genbindings: merge enums with redundant definitions

cmd/genbindings/clang2il.go

@@ -94,9 +94,12 @@ func parseHeader(topLevel []interface{}, addNamePrefix string) (*CppParsedHeader
 			if err != nil {
 				panic(fmt.Errorf("processEnum: %w", err)) // A real problem
 			}
-			if len(en.Entries) > 0 { // e.g. qmetatype's version of QCborSimpleType (the real one is in qcborcommon)
+
+			// n.b. In some cases we may produce multiple "copies" of an enum
+			// (e.g. qcborcommon and qmetatype both define QCborSimpleType)
+			// Allow, but use a transform pass to avoid multiple definitions of
+			// it
 			ret.Enums = append(ret.Enums, en)
-			}
 
 		case "VarDecl":
 			// TODO e.g. qmath.h

cmd/genbindings/emitgo.go

@@ -400,20 +400,27 @@ import "C"
 	}
 
 	for _, e := range src.Enums {
+		if e.EnumName == "" {
+			continue // Removed by transformRedundant AST pass
+		}
+
 		goEnumName := cabiClassName(e.EnumName)
 
 		ret.WriteString(`
 		type ` + goEnumName + ` ` + parseSingleTypeString(e.UnderlyingType).RenderTypeGo() + `
-		
-		const (
 		`)
 
+		if len(e.Entries) > 0 {
+
+			ret.WriteString("const (\n")
+
 			for _, ee := range e.Entries {
 				ret.WriteString(cabiClassName(goEnumName+"::"+ee.EntryName) + " " + goEnumName + " = " + ee.EntryValue + "\n")
 			}
 
 			ret.WriteString("\n)\n\n")
 		}
+	}
 
 	for _, c := range src.Classes {
 

cmd/genbindings/exceptions.go

@@ -195,10 +195,6 @@ func CheckComplexity(p CppParameter, isReturnType bool) error {
 		"QXmlStreamAttributes",            // e.g. qxmlstream.h
 		"QVariantMap",                     // e.g. qcbormap.h
 		"QVariantHash",                    // e.g. qcbormap.h
-		"QCborTag",                        // e.g. qcborstreamreader.h.TODO Needs support for enums
-		"QCborSimpleType",                 // e.g. qcborstreamreader.h TODO Needs support for enums
-		"QCborKnownTags",                  // e.g. qcborstreamreader.h TODO Needs support for enums
-		"QCborNegativeInteger",            // e.g. qcborstreamreader.h TODO Needs support for enums
 		"QtMsgType",                       // e.g. qdebug.h TODO Needs support for enums
 		"QTextStreamFunction",             // e.g. qdebug.h
 		"QFactoryInterface",               // qfactoryinterface.h

cmd/genbindings/main.go

@@ -84,6 +84,9 @@ func main() {
 	}
 
 	var processHeaders []*CppParsedHeader
+	atr := astTransformRedundant{
+		preserve: make(map[string]*CppEnum),
+	}
 
 	for _, inputHeader := range includeFiles {
 
@@ -149,6 +152,7 @@ func main() {
 		astTransformChildClasses(parsed) // must be first
 		astTransformOptional(parsed)
 		astTransformOverloads(parsed)
+		atr.Process(parsed)
 
 		// Update global state tracker (AFTER astTransformChildClasses)
 		// Currently, this is only used for inner classes

cmd/genbindings/transformredundant.go

@@ -0,0 +1,31 @@
+package main
+
+// astTransformRedundant merges duplicate enum definitions.
+type astTransformRedundant struct {
+	preserve map[string]*CppEnum
+}
+
+func (a *astTransformRedundant) Process(parsed *CppParsedHeader) {
+
+	for i, e := range parsed.Enums {
+		prev, ok := a.preserve[e.EnumName]
+		if !ok {
+			// It's new
+			a.preserve[e.EnumName] = &parsed.Enums[i]
+			continue
+		}
+
+		// It's pre-existing
+		if prev.UnderlyingType != e.UnderlyingType {
+			panic("Enum " + e.EnumName + " is defined multiple times with different underlying types")
+		}
+
+		// Merge entries
+		prev.Entries = append(prev.Entries, e.Entries...)
+
+		// Remove from second matched header
+		// This is difficult to manipulate while preserving pointers, so only
+		// wipe out the name and use that as a signal later on
+		parsed.Enums[i].EnumName = ""
+	}
+}