(GH-1336) Add syntax aware folding provider

This is a work-in-progress

Author: glennsarti

package.json

@@ -5,7 +5,7 @@
   "publisher": "ms-vscode",
   "description": "Develop PowerShell scripts in Visual Studio Code!",
   "engines": {
-    "vscode": "^1.19.0"
+    "vscode": "^1.23.0"
   },
   "license": "SEE LICENSE IN LICENSE.txt",
   "homepage": "https://github.com/PowerShell/vscode-powershell/blob/master/README.md",

src/features/Folding.ts

@@ -0,0 +1,142 @@
+import * as path from "path";
+import * as vscode from "vscode";
+import {
+    DocumentFormattingRequest,
+    DocumentRangeFormattingParams,
+    DocumentRangeFormattingRequest,
+    DocumentSelector,
+    LanguageClient,
+    RequestType,
+} from "vscode-languageclient";
+import { IFeature } from "../feature";
+
+const rangeLimit = 5000;
+
+// https://github.com/Microsoft/vscode/issues/46281
+const tm = getCoreNodeModule("vscode-textmate");
+/**
+ * Returns a node module installed with VSCode, or null if it fails.
+ */
+function getCoreNodeModule(moduleName: string) {
+  try {
+    return require(`${vscode.env.appRoot}/node_modules.asar/${moduleName}`);
+  } catch (err) { }
+
+  try {
+    return require(`${vscode.env.appRoot}/node_modules/${moduleName}`);
+  } catch (err) { }
+
+  return null;
+}
+
+interface IExtensionGrammar {
+    language?: string, scopeName?: string, path?: string, embeddedLanguages?: {[scopeName:string]:string}, injectTo?: string[]
+}
+
+interface IExtensionPackage {
+    contributes?: {
+      languages?: {id: string, configuration: string }[],
+      grammars?: IExtensionGrammar[],
+    }
+  }
+
+export class FoldingProvider implements vscode.FoldingRangeProvider {
+    private powershellGrammar;
+
+    // constructor(
+    // ) { }
+
+    public async provideFoldingRanges(
+        document: vscode.TextDocument,
+        context: vscode.FoldingContext,
+        token: vscode.CancellationToken,
+    ): Promise<vscode.FoldingRange[]> {
+
+        const foldingRanges = [];
+
+        console.log(document);
+        console.log(context);
+        console.log(token);
+
+        const content = document.getText();
+
+        let tokens = this.grammar().tokenizeLine(content).tokens;
+        for (var i = 0; i < tokens.length; i++) {
+            tokens[i]['value'] = content.substring(tokens[i]['startIndex'], tokens[i]['endIndex']);
+            tokens[i]['startLine'] = document.positionAt(tokens[i]["startIndex"]).line;
+            tokens[i]['endLine'] = document.positionAt(tokens[i]["endIndex"]).line;
+          }
+
+        // Just force a fixed folding range to see what happens
+        foldingRanges.push(new vscode.FoldingRange(1, 3, vscode.FoldingRangeKind.Region));
+
+        console.log(tokens);
+        // const tocProvider = new TableOfContentsProvider(this.engine, document);
+        // let toc = await tocProvider.getToc();
+        // if (toc.length > rangeLimit) {
+        //     toc = toc.slice(0, rangeLimit);
+        // }
+
+        // const foldingRanges = toc.map((entry, startIndex) => {
+        //     const start = entry.line;
+        //     let end: number | undefined = undefined;
+        //     for (let i = startIndex + 1; i < toc.length; ++i) {
+        //         if (toc[i].level <= entry.level) {
+        //             end = toc[i].line - 1;
+        //             if (document.lineAt(end).isEmptyOrWhitespace && end >= start + 1) {
+        //                 end = end - 1;
+        //             }
+        //             break;
+        //         }
+        //     }
+        //     return new vscode.FoldingRange(
+        //         start,
+        //         typeof end === 'number' ? end : document.lineCount - 1);
+        // });
+        return foldingRanges;
+    }
+
+    private powerShellGrammarPath(): string {
+        // "c:\Program Files\Microsoft VS Code\resources\app\extensions\powershell\syntaxes\powershell.tmLanguage.json"
+        try {
+            const psGrammars =
+                vscode.extensions.all
+                .filter( (x) => x.packageJSON && x.packageJSON.contributes && x.packageJSON.contributes.grammars)
+                .reduce((a: (IExtensionGrammar&{extensionPath: string})[], b) =>
+                    [...a, ...(b.packageJSON as IExtensionPackage).contributes.grammars
+                        .map( (x) => Object.assign({extensionPath: b.extensionPath}, x))], [])
+                .filter( (x) => x.language === "powershell");
+            if (psGrammars.length === 0) { return ""; }
+            return path.join(psGrammars[0].extensionPath, psGrammars[0].path);
+        } catch (err) { return ""; }
+    }
+
+    private grammar() {
+        if (this.powershellGrammar !== undefined) { return this.powershellGrammar; }
+        const registry = new tm.Registry();
+        this.powershellGrammar = registry.loadGrammarFromPathSync(this.powerShellGrammarPath());
+        return this.powershellGrammar;
+    }
+
+}
+
+export class FoldingFeature implements IFeature {
+    private foldingProvider: FoldingProvider;
+    private languageClient: LanguageClient;
+
+    constructor(documentSelector: DocumentSelector) {
+        this.foldingProvider = new FoldingProvider();
+        vscode.languages.registerFoldingRangeProvider(
+            documentSelector,
+            this.foldingProvider);
+    }
+
+    public dispose(): any {
+        // Should be empty
+    }
+
+    public setLanguageClient(languageclient: LanguageClient): void {
+        this.languageClient = languageclient;
+        // this.foldingProvider.setLanguageClient(languageclient);
+    }
+}

src/main.ts

@@ -18,6 +18,7 @@ import { DocumentFormatterFeature } from "./features/DocumentFormatter";
 import { ExamplesFeature } from "./features/Examples";
 import { ExpandAliasFeature } from "./features/ExpandAlias";
 import { ExtensionCommandsFeature } from "./features/ExtensionCommands";
+import { FoldingFeature } from "./features/Folding";
 import { GenerateBugReportFeature } from "./features/GenerateBugReport";
 import { HelpCompletionFeature } from "./features/HelpCompletion";
 import { NewFileOrProjectFeature } from "./features/NewFileOrProject";
@@ -132,6 +133,7 @@ export function activate(context: vscode.ExtensionContext): void {
         new SpecifyScriptArgsFeature(context),
         new HelpCompletionFeature(logger),
         new CustomViewsFeature(),
+        new FoldingFeature(documentSelector),
     ];
 
     sessionManager.setExtensionFeatures(extensionFeatures);