/
codec.go
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/
codec.go
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// Copyright 2019 The Go Cloud Development Kit Authors
//
// 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
//
// https://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 memdocstore
import (
"fmt"
"reflect"
"time"
"gocloud.dev/gcerrors"
"gocloud.dev/docstore/driver"
)
// encodeDoc encodes a driver.Document as a storedDoc.
func encodeDoc(doc driver.Document) (storedDoc, error) {
var e encoder
if err := doc.Encode(&e); err != nil {
return nil, err
}
return storedDoc(e.val.(map[string]interface{})), nil
}
func encodeValue(v interface{}) (interface{}, error) {
var e encoder
if err := driver.Encode(reflect.ValueOf(v), &e); err != nil {
return nil, err
}
return e.val, nil
}
type encoder struct {
val interface{}
}
func (e *encoder) EncodeNil() { e.val = nil }
func (e *encoder) EncodeBool(x bool) { e.val = x }
func (e *encoder) EncodeInt(x int64) { e.val = x }
func (e *encoder) EncodeUint(x uint64) { e.val = int64(x) }
func (e *encoder) EncodeBytes(x []byte) { e.val = x }
func (e *encoder) EncodeFloat(x float64) { e.val = x }
func (e *encoder) EncodeString(x string) { e.val = x }
func (e *encoder) ListIndex(int) { panic("impossible") }
func (e *encoder) MapKey(string) { panic("impossible") }
var typeOfGoTime = reflect.TypeOf(time.Time{})
func (e *encoder) EncodeSpecial(v reflect.Value) (bool, error) {
if v.Type() == typeOfGoTime {
e.val = v.Interface()
return true, nil
}
return false, nil
}
func (e *encoder) EncodeList(n int) driver.Encoder {
// All slices and arrays are encoded as []interface{}
s := make([]interface{}, n)
e.val = s
return &listEncoder{s: s}
}
type listEncoder struct {
s []interface{}
encoder
}
func (e *listEncoder) ListIndex(i int) { e.s[i] = e.val }
type mapEncoder struct {
m map[string]interface{}
encoder
}
func (e *encoder) EncodeMap(n int) driver.Encoder {
m := make(map[string]interface{}, n)
e.val = m
return &mapEncoder{m: m}
}
func (e *mapEncoder) MapKey(k string) { e.m[k] = e.val }
////////////////////////////////////////////////////////////////
// decodeDoc decodes m into ddoc.
func decodeDoc(m storedDoc, ddoc driver.Document, fps [][]string) error {
var m2 map[string]interface{}
if len(fps) == 0 {
m2 = m
} else {
// Make a document to decode from that has only the field paths.
// (We don't need the key field because ddoc must already have it.)
m2 = map[string]interface{}{}
for _, fp := range fps {
val, err := getAtFieldPath(m, fp)
if err != nil {
if gcerrors.Code(err) == gcerrors.NotFound {
continue
}
return err
}
if err := setAtFieldPath(m2, fp, val); err != nil {
return err
}
}
}
return ddoc.Decode(decoder{m2})
}
type decoder struct {
val interface{}
}
func (d decoder) String() string {
return fmt.Sprint(d.val)
}
func (d decoder) AsNull() bool {
return d.val == nil
}
func (d decoder) AsBool() (bool, bool) {
b, ok := d.val.(bool)
return b, ok
}
func (d decoder) AsString() (string, bool) {
s, ok := d.val.(string)
return s, ok
}
func (d decoder) AsInt() (int64, bool) {
i, ok := d.val.(int64)
return i, ok
}
func (d decoder) AsUint() (uint64, bool) {
i, ok := d.val.(int64)
return uint64(i), ok
}
func (d decoder) AsFloat() (float64, bool) {
f, ok := d.val.(float64)
return f, ok
}
func (d decoder) AsBytes() ([]byte, bool) {
bs, ok := d.val.([]byte)
return bs, ok
}
func (d decoder) AsInterface() (interface{}, error) {
return d.val, nil
}
func (d decoder) ListLen() (int, bool) {
if s, ok := d.val.([]interface{}); ok {
return len(s), true
}
return 0, false
}
func (d decoder) DecodeList(f func(i int, d2 driver.Decoder) bool) {
for i, e := range d.val.([]interface{}) {
if !f(i, decoder{e}) {
return
}
}
}
func (d decoder) MapLen() (int, bool) {
if m, ok := d.val.(map[string]interface{}); ok {
return len(m), true
}
return 0, false
}
func (d decoder) DecodeMap(f func(key string, d2 driver.Decoder, _ bool) bool) {
for k, v := range d.val.(map[string]interface{}) {
if !f(k, decoder{v}, true) {
return
}
}
}
func (d decoder) AsSpecial(v reflect.Value) (bool, interface{}, error) {
if v.Type() == typeOfGoTime {
return true, d.val, nil
}
return false, nil, nil
}