Check whether the "INBOX" folder has the "noinferiors" flag set before declaring that it accepts subfolder creation

OpenChange/MAPIStoreMailFolder.m

@@ -53,6 +53,7 @@
 #import "MAPIStoreMailMessageTable.h"
 #import "MAPIStoreMapping.h"
 #import "MAPIStoreTypes.h"
+#import "MAPIStoreUserContext.h"
 #import "NSData+MAPIStore.h"
 #import "NSString+MAPIStore.h"
 #import "SOGoMAPIDBMessage.h"
@@ -408,7 +409,18 @@ static Class SOGoMailFolderK, MAPIStoreMailFolderK, MAPIStoreOutboxFolderK;
 
 - (BOOL) supportsSubFolders
 {
-  return YES;
+  BOOL supportsSubFolders;
+  MAPIStoreUserContext *userContext;
+
+  if ([[self nameInContainer] isEqualToString: @"folderINBOX"])
+    {
+      userContext = [self userContext];
+      supportsSubFolders = ![userContext inboxHasNoInferiors];
+    }
+  else
+    supportsSubFolders = YES;
+  
+  return supportsSubFolders;
 }
 
 /* synchronisation */

OpenChange/MAPIStoreUserContext.h

@@ -58,6 +58,8 @@
 
   WOContext *woContext;
   MAPIStoreAuthenticator *authenticator;
+
+  BOOL inboxHasNoInferiors;
 }
 
 + (id) userContextWithUsername: (NSString *) username
@@ -75,6 +77,8 @@
 
 - (NSDictionary *) rootFolders;
 
+- (BOOL) inboxHasNoInferiors;
+
 - (NSURL *) folderTableURL;
 - (MAPIStoreMapping *) mapping;
 

OpenChange/MAPIStoreUserContext.m

@@ -206,6 +206,9 @@ static NSMapTable *contextsTable = nil;
 {
   SOGoMailAccounts *accountsFolder;
   id currentFolder;
+  NGImap4Connection *connection;
+  NSDictionary *hierarchy;
+  NSArray *flags;
 
   if (!rootFolders)
     {
@@ -236,17 +239,32 @@ static NSMapTable *contextsTable = nil;
       [containersBag addObject: accountsFolder];
       [woContext setClientObject: accountsFolder];
       currentFolder = [accountsFolder lookupName: @"0"
-                                  inContext: woContext
-                                    acquire: NO];
+                                       inContext: woContext
+                                         acquire: NO];
+
       [rootFolders setObject: currentFolder
                       forKey: @"mail"];
-      [[currentFolder imap4Connection]
-        enableExtensions: [NSArray arrayWithObject: @"QRESYNC"]];
+      connection = [currentFolder imap4Connection];
+      [connection enableExtensions: [NSArray arrayWithObject: @"QRESYNC"]];
+
+      /* ensure the folder cache is filled */
+      [currentFolder toManyRelationshipKeysWithNamespaces: YES];
+      hierarchy = [connection
+                    cachedHierarchyResultsForURL: [currentFolder imap4URL]];
+      flags = [[hierarchy  objectForKey: @"list"] objectForKey: @"/INBOX"];
+      inboxHasNoInferiors = [flags containsObject: @"noinferiors"];
     }
 
   return rootFolders;
 }
 
+- (BOOL) inboxHasNoInferiors
+{
+  [self rootFolders];
+
+  return inboxHasNoInferiors;
+}
+
 - (MAPIStoreMapping *) mapping
 {
   return mapping;