From e5a2ebda0e2fa2fbd55971e975e3c6675abbc0cf Mon Sep 17 00:00:00 2001
From: Per Bothner <per@bothner.com>
Date: Mon, 21 Aug 2023 13:03:06 -0700
Subject: [PATCH] Provide with "15" and "15-graphemes" UnicodeProviders

Th former doesn't support grapheme clusters, except the old-fashioned
kind of simple modifiers.  However, "15-graphemes" (with full
cluster support) is the default.
---
 .../src/UnicodeGraphemeProvider.ts                 | 14 +++++++++++---
 .../src/UnicodeGraphemesAddon.ts                   | 13 +++++++++----
 .../test/UnicodeGraphemesAddon.api.ts              |  2 +-
 3 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/addons/xterm-addon-unicode-graphemes/src/UnicodeGraphemeProvider.ts b/addons/xterm-addon-unicode-graphemes/src/UnicodeGraphemeProvider.ts
index b1c62020..39fbec84 100644
--- a/addons/xterm-addon-unicode-graphemes/src/UnicodeGraphemeProvider.ts
+++ b/addons/xterm-addon-unicode-graphemes/src/UnicodeGraphemeProvider.ts
@@ -9,9 +9,13 @@ import { UnicodeService } from 'common/services/UnicodeService';
 import * as UC from './third-party/UnicodeProperties';
 
 export class UnicodeGraphemeProvider implements IUnicodeVersionProvider {
-  public readonly version = '15-graphemes';
+  public readonly version;
   public ambiguousCharsAreWide: boolean = false;
-  constructor() {
+  public readonly handleGraphemes: boolean;
+
+  constructor(handleGraphemes: boolean = true) {
+    this.version = handleGraphemes ? '15-graphemes' : '15';
+    this.handleGraphemes = handleGraphemes;
   }
 
   private static readonly _plainNarrowProperties: UnicodeCharProperties
@@ -36,7 +40,11 @@ export class UnicodeGraphemeProvider implements IUnicodeVersionProvider {
     }
     if (preceding !== 0) {
       const oldWidth = UnicodeService.extractWidth(preceding);
-      charInfo = UC.shouldJoin(UnicodeService.extractCharKind(preceding), charInfo);
+      if (this.handleGraphemes) {
+        charInfo = UC.shouldJoin(UnicodeService.extractCharKind(preceding), charInfo);
+      } else {
+        charInfo = w === 0 ? 1 : 0;
+      }
       shouldJoin = charInfo > 0;
       if (shouldJoin) {
         if (oldWidth > w) {
diff --git a/addons/xterm-addon-unicode-graphemes/src/UnicodeGraphemesAddon.ts b/addons/xterm-addon-unicode-graphemes/src/UnicodeGraphemesAddon.ts
index c9154ed6..80290edf 100644
--- a/addons/xterm-addon-unicode-graphemes/src/UnicodeGraphemesAddon.ts
+++ b/addons/xterm-addon-unicode-graphemes/src/UnicodeGraphemesAddon.ts
@@ -10,17 +10,22 @@ import { UnicodeGraphemeProvider } from './UnicodeGraphemeProvider';
 
 
 export class UnicodeGraphemesAddon implements ITerminalAddon {
-  private _provider?: UnicodeGraphemeProvider;
+  private _provider15Graphemes?: UnicodeGraphemeProvider;
+  private _provider15?: UnicodeGraphemeProvider;
   private _unicode?: IUnicodeHandling;
   private _oldVersion: string = '';
 
   public activate(terminal: Terminal): void {
-    if (! this._provider) {
-      this._provider = new UnicodeGraphemeProvider();
+    if (! this._provider15) {
+      this._provider15 = new UnicodeGraphemeProvider(false);
+    }
+    if (! this._provider15Graphemes) {
+      this._provider15Graphemes = new UnicodeGraphemeProvider(true);
     }
     const unicode = terminal.unicode;
     this._unicode = unicode;
-    unicode.register(this._provider);
+    unicode.register(this._provider15);
+    unicode.register(this._provider15Graphemes);
     this._oldVersion = unicode.activeVersion;
     unicode.activeVersion = '15-graphemes';
   }
diff --git a/addons/xterm-addon-unicode-graphemes/test/UnicodeGraphemesAddon.api.ts b/addons/xterm-addon-unicode-graphemes/test/UnicodeGraphemesAddon.api.ts
index ff4f52aa..622bf531 100644
--- a/addons/xterm-addon-unicode-graphemes/test/UnicodeGraphemesAddon.api.ts
+++ b/addons/xterm-addon-unicode-graphemes/test/UnicodeGraphemesAddon.api.ts
@@ -39,7 +39,7 @@ describe('UnicodeGraphemesAddon', () => {
       window.term.loadAddon(window.unicode);
     `);
     // should have loaded '15-graphemes'
-    assert.deepEqual(await page.evaluate(`window.term.unicode.versions`), ['6', ourVersion]);
+    assert.deepEqual(await page.evaluate(`window.term.unicode.versions`), ['6', '15', '15-graphemes']);
     // switch should not throw
     await page.evaluate(`window.term.unicode.activeVersion = '${ourVersion}';`);
     assert.equal(await page.evaluate(`window.term.unicode.activeVersion`), ourVersion);