forked from upper/bond
/
session.go
218 lines (182 loc) · 4.28 KB
/
session.go
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package bond
import (
"context"
"database/sql"
"errors"
"fmt"
"reflect"
"sync"
"upper.io/db.v3"
"upper.io/db.v3/lib/sqlbuilder"
)
type txWithContext interface {
WithContext(context.Context) sqlbuilder.Tx
}
type databaseWithContext interface {
WithContext(context.Context) sqlbuilder.Database
}
type hasContext interface {
Context() context.Context
}
// SQLBackend represents a type that can execute SQL queries.
type SQLBackend interface {
Exec(string, ...interface{}) (sql.Result, error)
Prepare(string) (*sql.Stmt, error)
Query(string, ...interface{}) (*sql.Rows, error)
QueryRow(string, ...interface{}) *sql.Row
}
type Backend interface {
sqlbuilder.SQLBuilder
db.Database
SetTxOptions(sql.TxOptions)
TxOptions() *sql.TxOptions
}
type Session interface {
Backend
Store(collectionName string) Store
ResolveStore(interface{}) Store
Save(Model) error
Delete(Model) error
WithContext(context.Context) Session
Context() context.Context
SessionTx(context.Context, func(tx Session) error) error
}
type session struct {
Backend
stores map[string]*store
storesLock sync.Mutex
}
// Open connects to a database.
func Open(adapter string, url db.ConnectionURL) (Session, error) {
conn, err := sqlbuilder.Open(adapter, url)
if err != nil {
return nil, err
}
return New(conn), nil
}
// New returns a new session.
func New(conn Backend) Session {
return &session{Backend: conn, stores: make(map[string]*store)}
}
func (s *session) WithContext(ctx context.Context) Session {
var backendCtx Backend
switch t := s.Backend.(type) {
case databaseWithContext:
backendCtx = t.WithContext(ctx)
case txWithContext:
backendCtx = t.WithContext(ctx)
default:
panic("Bad session")
}
return &session{
Backend: backendCtx,
stores: make(map[string]*store),
}
}
func (s *session) Context() context.Context {
return s.Backend.(hasContext).Context()
}
// Bind binds to an existent database session. Possible backend values are:
// *sql.Tx or *sql.DB.
func Bind(adapter string, backend SQLBackend) (Session, error) {
var conn Backend
switch t := backend.(type) {
case *sql.Tx:
var err error
conn, err = sqlbuilder.NewTx(adapter, t)
if err != nil {
return nil, err
}
case *sql.DB:
var err error
conn, err = sqlbuilder.New(adapter, t)
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("Unknown backend type: %T", t)
}
return &session{Backend: conn, stores: make(map[string]*store)}, nil
}
func (s *session) SessionTx(ctx context.Context, fn func(sess Session) error) error {
txFn := func(sess sqlbuilder.Tx) error {
return fn(&session{
Backend: sess,
stores: make(map[string]*store),
})
}
switch t := s.Backend.(type) {
case sqlbuilder.Database:
return t.Tx(ctx, txFn)
case sqlbuilder.Tx:
defer t.Close()
err := txFn(t)
if err != nil {
return t.Rollback()
}
return t.Commit()
}
return errors.New("Missing backend, forgot to use bond.New?")
}
func (s *session) getStore(item interface{}) Store {
if c, ok := item.(HasStore); ok {
return c.Store(s)
}
if c, ok := item.(HasCollectionName); ok {
return s.Store(c.CollectionName())
}
panic("reached")
}
func (s *session) Save(item Model) error {
if item == nil {
return ErrExpectingNonNilModel
}
return s.getStore(item).Save(item)
}
func (s *session) Delete(item Model) error {
if item == nil {
return ErrExpectingNonNilModel
}
return s.getStore(item).Delete(item)
}
func (s *session) Store(collectionName string) Store {
if collectionName == "" {
return &store{session: s}
}
s.storesLock.Lock()
defer s.storesLock.Unlock()
if store, ok := s.stores[collectionName]; ok {
return store
}
store := &store{
Collection: s.Collection(collectionName),
session: s,
}
s.stores[collectionName] = store
return store
}
func (s *session) ResolveStore(item interface{}) Store {
var colName string
switch t := item.(type) {
case string:
colName = t
case func(sess Session) db.Collection:
colName = t(s).Name()
case Store:
return t
case db.Collection:
colName = t.Name()
case Model:
colName = t.Store(s).Name()
default:
itemv := reflect.ValueOf(item)
if itemv.Kind() == reflect.Ptr {
itemv = reflect.Indirect(itemv)
}
item = itemv.Interface()
if m, ok := item.(Model); ok {
colName = m.Store(s).Name()
}
}
return s.Store(colName)
}