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|
package fsutil
import (
"io/ioutil"
"os"
"path/filepath"
"runtime"
"sort"
strings "strings"
"github.com/pkg/errors"
)
func FollowLinks(root string, paths []string) ([]string, error) {
r := &symlinkResolver{root: root, resolved: map[string]struct{}{}}
for _, p := range paths {
if err := r.append(p); err != nil {
return nil, err
}
}
res := make([]string, 0, len(r.resolved))
for r := range r.resolved {
res = append(res, r)
}
sort.Strings(res)
return dedupePaths(res), nil
}
type symlinkResolver struct {
root string
resolved map[string]struct{}
}
func (r *symlinkResolver) append(p string) error {
p = filepath.Join(".", p)
current := "."
for {
parts := strings.SplitN(p, string(filepath.Separator), 2)
current = filepath.Join(current, parts[0])
targets, err := r.readSymlink(current, true)
if err != nil {
return err
}
p = ""
if len(parts) == 2 {
p = parts[1]
}
if p == "" || targets != nil {
if _, ok := r.resolved[current]; ok {
return nil
}
}
if targets != nil {
r.resolved[current] = struct{}{}
for _, target := range targets {
if err := r.append(filepath.Join(target, p)); err != nil {
return err
}
}
return nil
}
if p == "" {
r.resolved[current] = struct{}{}
return nil
}
}
}
func (r *symlinkResolver) readSymlink(p string, allowWildcard bool) ([]string, error) {
realPath := filepath.Join(r.root, p)
base := filepath.Base(p)
if allowWildcard && containsWildcards(base) {
fis, err := ioutil.ReadDir(filepath.Dir(realPath))
if err != nil {
if os.IsNotExist(err) {
return nil, nil
}
return nil, errors.Wrapf(err, "failed to read dir %s", filepath.Dir(realPath))
}
var out []string
for _, f := range fis {
if ok, _ := filepath.Match(base, f.Name()); ok {
res, err := r.readSymlink(filepath.Join(filepath.Dir(p), f.Name()), false)
if err != nil {
return nil, err
}
out = append(out, res...)
}
}
return out, nil
}
fi, err := os.Lstat(realPath)
if err != nil {
if os.IsNotExist(err) {
return nil, nil
}
return nil, errors.Wrapf(err, "failed to lstat %s", realPath)
}
if fi.Mode()&os.ModeSymlink == 0 {
return nil, nil
}
link, err := os.Readlink(realPath)
if err != nil {
return nil, errors.Wrapf(err, "failed to readlink %s", realPath)
}
link = filepath.Clean(link)
if filepath.IsAbs(link) {
return []string{link}, nil
}
return []string{
filepath.Join(string(filepath.Separator), filepath.Join(filepath.Dir(p), link)),
}, nil
}
func containsWildcards(name string) bool {
isWindows := runtime.GOOS == "windows"
for i := 0; i < len(name); i++ {
ch := name[i]
if ch == '\\' && !isWindows {
i++
} else if ch == '*' || ch == '?' || ch == '[' {
return true
}
}
return false
}
// dedupePaths expects input as a sorted list
func dedupePaths(in []string) []string {
out := make([]string, 0, len(in))
var last string
for _, s := range in {
// if one of the paths is root there is no filter
if s == "." {
return nil
}
if strings.HasPrefix(s, last+string(filepath.Separator)) {
continue
}
out = append(out, s)
last = s
}
return out
}
|
