app: servo page and control table subscribe through the bus manager

src/components/about-card.tsx

@@ -1,24 +1,13 @@
-import { unpackVersion, type Identity } from "@openservocore/client";
+import { unpackVersion } from "@openservocore/client";
 import { Cog } from "lucide-react";
-import { useEffect, useState, type ReactNode } from "react";
+import type { ReactNode } from "react";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { Skeleton } from "@/components/ui/skeleton";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
+import { useReadOnce } from "@/lib/bus/hooks";
 import { modelName } from "@/lib/descriptor";
 import { formatVersion, hex16 } from "@/lib/format";
-import { useSession } from "@/lib/session";
-
-/** `capability_flags` bit order (protocol sec 5.4). */
-const CAPABILITIES: readonly string[] = ["Motor encoder"];
-
-function features(caps: number): string {
-  const set: string[] = [];
-  for (let bit = 0; bit < 32; bit++) {
-    if ((caps & (1 << bit)) === 0) continue;
-    set.push(CAPABILITIES[bit] ?? `bit ${bit}`);
-  }
-  return set.length === 0 ? "None" : set.join(", ");
-}
+import { features, identityFrom, IDENTITY_REGISTERS } from "@/lib/identity";
 
 function Row({ label, children }: { label: string; children: ReactNode }) {
   return (
@@ -30,24 +19,8 @@ function Row({ label, children }: { label: string; children: ReactNode }) {
 }
 
 export function AboutCard({ id, uid }: { id: number; uid: string }) {
-  const { run } = useSession();
-  const [identity, setIdentity] = useState<Identity>();
-  const [error, setError] = useState<string>();
-
-  useEffect(() => {
-    let live = true;
-    void (async () => {
-      try {
-        const read = await run((c) => c.identity(id));
-        if (live) setIdentity(read);
-      } catch (e) {
-        if (live) setError(e instanceof Error ? e.message : String(e));
-      }
-    })();
-    return () => {
-      live = false;
-    };
-  }, [run, id]);
+  const { snapshot, error } = useReadOnce(id, IDENTITY_REGISTERS);
+  const identity = snapshot === undefined ? undefined : identityFrom(snapshot.read);
 
   const name = identity === undefined ? undefined : modelName(identity.model);
   return (

src/components/calibration-card.tsx

@@ -1,46 +1,29 @@
-import type { Field, OscClient } from "@openservocore/client";
+import type { Field } from "@openservocore/client";
 import { Check, CircleQuestionMark, Ruler } from "lucide-react";
-import { useId, useState } from "react";
+import { useId } from "react";
 import { ValueEditor } from "@/components/value-editor";
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
 import { Card, CardAction, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
 import { Skeleton } from "@/components/ui/skeleton";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
+import { useBus } from "@/lib/bus/hooks";
 import { CALIBRATION_REGISTERS, editReason, type CalibrationRegister } from "@/lib/calibration";
-import { decodeSpan, span } from "@/lib/bus/spans";
 import { hexAddr } from "@/lib/format";
 import { useSession } from "@/lib/session";
-import { calibrationFromTable, calibrationStatus, type Calibration } from "@/lib/units";
-
-const NAMES = CALIBRATION_REGISTERS.map((r) => r.name);
-
-async function readCalibration(
-  client: OscClient,
-  id: number,
-  fields: readonly Field[],
-): Promise<Calibration> {
-  const block = span(fields, NAMES);
-  const bytes = await client.read(id, block.addr, block.count);
-  return calibrationFromTable(decodeSpan(fields, block, bytes));
-}
+import { calibrationStatus, type Calibration } from "@/lib/units";
 
 export function CalibrationCard({ id, uid }: { id: number; uid: string }) {
-  const { descriptor, descriptorError, values, run, refreshConstants } = useSession();
-  const [own, setOwn] = useState<Calibration>();
-  const cal = own ?? values.get(uid)?.constants.calibration;
+  const { descriptor, descriptorError, values, refreshConstants } = useSession();
+  const bus = useBus();
+  const cal = values.get(uid)?.constants.calibration;
   const fields = descriptor?.fields();
 
   async function apply(field: Field, raw: number) {
-    if (descriptor === undefined || fields === undefined) return;
-    const kind = field.kind === "int" ? "int" : "uint";
-    const bytes = descriptor.encode(field.name, { kind, value: raw });
-    const fresh = await run(async (c) => {
-      await c.write(id, field.addr, bytes);
-      return readCalibration(c, id, fields);
-    });
-    setOwn(fresh);
+    await bus.write(id, field.name, { kind: field.kind === "int" ? "int" : "uint", value: raw });
+    // The write dirties the CALIB span; the session re-reads the constants
+    // every card on the page shows.
     refreshConstants(uid);
   }
 

src/components/connection-popover.tsx

@@ -46,12 +46,12 @@ export function ConnectionPopover({
   children: ReactNode;
 }) {
   const session = useSession();
-  const { status, client, simulated, baud, rails, missing, error } = session;
+  const { status, linkInfo, simulated, baud, rails, missing, error } = session;
   const [confirming, setConfirming] = useState(false);
   const [choice, setChoice] = useState<BaudRate>();
   const [railsError, setRailsError] = useState<string>();
   const rate = choice ?? baud ?? "b1000000";
-  const connected = client !== undefined;
+  const connected = linkInfo !== undefined;
   const ready = status === "ready";
   const badge = chip(status);
 
@@ -92,8 +92,8 @@ export function ConnectionPopover({
             <span className="font-medium">{simulated ? "Simulated adapter" : "osc-adapter"}</span>
             <Badge className={badge.className}>{badge.text}</Badge>
           </div>
-          {connected && (
-            <span className="text-xs text-text-3">Firmware {client.linkInfo().version}</span>
+          {linkInfo !== undefined && (
+            <span className="text-xs text-text-3">Firmware {linkInfo.version}</span>
           )}
         </div>
 

src/components/health-card.tsx

@@ -1,14 +1,12 @@
-import type { Health } from "@openservocore/client";
 import { CircleAlert, CircleCheck, HeartPulse, TriangleAlert } from "lucide-react";
-import { useEffect, useState } from "react";
+import { useState } from "react";
 import { Button } from "@/components/ui/button";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { Separator } from "@/components/ui/separator";
 import { Skeleton } from "@/components/ui/skeleton";
+import { useBus, useRegisters } from "@/lib/bus/hooks";
+import { healthFrom, HEALTH_REGISTERS } from "@/lib/bus/spans";
 import { countersLine, statements, trimLine, type Level } from "@/lib/health";
-import { useSession } from "@/lib/session";
-
-const POLL_MS = 1000;
 
 const icons = { fault: CircleAlert, warn: TriangleAlert, ok: CircleCheck };
 const tone: Record<Level, string> = {
@@ -18,44 +16,22 @@ const tone: Record<Level, string> = {
 };
 
 export function HealthCard({ id }: { id: number }) {
-  const { run } = useSession();
-  const [health, setHealth] = useState<Health>();
+  const bus = useBus();
+  const snapshot = useRegisters(id, HEALTH_REGISTERS, "slow");
   const [error, setError] = useState<string>();
   const [clearing, setClearing] = useState(false);
 
-  useEffect(() => {
-    let live = true;
-    // One read in flight at a time: a poll that outlasts its period is skipped
-    // rather than queued behind itself.
-    let busy = false;
-    async function poll() {
-      if (busy || !live) return;
-      busy = true;
-      try {
-        const read = await run((c) => c.health(id));
-        if (live) {
-          setHealth(read);
-          setError(undefined);
-        }
-      } catch (e) {
-        if (live) setError(e instanceof Error ? e.message : String(e));
-      } finally {
-        busy = false;
-      }
-    }
-    void poll();
-    const timer = window.setInterval(() => void poll(), POLL_MS);
-    return () => {
-      live = false;
-      window.clearInterval(timer);
-    };
-  }, [run, id]);
+  // A stale snapshot carries what the cache still holds, which may be nothing.
+  const complete =
+    snapshot !== undefined && HEALTH_REGISTERS.every((name) => snapshot.values.has(name));
+  const health = complete ? healthFrom(snapshot.read) : undefined;
+  const problem = error ?? (snapshot?.stale === true ? snapshot.error : undefined);
 
   async function clear() {
     setClearing(true);
     try {
-      await run((c) => c.clearCounters(id));
-      setHealth(await run((c) => c.health(id)));
+      // The counters come back on the subscription's next read.
+      await bus.command((c) => c.clearCounters(id));
       setError(undefined);
     } catch (e) {
       setError(e instanceof Error ? e.message : String(e));
@@ -73,7 +49,7 @@ export function HealthCard({ id }: { id: number }) {
         </CardTitle>
       </CardHeader>
       <CardContent>
-        {error !== undefined && <p className="text-danger">{error}</p>}
+        {problem !== undefined && <p className="text-danger">{problem}</p>}
         {health === undefined ? (
           <>
             <Skeleton className="h-5 w-full" />

src/components/manage-card.tsx

@@ -1,4 +1,4 @@
-import type { Descriptor, OscClient } from "@openservocore/client";
+import type { OscClient } from "@openservocore/client";
 import { LoaderCircle, RotateCcw, Save, SlidersHorizontal, TriangleAlert } from "lucide-react";
 import { useEffect, useId, useState, type KeyboardEvent } from "react";
 import { Button } from "@/components/ui/button";
@@ -7,11 +7,13 @@ import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 import { Separator } from "@/components/ui/separator";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
+import { useBus, useRegisters } from "@/lib/bus/hooks";
 import { ID_MAX, ID_MIN, idIssue, rescans, selectAfter, type ManageAction } from "@/lib/manage";
 import { useSession } from "@/lib/session";
 
-const POLL_MS = 1000;
 const NOTE_MS = 4000;
+/** Inside the cards' span on every servo, so the gate costs no exchange. */
+const TORQUE_REGISTERS: readonly string[] = ["torque_enable"];
 
 const HELP = {
   id: "Addressed by serial, so it also fixes two servos sharing an id. Ids 1 to 249.",
@@ -31,13 +33,14 @@ interface Note {
 }
 
 export function ManageCard({ id, uid }: { id: number; uid: string }) {
-  const { servos, descriptor, run, discover, select } = useSession();
+  const { servos, discover, select } = useSession();
+  const bus = useBus();
   const inputId = useId();
   const [text, setText] = useState(String(id));
   const [busy, setBusy] = useState<ManageAction>();
   const [note, setNote] = useState<Note>();
   const [confirming, setConfirming] = useState(false);
-  const torque = useTorque(id, descriptor);
+  const torque = useTorque(id);
 
   useEffect(() => {
     if (note === undefined || note.bad) return;
@@ -70,7 +73,7 @@ export function ManageCard({ id, uid }: { id: number; uid: string }) {
     setBusy(action);
     setNote(undefined);
     try {
-      await run(fn);
+      await bus.command(fn);
       if (rescans(action)) await discover();
       const pick = selectAfter(action, newId);
       if (pick !== undefined) select(pick);
@@ -246,39 +249,11 @@ function Hint({ note }: { note: Note }) {
   return <p className={`text-xs ${note.bad ? "text-danger" : "text-text-3"}`}>{note.text}</p>;
 }
 
-/** The Save gate: `torque_enable` read off the table on the cards' cadence. */
-function useTorque(id: number, descriptor: Descriptor | undefined): boolean | undefined {
-  const { run } = useSession();
-  const [on, setOn] = useState<boolean>();
-
-  useEffect(() => {
-    if (descriptor === undefined) return;
-    const table = descriptor;
-    const field = table.fields().find((f) => f.name === "torque_enable");
-    if (field === undefined) return;
-    const { name, addr, width } = field;
-    let live = true;
-    let busy = false;
-    async function poll() {
-      if (busy || !live) return;
-      busy = true;
-      try {
-        const bytes = await run((c) => c.read(id, addr, width));
-        const value = table.decode(name, bytes);
-        if (live && value.kind === "bool") setOn(value.value);
-      } catch {
-        // The gate holds its last reading; Health reports a servo gone quiet.
-      } finally {
-        busy = false;
-      }
-    }
-    void poll();
-    const timer = window.setInterval(() => void poll(), POLL_MS);
-    return () => {
-      live = false;
-      window.clearInterval(timer);
-    };
-  }, [run, id, descriptor]);
-
-  return on;
+/**
+ * The Save gate: `torque_enable` on the cards' cadence. A stale snapshot still
+ * carries the last reading; Health reports a servo gone quiet.
+ */
+function useTorque(id: number): boolean | undefined {
+  const value = useRegisters(id, TORQUE_REGISTERS, "slow")?.values.get("torque_enable");
+  return value?.kind === "bool" ? value.value : undefined;
 }

src/lib/identity.test.ts

@@ -0,0 +1,26 @@
+import { expect, test } from "vitest";
+import { features, identityFrom, IDENTITY_REGISTERS } from "./identity";
+
+test("identityFrom reads the four identity registers", () => {
+  const table = new Map([
+    ["model_number", 0x0101],
+    ["firmware_version", 0x0100],
+    ["hardware_revision", 3],
+    ["capability_flags", 1],
+  ]);
+  const names: string[] = [];
+  const read = (name: string): number => {
+    names.push(name);
+    const v = table.get(name);
+    if (v === undefined) throw new Error(`${name} outside the read`);
+    return v;
+  };
+  expect(identityFrom(read)).toEqual({ model: 0x0101, fw: 0x0100, hw: 3, capabilities: 1 });
+  expect(new Set(names)).toEqual(new Set(IDENTITY_REGISTERS));
+});
+
+test("features names the known bits and numbers the rest", () => {
+  expect(features(0)).toBe("None");
+  expect(features(1)).toBe("Motor encoder");
+  expect(features(0b101)).toBe("Motor encoder, bit 2");
+});

src/lib/identity.ts

@@ -0,0 +1,31 @@
+import type { Identity } from "@openservocore/client";
+import type { ReadRegister } from "./units";
+
+/** CONFIG-COMMON front: what a servo says about itself, read once per servo. */
+export const IDENTITY_REGISTERS: readonly string[] = [
+  "model_number",
+  "firmware_version",
+  "hardware_revision",
+  "capability_flags",
+];
+
+export function identityFrom(read: ReadRegister): Identity {
+  return {
+    model: read("model_number"),
+    fw: read("firmware_version"),
+    hw: read("hardware_revision"),
+    capabilities: read("capability_flags"),
+  };
+}
+
+/** `capability_flags` bit order (protocol sec 5.4). */
+const CAPABILITIES: readonly string[] = ["Motor encoder"];
+
+export function features(caps: number): string {
+  const set: string[] = [];
+  for (let bit = 0; bit < 32; bit++) {
+    if ((caps & (1 << bit)) === 0) continue;
+    set.push(CAPABILITIES[bit] ?? `bit ${bit}`);
+  }
+  return set.length === 0 ? "None" : set.join(", ");
+}