Merge pull request #93 from sclasen/snapshots-streams

Snapshots streams

awsinternal/jsonutil/unmarshal.go

@@ -0,0 +1,218 @@
+package jsonutil
+
+// copied from github.com/aws/aws-sdk-go/internal/protocol/json/jsonutil/unmarshal.go
+// to give access to AWS-internal unmarshalling disallowed in go 1.5.
+// do not use for anything in the critical path. use AWS public packages where possible.
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"reflect"
+	"strings"
+	"time"
+)
+
+// UnmarshalJSON reads a stream and unmarshals the results in object v.
+func UnmarshalJSON(v interface{}, stream io.Reader) error {
+	var out interface{}
+
+	b, err := ioutil.ReadAll(stream)
+	if err != nil {
+		return err
+	}
+
+	if len(b) == 0 {
+		return nil
+	}
+
+	if err := json.Unmarshal(b, &out); err != nil {
+		return err
+	}
+
+	return unmarshalAny(reflect.ValueOf(v), out, "")
+}
+
+func unmarshalAny(value reflect.Value, data interface{}, tag reflect.StructTag) error {
+	vtype := value.Type()
+	if vtype.Kind() == reflect.Ptr {
+		vtype = vtype.Elem() // check kind of actual element type
+	}
+
+	t := tag.Get("type")
+	if t == "" {
+		switch vtype.Kind() {
+		case reflect.Struct:
+			// also it can't be a time object
+			if _, ok := value.Interface().(*time.Time); !ok {
+				t = "structure"
+			}
+		case reflect.Slice:
+			// also it can't be a byte slice
+			if _, ok := value.Interface().([]byte); !ok {
+				t = "list"
+			}
+		case reflect.Map:
+			t = "map"
+		}
+	}
+
+	switch t {
+	case "structure":
+		if field, ok := vtype.FieldByName("SDKShapeTraits"); ok {
+			tag = field.Tag
+		}
+		return unmarshalStruct(value, data, tag)
+	case "list":
+		return unmarshalList(value, data, tag)
+	case "map":
+		return unmarshalMap(value, data, tag)
+	default:
+		return unmarshalScalar(value, data, tag)
+	}
+}
+
+func unmarshalStruct(value reflect.Value, data interface{}, tag reflect.StructTag) error {
+	if data == nil {
+		return nil
+	}
+	mapData, ok := data.(map[string]interface{})
+	if !ok {
+		return fmt.Errorf("JSON value is not a structure (%#v)", data)
+	}
+
+	t := value.Type()
+	if value.Kind() == reflect.Ptr {
+		if value.IsNil() { // create the structure if it's nil
+			s := reflect.New(value.Type().Elem())
+			value.Set(s)
+			value = s
+		}
+
+		value = value.Elem()
+		t = t.Elem()
+	}
+
+	// unwrap any payloads
+	if payload := tag.Get("payload"); payload != "" {
+		field, _ := t.FieldByName(payload)
+		return unmarshalAny(value.FieldByName(payload), data, field.Tag)
+	}
+
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		if c := field.Name[0:1]; strings.ToLower(c) == c {
+			continue // ignore unexported fields
+		}
+
+		// figure out what this field is called
+		name := field.Name
+		if locName := field.Tag.Get("locationName"); locName != "" {
+			name = locName
+		}
+
+		member := value.FieldByName(field.Name)
+		err := unmarshalAny(member, mapData[name], field.Tag)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func unmarshalList(value reflect.Value, data interface{}, tag reflect.StructTag) error {
+	if data == nil {
+		return nil
+	}
+	listData, ok := data.([]interface{})
+	if !ok {
+		return fmt.Errorf("JSON value is not a list (%#v)", data)
+	}
+
+	if value.IsNil() {
+		l := len(listData)
+		value.Set(reflect.MakeSlice(value.Type(), l, l))
+	}
+
+	for i, c := range listData {
+		err := unmarshalAny(value.Index(i), c, "")
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func unmarshalMap(value reflect.Value, data interface{}, tag reflect.StructTag) error {
+	if data == nil {
+		return nil
+	}
+	mapData, ok := data.(map[string]interface{})
+	if !ok {
+		return fmt.Errorf("JSON value is not a map (%#v)", data)
+	}
+
+	if value.IsNil() {
+		value.Set(reflect.MakeMap(value.Type()))
+	}
+
+	for k, v := range mapData {
+		kvalue := reflect.ValueOf(k)
+		vvalue := reflect.New(value.Type().Elem()).Elem()
+
+		unmarshalAny(vvalue, v, "")
+		value.SetMapIndex(kvalue, vvalue)
+	}
+
+	return nil
+}
+
+func unmarshalScalar(value reflect.Value, data interface{}, tag reflect.StructTag) error {
+	errf := func() error {
+		return fmt.Errorf("unsupported value: %v (%s)", value.Interface(), value.Type())
+	}
+
+	switch d := data.(type) {
+	case nil:
+		return nil // nothing to do here
+	case string:
+		switch value.Interface().(type) {
+		case *string:
+			value.Set(reflect.ValueOf(&d))
+		case []byte:
+			b, err := base64.StdEncoding.DecodeString(d)
+			if err != nil {
+				return err
+			}
+			value.Set(reflect.ValueOf(b))
+		default:
+			return errf()
+		}
+	case float64:
+		switch value.Interface().(type) {
+		case *int64:
+			di := int64(d)
+			value.Set(reflect.ValueOf(&di))
+		case *float64:
+			value.Set(reflect.ValueOf(&d))
+		case *time.Time:
+			t := time.Unix(int64(d), 0).UTC()
+			value.Set(reflect.ValueOf(&t))
+		default:
+			return errf()
+		}
+	case bool:
+		switch value.Interface().(type) {
+		case *bool:
+			value.Set(reflect.ValueOf(&d))
+		default:
+			return errf()
+		}
+	default:
+		return fmt.Errorf("unsupported JSON value (%v)", data)
+	}
+	return nil
+}