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// Copyright 2018 Google LLC
//
// 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 datastore
import (
"fmt"
pb "google.golang.org/genproto/googleapis/datastore/v1"
)
// A Mutation represents a change to a Datastore entity.
type Mutation struct {
key *Key // needed for transaction PendingKeys and to dedup deletions
mut *pb.Mutation
err error
}
func (m *Mutation) isDelete() bool {
_, ok := m.mut.Operation.(*pb.Mutation_Delete)
return ok
}
// NewInsert creates a mutation that will save the entity src into the datastore with
// key k, returning an error if k already exists.
// See Client.Put for valid values of src.
func NewInsert(k *Key, src interface{}) *Mutation {
if !k.valid() {
return &Mutation{err: ErrInvalidKey}
}
p, err := saveEntity(k, src)
if err != nil {
return &Mutation{err: err}
}
return &Mutation{
key: k,
mut: &pb.Mutation{Operation: &pb.Mutation_Insert{Insert: p}},
}
}
// NewUpsert creates a mutation that saves the entity src into the datastore with key
// k, whether or not k exists. See Client.Put for valid values of src.
func NewUpsert(k *Key, src interface{}) *Mutation {
if !k.valid() {
return &Mutation{err: ErrInvalidKey}
}
p, err := saveEntity(k, src)
if err != nil {
return &Mutation{err: err}
}
return &Mutation{
key: k,
mut: &pb.Mutation{Operation: &pb.Mutation_Upsert{Upsert: p}},
}
}
// NewUpdate creates a mutation that replaces the entity in the datastore with key k,
// returning an error if k does not exist. See Client.Put for valid values of src.
func NewUpdate(k *Key, src interface{}) *Mutation {
if !k.valid() {
return &Mutation{err: ErrInvalidKey}
}
if k.Incomplete() {
return &Mutation{err: fmt.Errorf("datastore: can't update the incomplete key: %v", k)}
}
p, err := saveEntity(k, src)
if err != nil {
return &Mutation{err: err}
}
return &Mutation{
key: k,
mut: &pb.Mutation{Operation: &pb.Mutation_Update{Update: p}},
}
}
// NewDelete creates a mutation that deletes the entity with key k.
func NewDelete(k *Key) *Mutation {
if !k.valid() {
return &Mutation{err: ErrInvalidKey}
}
if k.Incomplete() {
return &Mutation{err: fmt.Errorf("datastore: can't delete the incomplete key: %v", k)}
}
return &Mutation{
key: k,
mut: &pb.Mutation{Operation: &pb.Mutation_Delete{Delete: keyToProto(k)}},
}
}
func mutationProtos(muts []*Mutation) ([]*pb.Mutation, error) {
// If any of the mutations have errors, collect and return them.
var merr MultiError
for i, m := range muts {
if m.err != nil {
if merr == nil {
merr = make(MultiError, len(muts))
}
merr[i] = m.err
}
}
if merr != nil {
return nil, merr
}
var protos []*pb.Mutation
// Collect protos. Remove duplicate deletions (see deleteMutations).
seen := map[string]bool{}
for _, m := range muts {
if m.isDelete() {
ks := m.key.String()
if seen[ks] {
continue
}
seen[ks] = true
}
protos = append(protos, m.mut)
}
return protos, nil
}