txwrap can now be properly nested. add json conversion functions to quick

pkg/sstore/dbops.go

@@ -10,7 +10,7 @@ import (
 )
 
 func NumSessions(ctx context.Context) (int, error) {
-	db, err := GetDB()
+	db, err := GetDB(ctx)
 	if err != nil {
 		return 0, err
 	}
@@ -71,7 +71,7 @@ func InsertRemote(ctx context.Context, remote *RemoteType) error {
 	if remote == nil {
 		return fmt.Errorf("cannot insert nil remote")
 	}
-	db, err := GetDB()
+	db, err := GetDB(ctx)
 	if err != nil {
 		return err
 	}
@@ -156,7 +156,7 @@ func GetSessionById(ctx context.Context, id string) (*SessionType, error) {
 }
 
 func GetSessionByName(ctx context.Context, name string) (*SessionType, error) {
-	db, err := GetDB()
+	db, err := GetDB(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -228,6 +228,14 @@ func containsStr(strs []string, testStr string) bool {
 	return false
 }
 
+func InsertScreen(ctx context.Context, sessionId string, screenName string) (string, error) {
+	var newScreenId string
+	txErr := WithTx(ctx, func(tx *TxWrap) error {
+		return nil
+	})
+	return newScreenId, txErr
+}
+
 // if windowName == "", it will be generated
 // returns (windowid, err)
 func InsertWindow(ctx context.Context, sessionId string, windowName string) (string, error) {

pkg/sstore/quick.go

@@ -72,19 +72,27 @@ func quickJson(v interface{}) string {
 }
 
 func quickScanJson(ptr interface{}, val interface{}) error {
-	strVal, ok := val.(string)
+	barrVal, ok := val.([]byte)
 	if !ok {
-		return fmt.Errorf("cannot scan '%T' into '%T'", val, ptr)
+		strVal, ok := val.(string)
+		if !ok {
+			return fmt.Errorf("cannot scan '%T' into '%T'", val, ptr)
+		}
+		barrVal = []byte(strVal)
 	}
-	if strVal == "" {
+	if len(barrVal) == 0 {
 		return nil
 	}
-	return json.Unmarshal([]byte(strVal), ptr)
+	return json.Unmarshal(barrVal, ptr)
 }
 
 func quickValueJson(v interface{}) (driver.Value, error) {
 	if v == nil {
 		return "", nil
 	}
-	return json.Marshal(v)
+	barr, err := json.Marshal(v)
+	if err != nil {
+		return nil, err
+	}
+	return string(barr), nil
 }

pkg/sstore/sstore.go

@@ -43,7 +43,10 @@ func GetSessionDBName() string {
 	return path.Join(scHome, DBFileName)
 }
 
-func GetDB() (*sqlx.DB, error) {
+func GetDB(ctx context.Context) (*sqlx.DB, error) {
+	if IsTxWrapContext(ctx) {
+		return nil, fmt.Errorf("cannot call GetDB from within a running transaction")
+	}
 	globalDBLock.Lock()
 	defer globalDBLock.Unlock()
 	if globalDB == nil && globalDBErr == nil {
@@ -69,7 +72,7 @@ func (opts *WindowOptsType) Scan(val interface{}) error {
 	return quickScanJson(opts, val)
 }
 
-func (opts *WindowOptsType) Value() (driver.Value, error) {
+func (opts WindowOptsType) Value() (driver.Value, error) {
 	return quickValueJson(opts)
 }
 
@@ -107,7 +110,7 @@ func (l *LayoutType) Scan(val interface{}) error {
 	return quickScanJson(l, val)
 }
 
-func (l *LayoutType) Value() (driver.Value, error) {
+func (l LayoutType) Value() (driver.Value, error) {
 	return quickValueJson(l)
 }
 
@@ -130,7 +133,7 @@ func (s *RemoteState) Scan(val interface{}) error {
 	return quickScanJson(s, val)
 }
 
-func (s *RemoteState) Value() (driver.Value, error) {
+func (s RemoteState) Value() (driver.Value, error) {
 	return quickValueJson(s)
 }
 
@@ -144,7 +147,7 @@ func (opts *TermOpts) Scan(val interface{}) error {
 	return quickScanJson(opts, val)
 }
 
-func (opts *TermOpts) Value() (driver.Value, error) {
+func (opts TermOpts) Value() (driver.Value, error) {
 	return quickValueJson(opts)
 }
 

pkg/sstore/txwrap.go

@@ -10,32 +10,47 @@ import (
 type TxWrap struct {
 	Txx *sqlx.Tx
 	Err error
+	Ctx context.Context
+}
+
+type txWrapKey struct{}
+
+func IsTxWrapContext(ctx context.Context) bool {
+	ctxVal := ctx.Value(txWrapKey{})
+	return ctxVal != nil
 }
 
 func WithTx(ctx context.Context, fn func(tx *TxWrap) error) (rtnErr error) {
-	db, err := GetDB()
-	if err != nil {
-		return err
+	var txWrap *TxWrap
+	ctxVal := ctx.Value(txWrapKey{})
+	if ctxVal != nil {
+		txWrap = ctxVal.(*TxWrap)
 	}
-	tx, beginErr := db.BeginTxx(ctx, nil)
-	if beginErr != nil {
-		return beginErr
+	if txWrap == nil {
+		db, err := GetDB(ctx)
+		if err != nil {
+			return err
+		}
+		tx, beginErr := db.BeginTxx(ctx, nil)
+		if beginErr != nil {
+			return beginErr
+		}
+		txWrap = &TxWrap{Txx: tx, Ctx: ctx}
+		defer func() {
+			if p := recover(); p != nil {
+				txWrap.Txx.Rollback()
+				panic(p)
+			}
+			if rtnErr != nil {
+				txWrap.Txx.Rollback()
+			} else {
+				rtnErr = txWrap.Txx.Commit()
+			}
+		}()
 	}
-	txWrap := &TxWrap{Txx: tx}
-	defer func() {
-		if p := recover(); p != nil {
-			tx.Rollback()
-			panic(p)
-		}
-		if rtnErr != nil {
-			tx.Rollback()
-		} else {
-			rtnErr = tx.Commit()
-		}
-	}()
 	fnErr := fn(txWrap)
-	if fnErr != nil {
-		return fnErr
+	if txWrap.Err == nil && fnErr != nil {
+		txWrap.Err = fnErr
 	}
 	if txWrap.Err != nil {
 		return txWrap.Err
@@ -43,6 +58,10 @@ func WithTx(ctx context.Context, fn func(tx *TxWrap) error) (rtnErr error) {
 	return nil
 }
 
+func (tx *TxWrap) Context() context.Context {
+	return context.WithValue(tx.Ctx, txWrapKey{}, tx)
+}
+
 func (tx *TxWrap) NamedExecWrap(query string, arg interface{}) sql.Result {
 	if tx.Err != nil {
 		return nil