go-mtree/parse.go

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package mtree
import (
"bufio"
"io"
"path/filepath"
"strings"
)
// ParseSpec reads a stream of an mtree specification, and returns the DirectoryHierarchy
func ParseSpec(r io.Reader) (*DirectoryHierarchy, error) {
s := bufio.NewScanner(r)
i := int(0)
creator := dhCreator{
DH: &DirectoryHierarchy{},
}
for s.Scan() {
str := s.Text()
e := Entry{Pos: i}
switch {
case strings.HasPrefix(str, "#"):
e.Raw = str
if strings.HasPrefix(str, "#mtree") {
e.Type = SignatureType
} else {
e.Type = CommentType
// from here, the comment could be "# key: value" metadata
// or a relative path hint
}
case str == "":
e.Type = BlankType
// nothing else to do here
case strings.HasPrefix(str, "/"):
e.Type = SpecialType
// collapse any escaped newlines
for {
if strings.HasSuffix(str, `\`) {
str = str[:len(str)-1]
s.Scan()
str += s.Text()
} else {
break
}
}
// parse the options
f := strings.Fields(str)
e.Name = f[0]
e.Keywords = f[1:]
if e.Name == "/set" {
creator.curSet = &e
} else if e.Name == "/unset" {
creator.curSet = nil
}
case len(strings.Fields(str)) > 0 && strings.Fields(str)[0] == "..":
e.Type = DotDotType
e.Raw = str
if creator.curDir != nil {
creator.curDir = creator.curDir.Parent
}
// nothing else to do here
case len(strings.Fields(str)) > 0:
// collapse any escaped newlines
for {
if strings.HasSuffix(str, `\`) {
str = str[:len(str)-1]
s.Scan()
str += s.Text()
} else {
break
}
}
// parse the options
f := strings.Fields(str)
e.Name = filepath.Clean(f[0])
if strings.Contains(e.Name, "/") {
e.Type = FullType
} else {
e.Type = RelativeType
}
e.Keywords = f[1:]
e.Parent = creator.curDir
for i := range e.Keywords {
kv := KeyVal(e.Keywords[i])
if kv.Keyword() == "type" {
if kv.Value() == "dir" {
creator.curDir = &e
} else {
creator.curEnt = &e
}
}
}
default:
// TODO(vbatts) log a warning?
continue
}
creator.DH.Entries = append(creator.DH.Entries, e)
i++
}
return creator.DH, s.Err()
}