Safepolling (#915)

* headstart on safe polling

* poke in sensors

* more poking

* typo

libs/color-sensor/color.ts

@@ -179,6 +179,7 @@ namespace sensors {
         //% group="Color Sensor"
         //% blockGap=8
         color(): ColorSensorColor {
+            this.poke();
             this.setMode(ColorSensorMode.Color)
             return this.getNumber(NumberFormat.UInt8LE, 0)
         }
@@ -196,6 +197,7 @@ namespace sensors {
         //% group="Color Sensor"
         //% blockGap=8
         rgbRaw(): number[] {
+            this.poke();
             this.setMode(ColorSensorMode.RgbRaw);
             return [this.getNumber(NumberFormat.UInt16LE, 0), this.getNumber(NumberFormat.UInt16LE, 2), this.getNumber(NumberFormat.UInt16LE, 4)];
         }
@@ -249,6 +251,7 @@ namespace sensors {
         //% weight=87 blockGap=8
         //% group="Color Sensor"
         light(mode: LightIntensityMode) {
+            this.poke();
             this.setMode(<ColorSensorMode><number>mode)
             switch(mode) {
                 case LightIntensityMode.ReflectedRaw:
@@ -279,6 +282,7 @@ namespace sensors {
          */
         //%
         reflectedLightRaw(): number {
+            this.poke();
             this.setMode(ColorSensorMode.RefRaw);
             return this.getNumber(NumberFormat.UInt16LE, 0);
         }

libs/core/buttons.ts

@@ -55,6 +55,10 @@ namespace brick {
             this._wasPressed = false
         }
 
+        protected poke() {
+
+        }
+
         //% hidden
         _update(curr: boolean) {
             if (this == null) return
@@ -85,6 +89,7 @@ namespace brick {
         //% group="Buttons"
         //% button.fieldEditor="brickbuttons"
         isPressed() {
+            this.poke();
             return this._isPressed
         }
 
@@ -102,6 +107,7 @@ namespace brick {
         //% group="Buttons"
         //% button.fieldEditor="brickbuttons"
         wasPressed() {
+            this.poke();
             const r = this._wasPressed
             this._wasPressed = false
             return r
@@ -144,6 +150,7 @@ namespace brick {
 namespace brick {
     let btnsMM: MMap
     let buttons: DevButton[]
+    let buttonPoller: sensors.internal.Poller;
 
     export namespace internal {
         export function getBtnsMM() {
@@ -167,7 +174,7 @@ namespace brick {
         btnsMM = control.mmap("/dev/lms_ui", DAL.NUM_BUTTONS, 0)
         if (!btnsMM) control.fail("no buttons?")
         buttons = []
-        sensors.internal.unsafePollForChanges(50, readButtons, (prev, curr) => {
+        buttonPoller = new sensors.internal.Poller(50, readButtons, (prev, curr) => {
             for (let b of buttons)
                 b._update(!!(curr & b.mask))
         })
@@ -182,6 +189,10 @@ namespace brick {
             initBtns()
             buttons.push(this)
         }
+
+        protected poke() {
+            buttonPoller.poke();
+        }
     }    
 
     initBtns() // always ON as it handles ESCAPE button

libs/core/input.ts

@@ -1,29 +1,52 @@
 namespace sensors.internal {
-    //% shim=pxt::unsafePollForChanges
+    export class Poller {
-    export function unsafePollForChanges(
+        private query: () => number;
-        periodMs: number,
+        private update: (previous: number, current: number) => void;
-        query: () => number,
+        public interval: number;
-        changeHandler: (prev: number, curr: number) => void
-    ) {
-        // This is implemented in C++ without blocking the regular JS when query() is runnning
-        // which is generally unsafe. Query should not update globally visible state, and cannot
-        // call any yielding functions, like sleep().
 
-        // This is implementation for the simulator.
+        private previousValue: number;
+        private currentValue: number;
+        private lastQuery: number; // track down the last time we did a query/update cycle
+        private lastPause: number;  // track down the last time we pause in the sensor polling loop
 
-        control.runInParallel(() => {
+        constructor(interval: number, query: () => number, update: (previous: number, current: number) => void) {
-            let prev = query()
+            this.interval = interval | 0;
-            changeHandler(prev, prev)
+            this.query = query;
-            while (true) {
+            this.update = update;
-                pause(periodMs)
+
-                let curr = query()
+            this.poll();
-                if (prev !== curr) {
-                    changeHandler(prev, curr)
-                    prev = curr
         }
+
+        poke(): void {
+            const now = control.millis();
+            if (now - this.lastQuery >= this.interval * 2)
+                this.queryAndUpdate(); // sensor poller is not allowed to run
+            if (now - this.lastPause >= this.interval * 5)
+                pause(1); // allow events to trigger
+        }
+
+        private queryAndUpdate() {
+            this.lastQuery = control.millis();
+            this.currentValue = this.query();
+            if (this.previousValue != this.currentValue) {
+                this.update(this.previousValue, this.currentValue);
+                this.previousValue = this.currentValue;
+            }
+        }
+
+        private poll() {
+            control.runInBackground(() => {
+                this.lastQuery = this.lastPause = control.millis();
+                this.previousValue = this.currentValue = this.query();
+                this.update(this.previousValue, this.currentValue);
+                while (true) {
+                    this.lastPause = control.millis();
+                    pause(this.interval);
+                    this.queryAndUpdate();
                 }
             })
         }
+    }
 
     export function bufferToString(buf: Buffer): string {
         let s = ''
@@ -38,6 +61,7 @@ namespace sensors.internal {
     let IICMM: MMap
     let powerMM: MMap
     let devcon: Buffer
+    let devPoller: Poller
     let sensorInfos: SensorInfo[];
 
     let batteryInfo: {
@@ -55,6 +79,7 @@ namespace sensors.internal {
         connType: number
         devType: number
         iicid: string
+        poller: Poller;
 
         constructor(p: number) {
             this.port = p
@@ -62,6 +87,20 @@ namespace sensors.internal {
             this.devType = DAL.DEVICE_TYPE_NONE
             this.iicid = ''
             this.sensors = []
+            this.poller = new Poller(50, () => this.query(), (prev, curr) => this.update(prev, curr));
+        }
+
+        poke() {
+            this.poller.poke();
+        }
+
+        private query() {
+            if (this.sensor) return this.sensor._query();
+            return 0;
+        }
+
+        private update(prev: number, curr: number) {
+            if (this.sensor) this.sensor._update(prev, curr)
         }
     }
 
@@ -82,19 +121,10 @@ namespace sensors.internal {
 
         powerMM = control.mmap("/dev/lms_power", 2, 0)
 
-        unsafePollForChanges(500,
+        devPoller = new Poller(500, () => { return hashDevices(); },
-            () => { return hashDevices(); },
             (prev, curr) => {
                 detectDevices();
             });
-        sensorInfos.forEach(info => {
-            unsafePollForChanges(50, () => {
-                if (info.sensor) return info.sensor._query()
-                return 0
-            }, (prev, curr) => {
-                if (info.sensor) info.sensor._update(prev, curr)
-            })
-        })        
     }
 
     export function getActiveSensors(): Sensor[] {
@@ -337,6 +367,11 @@ void      cUiUpdatePower(void)
             this.markUsed();
         }
 
+        poke() {
+            if (this.isActive())
+                sensorInfos[this._port].poke();
+        }
+
         markUsed() {
             sensors.__sensorUsed(this._port, this._deviceType());
         }

libs/core/linux.cpp

@@ -446,11 +446,6 @@ static void runPoller(Thread *thr) {
     //    disposeThread(thr);
 }
 
-//%
-void unsafePollForChanges(int ms, Action query, Action handler) {
-    setupThread(handler, 0, runPoller, query, fromInt(ms));
-}
-
 uint32_t afterProgramPage() {
     return 0;
 }

libs/gyro-sensor/gyro.ts

@@ -45,6 +45,7 @@ namespace sensors {
         //% weight=64 blockGap=8
         //% group="Gyro Sensor"
         angle(): number {
+            this.poke();
             if (this.calibrating)
                 pauseUntil(() => !this.calibrating, 2000);
 
@@ -65,6 +66,7 @@ namespace sensors {
         //% weight=65 blockGap=8
         //% group="Gyro Sensor"
         rate(): number {
+            this.poke();
             if (this.calibrating)
                 pauseUntil(() => !this.calibrating, 2000);
 

libs/infrared-sensor/ir.ts

@@ -235,6 +235,7 @@ namespace sensors {
         //% group="Infrared Sensor"
         //% this.fieldEditor="ports"
         proximity(): number {
+            this.poke();
             this._setMode(InfraredSensorMode.Proximity)
             return this.getNumber(NumberFormat.UInt8LE, 0)
         }
@@ -284,6 +285,7 @@ namespace sensors {
 
         // TODO
         private getDirectionAndDistance() {
+            this.poke();
             this._setMode(InfraredSensorMode.Seek)
             return this.getNumber(NumberFormat.UInt16LE, this._channel * 2)
         }

libs/touch-sensor/touch.ts

@@ -73,6 +73,7 @@ namespace sensors {
         //% weight=81 blockGap=8
         //% group="Touch Sensor"
         isPressed() {
+            this.poke();
             return this.button.isPressed();
         }
 
@@ -90,6 +91,7 @@ namespace sensors {
         //% weight=81
         //% group="Touch Sensor"
         wasPressed() {
+            this.poke();
             return this.button.wasPressed();
         }
     }

libs/ultrasonic-sensor/ultrasonic.ts

@@ -84,6 +84,7 @@ namespace sensors {
         //% weight=65
         //% group="Ultrasonic Sensor"
         distance(): number {
+            this.poke();
             // it supposedly also has an inch mode, but we stick to cm
             this._setMode(0)
             return this._query();