Make mobile terminals load faster (#1147)

* Speed up terminal restores on mobile * Preserve terminal output bytes in the app
2026-05-23 18:41:10 +08:00
parent 84f1dfc8cb
commit 846c9b9da3
32 changed files with 1304 additions and 357 deletions
@@ -0,0 +1,75 @@
+import type { SubscribeTerminalRequest } from "../server/messages.js";
+import {
+  TerminalStreamOpcode,
+  encodeTerminalSnapshotPayload,
+  encodeTerminalStreamFrame,
+} from "../shared/binary-frames/index.js";
+import { renderTerminalSnapshotToAnsi } from "../shared/terminal-snapshot.js";
+import type { TerminalStateSnapshot, TerminalStateSnapshotOptions } from "./terminal.js";
+
+export const MAX_TERMINAL_OUTPUT_FRAME_BYTES = 256 * 1024;
+
+const DEFAULT_VISIBLE_RESTORE_SCROLLBACK_LINES = 200;
+const MAX_VISIBLE_RESTORE_SCROLLBACK_LINES = 500;
+
+export type TerminalRestoreOptions = NonNullable<SubscribeTerminalRequest["restore"]>;
+
+export type TerminalSubscriptionSnapshotMode = "state" | "ready";
+
+export function resolveTerminalSubscriptionSnapshotMode(
+  restore: TerminalRestoreOptions | undefined,
+): TerminalSubscriptionSnapshotMode {
+  return restore ? "ready" : "state";
+}
+
+export function resolveRestoreAfterOutputOverflow(
+  restore: TerminalRestoreOptions | undefined,
+): TerminalRestoreOptions | undefined {
+  if (restore?.mode === "live") {
+    return { mode: "visible-snapshot" };
+  }
+  return restore;
+}
+
+export function resolveTerminalRestoreSnapshotOptions(
+  restore: TerminalRestoreOptions,
+): TerminalStateSnapshotOptions | null | undefined {
+  if (restore.mode === "live") {
+    return null;
+  }
+  if (restore.mode === "visible-snapshot") {
+    return {
+      scrollbackLines: resolveVisibleRestoreScrollbackLines(restore.scrollbackLines),
+    };
+  }
+  return undefined;
+}
+
+export function encodeLegacyTerminalSnapshotFrame(input: {
+  slot: number;
+  snapshot: TerminalStateSnapshot;
+}): Uint8Array {
+  return encodeTerminalStreamFrame({
+    opcode: TerminalStreamOpcode.Snapshot,
+    slot: input.slot,
+    payload: encodeTerminalSnapshotPayload(input.snapshot.state),
+  });
+}
+
+export function encodeTerminalRestoreFrame(input: {
+  slot: number;
+  snapshot: TerminalStateSnapshot;
+}): Uint8Array {
+  return encodeTerminalStreamFrame({
+    opcode: TerminalStreamOpcode.Restore,
+    slot: input.slot,
+    payload: renderTerminalSnapshotToAnsi(input.snapshot.state),
+  });
+}
+
+function resolveVisibleRestoreScrollbackLines(value: number | undefined): number {
+  if (typeof value !== "number") {
+    return DEFAULT_VISIBLE_RESTORE_SCROLLBACK_LINES;
+  }
+  return Math.min(Math.max(0, value), MAX_VISIBLE_RESTORE_SCROLLBACK_LINES);
+}