go-mtree/hierarchy.go
Vincent Batts a05d8ebbbd *: cleaner Parent handling
Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>
2016-03-24 16:35:09 -04:00

85 lines
2.6 KiB
Go

package mtree
import (
"fmt"
"io"
"path/filepath"
"sort"
"strings"
)
// DirectoryHierarchy is the mapped structure for an mtree directory hierarchy
// spec
type DirectoryHierarchy struct {
Entries []Entry
}
// WriteTo simplifies the output of the resulting hierarchy spec
func (dh DirectoryHierarchy) WriteTo(w io.Writer) (n int64, err error) {
sort.Sort(byPos(dh.Entries))
var sum int64
for _, e := range dh.Entries {
i, err := io.WriteString(w, e.String()+"\n")
if err != nil {
return sum, err
}
sum += int64(i)
}
return sum, nil
}
type byPos []Entry
func (bp byPos) Len() int { return len(bp) }
func (bp byPos) Less(i, j int) bool { return bp[i].Pos < bp[j].Pos }
func (bp byPos) Swap(i, j int) { bp[i], bp[j] = bp[j], bp[i] }
// Entry is each component of content in the mtree spec file
type Entry struct {
Parent, Child *Entry // up, down
Prev, Next *Entry // left, right
Set *Entry // current `/set` for additional keywords
Pos int // order in the spec
Raw string // file or directory name
Name string // file or directory name
Keywords []string // TODO(vbatts) maybe a keyword typed set of values?
Type EntryType
}
func (e Entry) Path() string {
if e.Parent == nil {
return e.Name
}
return filepath.Join(e.Parent.Path(), e.Name)
}
func (e Entry) String() string {
if e.Raw != "" {
return e.Raw
}
if e.Type == BlankType {
return ""
}
if e.Type == DotDotType {
return e.Name
}
// TODO(vbatts) if type is RelativeType and a keyword of not type=dir
if e.Type == SpecialType || e.Type == FullType || inSlice("type=dir", e.Keywords) {
return fmt.Sprintf("%s %s", e.Name, strings.Join(e.Keywords, " "))
}
return fmt.Sprintf(" %s %s", e.Name, strings.Join(e.Keywords, " "))
}
// EntryType are the formats of lines in an mtree spec file
type EntryType int
// The types of lines to be found in an mtree spec file
const (
SignatureType EntryType = iota // first line of the file, like `#mtree v2.0`
BlankType // blank lines are ignored
CommentType // Lines beginning with `#` are ignored
SpecialType // line that has `/` prefix issue a "special" command (currently only /set and /unset)
RelativeType // if the first white-space delimited word does not have a '/' in it. Options/keywords are applied.
DotDotType // .. - A relative path step. keywords/options are ignored
FullType // if the first word on the line has a `/` after the first character, it interpretted as a file pathname with options
)