Files
satbd-explorer/album_database.go

113 lines
2.2 KiB
Go

package main
import (
"encoding/json"
"fmt"
"sort"
"github.com/peterbourgon/diskv"
)
type AlbumDatabase struct {
dv *diskv.Diskv
sorted bool
sortedList []AlbumID
}
func OpenAlbumDatabase(basepath string) *AlbumDatabase {
return &AlbumDatabase{
dv: diskv.New(diskv.Options{
BasePath: basepath,
CacheSizeMax: 100 * 1024 * 1024, // 100 MB
Compression: diskv.NewGzipCompression(),
}),
sorted: false,
sortedList: make([]AlbumID, 0, 10),
}
}
func (db *AlbumDatabase) AddOrUpdate(a *Album) error {
data, err := json.Marshal(a)
if err != nil {
return err
}
aInDb, err := db.Get(a.ID)
dbNewSorted := false
if err == nil {
dbNewSorted = (a.PurchaseDate != aInDb.PurchaseDate)
}
err = db.dv.Write(AlbumIDString(a.ID), data)
if err == nil {
db.sorted = dbNewSorted
}
return err
}
func (db *AlbumDatabase) Delete(ID AlbumID) error {
if db.dv.Has(AlbumIDString(ID)) == false {
return fmt.Errorf("Album %d not found", ID)
}
return db.dv.Erase(AlbumIDString(ID))
}
func (db *AlbumDatabase) get(ID string) (*Album, error) {
res := &Album{}
r, err := db.dv.ReadStream(ID, false)
if err != nil {
return nil, fmt.Errorf("Album %s not found: %s", ID, err)
}
dec := json.NewDecoder(r)
defer closeOrPanic(r, "db record "+ID)
return res, dec.Decode(res)
}
func (db *AlbumDatabase) Get(ID AlbumID) (*Album, error) {
return db.get(AlbumIDString(ID))
}
func (db *AlbumDatabase) GetJSON(ID AlbumID) ([]byte, error) {
return db.dv.Read(AlbumIDString(ID))
}
type ListOfAlbum []*Album
func (l ListOfAlbum) Len() int {
return len(l)
}
func (l ListOfAlbum) Less(i, j int) bool {
return l[i].PurchaseDate.Before(l[j].PurchaseDate)
}
func (l ListOfAlbum) Swap(i, j int) {
l[i], l[j] = l[j], l[i]
}
func (db *AlbumDatabase) ByPurchaseDate() ([]AlbumID, error) {
if db.sorted == false {
allAlbums := []*Album{}
for aIDStr := range db.dv.Keys(nil) {
a, err := db.get(aIDStr)
if err != nil {
return nil, err
}
allAlbums = append(allAlbums, a)
}
sort.Sort(sort.Reverse(ListOfAlbum(allAlbums)))
db.sortedList = make([]AlbumID, 0, len(allAlbums))
for _, a := range allAlbums {
db.sortedList = append(db.sortedList, a.ID)
}
db.sorted = true
}
return db.sortedList, nil
}