microbit: further fixes to #73

issue #73 highlighted an issue whereby the destruction of an instance
registered as an idle or system component, would result in a hardfault.

This was due to not deregistering idle or system callbacks.

This patch has been applied to all components currently in use by the
idle or system callbacks.

inc/MicroBitAccelerometer.h

@@ -310,6 +310,11 @@ class MicroBitAccelerometer : public MicroBitComponent
      */
     virtual int isIdleCallbackNeeded();
 
+    /**
+      * Destructor for MicroBitButton, so that we deregister ourselves as an idleComponent
+      */
+    ~MicroBitAccelerometer();
+
     private:
     /**
      * Issues a standard, 2 byte I2C command write to the accelerometer.

inc/MicroBitCompass.h

@@ -328,6 +328,11 @@ class MicroBitCompass : public MicroBitComponent
       */
     virtual int isIdleCallbackNeeded();
 
+    /**
+      * Destructor for MicroBitCompass, so that we deregister ourselves as an idleComponent
+      */
+    ~MicroBitCompass();
+
     private:
 
     /**

inc/MicroBitDisplay.h

@@ -562,6 +562,11 @@ public:
       * Captures the bitmap currently being rendered on the display.
       */
     MicroBitImage screenShot();
+
+    /**
+      * Destructor for MicroBitDisplay, so that we deregister ourselves as a systemComponent
+      */
+    ~MicroBitDisplay();
 };
 
 #endif

inc/MicroBitMessageBus.h

@@ -223,6 +223,11 @@ class MicroBitMessageBus : public MicroBitComponent
       */
     MicroBitListener *elementAt(int n);
 
+    /**
+      * Destructor for MicroBitMessageBus, so that we deregister ourselves as an idleComponent
+      */
+    ~MicroBitMessageBus();
+
 	private:
 
     /**

source/MicroBitAccelerometer.cpp

@@ -571,6 +571,14 @@ int MicroBitAccelerometer::isIdleCallbackNeeded()
     return !int1;
 }
 
+/**
+  * Destructor for MicroBitAccelerometer, so that we deregister ourselves as an idleComponent
+  */
+MicroBitAccelerometer::~MicroBitAccelerometer()
+{
+    uBit.removeIdleComponent(this);
+}
+
 const MMA8653SampleRangeConfig MMA8653SampleRange[MMA8653_SAMPLE_RANGES] = {
     {2, 0},
     {4, 1},

source/MicroBitCompass.cpp

@@ -537,6 +537,14 @@ int MicroBitCompass::isIdleCallbackNeeded()
     return int1;
 }
 
+/**
+  * Destructor for MicroBitMessageBus, so that we deregister ourselves as an idleComponent
+  */
+MicroBitCompass::~MicroBitCompass()
+{
+    uBit.removeIdleComponent(this);
+}
+
 const MAG3110SampleRateConfig MAG3110SampleRate[MAG3110_SAMPLE_RATES] = {
     {12500,      0x00},        // 80 Hz
     {25000,      0x20},        // 40 Hz

source/MicroBitDisplay.cpp

@@ -1080,3 +1080,11 @@ MicroBitImage MicroBitDisplay::screenShot()
 {
     return image.crop(0,0,MICROBIT_DISPLAY_WIDTH,MICROBIT_DISPLAY_HEIGHT);
 }
+
+/**
+  * Destructor for MicroBitDisplay, so that we deregister ourselves as a systemComponent
+  */
+MicroBitDisplay::~MicroBitDisplay()
+{
+    uBit.removeSystemComponent(this);
+}

source/MicroBitMessageBus.cpp

@@ -585,3 +585,11 @@ MicroBitListener* MicroBitMessageBus::elementAt(int n)
 
     return l;
 }
+
+/**
+  * Destructor for MicroBitMessageBus, so that we deregister ourselves as an idleComponent
+  */
+MicroBitMessageBus::~MicroBitMessageBus()
+{
+    uBit.removeIdleComponent(this);
+}