Restart the WASM module when stopping/starting/panicking (#51)

Fixes panic HAL calls so the device is no longer operable afterwards.

- Use the same logic for a normal stop/start.
- Cache the WASM to avoid downloading and compiling it for each module
  instantiation.
- Prefer using the _foo functions on the module vs cwrap.
- Incidental fix to the radio message handling in demo.html

Co-authored-by: Robert Knight <[email protected]>

Author: microbit-matt-hillsdon

Makefile

@@ -9,7 +9,7 @@ build:
 dist: build
 	mkdir -p $(BUILD)/build
 	cp -r $(SRC)/*.html $(SRC)/term.js src/examples $(BUILD)
-	cp $(SRC)/build/micropython.js $(SRC)/build/firmware.wasm  $(BUILD)/build/
+	cp $(SRC)/build/firmware.js $(SRC)/build/simulator.js $(SRC)/build/firmware.wasm  $(BUILD)/build/
 
 watch: dist
 	fswatch -o -e src/build src  | while read _; do $(MAKE) dist; done

README.md

@@ -151,6 +151,19 @@ The following sections documents the messages supported via postMessage.
 <td>Radio output (sent from the user's program) as bytes.
 If you send string data from the program then it will be prepended with the three bytes 0x01, 0x00, 0x01.
 
+<tr>
+<td>internal_error
+<td>
+
+```javascript
+{
+  "kind": "internal_error",
+  "error": new Error()
+}
+```
+
+<td>A debug message sent for internal (unexpected) errors thrown by the simulator. Suitable for application-level logging. Please raise issues in this project as these indicate a bug in the simulator.
+
 </table>
 
 ## Messages supported by the iframe

src/Makefile

@@ -1,4 +1,4 @@
-# Makefile to build micropython.js
+# Makefile to build WASM and simulator JS.
 
 # Build upon the codal_port code.
 CODAL_PORT = $(abspath ../lib/micropython-microbit-v2/src/codal_port)
@@ -44,9 +44,11 @@ COPT += -O3 -DNDEBUG
 endif
 
 JSFLAGS += -s ASYNCIFY
-JSFLAGS += -s EXPORTED_FUNCTIONS="['_mp_js_main','_mp_js_request_stop','_microbit_hal_audio_ready_callback','_microbit_hal_audio_speech_ready_callback','_microbit_hal_gesture_callback','_microbit_hal_level_detector_callback','_microbit_radio_rx_buffer']"
+JSFLAGS += -s EXIT_RUNTIME
+JSFLAGS += -s MODULARIZE=1
+JSFLAGS += -s EXPORT_NAME=createModule
+JSFLAGS += -s EXPORTED_FUNCTIONS="['_mp_js_main','_microbit_hal_audio_ready_callback','_microbit_hal_audio_speech_ready_callback','_microbit_hal_gesture_callback','_microbit_hal_level_detector_callback','_microbit_radio_rx_buffer','_mp_js_force_stop','_mp_js_request_stop']"
 JSFLAGS += -s EXPORTED_RUNTIME_METHODS="['ccall', 'cwrap']" --js-library jshal.js
-JSFLAGS += --pre-js $(BUILD)/pre.js
 
 ifdef DEBUG
 JSFLAGS += -g
@@ -136,14 +138,13 @@ $(MBIT_VER_FILE): FORCE
 	$(PYTHON) $(TOP)/py/makeversionhdr.py $(MBIT_VER_FILE).pre
 	$(CAT) $(MBIT_VER_FILE).pre | $(SED) s/MICROPY_/MICROBIT_/ > $(MBIT_VER_FILE)
 
-$(BUILD)/micropython.js: $(OBJ) jshal.js main.js pre-js
+$(BUILD)/micropython.js: $(OBJ) jshal.js simulator-js
 	$(ECHO) "LINK $(BUILD)/firmware.js"
 	$(Q)emcc $(LDFLAGS) -o $(BUILD)/firmware.js $(OBJ) $(JSFLAGS)
-	cat main.js $(BUILD)/firmware.js > $@
 
-pre-js:
-	npx esbuild ./pre.ts --bundle --outfile=$(BUILD)/pre.js --loader:.svg=text
+simulator-js:
+	npx esbuild ./simulator.ts --bundle --outfile=$(BUILD)/simulator.js --loader:.svg=text
 
 include $(TOP)/py/mkrules.mk
 
-.PHONY: pre-js
+.PHONY: simulator-js

src/board/accelerometer.ts

@@ -48,8 +48,8 @@ export class Accelerometer {
 
   setValue(id: StateKeys, value: any) {
     this.state[id].setValue(value);
-    if (id === "gesture") {
-      this.gestureCallback!(
+    if (id === "gesture" && this.gestureCallback) {
+      this.gestureCallback(
         convertAccelerometerStringToNumber(this.state.gesture.value)
       );
     }
@@ -71,11 +71,9 @@ export class Accelerometer {
     });
   }
 
-  initialize(gestureCallback: GestureCallback) {
+  initializeCallbacks(gestureCallback: GestureCallback) {
     this.gestureCallback = gestureCallback;
   }
 
-  dispose() {
-    this.gestureCallback = undefined;
-  }
+  dispose() {}
 }

src/board/audio/index.ts

@@ -23,7 +23,10 @@ export class Audio {
 
   constructor() {}
 
-  initialize({ defaultAudioCallback, speechAudioCallback }: AudioOptions) {
+  initializeCallbacks({
+    defaultAudioCallback,
+    speechAudioCallback,
+  }: AudioOptions) {
     this.context = new AudioContext({
       // The highest rate is the sound expression synth.
       sampleRate: 44100,

src/board/buttons.ts

@@ -115,8 +115,6 @@ export class Button {
     return result;
   }
 
-  initialize() {}
-
   dispose() {
     this._presses = 0;
   }

src/board/compass.ts

@@ -27,7 +27,5 @@ export class Compass {
     return Math.sqrt(x * x + y * y + z * z);
   }
 
-  initialize() {}
-
   dispose() {}
 }

src/board/conversions.ts

@@ -12,22 +12,10 @@ import {
   MICROBIT_HAL_ACCELEROMETER_EVT_TILT_LEFT,
   MICROBIT_HAL_ACCELEROMETER_EVT_TILT_RIGHT,
   MICROBIT_HAL_ACCELEROMETER_EVT_TILT_UP,
-  MICROBIT_HAL_MICROPHONE_EVT_THRESHOLD_HIGH,
-  MICROBIT_HAL_MICROPHONE_EVT_THRESHOLD_LOW,
   MICROBIT_HAL_MICROPHONE_SET_THRESHOLD_HIGH,
   MICROBIT_HAL_MICROPHONE_SET_THRESHOLD_LOW,
 } from "./constants";
 
-export function convertAudioBuffer(source: number, target: AudioBuffer) {
-  const channel = target.getChannelData(0);
-  const heap = window.HEAPU8;
-  for (let i = 0; i < channel.length; ++i) {
-    // Convert from uint8 to -1..+1 float.
-    channel[i] = (heap[source + i] / 255) * 2 - 1;
-  }
-  return target;
-}
-
 export function convertSoundThresholdNumberToString(
   value: number
 ): "low" | "high" {
@@ -106,3 +94,16 @@ export function convertAccelerometerNumberToString(value: number): string {
       throw new Error(`Invalid value ${value}`);
   }
 }
+
+export const convertAudioBuffer = (
+  heap: Uint8Array,
+  source: number,
+  target: AudioBuffer
+) => {
+  const channel = target.getChannelData(0);
+  for (let i = 0; i < channel.length; ++i) {
+    // Convert from uint8 to -1..+1 float.
+    channel[i] = (heap[source + i] / 255) * 2 - 1;
+  }
+  return target;
+};

src/board/display.ts

@@ -73,8 +73,6 @@ export class Display {
     }
   }
 
-  initialize() {}
-
   dispose() {
     this.clear();
   }