nix-amer/internal/cnf/bash.go

package cnf

import (
	lib "git.xdrm.io/go/nix-amer/internal/cnf/parser/bash"
	"io"
	"strings"
)

type bash struct {
	data   *lib.File
	parsed bool
}

// ReadFrom implements io.ReaderFrom
func (d *bash) ReadFrom(_reader io.Reader) (int64, error) {

	d.data = new(lib.File)

	// 1. get bash decoder
	decoder := lib.NewDecoder(_reader)
	err := decoder.Decode(d.data)
	if err != nil {
		return 0, err
	}

	d.parsed = true
	return 0, nil

}

// WriteTo implements io.WriterTo
func (d *bash) WriteTo(_writer io.Writer) (int64, error) {
	encoder := lib.NewEncoder(_writer)
	return 0, encoder.Encode(d.data)
}

// browse returns the target of a dot-separated path (as an interface{} chain where the last is the target if found)
// if <create> is true, create if does not exist
func (d *bash) browse(_path string, create ...bool) (*lib.Line, bool) {

	mustCreate := len(create) > 0 && create[0]

	// 1. extract path
	path := strings.Split(_path, ".")
	field := path[len(path)-1]

	// 2. nothing
	if len(path) < 1 {
		return &lib.Line{}, true
	}

	// 3. iterate over path / nested fields
	for _, line := range d.data.Lines {
		if line.Type == lib.ASSIGNMENT && len(line.Components) > 1 && line.Components[1] == field {
			return line, true
		}
	}

	// 4. create assignment
	if mustCreate {
		assignment := &lib.Line{
			Type:       lib.ASSIGNMENT,
			Components: []string{"", field, "", ""},
		}
		d.data.Lines = append(d.data.Lines, assignment)
		return assignment, true
	}

	return nil, false
}

// Get returns the value of a dot-separated path, and if it exists
func (d *bash) Get(_path string) (string, bool) {

	// 1. browse path
	last, found := d.browse(_path, true)
	if !found {
		return "", false
	}

	// 2. Get last field
	return last.Components[2], true

}

// Set the value of a dot-separated path, and creates it if not found
func (d *bash) Set(_path, _value string) bool {

	// 1. browse path
	last, found := d.browse(_path, true)
	if !found {
		return false
	}

	// 2. Set value
	last.Components[2] = _value
	return true

}