dex/vendor/github.com/rubenv/sql-migrate/sqlparse/sqlparse.go
2016-03-09 13:04:05 -08:00

128 lines
2.9 KiB
Go

package sqlparse
import (
"bufio"
"bytes"
"errors"
"io"
"strings"
)
const sqlCmdPrefix = "-- +migrate "
// Checks the line to see if the line has a statement-ending semicolon
// or if the line contains a double-dash comment.
func endsWithSemicolon(line string) bool {
prev := ""
scanner := bufio.NewScanner(strings.NewReader(line))
scanner.Split(bufio.ScanWords)
for scanner.Scan() {
word := scanner.Text()
if strings.HasPrefix(word, "--") {
break
}
prev = word
}
return strings.HasSuffix(prev, ";")
}
// Split the given sql script into individual statements.
//
// The base case is to simply split on semicolons, as these
// naturally terminate a statement.
//
// However, more complex cases like pl/pgsql can have semicolons
// within a statement. For these cases, we provide the explicit annotations
// 'StatementBegin' and 'StatementEnd' to allow the script to
// tell us to ignore semicolons.
func SplitSQLStatements(r io.ReadSeeker, direction bool) ([]string, error) {
_, err := r.Seek(0, 0)
if err != nil {
return nil, err
}
var buf bytes.Buffer
scanner := bufio.NewScanner(r)
// track the count of each section
// so we can diagnose scripts with no annotations
upSections := 0
downSections := 0
statementEnded := false
ignoreSemicolons := false
directionIsActive := false
stmts := make([]string, 0)
for scanner.Scan() {
line := scanner.Text()
// handle any migrate-specific commands
if strings.HasPrefix(line, sqlCmdPrefix) {
cmd := strings.TrimSpace(line[len(sqlCmdPrefix):])
switch cmd {
case "Up":
directionIsActive = (direction == true)
upSections++
break
case "Down":
directionIsActive = (direction == false)
downSections++
break
case "StatementBegin":
if directionIsActive {
ignoreSemicolons = true
}
break
case "StatementEnd":
if directionIsActive {
statementEnded = (ignoreSemicolons == true)
ignoreSemicolons = false
}
break
}
}
if !directionIsActive {
continue
}
if _, err := buf.WriteString(line + "\n"); err != nil {
return nil, err
}
// Wrap up the two supported cases: 1) basic with semicolon; 2) psql statement
// Lines that end with semicolon that are in a statement block
// do not conclude statement.
if (!ignoreSemicolons && endsWithSemicolon(line)) || statementEnded {
statementEnded = false
stmts = append(stmts, buf.String())
buf.Reset()
}
}
if err := scanner.Err(); err != nil {
return nil, err
}
// diagnose likely migration script errors
if ignoreSemicolons {
return nil, errors.New("ERROR: saw '-- +migrate StatementBegin' with no matching '-- +migrate StatementEnd'")
}
if upSections == 0 && downSections == 0 {
return nil, errors.New(`ERROR: no Up/Down annotations found, so no statements were executed.
See https://github.com/rubenv/sql-migrate for details.`)
}
return stmts, nil
}