Edit new file names

When a new file or folder is added, its new (generic) label is right put into an editing state right away.

Fixes #12

Author: mchakravarty

NavigatorDemo/ContentView.swift

@@ -70,8 +70,14 @@ struct FolderContextMenu: View {
     Button {
       withAnimation {
         let newFile = FileOrFolder<File<Payload>, Payload>(file: File(contents: Payload(text: "")))
-        viewContext.add(item: newFile, $to: $folder, withPreferredName: "Text.txt")
-        viewContext.viewState.selection = newFile.id
+        if let newName = viewContext.add(item: newFile, $to: $folder, withPreferredName: "Text.txt") {
+
+          viewContext.viewState.selection = newFile.id
+          Task { @MainActor in
+            viewContext.viewState.editedLabel = FileNavigatorViewState.EditedLabel(id: newFile.id, text: newName)
+          }
+
+        }
       }
     } label: {
       Label("New file", systemImage: "doc.badge.plus")
@@ -80,8 +86,14 @@ struct FolderContextMenu: View {
     Button {
       withAnimation {
         let newFolder = FileOrFolder<File<Payload>, Payload>(folder: Folder(children: [:]))
-        viewContext.add(item: newFolder, $to: $folder, withPreferredName: "Folder")
-        viewContext.viewState.selection = newFolder.id
+        if let newName = viewContext.add(item: newFolder, $to: $folder, withPreferredName: "Folder") {
+
+          viewContext.viewState.selection = newFolder.id
+          Task { @MainActor in
+            viewContext.viewState.editedLabel = FileNavigatorViewState.EditedLabel(id: newFolder.id, text: newName)
+          }
+
+        }
       }
     } label: {
       Label("New folder", systemImage: "folder.badge.plus")
@@ -267,10 +279,10 @@ struct Navigator: View {
                   // environment. Hence, the SwiftUI document system is not informed of changes to the text by the
                   // `TextEditor`. As a consequence, (auto)saving does not work.
                   //
-                  // The following codes works around this issues by explicitly registering text changes with the undo
-                  // manager provided by the SwiftUI document system. This is only a work around and not a proper solution
-                  // as it will also undo changes made to the text outside of the `TextEditor`. (This is not a problem
-                  // in this little demo app.)
+                  // The following code works around this issues by explicitly registering text changes with the undo
+                  // manager provided by the SwiftUI document system. This is only a work around and not a proper
+                  // solution as it will also undo changes made to the text outside of the `TextEditor`. (This is not a
+                  // problem in this little demo app, but generally not desirable.)
                   undoManager?.registerUndo(withTarget: model) { [weak undoManager] _ in
                     $text.wrappedValue = oldValue
                     changeByUndoManager =  true

NavigatorDemo/ViewContext.swift

@@ -69,16 +69,22 @@ extension ViewContext {
   ///   - item: The item to add.
   ///   - to: The folder to which the item is to be added.
   ///   - preferredName: The preferred name of the given item.
+  /// - Returns:If successful, the actual name under which the item was added.
   ///
   ///   If the preferred name is already taken, an alternative name, derived from the preferred name, will be used.
   ///
   ///   If needed the dominant folder is being refreshed accordingly.
   ///
-  func add(item: FullFileOrFolder<Payload>, @Binding to folder: ProxyFolder<Payload>, withPreferredName preferredName: String) {
-
-    registerUndo {
-      folder.add(item: item, withPreferredName: preferredName)
+  @discardableResult
+  func add(item: FullFileOrFolder<Payload>,
+           @Binding to folder: ProxyFolder<Payload>,
+           withPreferredName preferredName: String)
+  -> String?
+  {
+    return registerUndo {
+      let newName = folder.add(item: item, withPreferredName: preferredName)
       viewState.refreshDominantFolder(updatedFolder: Binding($folder))
+      return newName
     }
   }
 
@@ -106,19 +112,20 @@ extension ViewContext {
   ///
   /// During undo, register a redo in a symmetric manner.
   ///
-  private func registerUndo(action: () -> Void) {
+  private func registerUndo<Result>(action: () -> Result) -> Result {
 
     // Preserve old value for undo
     let oldTextsCopy = FileTree<Payload>(fileTree: model.document.texts)
 
     // Perform action
-    action()
+    let result = action()
 
     // Register undoing the change
     undoManager?.registerUndo(withTarget: model) { ourModel in
       registerUndo {
         ourModel.document.texts.set(to: oldTextsCopy)
       }
     }
+    return result
   }
 }

Sources/Files/FileOperations.swift

@@ -23,19 +23,22 @@ extension Folder {
   ///       100 attempts, the item will not be inserted.
   ///   - index: Optional index at which to insert the new item into the ordered set of children. If no index is given,
   ///       the new child will be added at the first position where it fits alphabetically.
+  /// - Returns:If successful, the name under which the item was added.
   ///
   /// This function only works on folders in proxy trees. (It would be easy to provide a corresponding version on
   /// folders containing full files.)
   ///
+  @discardableResult
   public mutating func add(item: FullFileOrFolder<Contents>,
                            withPreferredName preferredName: String,
                            at index: Int? = nil)
+  -> String?
   where FileType == File<Contents>.Proxy
   {
     // Folders in proxy tree must have a file tree set.
     guard let fileTree else {
       logger.error("Folder.add(item:withPreferredName:at:) in a proxy tree without having a file tree set")
-      return
+      return nil
     }
 
     let ext  = (preferredName as NSString).pathExtension,
@@ -67,6 +70,7 @@ extension Folder {
                              // ...in case the caller passes an out of range index
 
     }
+    return finalName
   }
 
   /// Remove the item with the given name from the a folder.