Remove event binding from code editors transformed to markdown cells

Author: krassowski

packages/jupyterlab-lsp/src/adapters/adapter.ts

@@ -96,6 +96,7 @@ export abstract class WidgetAdapter<T extends IDocumentWidget> {
   protected app: JupyterFrontEnd;
 
   public activeEditorChanged: Signal<WidgetAdapter<T>, IEditorChangedData>;
+  public editorRemoved: Signal<WidgetAdapter<T>, IEditorChangedData>;
   public update_finished: Promise<void>;
 
   /**
@@ -117,6 +118,7 @@ export abstract class WidgetAdapter<T extends IDocumentWidget> {
     this.connection_manager = extension.connection_manager;
     this.adapterConnected = new Signal(this);
     this.activeEditorChanged = new Signal(this);
+    this.editorRemoved = new Signal(this);
     this.adapters = new Map();
     this.status_message = new StatusMessage();
     this.isConnected = false;

packages/jupyterlab-lsp/src/adapters/notebook/notebook.ts

@@ -136,6 +136,42 @@ export class NotebookAdapter extends WidgetAdapter<NotebookPanel> {
     );
 
     this.widget.content.activeCellChanged.connect(this.activeCellChanged, this);
+    this.widget.model.cells.changed.connect((cells, change) => {
+      console.log(change);
+
+      if (change.type !== 'set') {
+        return;
+      }
+      let convertedToMarkdown = [];
+
+      if (change.newValues.length !== change.oldValues.length) {
+        // during conversion the cells should not get deleted nor added
+        return;
+      }
+
+      for (let i = 0; i < change.newValues.length; i++) {
+        if (
+          change.oldValues[i].type === 'code' &&
+          change.newValues[i].type === 'markdown'
+        ) {
+          convertedToMarkdown.push(change.newValues[i]);
+        }
+      }
+
+      for (let cellModel of convertedToMarkdown) {
+        let cellWidget = this.widget.content.widgets.find(
+          cell => cell.model.id === cellModel.id
+        );
+
+        // for practical purposes this editor got removed from our consideration;
+        // it might seem that we should instead look for the editor indicated by
+        // the oldValues[i] cellModel, but this one got already transferred to the
+        // markdown cell in newValues[i]
+        this.editorRemoved.emit({
+          editor: cellWidget.editor
+        });
+      }
+    });
   }
 
   get editors(): CodeEditor.IEditor[] {

packages/jupyterlab-lsp/src/virtual/codemirror_editor.ts

@@ -280,9 +280,15 @@ export class CodeMirrorVirtualEditor
     };
     this._event_wrappers.set([eventName, handler], wrapped_handler);
 
-    this.forEveryBlockEditor(cm_editor => {
-      cm_editor.on(eventName, wrapped_handler);
-    });
+    this.forEveryBlockEditor(
+      cm_editor => {
+        cm_editor.on(eventName, wrapped_handler);
+      },
+      true,
+      cm_editor => {
+        cm_editor.off(eventName, wrapped_handler);
+      }
+    );
   }
 
   off(eventName: string, handler: CodeMirrorHandler, ...args: any[]): void {
@@ -496,20 +502,17 @@ export class CodeMirrorVirtualEditor
     return 0;
   }
 
-  addEventListener(type: string, listener: EventListenerOrEventListenerObject) {
-    this.forEveryBlockEditor(cm_editor => {
-      cm_editor.getWrapperElement().addEventListener(type, listener);
-    });
-  }
-
   forEveryBlockEditor(
     callback: (cm_editor: CodeMirror.Editor) => any,
-    monitor_for_new_blocks = true
+    monitor_for_new_blocks = true,
+    on_editor_removed_callback: (cm_editor: CodeMirror.Editor) => any = null
   ) {
     const editors_with_handlers = new Set<CodeMirror.Editor>();
 
-    // TODO... the need of iterating over all editors is universal. How does the virtual
-    //  editor gets knowledge of the editor instances? From the adapter obviously.
+    // TODO... the need of iterating over all editors is universal - so this could be
+    //  generalised to the VirtualEditor rather than live in CodeMirrorVirtualEditor;
+    //  How would the VirtualEditor get knowledge of the editor instances?
+    //  From the adapter (obviously).
     for (let editor of this.adapter.editors) {
       let cm_editor = (editor as CodeMirrorEditor).editor;
       editors_with_handlers.add(cm_editor);
@@ -528,6 +531,16 @@ export class CodeMirrorVirtualEditor
           }
         }
       );
+      this.adapter.editorRemoved.connect(
+        (adapter, data: IEditorChangedData) => {
+          let { editor } = data;
+          if (editor == null) {
+            return;
+          }
+          let cm_editor = (editor as CodeMirrorEditor).editor;
+          on_editor_removed_callback(cm_editor);
+        }
+      );
     }
   }