275 lines
6.9 KiB
Go
275 lines
6.9 KiB
Go
// Copyright 2014 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package datastore
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import (
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"fmt"
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"reflect"
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"time"
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pb "google.golang.org/cloud/internal/datastore"
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)
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var (
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typeOfByteSlice = reflect.TypeOf([]byte(nil))
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typeOfTime = reflect.TypeOf(time.Time{})
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)
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// typeMismatchReason returns a string explaining why the property p could not
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// be stored in an entity field of type v.Type().
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func typeMismatchReason(p Property, v reflect.Value) string {
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entityType := "empty"
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switch p.Value.(type) {
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case int64:
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entityType = "int"
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case bool:
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entityType = "bool"
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case string:
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entityType = "string"
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case float64:
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entityType = "float"
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case *Key:
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entityType = "*datastore.Key"
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case time.Time:
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entityType = "time.Time"
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case []byte:
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entityType = "[]byte"
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}
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return fmt.Sprintf("type mismatch: %s versus %v", entityType, v.Type())
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}
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type propertyLoader struct {
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// m holds the number of times a substruct field like "Foo.Bar.Baz" has
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// been seen so far. The map is constructed lazily.
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m map[string]int
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}
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func (l *propertyLoader) load(codec *structCodec, structValue reflect.Value, p Property, prev map[string]struct{}) string {
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var sliceOk bool
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var v reflect.Value
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// Traverse a struct's struct-typed fields.
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for name := p.Name; ; {
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decoder, ok := codec.byName[name]
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if !ok {
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return "no such struct field"
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}
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v = structValue.Field(decoder.index)
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if !v.IsValid() {
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return "no such struct field"
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}
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if !v.CanSet() {
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return "cannot set struct field"
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}
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if decoder.substructCodec == nil {
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break
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}
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if v.Kind() == reflect.Slice {
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if l.m == nil {
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l.m = make(map[string]int)
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}
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index := l.m[p.Name]
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l.m[p.Name] = index + 1
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for v.Len() <= index {
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v.Set(reflect.Append(v, reflect.New(v.Type().Elem()).Elem()))
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}
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structValue = v.Index(index)
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sliceOk = true
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} else {
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structValue = v
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}
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// Strip the "I." from "I.X".
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name = name[len(codec.byIndex[decoder.index].name):]
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codec = decoder.substructCodec
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}
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var slice reflect.Value
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if v.Kind() == reflect.Slice && v.Type().Elem().Kind() != reflect.Uint8 {
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slice = v
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v = reflect.New(v.Type().Elem()).Elem()
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} else if _, ok := prev[p.Name]; ok && !sliceOk {
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// Zero the field back out that was set previously, turns out its a slice and we don't know what to do with it
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v.Set(reflect.Zero(v.Type()))
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return "multiple-valued property requires a slice field type"
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}
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prev[p.Name] = struct{}{}
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pValue := p.Value
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switch v.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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x, ok := pValue.(int64)
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if !ok && pValue != nil {
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return typeMismatchReason(p, v)
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}
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if v.OverflowInt(x) {
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return fmt.Sprintf("value %v overflows struct field of type %v", x, v.Type())
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}
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v.SetInt(x)
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case reflect.Bool:
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x, ok := pValue.(bool)
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if !ok && pValue != nil {
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return typeMismatchReason(p, v)
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}
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v.SetBool(x)
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case reflect.String:
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x, ok := pValue.(string)
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if !ok && pValue != nil {
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return typeMismatchReason(p, v)
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}
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v.SetString(x)
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case reflect.Float32, reflect.Float64:
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x, ok := pValue.(float64)
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if !ok && pValue != nil {
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return typeMismatchReason(p, v)
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}
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if v.OverflowFloat(x) {
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return fmt.Sprintf("value %v overflows struct field of type %v", x, v.Type())
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}
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v.SetFloat(x)
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case reflect.Ptr:
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x, ok := pValue.(*Key)
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if !ok && pValue != nil {
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return typeMismatchReason(p, v)
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}
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if _, ok := v.Interface().(*Key); !ok {
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return typeMismatchReason(p, v)
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}
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v.Set(reflect.ValueOf(x))
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case reflect.Struct:
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switch v.Type() {
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case typeOfTime:
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x, ok := pValue.(time.Time)
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if !ok && pValue != nil {
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return typeMismatchReason(p, v)
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}
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v.Set(reflect.ValueOf(x))
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default:
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return typeMismatchReason(p, v)
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}
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case reflect.Slice:
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x, ok := pValue.([]byte)
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if !ok && pValue != nil {
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return typeMismatchReason(p, v)
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}
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if v.Type().Elem().Kind() != reflect.Uint8 {
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return typeMismatchReason(p, v)
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}
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v.SetBytes(x)
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default:
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return typeMismatchReason(p, v)
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}
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if slice.IsValid() {
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slice.Set(reflect.Append(slice, v))
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}
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return ""
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}
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// loadEntity loads an EntityProto into PropertyLoadSaver or struct pointer.
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func loadEntity(dst interface{}, src *pb.Entity) (err error) {
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props := protoToProperties(src)
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if e, ok := dst.(PropertyLoadSaver); ok {
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return e.Load(props)
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}
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return LoadStruct(dst, props)
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}
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func (s structPLS) Load(props []Property) error {
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var fieldName, reason string
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var l propertyLoader
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prev := make(map[string]struct{})
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for _, p := range props {
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if errStr := l.load(s.codec, s.v, p, prev); errStr != "" {
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// We don't return early, as we try to load as many properties as possible.
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// It is valid to load an entity into a struct that cannot fully represent it.
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// That case returns an error, but the caller is free to ignore it.
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fieldName, reason = p.Name, errStr
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}
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}
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if reason != "" {
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return &ErrFieldMismatch{
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StructType: s.v.Type(),
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FieldName: fieldName,
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Reason: reason,
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}
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}
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return nil
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}
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func protoToProperties(src *pb.Entity) []Property {
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props := src.Property
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out := make([]Property, 0, len(props))
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for {
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var (
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x *pb.Property
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noIndex bool
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)
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if len(props) > 0 {
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x, props = props[0], props[1:]
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noIndex = !x.GetValue().GetIndexed()
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} else {
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break
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}
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if x.Value.ListValue == nil {
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out = append(out, Property{
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Name: x.GetName(),
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Value: propValue(x.Value),
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NoIndex: noIndex,
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Multiple: false,
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})
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} else {
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for _, v := range x.Value.ListValue {
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out = append(out, Property{
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Name: x.GetName(),
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Value: propValue(v),
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NoIndex: noIndex,
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Multiple: true,
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})
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}
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}
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}
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return out
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}
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// propValue returns a Go value that combines the raw PropertyValue with a
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// meaning. For example, an Int64Value with GD_WHEN becomes a time.Time.
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func propValue(v *pb.Value) interface{} {
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//TODO(PSG-Luna): Support EntityValue
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//TODO(PSG-Luna): GeoPoint seems gone from the v1 proto, reimplement it once it's readded
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switch {
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case v.IntegerValue != nil:
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return *v.IntegerValue
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case v.TimestampMicrosecondsValue != nil:
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return fromUnixMicro(*v.TimestampMicrosecondsValue)
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case v.BooleanValue != nil:
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return *v.BooleanValue
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case v.StringValue != nil:
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return *v.StringValue
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case v.BlobValue != nil:
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return []byte(v.BlobValue)
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case v.BlobKeyValue != nil:
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return *v.BlobKeyValue
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case v.DoubleValue != nil:
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return *v.DoubleValue
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case v.KeyValue != nil:
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return protoToKey(v.KeyValue)
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}
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return nil
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}
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