47 lines
1.3 KiB
Go
47 lines
1.3 KiB
Go
// Package multistmt provides methods for parsing multi-statement database migrations
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package multistmt
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import (
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"bufio"
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"bytes"
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"io"
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)
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// StartBufSize is the default starting size of the buffer used to scan and parse multi-statement migrations
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var StartBufSize = 4096
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// Handler handles a single migration parsed from a multi-statement migration.
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// It's given the single migration to handle and returns whether or not further statements
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// from the multi-statement migration should be parsed and handled.
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type Handler func(migration []byte) bool
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func splitWithDelimiter(delimiter []byte) func(d []byte, atEOF bool) (int, []byte, error) {
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return func(d []byte, atEOF bool) (int, []byte, error) {
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// SplitFunc inspired by bufio.ScanLines() implementation
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if atEOF {
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if len(d) == 0 {
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return 0, nil, nil
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}
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return len(d), d, nil
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}
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if i := bytes.Index(d, delimiter); i >= 0 {
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return i + len(delimiter), d[:i+len(delimiter)], nil
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}
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return 0, nil, nil
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}
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}
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// Parse parses the given multi-statement migration
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func Parse(reader io.Reader, delimiter []byte, maxMigrationSize int, h Handler) error {
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scanner := bufio.NewScanner(reader)
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scanner.Buffer(make([]byte, 0, StartBufSize), maxMigrationSize)
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scanner.Split(splitWithDelimiter(delimiter))
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for scanner.Scan() {
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cont := h(scanner.Bytes())
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if !cont {
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break
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}
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}
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return scanner.Err()
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}
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