nix-amer/internal/cnf/parser/bash/decoder.go

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package bash
import (
"bufio"
"io"
"regexp"
"strings"
)
// Decoder implements parser.Decoder
type Decoder struct{ reader io.Reader }
// Decode is the main function of the parser.Decoder interface
func (d *Decoder) Decode(v interface{}) error {
// check 'v'
if v == nil {
return ErrNullReceiver
}
vcast, ok := v.(*File)
if !ok {
return ErrInvalidReceiver
}
vcast.Lines = make([]*Line, 0)
r := bufio.NewReader(d.reader)
n := -1 // line number
// regexes
reAssign := regexp.MustCompile(`(?m)^(\s*)([A-Za-z0-9_]+)=([^;]+);?\s*(#.+)?$`)
eof := false
for {
n++
if eof {
break
}
l := &Line{Type: ANY}
// 1. read line
line, err := r.ReadString('\n')
if err == io.EOF {
if len(line) > 0 {
eof = true
} else {
break
}
} else if err != nil {
return &LineError{n, err}
}
line = strings.Trim(line, "\r\n")
// 2. ignore empty
if len(strings.Trim(line, " \t\r\n")) < 1 {
continue
}
// 3. assignment
match := reAssign.FindStringSubmatch(line)
if match != nil {
l.Type = ASSIGNMENT
l.Components = match[1:]
} else {
l.Components = []string{line}
}
// 4. add to file
vcast.Lines = append(vcast.Lines, l)
}
return nil
}