[Init] Initial commit - NetMesh terminal manager

components/terminal/pluginTerminalBufferText.ts

@@ -0,0 +1,55 @@
+import type { IBufferLine } from '@xterm/xterm';
+
+export interface PluginTerminalBufferText {
+  readonly text: string;
+  /** Maps UTF-16 string boundaries to zero-based xterm cell boundaries. */
+  readonly cellAtStringOffset: readonly number[];
+}
+
+function identityMapping(text: string): PluginTerminalBufferText {
+  return Object.freeze({
+    text,
+    cellAtStringOffset: Object.freeze(Array.from({ length: text.length + 1 }, (_, index) => index)),
+  });
+}
+
+export function readPluginTerminalBufferText(
+  line: IBufferLine,
+  trimRight: boolean,
+): PluginTerminalBufferText {
+  if (typeof line.getCell !== 'function' || !Number.isInteger(line.length) || line.length < 0) {
+    return identityMapping(line.translateToString(trimRight));
+  }
+  let text = '';
+  const cellAtStringOffset: number[] = [0];
+  for (let cellIndex = 0; cellIndex < line.length; cellIndex += 1) {
+    const cell = line.getCell(cellIndex);
+    if (!cell) continue;
+    const width = cell.getWidth();
+    if (width === 0) continue;
+    const characters = cell.getChars() || ' ';
+    const startOffset = text.length;
+    text += characters;
+    for (let offset = startOffset; offset < text.length; offset += 1) {
+      cellAtStringOffset[offset] = cellIndex;
+    }
+    cellAtStringOffset[text.length] = cellIndex + Math.max(1, width);
+  }
+  if (trimRight) {
+    const trimmed = text.trimEnd();
+    cellAtStringOffset.length = trimmed.length + 1;
+    text = trimmed;
+  }
+  return Object.freeze({ text, cellAtStringOffset: Object.freeze(cellAtStringOffset) });
+}
+
+export function pluginTerminalCellRange(
+  line: PluginTerminalBufferText,
+  start: number,
+  length: number,
+): { x: number; width: number } | null {
+  const startCell = line.cellAtStringOffset[start];
+  const endCell = line.cellAtStringOffset[start + length];
+  if (!Number.isInteger(startCell) || !Number.isInteger(endCell) || endCell <= startCell) return null;
+  return { x: startCell, width: endCell - startCell };
+}