// Interface towards the Grapher
func (self *latestTransformer) TransformClientMutation(mutation grapher.MutationNode, concurrent <-chan grapher.MutationNode) (err os.Error) {
mut, e := decodeGenericMutation(mutation)
if e != nil {
log.Printf("Err: Decoding")
return e
}
// If any of these is later, then the mutation is transformed into the epsilon operation
for m := range concurrent {
if m.Time() > mut.Time {
mutation.SetOperation([]byte("null"))
return
}
}
return
}
func (self *channelAPI) Blob_Mutation(perma grapher.PermaNode, mutation grapher.MutationNode) {
mutJson := map[string]interface{}{"perma": perma.BlobRef(), "seq": mutation.SequenceNumber(), "type": "mutation", "signer": mutation.Signer(), "entity": mutation.EntityBlobRef(), "field": mutation.Field(), "time": mutation.Time()}
switch mutation.Operation().(type) {
case []ot.StringOperation:
op := mutation.Operation().([]ot.StringOperation) // The following two lines work around a problem in GO/JSON
mutJson["op"] = &op
case []byte:
msg := json.RawMessage(mutation.Operation().([]byte))
mutJson["op"] = &msg
default:
panic("Unsupported operation kind")
}
schema, err := json.Marshal(mutJson)
if err != nil {
panic(err.String())
}
if self.bufferOnly {
self.messageBuffer = append(self.messageBuffer, string(schema))
} else {
err = self.forwardToFollowers(perma.BlobRef(), string(schema))
}
if err != nil {
log.Printf("Err Forward: %v", err)
}
}
// Interface towards the Grapher
func (self *latestTransformer) TransformMutation(mutation grapher.MutationNode, rollback <-chan grapher.MutationNode, concurrent []string) (err os.Error) {
mut, e := decodeGenericMutation(mutation)
if e != nil {
return e
}
// Get a list of all concurrent mutations
conc := make(map[string]bool)
for _, id := range concurrent {
conc[id] = true
}
for m := range rollback {
// Skip those which are not concurrent
if _, ok := conc[m.BlobRef()]; !ok {
continue
}
if m.Time() > mut.Time {
mutation.SetOperation([]byte("null"))
return
}
}
return
}
// TODO: Perform type checking for other data types. This one does only strings
func decodeGenericMutation(mutation grapher.MutationNode) (mut latestMutation, err os.Error) {
switch mutation.Operation().(type) {
case []byte:
buffer := []byte(`{"op":`)
buffer = append(buffer, mutation.Operation().([]byte)...)
buffer = append(buffer, []byte("}")...)
var val stringDummy
err = json.Unmarshal(buffer, &val)
if err != nil {
return mut, err
}
mut.Operation = val.Value
default:
mut.Operation = mutation.Operation()
}
mut.Time = mutation.Time()
return
}