From 8d1c871de3d0378ae4fa42d6fabf5e8aa0686bdc Mon Sep 17 00:00:00 2001
From: mappu <mappu04@gmail.com>
Date: Tue, 19 Nov 2024 19:24:50 +1300
Subject: [PATCH] genbindings/inherits: direct vs indirect inheritance

---
 cmd/genbindings/clang2il.go     |  2 +-
 cmd/genbindings/emitgo.go       |  4 ++-
 cmd/genbindings/intermediate.go | 44 +++++++++++++++++++++++++++------
 3 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/cmd/genbindings/clang2il.go b/cmd/genbindings/clang2il.go
index 9ad21f94..e8747a5b 100644
--- a/cmd/genbindings/clang2il.go
+++ b/cmd/genbindings/clang2il.go
@@ -265,7 +265,7 @@ func processClassType(node map[string]interface{}, addNamePrefix string) (CppCla
 
 			if typ, ok := base["type"].(map[string]interface{}); ok {
 				if qualType, ok := typ["qualType"].(string); ok {
-					ret.Inherits = append(ret.Inherits, qualType)
+					ret.DirectInherits = append(ret.DirectInherits, qualType)
 				}
 			}
 		}
diff --git a/cmd/genbindings/emitgo.go b/cmd/genbindings/emitgo.go
index ff67fe94..80324043 100644
--- a/cmd/genbindings/emitgo.go
+++ b/cmd/genbindings/emitgo.go
@@ -709,7 +709,9 @@ import "C"
 		`)
 
 		// Embed all inherited types to directly allow calling inherited methods
-		for _, base := range c.Inherits {
+		// Only include the direct inherits; the recursive inherits will exist
+		// on these types already
+		for _, base := range c.DirectInherits {
 
 			if pkg, ok := KnownClassnames[base]; ok && pkg.PackageName != gfs.currentPackageName {
 				// Cross-package parent class
diff --git a/cmd/genbindings/intermediate.go b/cmd/genbindings/intermediate.go
index eff54906..2ed07665 100644
--- a/cmd/genbindings/intermediate.go
+++ b/cmd/genbindings/intermediate.go
@@ -372,13 +372,13 @@ func (e CppEnum) ShortEnumName() string {
 }
 
 type CppClass struct {
-	ClassName string
-	Abstract  bool
-	Ctors     []CppMethod // only use the parameters
-	Inherits  []string    // other class names
-	Methods   []CppMethod
-	Props     []CppProperty
-	CanDelete bool
+	ClassName      string
+	Abstract       bool
+	Ctors          []CppMethod // only use the parameters
+	DirectInherits []string    // other class names. This only includes direct inheritance - use AllInherits() to find recursive inheritance
+	Methods        []CppMethod
+	Props          []CppProperty
+	CanDelete      bool
 
 	ChildTypedefs  []CppTypedef
 	ChildClassdefs []CppClass
@@ -431,7 +431,10 @@ func (c *CppClass) VirtualMethods() []CppMethod {
 		retNames[m.CppCallTarget()] = struct{}{}
 	}
 
-	for _, inh := range c.Inherits {
+	// Only allow virtual overrides for direct inherits, not all inherits -
+	// Go will automatically allow virtual overrides for the base type because
+	// the parent struct is nested
+	for _, inh := range c.DirectInherits { // AllInherits() {
 		cinfo, ok := KnownClassnames[inh]
 		if !ok {
 			panic("Class " + c.ClassName + " inherits from unknown class " + inh)
@@ -481,6 +484,31 @@ func (c *CppClass) VirtualMethods() []CppMethod {
 	return ret
 }
 
+// AllInherits recursively finds and lists all the parent classes of this class.
+func (c *CppClass) AllInherits() []string {
+	var ret []string
+
+	// FIXME prevent duplicates arising from diamond inheritance
+
+	for _, baseClass := range c.DirectInherits {
+
+		ret = append(ret, baseClass)
+
+		// And everything that class inherits - unless - we've seen it before
+		baseClassInfo, ok := KnownClassnames[baseClass]
+		if !ok {
+			panic("Class " + c.ClassName + " inherits from unknown class " + baseClass)
+		}
+
+		recurseInfo := baseClassInfo.Class.AllInherits()
+		for _, childClass := range recurseInfo {
+			ret = append(ret, childClass)
+		}
+	}
+
+	return ret
+}
+
 type CppTypedef struct {
 	Alias          string
 	UnderlyingType CppParameter