Add attribute and resetSource() to IndirectAttribute

Author: jcmosc

Sources/OpenGraph/Attribute/Indirect/IndirectAttribute.swift

@@ -15,11 +15,19 @@ public struct IndirectAttribute<Value> {
         identifier = source.identifier.createIndirect(size: UInt64(MemoryLayout<Value>.size))
     }
 
+    public var attribute: Attribute<Value> {
+        Attribute(identifier: identifier)
+    }
+    
     public var source: Attribute<Value> {
         get { Attribute(identifier: identifier.source) }
         nonmutating set { identifier.source = newValue.identifier }
     }
 
+    public func resetSource() {
+        __OGGraphResetIndirectAttribute(identifier, false)
+    }
+    
     public var dependency: AnyAttribute? {
         get {
             let dependency = identifier._indirectDependency

Sources/OpenGraphCxx/Attribute/OGAttribute.cpp

@@ -98,6 +98,10 @@ void OGGraphSetIndirectAttribute(OGAttribute attribute1, OGAttribute attribute2)
     // TODO
 }
 
+void OGGraphResetIndirectAttribute(OGAttribute attribute, bool non_nil) {
+    // TODO
+}
+
 OGAttribute OGGraphCreateAttribute(long index, const void *body, const void * value) {
     // TODO
     return OGAttributeNil;

Sources/OpenGraphCxx/include/OpenGraph/OGAttribute.h

@@ -83,6 +83,10 @@ OG_EXPORT
 OG_REFINED_FOR_SWIFT
 void OGGraphSetIndirectAttribute(OGAttribute attribute1, OGAttribute attribute2) OG_SWIFT_NAME(setter:OGAttribute.source(self:_:));
 
+OG_EXPORT
+OG_REFINED_FOR_SWIFT
+void OGGraphResetIndirectAttribute(OGAttribute attribute, bool non_nil);
+
 OG_EXPORT
 OG_REFINED_FOR_SWIFT
 OGAttribute OGGraphCreateAttribute(long index, const void *body, const void * _Nullable value);