restic/vendor/cloud.google.com/go/firestore/to_value.go

295 lines
9.1 KiB
Go

// Copyright 2017 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package firestore
import (
"errors"
"fmt"
"reflect"
"strings"
"time"
"cloud.google.com/go/internal/fields"
pb "google.golang.org/genproto/googleapis/firestore/v1beta1"
"github.com/golang/protobuf/ptypes"
"google.golang.org/genproto/googleapis/type/latlng"
)
var nullValue = &pb.Value{&pb.Value_NullValue{}}
var (
typeOfByteSlice = reflect.TypeOf([]byte{})
typeOfGoTime = reflect.TypeOf(time.Time{})
typeOfLatLng = reflect.TypeOf((*latlng.LatLng)(nil))
typeOfDocumentRef = reflect.TypeOf((*DocumentRef)(nil))
)
// toProtoValue converts a Go value to a Firestore Value protobuf.
// Some corner cases:
// - All nils (nil interface, nil slice, nil map, nil pointer) are converted to
// a NullValue (not a nil *pb.Value). toProtoValue never returns (nil, false, nil).
// It returns (nil, true, nil) if everything in the value is ServerTimestamp.
// - An error is returned for uintptr, uint and uint64, because Firestore uses
// an int64 to represent integral values, and those types can't be properly
// represented in an int64.
// - An error is returned for the special Delete value.
func toProtoValue(v reflect.Value) (pbv *pb.Value, sawServerTimestamp bool, err error) {
if !v.IsValid() {
return nullValue, false, nil
}
vi := v.Interface()
if vi == Delete {
return nil, false, errors.New("firestore: cannot use Delete in value")
}
if vi == ServerTimestamp {
return nil, false, errors.New("firestore: must use ServerTimestamp as a map value")
}
switch x := vi.(type) {
case []byte:
return &pb.Value{&pb.Value_BytesValue{x}}, false, nil
case time.Time:
ts, err := ptypes.TimestampProto(x)
if err != nil {
return nil, false, err
}
return &pb.Value{&pb.Value_TimestampValue{ts}}, false, nil
case *latlng.LatLng:
if x == nil {
// gRPC doesn't like nil oneofs. Use NullValue.
return nullValue, false, nil
}
return &pb.Value{&pb.Value_GeoPointValue{x}}, false, nil
case *DocumentRef:
if x == nil {
// gRPC doesn't like nil oneofs. Use NullValue.
return nullValue, false, nil
}
return &pb.Value{&pb.Value_ReferenceValue{x.Path}}, false, nil
// Do not add bool, string, int, etc. to this switch; leave them in the
// reflect-based switch below. Moving them here would drop support for
// types whose underlying types are those primitives.
// E.g. Given "type mybool bool", an ordinary type switch on bool will
// not catch a mybool, but the reflect.Kind of a mybool is reflect.Bool.
}
switch v.Kind() {
case reflect.Bool:
return &pb.Value{&pb.Value_BooleanValue{v.Bool()}}, false, nil
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return &pb.Value{&pb.Value_IntegerValue{v.Int()}}, false, nil
case reflect.Uint8, reflect.Uint16, reflect.Uint32:
return &pb.Value{&pb.Value_IntegerValue{int64(v.Uint())}}, false, nil
case reflect.Float32, reflect.Float64:
return &pb.Value{&pb.Value_DoubleValue{v.Float()}}, false, nil
case reflect.String:
return &pb.Value{&pb.Value_StringValue{v.String()}}, false, nil
case reflect.Slice:
return sliceToProtoValue(v)
case reflect.Map:
return mapToProtoValue(v)
case reflect.Struct:
return structToProtoValue(v)
case reflect.Ptr:
if v.IsNil() {
return nullValue, false, nil
}
return toProtoValue(v.Elem())
case reflect.Interface:
if v.NumMethod() == 0 { // empty interface: recurse on its contents
return toProtoValue(v.Elem())
}
fallthrough // any other interface value is an error
default:
return nil, false, fmt.Errorf("firestore: cannot convert type %s to value", v.Type())
}
}
func sliceToProtoValue(v reflect.Value) (*pb.Value, bool, error) {
// A nil slice is converted to a null value.
if v.IsNil() {
return nullValue, false, nil
}
vals := make([]*pb.Value, v.Len())
for i := 0; i < v.Len(); i++ {
val, sawServerTimestamp, err := toProtoValue(v.Index(i))
if err != nil {
return nil, false, err
}
if sawServerTimestamp {
return nil, false, errors.New("firestore: ServerTimestamp cannot occur in an array")
}
vals[i] = val
}
return &pb.Value{&pb.Value_ArrayValue{&pb.ArrayValue{vals}}}, false, nil
}
func mapToProtoValue(v reflect.Value) (*pb.Value, bool, error) {
if v.Type().Key().Kind() != reflect.String {
return nil, false, errors.New("firestore: map key type must be string")
}
// A nil map is converted to a null value.
if v.IsNil() {
return nullValue, false, nil
}
m := map[string]*pb.Value{}
sawServerTimestamp := false
for _, k := range v.MapKeys() {
mi := v.MapIndex(k)
if mi.Interface() == ServerTimestamp {
sawServerTimestamp = true
continue
}
val, sst, err := toProtoValue(mi)
if err != nil {
return nil, false, err
}
if sst {
sawServerTimestamp = true
}
if val == nil { // value was a map with all ServerTimestamp values
continue
}
m[k.String()] = val
}
var pv *pb.Value
if len(m) == 0 && sawServerTimestamp {
// The entire map consisted of ServerTimestamp values.
pv = nil
} else {
pv = &pb.Value{&pb.Value_MapValue{&pb.MapValue{m}}}
}
return pv, sawServerTimestamp, nil
}
func structToProtoValue(v reflect.Value) (*pb.Value, bool, error) {
m := map[string]*pb.Value{}
fields, err := fieldCache.Fields(v.Type())
if err != nil {
return nil, false, err
}
sawServerTimestamp := false
for _, f := range fields {
fv := v.FieldByIndex(f.Index)
opts := f.ParsedTag.(tagOptions)
if opts.serverTimestamp {
// TODO(jba): should we return a non-zero time?
sawServerTimestamp = true
continue
}
if opts.omitEmpty && isEmptyValue(fv) {
continue
}
val, sst, err := toProtoValue(fv)
if err != nil {
return nil, false, err
}
if sst {
sawServerTimestamp = true
}
if val == nil { // value was a map with all ServerTimestamp values
continue
}
m[f.Name] = val
}
var pv *pb.Value
if len(m) == 0 && sawServerTimestamp {
// The entire struct consisted of ServerTimestamp or omitempty values.
pv = nil
} else {
pv = &pb.Value{&pb.Value_MapValue{&pb.MapValue{m}}}
}
return pv, sawServerTimestamp, nil
}
type tagOptions struct {
omitEmpty bool // do not marshal value if empty
serverTimestamp bool // set time.Time to server timestamp on write
}
// parseTag interprets firestore struct field tags.
func parseTag(t reflect.StructTag) (name string, keep bool, other interface{}, err error) {
name, keep, opts, err := parseStandardTag("firestore", t)
if err != nil {
return "", false, nil, fmt.Errorf("firestore: %v", err)
}
tagOpts := tagOptions{}
for _, opt := range opts {
switch opt {
case "omitempty":
tagOpts.omitEmpty = true
case "serverTimestamp":
tagOpts.serverTimestamp = true
default:
return "", false, nil, fmt.Errorf("firestore: unknown tag option: %q", opt)
}
}
return name, keep, tagOpts, nil
}
// parseStandardTag extracts the sub-tag named by key, then parses it using the
// de facto standard format introduced in encoding/json:
// "-" means "ignore this tag". It must occur by itself. (parseStandardTag returns an error
// in this case, whereas encoding/json accepts the "-" even if it is not alone.)
// "<name>" provides an alternative name for the field
// "<name>,opt1,opt2,..." specifies options after the name.
// The options are returned as a []string.
//
// TODO(jba): move this into the fields package, and use it elsewhere, like bigquery.
func parseStandardTag(key string, t reflect.StructTag) (name string, keep bool, options []string, err error) {
s := t.Get(key)
parts := strings.Split(s, ",")
if parts[0] == "-" {
if len(parts) > 1 {
return "", false, nil, errors.New(`"-" field tag with options`)
}
return "", false, nil, nil
}
return parts[0], true, parts[1:], nil
}
// isLeafType determines whether or not a type is a 'leaf type'
// and should not be recursed into, but considered one field.
func isLeafType(t reflect.Type) bool {
return t == typeOfGoTime || t == typeOfLatLng
}
var fieldCache = fields.NewCache(parseTag, nil, isLeafType)
// isEmptyValue is taken from the encoding/json package in the
// standard library.
// TODO(jba): move to the fields package
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()
}
if v.Type() == typeOfGoTime {
return v.Interface().(time.Time).IsZero()
}
return false
}