+/*
+recfile -- GNU recutils'es recfiles parser on pure Go
+Copyright (C) 2020 Sergey Matveev <stargrave@stargrave.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, version 3 of the License.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package recfile
+
+import (
+ "bufio"
+ "errors"
+ "io"
+ "regexp"
+ "strings"
+)
+
+type Reader struct {
+ scanner *bufio.Scanner
+}
+
+func NewReader(r io.Reader) *Reader {
+ return &Reader{bufio.NewScanner(r)}
+}
+
+type Field struct {
+ Name string
+ Value string
+}
+
+var KeyValRe = regexp.MustCompile(`([a-zA-Z%][a-zA-Z0-9_]*):\s*(.*)$`)
+
+func (r *Reader) Next() ([]Field, error) {
+ fields := make([]Field, 0, 1)
+ var text string
+ var name string
+ var line string
+ lines := make([]string, 0)
+ continuation := false
+ var err error
+ for {
+ if !r.scanner.Scan() {
+ if err := r.scanner.Err(); err != nil {
+ return fields, err
+ }
+ err = io.EOF
+ break
+ }
+ text = r.scanner.Text()
+
+ if continuation {
+ if text[len(text)-1] == '\\' {
+ lines = append(lines, text[:len(text)-1])
+ } else {
+ lines = append(lines, text)
+ fields = append(fields, Field{name, strings.Join(lines, "")})
+ lines = make([]string, 0)
+ continuation = false
+ }
+ continue
+ }
+
+ if len(text) > 0 && text[0] == '#' {
+ continue
+ }
+
+ if len(text) > 0 && text[0] == '+' {
+ lines = append(lines, "\n")
+ if len(text) > 1 {
+ if text[1] == ' ' {
+ lines = append(lines, text[2:])
+ } else {
+ lines = append(lines, text[1:])
+ }
+ }
+ continue
+ }
+
+ if len(lines) > 0 {
+ fields = append(fields, Field{name, strings.Join(lines, "")})
+ lines = make([]string, 0)
+ }
+
+ if text == "" {
+ break
+ }
+
+ matches := KeyValRe.FindStringSubmatch(text)
+ if len(matches) == 0 {
+ return fields, errors.New("invalid field format")
+ }
+ name = matches[1]
+ line = matches[2]
+
+ if len(line) > 0 && line[len(line)-1] == '\\' {
+ continuation = true
+ lines = append(lines, line[:len(line)-1])
+ } else {
+ lines = append(lines, line)
+ }
+ }
+ if continuation {
+ return fields, errors.New("left continuation")
+ }
+ if len(lines) > 0 {
+ fields = append(fields, Field{name, strings.Join(lines, "")})
+ }
+ if len(fields) == 0 {
+ if err == nil {
+ return r.Next()
+ }
+ return fields, err
+ }
+ return fields, nil
+}