globpath refactor into pkg separate from filestat

internal/globpath/globpath.go

@@ -0,0 +1,93 @@
+package globpath
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/gobwas/glob"
+)
+
+var sepStr = fmt.Sprintf("%v", string(os.PathSeparator))
+
+type GlobPath struct {
+	path    string
+	hasMeta bool
+	g       glob.Glob
+	root    string
+}
+
+func Compile(path string) (*GlobPath, error) {
+	out := GlobPath{
+		hasMeta: hasMeta(path),
+		path:    path,
+	}
+
+	// if there are no glob meta characters in the path, don't bother compiling
+	// a glob object or finding the root directory. (see short-circuit in Match)
+	if !out.hasMeta {
+		return &out, nil
+	}
+
+	var err error
+	if out.g, err = glob.Compile(path, os.PathSeparator); err != nil {
+		return nil, err
+	}
+	// Get the root directory for this filepath
+	out.root = findRootDir(path)
+	return &out, nil
+}
+
+func (g *GlobPath) Match() []string {
+	if !g.hasMeta {
+		return []string{g.path}
+	}
+	return walkFilePath(g.root, g.g)
+}
+
+// walk the filepath from the given root and return a list of files that match
+// the given glob.
+func walkFilePath(root string, g glob.Glob) []string {
+	matchedFiles := []string{}
+	walkfn := func(path string, _ os.FileInfo, _ error) error {
+		if g.Match(path) {
+			matchedFiles = append(matchedFiles, path)
+		}
+		return nil
+	}
+	filepath.Walk(root, walkfn)
+	return matchedFiles
+}
+
+// find the root dir of the given path (could include globs).
+// ie:
+//   /var/log/telegraf.conf -> /var/log
+//   /home/** ->               /home
+//   /home/*/** ->             /home
+//   /lib/share/*/*/**.txt ->  /lib/share
+func findRootDir(path string) string {
+	pathItems := strings.Split(path, sepStr)
+	out := sepStr
+	for i, item := range pathItems {
+		if i == len(pathItems)-1 {
+			break
+		}
+		if item == "" {
+			continue
+		}
+		if hasMeta(item) {
+			break
+		}
+		out += item + sepStr
+	}
+	if out != "/" {
+		out = strings.TrimSuffix(out, "/")
+	}
+	return out
+}
+
+// hasMeta reports whether path contains any magic glob characters.
+func hasMeta(path string) bool {
+	return strings.IndexAny(path, "*?[") >= 0
+}