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