Move RefCounted class to a separate file

.gitignore

@@ -0,0 +1,6 @@
+.yotta.json
+build
+*.swp
+yotta_modules
+yotta_targets
+Makefile

inc/ManagedString.h

@@ -1,24 +1,7 @@
 #ifndef MANAGED_STRING_H
 #define MANAGED_STRING_H
 
-#include "mbed.h"
-
-struct RefCounted
-{
-public:
-    uint16_t refcnt;
-    uint16_t size;
-
-    void incr();
-    void decr();
-
-};
-
-class VirtualRefCounted : RefCounted
-{
-public:
-    virtual ~VirtualRefCounted();
-};
+#include "RefCounted.h"
 
 struct StringData : RefCounted
 {

inc/RefCounted.h

@@ -0,0 +1,51 @@
+#ifndef REF_COUNTED_H
+#define REF_COUNTED_H
+
+#include "mbed.h"
+
+/**
+  * Base class for payload for ref-counted objects. Used by ManagedString and MicroBitImage.
+  * There is no constructor, as this struct is typically malloc()ed.
+  */
+struct RefCounted
+{
+public:
+    /**
+      * Number of outstanding references. Should never be zero (object should be deleted then).
+      * When it's set to 0xffff, it means the object sits in flash and should not be counted.
+      */
+    uint16_t refcnt;
+
+    /**
+      * For strings this is length. For images this is both width and length (8 bit each).
+      * A value of 0xffff indicates that this is in fact an instance of VirtualRefCounted
+      * and therefore when the reference count reaches zero, the virtual destructor
+      * should be called.
+      */
+    union {
+        uint16_t size;
+        struct {
+            uint8_t width;
+            uint8_t height;
+        };
+    };
+
+    /** Increment reference count. */
+    void incr();
+
+    /** Decrement reference count. */
+    void decr();
+
+};
+
+/**
+  * Base class for ref-counted objects. Used in native compiler in TD for Collections,
+  * user-defined records, closures etc.
+  */
+class VirtualRefCounted : RefCounted
+{
+public:
+    virtual ~VirtualRefCounted();
+};
+
+#endif

source/CMakeLists.txt

@@ -28,6 +28,7 @@ set(YOTTA_AUTO_MICROBIT-DAL_CPP_FILES
     "MicroBitSerial.cpp"
     "MicroBitHeapAllocator.cpp"
     "MicroBitListener.cpp"
+    "RefCounted.cpp"
     "MemberFunctionCallback.cpp"
     "ble-services/MicroBitDFUService.cpp"
     "ble-services/MicroBitEventService.cpp"

source/ManagedString.cpp

@@ -366,33 +366,3 @@ char ManagedString::charAt(int16_t index)
   * Empty string constant literal
   */
 ManagedString ManagedString::EmptyString((StringData*)(void*)empty);
-
-
-void RefCounted::incr()
-{
-    if (refcnt == 0xffff)
-        return;
-    if (refcnt == 0)
-        uBit.panic(30);
-    refcnt++;
-}
-
-void RefCounted::decr()
-{
-    if (refcnt == 0xffff)
-        return;
-    if (refcnt == 0)
-        uBit.panic(31);
-    refcnt--;
-    if (refcnt == 0) {
-        // size of 0xffff indicates a class with a virtual destructor
-        if (size == 0xffff)
-            delete (VirtualRefCounted*)this;
-        else
-            free(this);
-    }
-}
-
-VirtualRefCounted::~VirtualRefCounted()
-{
-}

source/RefCounted.cpp

@@ -0,0 +1,31 @@
+#include "mbed.h"
+#include "MicroBit.h"
+
+void RefCounted::incr()
+{
+    if (refcnt == 0xffff)
+        return;
+    if (refcnt == 0)
+        uBit.panic(30);
+    refcnt++;
+}
+
+void RefCounted::decr()
+{
+    if (refcnt == 0xffff)
+        return;
+    if (refcnt == 0)
+        uBit.panic(31);
+    refcnt--;
+    if (refcnt == 0) {
+        // size of 0xffff indicates a class with a virtual destructor
+        if (size == 0xffff)
+            delete (VirtualRefCounted*)this;
+        else
+            free(this);
+    }
+}
+
+VirtualRefCounted::~VirtualRefCounted()
+{
+}