editors/code/src/inlay_hints.ts

   1 import * as vscode from 'vscode';
   2 import * as lc from 'vscode-languageclient';
   3
   4 import { Ctx } from './ctx';
   5
   6 export function activateInlayHints(ctx: Ctx) {
   7     const hintsUpdater = new HintsUpdater(ctx);
   8     vscode.window.onDidChangeVisibleTextEditors(async _ => {
   9         await hintsUpdater.refresh();
  10     }, ctx.subscriptions);
  11
  12     vscode.workspace.onDidChangeTextDocument(async e => {
  13         if (e.contentChanges.length === 0) return;
  14         if (e.document.languageId !== 'rust') return;
  15         await hintsUpdater.refresh();
  16     }, ctx.subscriptions);
  17
  18     vscode.workspace.onDidChangeConfiguration(_ => {
  19         hintsUpdater.setEnabled(ctx.config.displayInlayHints);
  20     }, ctx.subscriptions);
  21
  22     // XXX: don't await here;
  23     // Who knows what happens if an exception is thrown here...
  24     hintsUpdater.refresh();
  25 }
  26
  27 interface InlayHintsParams {
  28     textDocument: lc.TextDocumentIdentifier;
  29 }
  30
  31 interface InlayHint {
  32     range: vscode.Range;
  33     kind: string;
  34     label: string;
  35 }
  36
  37 const typeHintDecorationType = vscode.window.createTextEditorDecorationType({
  38     after: {
  39         color: new vscode.ThemeColor('rust-analyzer.inlayHint'),
  40     },
  41 });
  42
  43 class HintsUpdater {
  44     private pending: Map<string, vscode.CancellationTokenSource> = new Map();
  45     private ctx: Ctx;
  46     private enabled = true;
  47
  48     constructor(ctx: Ctx) {
  49         this.ctx = ctx;
  50     }
  51
  52     async setEnabled(enabled: boolean) {
  53         if (this.enabled == enabled) return;
  54         this.enabled = enabled;
  55
  56         if (this.enabled) {
  57             await this.refresh();
  58         } else {
  59             this.allEditors.forEach(it => this.setDecorations(it, []));
  60         }
  61     }
  62
  63     async refresh() {
  64         if (!this.enabled) return;
  65         const promises = this.allEditors.map(it => this.refreshEditor(it));
  66         await Promise.all(promises);
  67     }
  68
  69     private async refreshEditor(editor: vscode.TextEditor): Promise<void> {
  70         const newHints = await this.queryHints(editor.document.uri.toString());
  71         if (newHints == null) return;
  72         const newDecorations = newHints.map(hint => ({
  73             range: hint.range,
  74             renderOptions: {
  75                 after: {
  76                     contentText: `: ${hint.label}`,
  77                 },
  78             },
  79         }));
  80         this.setDecorations(editor, newDecorations);
  81     }
  82
  83     private get allEditors(): vscode.TextEditor[] {
  84         return vscode.window.visibleTextEditors.filter(
  85             editor => editor.document.languageId === 'rust',
  86         );
  87     }
  88
  89     private setDecorations(
  90         editor: vscode.TextEditor,
  91         decorations: vscode.DecorationOptions[],
  92     ) {
  93         editor.setDecorations(
  94             typeHintDecorationType,
  95             this.enabled ? decorations : [],
  96         );
  97     }
  98
  99     private async queryHints(documentUri: string): Promise<InlayHint[] | null> {
 100         const request: InlayHintsParams = {
 101             textDocument: { uri: documentUri },
 102         };
 103         let tokenSource = new vscode.CancellationTokenSource();
 104         let prev = this.pending.get(documentUri);
 105         if (prev) prev.cancel();
 106         this.pending.set(documentUri, tokenSource);
 107         try {
 108             return await this.ctx.sendRequestWithRetry<InlayHint[] | null>(
 109                 'rust-analyzer/inlayHints',
 110                 request,
 111                 tokenSource.token,
 112             );
 113         } finally {
 114             if (!tokenSource.token.isCancellationRequested) {
 115                 this.pending.delete(documentUri);
 116             }
 117         }
 118     }
 119 }