surrealpatch/util/diff/unmarshal.go
2016-07-21 22:50:53 +01:00

131 lines
2.9 KiB
Go

package diff
import (
"encoding/json"
"errors"
dmp "github.com/sergi/go-diff/diffmatchpatch"
"io"
"strconv"
)
type Unmarshaller struct {
}
func NewUnmarshaller() *Unmarshaller {
return &Unmarshaller{}
}
func (um *Unmarshaller) UnmarshalBytes(diffBytes []byte) (Diff, error) {
var diffObj map[string]interface{}
json.Unmarshal(diffBytes, &diffObj)
return um.UnmarshalObject(diffObj)
}
func (um *Unmarshaller) UnmarshalString(diffString string) (Diff, error) {
return um.UnmarshalBytes([]byte(diffString))
}
func (um *Unmarshaller) UnmarshalReader(diffReader io.Reader) (Diff, error) {
var diffBytes []byte
io.ReadFull(diffReader, diffBytes)
return um.UnmarshalBytes(diffBytes)
}
func (um *Unmarshaller) UnmarshalObject(diffObj map[string]interface{}) (Diff, error) {
result, err := process(Name(""), diffObj)
if err != nil {
return nil, err
}
return &diff{deltas: result.(*Object).Deltas}, nil
}
func process(position Position, object interface{}) (Delta, error) {
var delta Delta
switch object.(type) {
case map[string]interface{}:
o := object.(map[string]interface{})
if isArray, typed := o["_t"]; typed && isArray == "a" {
deltas := make([]Delta, 0, len(o))
for name, value := range o {
if name == "_t" {
continue
}
normalizedName := name
if normalizedName[0] == '_' {
normalizedName = name[1:]
}
index, err := strconv.Atoi(normalizedName)
if err != nil {
return nil, err
}
childDelta, err := process(Index(index), value)
if err != nil {
return nil, err
}
deltas = append(deltas, childDelta)
}
for _, d := range deltas {
switch d.(type) {
case *Moved:
moved := d.(*Moved)
var dd interface{}
var i int
for i, dd = range deltas {
switch dd.(type) {
case *Moved:
case PostDelta:
pd := dd.(PostDelta)
if moved.PostPosition() == pd.PostPosition() {
moved.Delta = pd
deltas = append(deltas[:i], deltas[i+1:]...)
}
}
}
}
}
delta = NewArray(position, deltas)
} else {
deltas := make([]Delta, 0, len(o))
for name, value := range o {
childDelta, err := process(Name(name), value)
if err != nil {
return nil, err
}
deltas = append(deltas, childDelta)
}
delta = NewObject(position, deltas)
}
case []interface{}:
o := object.([]interface{})
switch len(o) {
case 1:
delta = NewAdded(position, o[0])
case 2:
delta = NewModified(position, o[0], o[1])
case 3:
switch o[2] {
case float64(0):
delta = NewDeleted(position, o[0])
case float64(2):
dmp := dmp.New()
patches, err := dmp.PatchFromText(o[0].(string))
if err != nil {
return nil, err
}
delta = NewTextDiff(position, patches, nil, nil)
case float64(3):
delta = NewMoved(position, Index(int(o[1].(float64))), nil, nil)
default:
return nil, errors.New("Unknown delta type")
}
}
}
return delta, nil
}