vscode: Support onDidChangeFoldingRanges events for FoldingRangeProvider

packages/plugin-ext/src/common/plugin-api-rpc.ts

@@ -1550,7 +1550,8 @@ export interface LanguagesMain {
     $emitCodeLensEvent(eventHandle: number, event?: any): void;
     $registerOutlineSupport(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[], displayName?: string): void;
     $registerWorkspaceSymbolProvider(handle: number, pluginInfo: PluginInfo): void;
-    $registerFoldingRangeProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[]): void;
+    $registerFoldingRangeProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[], eventHandle?: number): void;
+    $emitFoldingRangeEvent(eventHandle: number, event?: any): void;
     $registerSelectionRangeProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[]): void;
     $registerDocumentColorProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[]): void;
     $registerRenameProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[], supportsResolveInitialValues: boolean): void;

packages/plugin-ext/src/main/browser/languages-main.ts

@@ -651,12 +651,27 @@ export class LanguagesMainImpl implements LanguagesMain, Disposable {
         return this.proxy.$provideOnTypeFormattingEdits(handle, model.uri, position, ch, options, token);
     }
 
-    $registerFoldingRangeProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[]): void {
+    $registerFoldingRangeProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[], eventHandle: number): void {
         const languageSelector = this.toLanguageSelector(selector);
         const provider = this.createFoldingRangeProvider(handle);
+
+        if (typeof eventHandle === 'number') {
+            const emitter = new Emitter<monaco.languages.FoldingRangeProvider>();
+            this.register(eventHandle, emitter);
+            provider.onDidChange = emitter.event;
+        }
+
         this.register(handle, (monaco.languages.registerFoldingRangeProvider as RegistrationFunction<monaco.languages.FoldingRangeProvider>)(languageSelector, provider));
     }
 
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    $emitFoldingRangeEvent(eventHandle: number, event?: any): void {
+        const obj = this.services.get(eventHandle);
+        if (obj instanceof Emitter) {
+            obj.fire(event);
+        }
+    }
+
     createFoldingRangeProvider(handle: number): monaco.languages.FoldingRangeProvider {
         return {
             provideFoldingRanges: (model, context, token) => this.provideFoldingRanges(handle, model, context, token)

packages/plugin-ext/src/plugin/languages.ts

@@ -567,8 +567,17 @@ export class LanguagesExtImpl implements LanguagesExt {
     // ### Folding Range Provider begin
     registerFoldingRangeProvider(selector: theia.DocumentSelector, provider: theia.FoldingRangeProvider, pluginInfo: PluginInfo): theia.Disposable {
         const callId = this.addNewAdapter(new FoldingProviderAdapter(provider, this.documents));
-        this.proxy.$registerFoldingRangeProvider(callId, pluginInfo, this.transformDocumentSelector(selector));
-        return this.createDisposable(callId);
+        const eventHandle = typeof provider.onDidChangeFoldingRanges === 'function' ? this.nextCallId() : undefined;
+
+        this.proxy.$registerFoldingRangeProvider(callId, pluginInfo, this.transformDocumentSelector(selector), eventHandle);
+        let result = this.createDisposable(callId);
+
+        if (eventHandle !== undefined && provider.onDidChangeFoldingRanges) {
+            const subscription = provider.onDidChangeFoldingRanges(() => this.proxy.$emitFoldingRangeEvent(eventHandle));
+            result = Disposable.from(result, subscription);
+        }
+
+        return result;
     }
 
     $provideFoldingRange(

packages/plugin-metrics/src/browser/plugin-metrics-languages-main.ts

@@ -294,9 +294,9 @@ export class LanguagesMainPluginMetrics extends LanguagesMainImpl {
         super.$registerOnTypeFormattingProvider(handle, pluginInfo, selector, autoFormatTriggerCharacters);
     }
 
-    override $registerFoldingRangeProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[]): void {
+    override $registerFoldingRangeProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[], eventHandle: number): void {
         this.registerPluginWithFeatureHandle(handle, pluginInfo.id);
-        super.$registerFoldingRangeProvider(handle, pluginInfo, selector);
+        super.$registerFoldingRangeProvider(handle, pluginInfo, selector, eventHandle);
     }
 
     override $registerDocumentColorProvider(handle: number, pluginInfo: PluginInfo, selector: SerializedDocumentFilter[]): void {

packages/plugin/src/theia.d.ts

@@ -7415,6 +7415,12 @@ export module '@theia/plugin' {
      * [Folding](https://code.visualstudio.com/docs/editor/codebasics#_folding) in the editor.
      */
     export interface FoldingRangeProvider {
+
+        /**
+         * An optional event to signal that the folding ranges from this provider have changed.
+         */
+        onDidChangeFoldingRanges?: Event<void>;
+
         /**
          * Returns a list of folding ranges or null and undefined if the provider
          * does not want to participate or was cancelled.