/
simplerepo.go
174 lines (136 loc) · 3.85 KB
/
simplerepo.go
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package blorm
import (
"errors"
"fmt"
"github.com/asdine/storm/codec/msgpack"
"go.etcd.io/bbolt"
)
type SimpleRepository struct {
bucketName []byte
alloc func() interface{}
idExtractor func(record interface{}) []byte
indices []Index
}
func NewSimpleRepo(bucketName string, allocator func() interface{}, idExtractor func(interface{}) []byte) *SimpleRepository {
return &SimpleRepository{
bucketName: []byte(bucketName),
alloc: allocator,
idExtractor: idExtractor,
indices: []Index{},
}
}
func (r *SimpleRepository) Bootstrap(tx *bbolt.Tx) error {
_, err := tx.CreateBucket(r.bucketName)
return err
}
func (r *SimpleRepository) Alloc() interface{} {
return r.alloc()
}
func (r *SimpleRepository) OpenByPrimaryKey(id []byte, record interface{}, tx *bbolt.Tx) error {
bucket := tx.Bucket(r.bucketName)
if bucket == nil {
return ErrBucketNotFound
}
data := bucket.Get(id)
if data == nil {
return ErrNotFound
}
if err := msgpack.Codec.Unmarshal(data, record); err != nil {
return fmt.Errorf("repo[%s] record[%s]: %v", r.bucketName, id, err)
}
return nil
}
func (r *SimpleRepository) Update(record interface{}, tx *bbolt.Tx) error {
bucket := tx.Bucket(r.bucketName)
if bucket == nil {
return ErrBucketNotFound
}
id := r.idExtractor(record)
data, err := msgpack.Codec.Marshal(record)
if err != nil {
return err
}
oldImage := r.alloc()
errOpenOld := r.OpenByPrimaryKey(id, oldImage, tx)
if errOpenOld != nil && errOpenOld != ErrNotFound {
return errOpenOld
}
oldIndices := []qualifiedIndexRef{}
newIndices := r.indexRefsForRecord(record)
if errOpenOld != ErrNotFound { // we have old and new image, must compare indices for old and new image
oldIndices = r.indexRefsForRecord(oldImage)
}
if err := r.updateIndices(oldIndices, newIndices, tx); err != nil {
return err
}
return bucket.Put(id, data)
}
func (r *SimpleRepository) Delete(record interface{}, tx *bbolt.Tx) error {
bucket := tx.Bucket(r.bucketName)
if bucket == nil {
return ErrBucketNotFound
}
id := r.idExtractor(record)
if bucket.Get(id) == nil { // bucket.Delete() does not return error for non-existing keys
return errors.New("record to delete does not exist")
}
oldIndices := r.indexRefsForRecord(record)
newIndices := []qualifiedIndexRef{} // = drop
if err := r.updateIndices(oldIndices, newIndices, tx); err != nil {
return err
}
return bucket.Delete(id)
}
func (r *SimpleRepository) Each(fn func(record interface{}) error, tx *bbolt.Tx) error {
return r.EachFrom([]byte(""), fn, tx)
}
func (r *SimpleRepository) EachFrom(from []byte, fn func(record interface{}) error, tx *bbolt.Tx) error {
bucket := tx.Bucket(r.bucketName)
if bucket == nil {
return ErrBucketNotFound
}
all := bucket.Cursor()
for key, value := all.Seek(from); key != nil; key, value = all.Next() {
record := r.alloc()
if err := msgpack.Codec.Unmarshal(value, record); err != nil {
return fmt.Errorf("repo[%s] record[%s]: %v", r.bucketName, key, err)
}
if err := fn(record); err != nil {
if err == StopIteration {
return nil // not an error, so don't give one out
}
return err
}
}
return nil
}
func (r *SimpleRepository) indexRefsForRecord(record interface{}) []qualifiedIndexRef {
refs := []qualifiedIndexRef{}
for _, repoIndex := range r.indices {
refs = append(refs, repoIndex.extractIndexRefs(record)...)
}
return refs
}
func (r *SimpleRepository) updateIndices(
oldIndices []qualifiedIndexRef,
newIndices []qualifiedIndexRef,
tx *bbolt.Tx,
) error {
for _, old := range oldIndices {
// old doesn't exist in new => drop
if !indexRefExistsIn(old, newIndices) {
if err := old.Drop(tx); err != nil {
return err
}
}
}
for _, nu := range newIndices {
// new doesn't exist in old => add
if !indexRefExistsIn(nu, oldIndices) {
if err := nu.Write(tx); err != nil {
return err
}
}
}
return nil
}