Add basic plumbing for Flutter Outline.

See #605.

package.json

@@ -32,7 +32,6 @@
 	"icon": "media/icon.png",
 	"activationEvents": [
 		"onLanguage:dart",
-		"onView:dartPackages",
 		"workspaceContains:**/pubspec.yaml",
 		"workspaceContains:**/*.dart",
 		"onCommand:flutter.createProject",
@@ -348,6 +347,11 @@
 		},
 		"views": {
 			"explorer": [
+				{
+					"id": "dartFlutterOutline",
+					"name": "Flutter Outline",
+					"when": "dart-code:flutterProjectLoaded && dart-code:showFlutterOutline"
+				},
 				{
 					"id": "dartPackages",
 					"name": "Dependencies",

src/analysis/analyzer.ts

@@ -21,6 +21,7 @@ class AnalyzerCapabilities {
 	get supportsDiagnostics() { return versionIsAtLeast(this.version, "1.18.1"); }
 	get supportsClosingLabels() { return versionIsAtLeast(this.version, "1.18.4"); }
 	get supportsGetDeclerations() { return versionIsAtLeast(this.version, "1.18.7"); }
+	get supportsFlutterOutline() { return versionIsAtLeast(this.version, "1.18.7"); }
 }
 
 export class Analyzer extends AnalyzerGen {

src/extension.ts

@@ -41,6 +41,7 @@ import { isFlutterProject } from "./utils";
 import { FixCodeActionProvider } from "./providers/fix_code_action_provider";
 import { AssistCodeActionProvider } from "./providers/assist_code_action_provider";
 import { LegacyDebugConfigProvider } from "./providers/legacy_debug_config_provider";
+import { FlutterOutlineProvider } from "./views/flutter_outline_view";
 
 const DART_MODE: vs.DocumentFilter[] = [{ language: "dart", scheme: "file" }];
 const HTML_MODE: vs.DocumentFilter[] = [{ language: "html", scheme: "file" }];
@@ -284,6 +285,9 @@ export function activate(context: vs.ExtensionContext) {
 			context.subscriptions.push(vs.languages.registerWorkspaceSymbolProvider(new LegacyDartWorkspaceSymbolProvider(analyzer)));
 		}
 
+		if (analyzer.capabilities.supportsFlutterOutline)
+			context.subscriptions.push(vs.window.registerTreeDataProvider("dartFlutterOutline", new FlutterOutlineProvider(analyzer)));
+
 		// Hook open/active file changes so we can set priority files with the analyzer.
 		const openFileTracker = new OpenFileTracker(analyzer);
 		context.subscriptions.push(vs.workspace.onDidOpenTextDocument((td) => openFileTracker.updatePriorityFiles()));
@@ -314,7 +318,7 @@ export function activate(context: vs.ExtensionContext) {
 	// Register misc commands.
 	context.subscriptions.push(new TypeHierarchyCommand(context, analyzer));
 
-	// Register our view providers.
+	// Register our dependency tree provider.
 	const dartPackagesProvider = new DartPackagesProvider();
 	dartPackagesProvider.setWorkspaces(util.getDartWorkspaceFolders());
 	context.subscriptions.push(dartPackagesProvider);

src/open_file_tracker.ts

@@ -56,5 +56,13 @@ export class OpenFileTracker {
 				},
 			});
 		}
+
+		if (this.analyzer.capabilities.supportsFlutterOutline) {
+			this.analyzer.flutterSetSubscriptions({
+				subscriptions: {
+					OUTLINE: priorityFiles,
+				},
+			});
+		}
 	}
 }

src/views/flutter_outline_view.ts

@@ -0,0 +1,93 @@
+"use strict";
+
+import * as vs from "vscode";
+import * as as from "../analysis/analysis_server_types";
+import { Analyzer } from "../analysis/analyzer";
+import { isAnalyzable } from "../utils";
+
+const DART_SHOW_FLUTTER_OUTLINE = "dart-code:showFlutterOutline";
+
+export class FlutterOutlineProvider implements vs.TreeDataProvider<FlutterWidgetItem>, vs.Disposable {
+	private subscriptions: vs.Disposable[] = [];
+	private analyzer: Analyzer;
+	private activeEditor: vs.TextEditor;
+	private flutterOutline: as.FlutterOutlineNotification;
+	private updateTimeout: NodeJS.Timer;
+	private onDidChangeTreeDataEmitter: vs.EventEmitter<FlutterWidgetItem | undefined> = new vs.EventEmitter<FlutterWidgetItem | undefined>();
+	public readonly onDidChangeTreeData: vs.Event<FlutterWidgetItem | undefined> = this.onDidChangeTreeDataEmitter.event;
+
+	constructor(analyzer: Analyzer) {
+		this.analyzer = analyzer;
+
+		this.analyzer.registerForFlutterOutline((n) => {
+			if (this.activeEditor && n.file === this.activeEditor.document.fileName) {
+				this.flutterOutline = n;
+				// Delay this so if we're getting lots of updates we don't flicker.
+				clearTimeout(this.updateTimeout);
+				this.updateTimeout = setTimeout(() => this.update(), 500);
+			}
+		});
+
+		this.subscriptions.push(vs.window.onDidChangeActiveTextEditor((e) => this.setTrackingFile(e)));
+		if (vs.window.activeTextEditor)
+			this.setTrackingFile(vs.window.activeTextEditor);
+	}
+
+	private update() {
+		if (!this.flutterOutline || !this.activeEditor || this.flutterOutline.file !== this.activeEditor.document.fileName)
+			return;
+
+		FlutterOutlineProvider.showTree();
+
+		// Do tree...
+	}
+
+	private setTrackingFile(editor: vs.TextEditor) {
+		if (editor && isAnalyzable(editor.document)) {
+			this.activeEditor = editor;
+			this.flutterOutline = null;
+
+			this.analyzer.forceNotificationsFor(editor.document.fileName);
+		} else {
+			FlutterOutlineProvider.hideTree();
+			this.activeEditor = null;
+		}
+	}
+
+	public refresh(): void {
+		this.onDidChangeTreeDataEmitter.fire();
+	}
+
+	public getTreeItem(element: FlutterWidgetItem): vs.TreeItem {
+		return element;
+	}
+
+	public getChildren(element?: FlutterWidgetItem): FlutterWidgetItem[] {
+		return [];
+	}
+
+	private static setTreeVisible(visible: boolean) {
+		vs.commands.executeCommand("setContext", DART_SHOW_FLUTTER_OUTLINE, visible);
+	}
+
+	public static showTree() { this.setTreeVisible(true); }
+	public static hideTree() { this.setTreeVisible(false); }
+
+	public dispose() {
+		this.activeEditor = null;
+		this.subscriptions.forEach((s) => s.dispose());
+	}
+}
+
+class FlutterWidgetItem extends vs.TreeItem {
+	constructor(
+		public readonly label: string,
+		public readonly depPath: string,
+		public readonly collapsibleState?: vs.TreeItemCollapsibleState,
+		public readonly command?: vs.Command,
+	) {
+		super(label, collapsibleState);
+	}
+
+	public contextValue = "flutterWidget";
+}