/
row.go
103 lines (84 loc) · 1.92 KB
/
row.go
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package sql
import (
"io"
)
// Row is a tuple of values.
type Row []interface{}
// NewRow creates a row from the given values.
func NewRow(values ...interface{}) Row {
row := make([]interface{}, len(values))
copy(row, values)
return row
}
// Copy creates a new row with the same values as the current one.
func (r Row) Copy() Row {
return NewRow(r...)
}
// Equals checks whether two rows are equal given a schema.
func (r Row) Equals(row Row, schema Schema) (bool, error) {
if len(row) != len(r) || len(row) != len(schema) {
return false, nil
}
for i, colLeft := range r {
colRight := row[i]
cmp, err := schema[i].Type.Compare(colLeft, colRight)
if err != nil {
return false, err
}
if cmp != 0 {
return false, nil
}
}
return true, nil
}
// RowIter is an iterator that produces rows.
type RowIter interface {
// Next retrieves the next row. It will return io.EOF if it's the last row.
// After retrieving the last row, Close will be automatically closed.
Next() (Row, error)
// Close the iterator.
Close() error
}
// RowIterToRows converts a row iterator to a slice of rows.
func RowIterToRows(i RowIter) ([]Row, error) {
var rows []Row
for {
row, err := i.Next()
if err == io.EOF {
break
}
if err != nil {
return nil, err
}
rows = append(rows, row)
}
return rows, i.Close()
}
// NodeToRows converts a node to a slice of rows.
func NodeToRows(ctx *Context, n Node) ([]Row, error) {
i, err := n.RowIter(ctx)
if err != nil {
return nil, err
}
return RowIterToRows(i)
}
// RowsToRowIter creates a RowIter that iterates over the given rows.
func RowsToRowIter(rows ...Row) RowIter {
return &sliceRowIter{rows: rows}
}
type sliceRowIter struct {
rows []Row
idx int
}
func (i *sliceRowIter) Next() (Row, error) {
if i.idx >= len(i.rows) {
return nil, io.EOF
}
r := i.rows[i.idx]
i.idx++
return r.Copy(), nil
}
func (i *sliceRowIter) Close() error {
i.rows = nil
return nil
}