Function SplitMessage

git/parser/commit_message.go:90–145

SplitMessage splits a commit message. Returns two strings: * subject (the one line commit summary, like "git log --oneline" or "git log --format=%s), * body only (like "git log --format=%b").

(message string)

// * subject (the one line commit summary, like "git log --oneline" or "git log --format=%s),
// * body only (like "git log --format=%b").
func SplitMessage(message string) (string, string) {
	var state int
	var lastLineEmpty bool
	const (
		stateInit = iota
		stateSubject
		stateSeparator
		stateBody
	)

	const eol = '\n'

	subjectBuilder := strings.Builder{}
	bodyBuilder := strings.Builder{}

	scan := bufio.NewScanner(strings.NewReader(message))
	for scan.Scan() {
		line := strings.TrimRightFunc(scan.Text(), unicode.IsSpace)

		// process empty lines
		if len(line) == 0 {
			switch state {
			case stateInit, stateSeparator:
				// ignore all empty lines before the first line of the subject
			case stateSubject:
				state = stateSeparator
			case stateBody:
				lastLineEmpty = true
			}
			continue
		}

		switch state {
		case stateInit:
			state = stateSubject
			subjectBuilder.WriteString(strings.TrimLeftFunc(line, unicode.IsSpace))
		case stateSubject:
			subjectBuilder.WriteByte(' ')
			subjectBuilder.WriteString(strings.TrimLeftFunc(line, unicode.IsSpace))
		case stateSeparator:
			state = stateBody
			bodyBuilder.WriteString(line)
			bodyBuilder.WriteByte(eol)
			lastLineEmpty = false
		case stateBody:
			if lastLineEmpty {
				bodyBuilder.WriteByte(eol)
			}
			bodyBuilder.WriteString(line)
			bodyBuilder.WriteByte(eol)
			lastLineEmpty = false
		}
	}

	return subjectBuilder.String(), bodyBuilder.String()
}