Update newValueReader to use bVR

Author: prestonvasquez

bson/copier.go

@@ -180,7 +180,10 @@ func copyValueFromBytes(dst ValueWriter, t Type, src []byte) error {
 	}
 
 	vr := newBufferedDocumentReader(src)
-	vr.pushElement(t)
+	vr.advanceFrame()
+
+	vr.stack[vr.frame].mode = mElement
+	vr.stack[vr.frame].vType = t
 
 	return copyValue(dst, vr)
 }

bson/mgoregistry_test.go

@@ -485,7 +485,7 @@ func (t *prefixPtr) SetBSON(raw RawValue) error {
 	if err != nil {
 		return err
 	}
-	vr := newValueReader(raw.Type, bytes.NewReader(raw.Value))
+	vr := newBufferedValueReader(raw.Type, raw.Value)
 	err = decoder.DecodeValue(DecodeContext{Registry: NewMgoRegistry()}, vr, rval)
 	if err != nil {
 		return err
@@ -512,7 +512,7 @@ func (t *prefixVal) SetBSON(raw RawValue) error {
 	if err != nil {
 		return err
 	}
-	vr := newValueReader(raw.Type, bytes.NewReader(raw.Value))
+	vr := newBufferedValueReader(raw.Type, raw.Value)
 	err = decoder.DecodeValue(DecodeContext{Registry: NewMgoRegistry()}, vr, rval)
 	if err != nil {
 		return err
@@ -936,7 +936,7 @@ func (o *setterType) SetBSON(raw RawValue) error {
 	if raw.Type == 0x00 {
 		raw.Type = TypeEmbeddedDocument
 	}
-	vr := newValueReader(raw.Type, bytes.NewReader(raw.Value))
+	vr := newBufferedValueReader(raw.Type, raw.Value)
 	err = decoder.DecodeValue(DecodeContext{Registry: NewMgoRegistry()}, vr, rval)
 	if err != nil {
 		return err
@@ -1289,7 +1289,7 @@ func (s *getterSetterD) SetBSON(raw RawValue) error {
 	if raw.Type == 0x00 {
 		raw.Type = TypeEmbeddedDocument
 	}
-	vr := newValueReader(raw.Type, bytes.NewReader(raw.Value))
+	vr := newBufferedValueReader(raw.Type, raw.Value)
 	err = decoder.DecodeValue(DecodeContext{Registry: NewMgoRegistry()}, vr, rval)
 	if err != nil {
 		return err
@@ -1315,7 +1315,7 @@ func (i *getterSetterInt) SetBSON(raw RawValue) error {
 	if raw.Type == 0x00 {
 		raw.Type = TypeEmbeddedDocument
 	}
-	vr := newValueReader(raw.Type, bytes.NewReader(raw.Value))
+	vr := newBufferedValueReader(raw.Type, raw.Value)
 	err = decoder.DecodeValue(DecodeContext{Registry: NewMgoRegistry()}, vr, rval)
 	if err != nil {
 		return err
@@ -1337,7 +1337,7 @@ func (s *ifaceSlice) SetBSON(raw RawValue) error {
 	if err != nil {
 		return err
 	}
-	vr := newValueReader(raw.Type, bytes.NewReader(raw.Value))
+	vr := newBufferedValueReader(raw.Type, raw.Value)
 	err = decoder.DecodeValue(DecodeContext{Registry: NewMgoRegistry()}, vr, rval)
 	if err != nil {
 		return err

bson/raw_value.go

@@ -71,7 +71,7 @@ func (rv RawValue) UnmarshalWithRegistry(r *Registry, val interface{}) error {
 		return ErrNilRegistry
 	}
 
-	vr := newValueReader(rv.Type, bytes.NewReader(rv.Value))
+	vr := newBufferedValueReader(rv.Type, rv.Value)
 	rval := reflect.ValueOf(val)
 	if rval.Kind() != reflect.Ptr {
 		return fmt.Errorf("argument to Unmarshal* must be a pointer to a type, but got %v", rval)
@@ -91,7 +91,7 @@ func (rv RawValue) UnmarshalWithContext(dc *DecodeContext, val interface{}) erro
 		return ErrNilContext
 	}
 
-	vr := newValueReader(rv.Type, bytes.NewReader(rv.Value))
+	vr := newBufferedValueReader(rv.Type, rv.Value)
 	rval := reflect.ValueOf(val)
 	if rval.Kind() != reflect.Ptr {
 		return fmt.Errorf("argument to Unmarshal* must be a pointer to a type, but got %v", rval)

bson/unmarshal.go

@@ -42,8 +42,8 @@ type ValueUnmarshaler interface {
 // When unmarshaling BSON, if the BSON value is null and the Go value is a
 // pointer, the pointer is set to nil without calling UnmarshalBSONValue.
 func Unmarshal(data []byte, val interface{}) error {
-	vr := getBufferedDocumentReader(bytes.NewReader(data))
-	defer putDocumentReader(vr)
+	vr := getBufferedDocumentReader(data)
+	defer putBufferedDocumentReader(vr)
 
 	if l, err := vr.peekLength(); err != nil {
 		return err
@@ -57,7 +57,7 @@ func Unmarshal(data []byte, val interface{}) error {
 // stores the result in the value pointed to by val. If val is nil or not a pointer,
 // UnmarshalValue returns an error.
 func UnmarshalValue(t Type, data []byte, val interface{}) error {
-	vr := newValueReader(t, bytes.NewReader(data))
+	vr := newBufferedValueReader(t, data)
 	return unmarshalFromReader(DecodeContext{Registry: defaultRegistry}, vr, val)
 }
 

bson/unmarshal_test.go

@@ -71,7 +71,7 @@ func TestUnmarshalWithRegistry(t *testing.T) {
 
 			// Assert that unmarshaling the input data results in the expected value.
 			gotValue := reflect.New(reflect.TypeOf(tc.val))
-			dec := NewDecoder(newValueReader(tc.bsontype, bytes.NewReader(tc.bytes)))
+			dec := NewDecoder(newBufferedValueReader(tc.bsontype, tc.bytes))
 			dec.SetRegistry(reg)
 			err := dec.Decode(gotValue.Interface())
 			noerr(t, err)

bson/unmarshal_value_test.go

@@ -7,7 +7,6 @@
 package bson
 
 import (
-	"bytes"
 	"reflect"
 	"strings"
 	"testing"
@@ -80,7 +79,7 @@ func BenchmarkSliceCodecUnmarshal(b *testing.B) {
 				dec := NewDecoder(nil)
 				dec.SetRegistry(reg)
 				for pb.Next() {
-					dec.Reset(newValueReader(bm.bsontype, bytes.NewReader(bm.bytes)))
+					dec.Reset(newBufferedValueReader(bm.bsontype, bm.bytes))
 					err := dec.Decode(&[]byte{})
 					if err != nil {
 						b.Fatal(err)

bson/unmarshaling_cases_test.go

@@ -7,7 +7,6 @@
 package bson
 
 import (
-	"bytes"
 	"reflect"
 )
 
@@ -269,7 +268,7 @@ func (mi *myInt64) UnmarshalBSONValue(t byte, b []byte) error {
 	}
 
 	if Type(t) == TypeInt64 {
-		i, err := newValueReader(TypeInt64, bytes.NewReader(b)).ReadInt64()
+		i, err := newBufferedValueReader(TypeInt64, b).ReadInt64()
 		if err != nil {
 			return err
 		}
@@ -284,7 +283,7 @@ func (mi *myInt64) UnmarshalBSON(b []byte) error {
 	if len(b) == 0 {
 		return nil
 	}
-	i, err := newValueReader(TypeInt64, bytes.NewReader(b)).ReadInt64()
+	i, err := newBufferedValueReader(TypeInt64, b).ReadInt64()
 	if err != nil {
 		return err
 	}
@@ -310,7 +309,7 @@ func (mb *myBytes) UnmarshalBSON(b []byte) error {
 	if len(b) == 0 {
 		return nil
 	}
-	b, _, err := newValueReader(TypeBinary, bytes.NewReader(b)).ReadBinary()
+	b, _, err := newBufferedValueReader(TypeBinary, b).ReadBinary()
 	if err != nil {
 		return err
 	}
@@ -324,7 +323,7 @@ func (ms *myString) UnmarshalBSON(b []byte) error {
 	if len(b) == 0 {
 		return nil
 	}
-	s, err := newValueReader(TypeString, bytes.NewReader(b)).ReadString()
+	s, err := newBufferedValueReader(TypeString, b).ReadString()
 	if err != nil {
 		return err
 	}

bson/value_reader.go

@@ -117,10 +117,14 @@ func NewDocumentReader(r io.Reader) ValueReader {
 	}
 }
 
-// newValueReader returns a ValueReader that starts in the Value mode instead of in top
-// level document mode. This enables the creation of a ValueReader for a single BSON value.
-func newValueReader(t Type, r io.Reader) ValueReader {
-	panic("TODO")
+// newBufferedValueReader returns a ValueReader that starts in the Value mode
+// instead of in top level document mode. This enables the creation of a
+// ValueReader for a single BSON value.
+func newBufferedValueReader(t Type, b []byte) ValueReader {
+	bVR := newBufferedDocumentReader(b)
+	bVR.stack[0].vType = t
+
+	return bVR
 }
 
 func newBufferedDocumentReader(b []byte) *valueReader {