go_sysutils/fsutils/funcs_fsattrs.go

package fsutils

import (
	`reflect`
	`strings`
)

/*
	String returns a string representation (comparable to lsattr(1)) of an FsAttrs.

	Not all flags are represented, as this aims for compatibility with e2fsprogs/lsattr output.
*/
func (f *FsAttrs) String() (s string) {

	// Flags have their short name printed if set, otherwise a '-' placeholder is used.
	// https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/tree/lib/e2p/pf.c

	var refType reflect.Type
	var refVal reflect.Value
	var refField reflect.StructField
	var fieldVal reflect.Value
	var tagVal string
	var sb strings.Builder

	if f == nil {
		s = strings.Repeat("-", len(linuxFsAttrsListOrder))
		return
	}

	refVal = reflect.ValueOf(*f)
	refType = refVal.Type()
	for _, fn := range linuxFsAttrsListOrder {
		refField, _ = refType.FieldByName(fn)
		tagVal = refField.Tag.Get("fsAttrShort")
		if tagVal == "" || tagVal == "-" {
			continue
		}
		fieldVal = refVal.FieldByName(fn)
		if fieldVal.Bool() {
			sb.WriteString(tagVal)
		} else {
			sb.WriteString("-")
		}
	}

	s = sb.String()

	return
}

/*
	StringLong returns a more extensive/"human-friendly" representation (comparable to lsattr(1) wiih -l) of an Fsattrs.

	Not all flags are represented, as this aims for compatibility with e2fsprogs/lsattr output.
*/
func (f *FsAttrs) StringLong() (s string) {

	// The long names are separated via a commma then a space.
	// If no attrs are set, the string "---" is used.
	// https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/tree/lib/e2p/pf.c

	var refType reflect.Type
	var refVal reflect.Value
	var refField reflect.StructField
	var fieldVal reflect.Value
	var tagVal string
	var out []string

	if f == nil {
		s = strings.Repeat("-", 3)
		return
	}

	refVal = reflect.ValueOf(*f)
	refType = refVal.Type()
	for _, fn := range linuxFsAttrsListOrder {
		refField, _ = refType.FieldByName(fn)
		tagVal = refField.Tag.Get("fsAttrLong")
		if tagVal == "" || tagVal == "-" {
			continue
		}
		fieldVal = refVal.FieldByName(fn)
		if fieldVal.Bool() {
			out = append(out, tagVal)
		}
	}

	if out == nil || len(out) == 0 {
		s = strings.Repeat("-", 3)
		return
	}

	s = strings.Join(out, ", ")

	return
}