fix: jetbrains by using dec instead of ansi for save/restore cursor (#427)

Signed-off-by: cpendery <cpendery@vt.edu>

Author: cpendery

src/tests/utils/suggestionRenderer.test.ts

@@ -0,0 +1,69 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+import ansi from "ansi-escapes";
+
+import type { ISTerm } from "../../isterm/pty.js";
+import * as dec from "../../utils/dec.js";
+import { SuggestionRenderer } from "../../ui/suggestionRenderer.js";
+import type { SuggestionManager } from "../../ui/suggestionManager.js";
+
+const originalTerminalEmulator = process.env.TERMINAL_EMULATOR;
+
+afterEach(() => {
+  if (originalTerminalEmulator == null) {
+    delete process.env.TERMINAL_EMULATOR;
+  } else {
+    process.env.TERMINAL_EMULATOR = originalTerminalEmulator;
+  }
+});
+
+const createRenderer = (writeOutput: (data: string) => void) => {
+  const term = {
+    cols: 80,
+    getCommandState: () => ({ commandText: "g", cursorTerminated: true, hasOutput: false }),
+    getCursorState: () => ({ cursorX: 1, cursorY: 0, remainingLines: 28, hidden: false, shift: 0 }),
+    getPatch: () => "patch",
+    isAlternateBuffer: () => false,
+  } as unknown as ISTerm;
+  const suggestions = {
+    render: () => [{ startX: 1, length: 5, data: "item" }],
+    suspend: async () => {},
+  } as unknown as SuggestionManager;
+
+  return new SuggestionRenderer(term, suggestions, writeOutput);
+};
+
+test("uses ANSI cursor position sequences by default", async () => {
+  delete process.env.TERMINAL_EMULATOR;
+  const output: string[] = [];
+  const renderer = createRenderer((data) => output.push(data));
+
+  renderer.renderSuggestionUpdate(false);
+  await renderer.handleBufferChange("alternate");
+
+  expect(output).toHaveLength(2);
+  output.forEach((data) => {
+    expect(data).toContain(ansi.cursorSavePosition);
+    expect(data).toContain(ansi.cursorRestorePosition);
+    expect(data).not.toContain(dec.cursorSavePosition);
+    expect(data).not.toContain(dec.cursorRestorePosition);
+  });
+});
+
+test("uses DEC cursor position sequences in JetBrains terminals", async () => {
+  process.env.TERMINAL_EMULATOR = "JetBrains-JediTerm";
+  const output: string[] = [];
+  const renderer = createRenderer((data) => output.push(data));
+
+  renderer.renderSuggestionUpdate(false);
+  await renderer.handleBufferChange("alternate");
+
+  expect(output).toHaveLength(2);
+  output.forEach((data) => {
+    expect(data).toContain(dec.cursorSavePosition);
+    expect(data).toContain(dec.cursorRestorePosition);
+    expect(data).not.toContain(ansi.cursorSavePosition);
+    expect(data).not.toContain(ansi.cursorRestorePosition);
+  });
+});

src/ui/suggestionRenderer.ts

@@ -4,7 +4,8 @@
 import ansi from "ansi-escapes";
 
 import type { ISTerm } from "../isterm/pty.js";
-import { eraseViewport } from "../utils/ansi.js";
+import { eraseViewport, shouldFallbackToDec } from "../utils/ansi.js";
+import * as dec from "../utils/dec.js";
 import { endTiming, startTiming } from "../utils/performance.js";
 import { getMaxLines, type SuggestionManager } from "./suggestionManager.js";
 
@@ -24,10 +25,16 @@ type RenderCache = {
   clear?: string;
 };
 
+type CursorPositionSequences = {
+  cursorSavePosition: string;
+  cursorRestorePosition: string;
+};
+
 export class SuggestionRenderer {
   readonly #term: ISTerm;
   readonly #suggestions: SuggestionManager;
   readonly #writeOutput: (data: string) => void;
+  readonly #cursorPositionSequences: CursorPositionSequences;
   readonly #cache: RenderCache = {};
   #visible = false;
   #direction: Direction;
@@ -39,6 +46,7 @@ export class SuggestionRenderer {
     this.#term = term;
     this.#suggestions = suggestions;
     this.#writeOutput = writeOutput;
+    this.#cursorPositionSequences = shouldFallbackToDec() ? dec : ansi;
     this.#direction = this.#snapshot().layout.direction;
   }
 
@@ -169,10 +177,11 @@ export class SuggestionRenderer {
       cursor: { hidden: cursorHidden },
     } = snapshot;
     const showCursor = cursorHidden ? "" : ansi.cursorShow;
+    const { cursorSavePosition, cursorRestorePosition } = this.#cursorPositionSequences;
     if (direction === "above") {
-      return data + ansi.cursorHide + ansi.cursorSavePosition + ansi.cursorPrevLine.repeat(lines) + patch + ansi.cursorRestorePosition + showCursor;
+      return data + ansi.cursorHide + cursorSavePosition + ansi.cursorPrevLine.repeat(lines) + patch + cursorRestorePosition + showCursor;
     }
-    return ansi.cursorHide + ansi.cursorSavePosition + ansi.cursorNextLine + patch + ansi.cursorRestorePosition + showCursor + data;
+    return ansi.cursorHide + cursorSavePosition + ansi.cursorNextLine + patch + cursorRestorePosition + showCursor + data;
   }
 
   #clearOutput(direction: Direction, snapshot: RenderSnapshot, bufferType: PatchBuffer = "active"): string {
@@ -182,11 +191,12 @@ export class SuggestionRenderer {
     const lines = direction === "above" ? Math.min(getMaxLines(), cursorY) : Math.min(getMaxLines(), remainingLines);
     const patch = this.#term.getPatch(lines, [], direction, bufferType);
     const showCursor = cursorHidden ? "" : ansi.cursorShow;
+    const { cursorSavePosition, cursorRestorePosition } = this.#cursorPositionSequences;
 
     if (direction === "above") {
-      return ansi.cursorHide + ansi.cursorSavePosition + ansi.cursorPrevLine.repeat(lines) + patch + ansi.cursorRestorePosition + showCursor;
+      return ansi.cursorHide + cursorSavePosition + ansi.cursorPrevLine.repeat(lines) + patch + cursorRestorePosition + showCursor;
     }
-    return ansi.cursorHide + ansi.cursorSavePosition + ansi.cursorNextLine + patch + ansi.cursorRestorePosition + showCursor;
+    return ansi.cursorHide + cursorSavePosition + ansi.cursorNextLine + patch + cursorRestorePosition + showCursor;
   }
 
   #clearPreviousDirection(snapshot: RenderSnapshot): void {

src/utils/ansi.ts

@@ -6,6 +6,8 @@ const CSI = ESC + "[";
 const OSC = "\u001B]";
 const BEL = "\u0007";
 
+export const shouldFallbackToDec = () => process.env.TERMINAL_EMULATOR === "JetBrains-JediTerm";
+
 export const IsTermOscPs = 6973;
 const IS_OSC = OSC + IsTermOscPs + ";";
 

src/utils/dec.ts

@@ -0,0 +1,7 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+const ESC = "\u001B";
+
+export const cursorSavePosition = ESC + "7";
+export const cursorRestorePosition = ESC + "8";