl;
@@ -45,7 +41,6 @@ Map<String, String> prepareHeaders(Map<String, String> headers) {
 }
 
 class HttpFileUploadManager extends XmppManagerBase {
-
   HttpFileUploadManager() : _gotSupported = false, _supported = false, super();
   JID? _entityJid;
   int? _maxUploadSize;
@@ -119,17 +114,17 @@ class HttpFileUploadManager extends XmppManagerBase {
   /// the file's size in octets. [contentType] is optional and refers to the file's
   /// Mime type.
   /// Returns an [HttpFileUploadSlot] if the request was successful; null otherwise.
-  Future<MayFail<HttpFileUploadSlot>> requestUploadSlot(String filename, int filesize, { String? contentType }) async {
-    if (!(await isSupported())) return MayFail.failure(errorNoUploadServer);
+  Future<Result<HttpFileUploadSlot, HttpFileUploadError>> requestUploadSlot(String filename, int filesize, { String? contentType }) async {
+    if (!(await isSupported())) return Result(NoEntityKnownError());
 
     if (_entityJid == null) {
       logger.warning('Attempted to request HTTP File Upload slot but no entity is known to send this request to.');
-      return MayFail.failure(errorNoUploadServer);
+      return Result(NoEntityKnownError());
     }
 
     if (_maxUploadSize != null && filesize > _maxUploadSize!) {
       logger.warning('Attempted to request HTTP File Upload slot for a file that exceeds the filesize limit');
-      return MayFail.failure(errorFileTooBig);
+      return Result(FileTooBigError());
     }
     
     final attrs = getAttributes();
@@ -154,7 +149,7 @@ class HttpFileUploadManager extends XmppManagerBase {
     if (response.attributes['type']! != 'result') {
       logger.severe('Failed to request HTTP File Upload slot.');
       // TODO(Unknown): Be more precise
-      return MayFail.failure(errorGeneric);
+      return Result(UnknownHttpFileUploadError());
     }
 
     final slot = response.firstTag('slot', xmlns: httpFileUploadXmlns)!;
@@ -169,7 +164,7 @@ class HttpFileUploadManager extends XmppManagerBase {
       }),
     );
 
-    return MayFail.success(
+    return Result(
       HttpFileUploadSlot(
         putUrl,
         getUrl,

packages/moxxmpp/lib/src/xeps/xep_0384/xep_0384.dart

@@ -44,7 +44,6 @@ const _doNotEncryptList = [
 ];
 
 abstract class OmemoManager extends XmppManagerBase {
-
   OmemoManager() : _handlerLock = Lock(), _handlerFutures = {}, super();
 
   final Lock _handlerLock;