[heap] export heap API (#4143)

include/openthread/heap.h

@@ -72,6 +72,14 @@ typedef void *(*otHeapCAllocFn)(size_t aCount, size_t aSize);
  */
 typedef void (*otHeapFreeFn)(void *aPointer);
 
+// This is a temporary API and would be removed after moving heap to platform.
+// TODO: Remove after moving heap to platform.
+void *otHeapCAlloc(size_t aCount, size_t aSize);
+
+// This is a temporary API and would be removed after moving heap to platform.
+// TODO: Remove after moving heap to platform.
+void otHeapFree(void *aPointer);
+
 /**
  * This function sets the external heap CAlloc and Free
  * functions to be used by the OpenThread stack.

src/core/Makefile.am

@@ -241,6 +241,7 @@ EXTRA_DIST                                 = \
 
 libopenthread_radio_a_SOURCES              = \
     api/diags_api.cpp                        \
+    api/heap_api.cpp                         \
     api/instance_api.cpp                     \
     api/link_raw_api.cpp                     \
     api/logging_api.cpp                      \

src/core/api/heap_api.cpp

@@ -37,7 +37,46 @@
 
 #include "common/instance.hpp"
 
-#if OPENTHREAD_CONFIG_HEAP_EXTERNAL_ENABLE
+#if !OPENTHREAD_CONFIG_MULTIPLE_INSTANCE_ENABLE || OPENTHREAD_CONFIG_HEAP_EXTERNAL_ENABLE
+
+#if OPENTHREAD_RADIO
+
+void *otHeapCAlloc(size_t aCount, size_t aSize)
+{
+    OT_UNUSED_VARIABLE(aCount);
+    OT_UNUSED_VARIABLE(aSize);
+
+    // Should never get called!
+    assert(false);
+
+    return NULL;
+}
+
+void otHeapFree(void *aPointer)
+{
+    OT_UNUSED_VARIABLE(aPointer);
+
+    // Should never get called!
+    assert(false);
+}
+
+#else // OPENTHREAD_RADIO
+
+void *otHeapCAlloc(size_t aCount, size_t aSize)
+{
+    return ot::Instance::Get().HeapCAlloc(aCount, aSize);
+}
+
+void otHeapFree(void *aPointer)
+{
+    ot::Instance::Get().HeapFree(aPointer);
+}
+
+#endif // OPENTHREAD_RADIO
+
+#endif // !OPENTHREAD_CONFIG_MULTIPLE_INSTANCE_ENABLE || OPENTHREAD_CONFIG_HEAP_EXTERNAL_ENABLE
+
+#if OPENTHREAD_CONFIG_HEAP_EXTERNAL_ENABLE && !OPENTHREAD_RADIO
 void otHeapSetCAllocFree(otHeapCAllocFn aCAlloc, otHeapFreeFn aFree)
 {
     ot::Instance::HeapSetCAllocFree(aCAlloc, aFree);

src/core/common/instance.hpp

@@ -272,6 +272,7 @@ public:
 #elif !OPENTHREAD_CONFIG_MULTIPLE_INSTANCE_ENABLE
     void  HeapFree(void *aPointer) { mHeap.Free(aPointer); }
     void *HeapCAlloc(size_t aCount, size_t aSize) { return mHeap.CAlloc(aCount, aSize); }
+
     /**
      * This method returns a reference to the Heap object.
      *