filelist/hookdirs: add new FileLister implementation for creating dirs

internal/filelist/hookdirs/hookdirs.go

@@ -0,0 +1,51 @@
+package hookdirs
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+
+	"gitlab.com/postmarketOS/postmarketos-mkinitfs/internal/filelist"
+)
+
+type HookDirs struct {
+	path string
+}
+
+// New returns a new HookDirs that will use the given path to provide a list
+// of directories use.
+func New(path string) *HookDirs {
+	return &HookDirs{
+		path: path,
+	}
+}
+
+func (h *HookDirs) List() (*filelist.FileList, error) {
+	log.Printf("- Creating directories specified in %s", h.path)
+
+	files := filelist.NewFileList()
+	fileInfo, err := os.ReadDir(h.path)
+	if err != nil {
+		log.Println("-- Unable to find dir, skipping...")
+		return files, nil
+	}
+	for _, file := range fileInfo {
+		path := filepath.Join(h.path, file.Name())
+		f, err := os.Open(path)
+		if err != nil {
+			return nil, fmt.Errorf("getHookDirs: unable to open hook file: %w", err)
+
+		}
+		defer f.Close()
+		log.Printf("-- Creating directories from: %s\n", path)
+
+		s := bufio.NewScanner(f)
+		for s.Scan() {
+			dir := s.Text()
+			files.Add(dir, dir)
+		}
+	}
+	return files, nil
+}