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go-mtree/entry.go
Stephen Chung decc72b335 tar: create and validate a manifest from a tar stream
This commit contains added features to go-mtree that allows
user to create an mtree spec with '-T' option when specifying
a tar archive. Users can also validate an mtree spec against
a tar archive with an mtree spec. Also for the test archive,
there is a mixture of files, and folders (empty & non-empty),
and symlinks (broken & unbroken).

Signed-off-by: Stephen Chung <schung@redhat.com>
2016-07-23 12:07:43 -04:00

102 lines
3.2 KiB
Go

package mtree
import (
"fmt"
"path/filepath"
"strings"
)
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 *Entry // up
Children []*Entry // 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
}
// Descend searches thru an Entry's children to find the Entry associated with
// `filename`. Directories are stored at the end of an Entry's children so do a
// traverse backwards. If you descend to a "."
func (e Entry) Descend(filename string) *Entry {
if filename == "." || filename == "" {
return &e
}
numChildren := len(e.Children)
for i := range e.Children {
c := e.Children[numChildren-1-i]
if c.Name == filename {
return c
}
}
return nil
}
// Ascend gets the parent of an Entry. Serves mainly to maintain readability
// when traversing up and down an Entry tree
func (e Entry) Ascend() *Entry {
return e.Parent
}
// Path provides the full path of the file, despite RelativeType or FullType
func (e Entry) Path() string {
if e.Parent == nil || e.Type == FullType {
return filepath.Clean(e.Name)
}
return filepath.Clean(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
}
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
)
// String returns the name of the EntryType
func (et EntryType) String() string {
return typeNames[et]
}
var typeNames = map[EntryType]string{
SignatureType: "SignatureType",
BlankType: "BlankType",
CommentType: "CommentType",
SpecialType: "SpecialType",
RelativeType: "RelativeType",
DotDotType: "DotDotType",
FullType: "FullType",
}