+
+
package store
+
+import (
+ "context"
+ "database/sql"
+ "encoding/json"
+ "fmt"
+
+ "github.com/gopatchy/metadata"
+ // Register sqlite3 db handler.
+ _ "github.com/mattn/go-sqlite3"
+)
+
+type Store struct {
+ db *sql.DB
+}
+
+func NewStore(conn string) (*Store, error) {
+ db, err := sql.Open("sqlite3", conn)
+ if err != nil {
+ return nil, err
+ }
+
+ // TODO: Keep a set of prepared statements with PrepareContext()
+ // TODO: Consider tuning per https://phiresky.github.io/blog/2020/sqlite-performance-tuning/
+
+ return &Store{
+ db: db,
+ }, nil
+}
+
+func (s *Store) Close() {
+ s.db.Close()
+}
+
+func (s *Store) Write(ctx context.Context, t string, obj any) error {
+ id := metadata.GetMetadata(obj).ID
+
+ js, err := json.Marshal(obj)
+ if err != nil {
+ return err
+ }
+
+ err = s.exec(ctx, "INSERT INTO `%s` (id, obj) VALUES (?,?) ON CONFLICT(id) DO UPDATE SET obj=?;", t, id, js, js)
+ if err != nil {
+ return err
+ }
+
+ return nil
+}
+
+func (s *Store) Delete(ctx context.Context, t, id string) error {
+ err := s.exec(ctx, "DELETE FROM `%s` WHERE id=?", t, id)
+ if err != nil {
+ return err
+ }
+
+ return nil
+}
+
+func (s *Store) Read(ctx context.Context, t, id string, factory func() any) (any, error) {
+ rows, err := s.query(ctx, "SELECT obj FROM `%s` WHERE id=?;", t, id)
+ if err != nil {
+ return nil, err
+ }
+
+ defer rows.Close()
+
+ if !rows.Next() {
+ return nil, nil
+ }
+
+ var js []byte
+
+ err = rows.Scan(&js)
+ if err != nil {
+ return nil, err
+ }
+
+ obj := factory()
+
+ err = json.Unmarshal(js, obj)
+ if err != nil {
+ return nil, err
+ }
+
+ return obj, nil
+}
+
+func (s *Store) List(ctx context.Context, t string, factory func() any) ([]any, error) {
+ rows, err := s.query(ctx, "SELECT obj FROM `%s`;", t)
+ if err != nil {
+ return nil, err
+ }
+
+ defer rows.Close()
+
+ ret := []any{}
+
+ for rows.Next() {
+ var js []byte
+
+ err = rows.Scan(&js)
+ if err != nil {
+ return nil, err
+ }
+
+ obj := factory()
+
+ err = json.Unmarshal(js, obj)
+ if err != nil {
+ return nil, err
+ }
+
+ ret = append(ret, obj)
+ }
+
+ return ret, nil
+}
+
+func (s *Store) exec(ctx context.Context, query, t string, args ...any) error {
+ query = fmt.Sprintf(query, t)
+
+ _, err := s.db.ExecContext(ctx, query, args...)
+ if err == nil {
+ return nil
+ }
+
+ _, err = s.db.ExecContext(ctx, s.tableSQL(t))
+ if err != nil {
+ return err
+ }
+
+ _, err = s.db.ExecContext(ctx, query, args...)
+ if err != nil {
+ return err
+ }
+
+ return nil
+}
+
+func (s *Store) query(ctx context.Context, query, t string, args ...any) (*sql.Rows, error) {
+ query = fmt.Sprintf(query, t)
+
+ rows, err := s.db.QueryContext(ctx, query, args...)
+ if err == nil {
+ return rows, nil
+ }
+
+ _, err = s.db.ExecContext(ctx, s.tableSQL(t))
+ if err != nil {
+ return nil, err
+ }
+
+ return s.db.QueryContext(ctx, query, args...)
+}
+
+func (s *Store) tableSQL(t string) string {
+ return fmt.Sprintf("CREATE TABLE IF NOT EXISTS `%s` (id TEXT NOT NULL PRIMARY KEY, obj TEXT NOT NULL);", t)
+}
+
+
+