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package migratetest
import (
"bufio"
"encoding/csv"
"fmt"
"io"
"strings"
)
// CopyScanner will scan COPY statements, returning TableSnapshots.
type CopyScanner struct {
s *bufio.Scanner
t TableSnapshot
err error
}
// NewCopyScanner will return a new CopyScanner.
func NewCopyScanner(r io.Reader) *CopyScanner {
return &CopyScanner{s: bufio.NewScanner(r)}
}
func (d *CopyScanner) nextTableName() string {
for d.s.Scan() {
if !strings.HasPrefix(d.s.Text(), "COPY ") {
continue
}
parts := strings.Split(d.s.Text(), `"`)
if len(parts) < 3 {
d.err = fmt.Errorf("invalid COPY line: %s", d.s.Text())
return ""
}
return parts[1]
}
d.err = d.s.Err()
return ""
}
func (d *CopyScanner) csvData() string {
var b strings.Builder
for d.s.Scan() {
if d.s.Text() == "\\." {
return b.String()
}
b.WriteString(d.s.Text())
b.WriteByte('\n')
}
d.err = d.s.Err()
return ""
}
// Scan will scan the next COPY statement.
func (d *CopyScanner) Scan() bool {
if d.err != nil {
return false
}
var t TableSnapshot
t.Name = d.nextTableName()
if t.Name == "" {
return false
}
data := d.csvData()
if data == "" {
return false
}
r := csv.NewReader(strings.NewReader(data))
t.Columns, d.err = r.Read()
if d.err != nil {
return false
}
t.Rows, d.err = r.ReadAll()
if d.err != nil {
return false
}
t.Sort()
d.t = t
return true
}
func (d *CopyScanner) Err() error { return d.err }
func (d *CopyScanner) Table() TableSnapshot { return d.t }
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