feat: session load perf (#17186)

packages/app/src/context/global-sync/session-prefetch.test.ts

@@ -0,0 +1,63 @@
+import { describe, expect, test } from "bun:test"
+import {
+  clearSessionPrefetch,
+  clearSessionPrefetchDirectory,
+  getSessionPrefetch,
+  runSessionPrefetch,
+  setSessionPrefetch,
+} from "./session-prefetch"
+
+describe("session prefetch", () => {
+  test("stores and clears message metadata by directory", () => {
+    clearSessionPrefetch("/tmp/a", ["ses_1"])
+    clearSessionPrefetch("/tmp/b", ["ses_1"])
+
+    setSessionPrefetch({
+      directory: "/tmp/a",
+      sessionID: "ses_1",
+      limit: 200,
+      complete: false,
+      at: 123,
+    })
+
+    expect(getSessionPrefetch("/tmp/a", "ses_1")).toEqual({ limit: 200, complete: false, at: 123 })
+    expect(getSessionPrefetch("/tmp/b", "ses_1")).toBeUndefined()
+
+    clearSessionPrefetch("/tmp/a", ["ses_1"])
+
+    expect(getSessionPrefetch("/tmp/a", "ses_1")).toBeUndefined()
+  })
+
+  test("dedupes inflight work", async () => {
+    clearSessionPrefetch("/tmp/c", ["ses_2"])
+
+    let calls = 0
+    const run = () =>
+      runSessionPrefetch({
+        directory: "/tmp/c",
+        sessionID: "ses_2",
+        task: async () => {
+          calls += 1
+          return { limit: 100, complete: true, at: 456 }
+        },
+      })
+
+    const [a, b] = await Promise.all([run(), run()])
+
+    expect(calls).toBe(1)
+    expect(a).toEqual({ limit: 100, complete: true, at: 456 })
+    expect(b).toEqual({ limit: 100, complete: true, at: 456 })
+  })
+
+  test("clears a whole directory", () => {
+    setSessionPrefetch({ directory: "/tmp/d", sessionID: "ses_1", limit: 10, complete: true, at: 1 })
+    setSessionPrefetch({ directory: "/tmp/d", sessionID: "ses_2", limit: 20, complete: false, at: 2 })
+    setSessionPrefetch({ directory: "/tmp/e", sessionID: "ses_1", limit: 30, complete: true, at: 3 })
+
+    clearSessionPrefetchDirectory("/tmp/d")
+
+    expect(getSessionPrefetch("/tmp/d", "ses_1")).toBeUndefined()
+    expect(getSessionPrefetch("/tmp/d", "ses_2")).toBeUndefined()
+    expect(getSessionPrefetch("/tmp/e", "ses_1")).toEqual({ limit: 30, complete: true, at: 3 })
+  })
+})