[Init] Initial commit - NetMesh terminal manager

components/terminalLayer/activityEscapeFilter.ts

@@ -0,0 +1,42 @@
+import { canRetainIncompleteTerminalControlSequence } from "../terminal/runtime/terminalControlSequenceLimits";
+
+// eslint-disable-next-line no-control-regex
+const TERMINAL_OSC_SEQUENCE_REGEX = new RegExp("\\u001B\\][^\\u0007\\u001B]*(?:\\u0007|\\u001B\\\\)", "g");
+// eslint-disable-next-line no-control-regex
+const TERMINAL_ESCAPE_SEQUENCE_REGEX = new RegExp("\\u001B(?:[@-Z\\\\-_]|\\[[0-?]*[ -/]*[@-~])", "g");
+// eslint-disable-next-line no-control-regex
+const TERMINAL_CONTROL_CHAR_REGEX = new RegExp("[\\u0000-\\u0008\\u000B-\\u001F\\u007F]", "g");
+// eslint-disable-next-line no-control-regex
+const INCOMPLETE_ESCAPE_TAIL_REGEX = new RegExp("\\u001B(?:\\][^\\u0007\\u001B]*(?:\\u001B)?|\\[[0-?]*[ -/]*)?$");
+
+const stripTerminalControlSequences = (data: string): string => data
+  .replace(TERMINAL_OSC_SEQUENCE_REGEX, "")
+  .replace(TERMINAL_ESCAPE_SEQUENCE_REGEX, "")
+  .replace(TERMINAL_CONTROL_CHAR_REGEX, "");
+
+export class ChunkedEscapeFilter {
+  private pending = "";
+
+  feed(chunk: string): string {
+    const data = this.pending + chunk;
+    const tailMatch = INCOMPLETE_ESCAPE_TAIL_REGEX.exec(data);
+    if (tailMatch) {
+      const incomplete = tailMatch[0];
+      if (canRetainIncompleteTerminalControlSequence(incomplete)) {
+        this.pending = incomplete;
+        return stripTerminalControlSequences(data.slice(0, tailMatch.index));
+      }
+      // Fail open after the safety budget. This filter is only an activity
+      // classifier; retaining an unterminated OSC/DCS forever is worse than
+      // treating its payload as visible activity once.
+      this.pending = "";
+      return `${stripTerminalControlSequences(data.slice(0, tailMatch.index))}${incomplete}`;
+    }
+    this.pending = "";
+    return stripTerminalControlSequences(data);
+  }
+}
+
+export const hasNotifiableTerminalOutput = (filter: ChunkedEscapeFilter, chunk: string): boolean => (
+  filter.feed(chunk).trim().length > 0
+);