diff options
Diffstat (limited to 'vendor/google.golang.org/api/gensupport/json.go')
| -rw-r--r-- | vendor/google.golang.org/api/gensupport/json.go | 172 | 
1 files changed, 172 insertions, 0 deletions
| diff --git a/vendor/google.golang.org/api/gensupport/json.go b/vendor/google.golang.org/api/gensupport/json.go new file mode 100644 index 0000000..dd7bcd2 --- /dev/null +++ b/vendor/google.golang.org/api/gensupport/json.go @@ -0,0 +1,172 @@ +// Copyright 2015 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 gensupport + +import ( +	"encoding/json" +	"fmt" +	"reflect" +	"strings" +) + +// MarshalJSON returns a JSON encoding of schema containing only selected fields. +// A field is selected if: +//   * it has a non-empty value, or +//     * its field name is present in forceSendFields, and +//     * it is not a nil pointer or nil interface. +// The JSON key for each selected field is taken from the field's json: struct tag. +func MarshalJSON(schema interface{}, forceSendFields []string) ([]byte, error) { +	if len(forceSendFields) == 0 { +		return json.Marshal(schema) +	} + +	mustInclude := make(map[string]struct{}) +	for _, f := range forceSendFields { +		mustInclude[f] = struct{}{} +	} + +	dataMap, err := schemaToMap(schema, mustInclude) +	if err != nil { +		return nil, err +	} +	return json.Marshal(dataMap) +} + +func schemaToMap(schema interface{}, mustInclude map[string]struct{}) (map[string]interface{}, error) { +	m := make(map[string]interface{}) +	s := reflect.ValueOf(schema) +	st := s.Type() + +	for i := 0; i < s.NumField(); i++ { +		jsonTag := st.Field(i).Tag.Get("json") +		if jsonTag == "" { +			continue +		} +		tag, err := parseJSONTag(jsonTag) +		if err != nil { +			return nil, err +		} +		if tag.ignore { +			continue +		} + +		v := s.Field(i) +		f := st.Field(i) +		if !includeField(v, f, mustInclude) { +			continue +		} + +		// nil maps are treated as empty maps. +		if f.Type.Kind() == reflect.Map && v.IsNil() { +			m[tag.apiName] = map[string]string{} +			continue +		} + +		// nil slices are treated as empty slices. +		if f.Type.Kind() == reflect.Slice && v.IsNil() { +			m[tag.apiName] = []bool{} +			continue +		} + +		if tag.stringFormat { +			m[tag.apiName] = formatAsString(v, f.Type.Kind()) +		} else { +			m[tag.apiName] = v.Interface() +		} +	} +	return m, nil +} + +// formatAsString returns a string representation of v, dereferencing it first if possible. +func formatAsString(v reflect.Value, kind reflect.Kind) string { +	if kind == reflect.Ptr && !v.IsNil() { +		v = v.Elem() +	} + +	return fmt.Sprintf("%v", v.Interface()) +} + +// jsonTag represents a restricted version of the struct tag format used by encoding/json. +// It is used to describe the JSON encoding of fields in a Schema struct. +type jsonTag struct { +	apiName      string +	stringFormat bool +	ignore       bool +} + +// parseJSONTag parses a restricted version of the struct tag format used by encoding/json. +// The format of the tag must match that generated by the Schema.writeSchemaStruct method +// in the api generator. +func parseJSONTag(val string) (jsonTag, error) { +	if val == "-" { +		return jsonTag{ignore: true}, nil +	} + +	var tag jsonTag + +	i := strings.Index(val, ",") +	if i == -1 || val[:i] == "" { +		return tag, fmt.Errorf("malformed json tag: %s", val) +	} + +	tag = jsonTag{ +		apiName: val[:i], +	} + +	switch val[i+1:] { +	case "omitempty": +	case "omitempty,string": +		tag.stringFormat = true +	default: +		return tag, fmt.Errorf("malformed json tag: %s", val) +	} + +	return tag, nil +} + +// Reports whether the struct field "f" with value "v" should be included in JSON output. +func includeField(v reflect.Value, f reflect.StructField, mustInclude map[string]struct{}) bool { +	// The regular JSON encoding of a nil pointer is "null", which means "delete this field". +	// Therefore, we could enable field deletion by honoring pointer fields' presence in the mustInclude set. +	// However, many fields are not pointers, so there would be no way to delete these fields. +	// Rather than partially supporting field deletion, we ignore mustInclude for nil pointer fields. +	// Deletion will be handled by a separate mechanism. +	if f.Type.Kind() == reflect.Ptr && v.IsNil() { +		return false +	} + +	// The "any" type is represented as an interface{}.  If this interface +	// is nil, there is no reasonable representation to send.  We ignore +	// these fields, for the same reasons as given above for pointers. +	if f.Type.Kind() == reflect.Interface && v.IsNil() { +		return false +	} + +	_, ok := mustInclude[f.Name] +	return ok || !isEmptyValue(v) +} + +// isEmptyValue reports whether v is the empty value for its type.  This +// implementation is based on that of the encoding/json package, but its +// correctness does not depend on it being identical. What's important is that +// this function return false in situations where v should not be sent as part +// of a PATCH operation. +func isEmptyValue(v reflect.Value) bool { +	switch v.Kind() { +	case reflect.Array, reflect.Map, reflect.Slice, reflect.String: +		return v.Len() == 0 +	case reflect.Bool: +		return !v.Bool() +	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: +		return v.Int() == 0 +	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: +		return v.Uint() == 0 +	case reflect.Float32, reflect.Float64: +		return v.Float() == 0 +	case reflect.Interface, reflect.Ptr: +		return v.IsNil() +	} +	return false +} | 
