1 files changed, 169 insertions, 0 deletions
diff --git a/libgo/go/exp/eval/bridge.go b/libgo/go/exp/eval/bridge.go
new file mode 100644
index 0000000000..12835c4c02
--- /dev/null
+++ b/libgo/go/exp/eval/bridge.go
@@ -0,0 +1,169 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package eval
+
+import (
+	"log"
+	"go/token"
+	"reflect"
+)
+
+/*
+ * Type bridging
+ */
+
+var (
+	evalTypes   = make(map[reflect.Type]Type)
+	nativeTypes = make(map[Type]reflect.Type)
+)
+
+// TypeFromNative converts a regular Go type into a the corresponding
+// interpreter Type.
+func TypeFromNative(t reflect.Type) Type {
+	if et, ok := evalTypes[t]; ok {
+		return et
+	}
+
+	var nt *NamedType
+	if t.Name() != "" {
+		name := t.PkgPath() + "·" + t.Name()
+		nt = &NamedType{token.NoPos, name, nil, true, make(map[string]Method)}
+		evalTypes[t] = nt
+	}
+
+	var et Type
+	switch t := t.(type) {
+	case *reflect.BoolType:
+		et = BoolType
+	case *reflect.FloatType:
+		switch t.Kind() {
+		case reflect.Float32:
+			et = Float32Type
+		case reflect.Float64:
+			et = Float64Type
+		}
+	case *reflect.IntType:
+		switch t.Kind() {
+		case reflect.Int16:
+			et = Int16Type
+		case reflect.Int32:
+			et = Int32Type
+		case reflect.Int64:
+			et = Int64Type
+		case reflect.Int8:
+			et = Int8Type
+		case reflect.Int:
+			et = IntType
+		}
+	case *reflect.UintType:
+		switch t.Kind() {
+		case reflect.Uint16:
+			et = Uint16Type
+		case reflect.Uint32:
+			et = Uint32Type
+		case reflect.Uint64:
+			et = Uint64Type
+		case reflect.Uint8:
+			et = Uint8Type
+		case reflect.Uint:
+			et = UintType
+		case reflect.Uintptr:
+			et = UintptrType
+		}
+	case *reflect.StringType:
+		et = StringType
+	case *reflect.ArrayType:
+		et = NewArrayType(int64(t.Len()), TypeFromNative(t.Elem()))
+	case *reflect.ChanType:
+		log.Panicf("%T not implemented", t)
+	case *reflect.FuncType:
+		nin := t.NumIn()
+		// Variadic functions have DotDotDotType at the end
+		variadic := t.DotDotDot()
+		if variadic {
+			nin--
+		}
+		in := make([]Type, nin)
+		for i := range in {
+			in[i] = TypeFromNative(t.In(i))
+		}
+		out := make([]Type, t.NumOut())
+		for i := range out {
+			out[i] = TypeFromNative(t.Out(i))
+		}
+		et = NewFuncType(in, variadic, out)
+	case *reflect.InterfaceType:
+		log.Panicf("%T not implemented", t)
+	case *reflect.MapType:
+		log.Panicf("%T not implemented", t)
+	case *reflect.PtrType:
+		et = NewPtrType(TypeFromNative(t.Elem()))
+	case *reflect.SliceType:
+		et = NewSliceType(TypeFromNative(t.Elem()))
+	case *reflect.StructType:
+		n := t.NumField()
+		fields := make([]StructField, n)
+		for i := 0; i < n; i++ {
+			sf := t.Field(i)
+			// TODO(austin) What to do about private fields?
+			fields[i].Name = sf.Name
+			fields[i].Type = TypeFromNative(sf.Type)
+			fields[i].Anonymous = sf.Anonymous
+		}
+		et = NewStructType(fields)
+	case *reflect.UnsafePointerType:
+		log.Panicf("%T not implemented", t)
+	default:
+		log.Panicf("unexpected reflect.Type: %T", t)
+	}
+
+	if nt != nil {
+		if _, ok := et.(*NamedType); !ok {
+			nt.Complete(et)
+			et = nt
+		}
+	}
+
+	nativeTypes[et] = t
+	evalTypes[t] = et
+
+	return et
+}
+
+// TypeOfNative returns the interpreter Type of a regular Go value.
+func TypeOfNative(v interface{}) Type { return TypeFromNative(reflect.Typeof(v)) }
+
+/*
+ * Function bridging
+ */
+
+type nativeFunc struct {
+	fn      func(*Thread, []Value, []Value)
+	in, out int
+}
+
+func (f *nativeFunc) NewFrame() *Frame {
+	vars := make([]Value, f.in+f.out)
+	return &Frame{nil, vars}
+}
+
+func (f *nativeFunc) Call(t *Thread) { f.fn(t, t.f.Vars[0:f.in], t.f.Vars[f.in:f.in+f.out]) }
+
+// FuncFromNative creates an interpreter function from a native
+// function that takes its in and out arguments as slices of
+// interpreter Value's.  While somewhat inconvenient, this avoids
+// value marshalling.
+func FuncFromNative(fn func(*Thread, []Value, []Value), t *FuncType) FuncValue {
+	return &funcV{&nativeFunc{fn, len(t.In), len(t.Out)}}
+}
+
+// FuncFromNativeTyped is like FuncFromNative, but constructs the
+// function type from a function pointer using reflection.  Typically,
+// the type will be given as a nil pointer to a function with the
+// desired signature.
+func FuncFromNativeTyped(fn func(*Thread, []Value, []Value), t interface{}) (*FuncType, FuncValue) {
+	ft := TypeOfNative(t).(*FuncType)
+	return ft, FuncFromNative(fn, ft)
+}