diff options
Diffstat (limited to 'select.go')
| -rw-r--r-- | select.go | 43 |
1 files changed, 16 insertions, 27 deletions
@@ -14,7 +14,7 @@ import ( // according to the column names reported by the database as part of the result set. // // An error is returned if any column name in the result set does not correspond to an addressable field in R. -func (s Store[R]) Select(db Handle, query string, args ...any) (result []R, returnedError error) { +func (s Store[R]) Select(db Handle, query string, args ...any) ([]R, error) { // NOTE: This function body should be as short as possible to reduce the binary size after monomorphization. // Any expression that does not depend on type R should be factored out into a reusable function. @@ -22,10 +22,8 @@ func (s Store[R]) Select(db Handle, query string, args ...any) (result []R, retu if err != nil { return nil, err } - defer func() { - returnedError = mergeCloseError("Rows", returnedError, rows.Close()) - }() + var result []R slots := make([]any, len(indexes)) for rows.Next() { var target R @@ -36,7 +34,7 @@ func (s Store[R]) Select(db Handle, query string, args ...any) (result []R, retu result = append(result, target) } - return result, nil + return result, newIOError(err, "Rows.Err", rows.Err()) } // SelectWhere is like [Store.Select], but you only provide the part of the SELECT query that comes after the WHERE. @@ -52,7 +50,7 @@ func (s Store[R]) Select(db Handle, query string, args ...any) (result []R, retu // Besides a condition for the WHERE clause, it may contain additional clauses, such as ORDER BY or LIMIT. // // Returns an error if [NewStore] was called without the [TableNameIs] option, which is required to generate a query for this method. -func (s Store[R]) SelectWhere(db Handle, partialQuery string, args ...any) (result []R, returnedError error) { +func (s Store[R]) SelectWhere(db Handle, partialQuery string, args ...any) ([]R, error) { // NOTE: This function body should be as short as possible to reduce the binary size after monomorphization. // Any expression that does not depend on type R should be factored out into a reusable function. @@ -60,10 +58,8 @@ func (s Store[R]) SelectWhere(db Handle, partialQuery string, args ...any) (resu if err != nil { return nil, err } - defer func() { - returnedError = mergeCloseError("Rows", returnedError, rows.Close()) - }() + var result []R slots := make([]any, len(indexes)) for rows.Next() { var target R @@ -74,7 +70,7 @@ func (s Store[R]) SelectWhere(db Handle, partialQuery string, args ...any) (resu result = append(result, target) } - return result, nil + return result, newIOError(err, "Rows.Err", rows.Err()) } func startSelectQuery(db Handle, plan plan, query string, args ...any) (returnedRows *sql.Rows, indexes [][]int, returnedError error) { @@ -84,10 +80,8 @@ func startSelectQuery(db Handle, plan plan, query string, args ...any) (returned } defer func() { if returnedError != nil { - closeErr := rows.Close() // NOTE: Not `returnedRows.Close()`! We may have `rows != nil && returnedRows == nil`. - if closeErr != nil { - returnedError = fmt.Errorf("%w (additional error during rows.Close(): %s)", returnedError, closeErr.Error()) - } + // NOTE: Not `returnedRows.Close()`! We may have `rows != nil && returnedRows == nil`. + returnedError = newIOError(returnedError, "Rows.Close", rows.Close()) } }() @@ -116,6 +110,9 @@ func startSelectWhereQuery(db Handle, plan plan, partialQuery string, args ...an } query := plan.Select.Query + partialQuery rows, err = db.Query(query, args...) + if err != nil { + err = fmt.Errorf("during Query(): %w", err) + } return rows, plan.Select.ScanIndexes, err } @@ -127,18 +124,11 @@ func collectRow(rows *sql.Rows, plan plan, v reflect.Value, slots []any, indexes for idx, index := range indexes { slots[idx] = v.FieldByIndex(index).Addr().Interface() } - return rows.Scan(slots...) -} - -func mergeCloseError(typeName string, err, closeErr error) error { - switch { - case closeErr == nil: - return err - case err == nil: - return fmt.Errorf("during %s.Close(): %w", typeName, closeErr) - default: - return fmt.Errorf("%w (additional error during %s.Close(): %s)", err, typeName, closeErr.Error()) + err := rows.Scan(slots...) + if err != nil { + return newIOError(err, "Rows.Close", rows.Close()) } + return nil } // SelectOne executes the provided SQL query and fills an instance of the record type R if there is exactly one row in the result set, @@ -167,8 +157,7 @@ func (s Store[R]) SelectOne(db Handle, query string, args ...any) (result R, err // SelectOneWhere is like [Store.SelectOne], but you only provide the part of the SELECT query that comes after the WHERE. // See [Store.SelectWhere] for an explanation of how the full query is constructed from this partial query. // -// This method is significantly more efficient than [Store.SelectOne]. -// Prefer using it instaed of [Store.SelectOne] whenever possible. +// This method is more efficient than [Store.SelectOne] on CPU runtime, but has a slight memory allocation overhead. func (s Store[R]) SelectOneWhere(db Handle, partialQuery string, args ...any) (result R, err error) { // NOTE: This function body should be as short as possible to reduce the binary size after monomorphization. // Any expression that does not depend on type R should be factored out into a reusable function. |