switch to config file and implement src path filter

pkg/provider/filter/file.go

@@ -0,0 +1,53 @@
+package filter
+
+import (
+	"cachefs/pkg/provider"
+	"io/fs"
+	"path/filepath"
+)
+
+var _ provider.File = (*file)(nil)
+
+type file struct {
+	provider.File
+	fs   *FS
+	path string
+}
+
+func newFile(f provider.File, fs *FS, path string) (nf provider.File, err error) {
+	nf = &file{
+		File: f,
+		fs:   fs,
+		path: path,
+	}
+	return nf, nil
+}
+
+func (f *file) Readdir(n int) ([]fs.FileInfo, error) {
+	fis, err := f.File.Readdir(n)
+	if err != nil {
+		return nil, err
+	}
+	fio := make([]fs.FileInfo, len(fis))
+	i := 0
+	for _, fi := range fis {
+		file := filepath.Join(f.path, fi.Name())
+		if f.fs.match(file) == nil {
+			fio[i] = fi
+			i++
+		}
+	}
+	return fio[:i], nil
+}
+
+func (f *file) ReadDir(n int) ([]fs.DirEntry, error) {
+	fis, err := f.Readdir(n)
+	if err != nil {
+		return nil, err
+	}
+	fio := make([]fs.DirEntry, len(fis))
+	for i, fi := range fis {
+		fio[i] = fs.FileInfoToDirEntry(fi)
+	}
+	return fio, nil
+}

pkg/provider/filter/fs.go

@@ -0,0 +1,78 @@
+package filter
+
+import (
+	stdfs "io/fs"
+	"os"
+	"regexp"
+
+	"cachefs/pkg/provider"
+)
+
+var _ provider.FS = (*FS)(nil)
+
+type FS struct {
+	provider.FS
+	re *regexp.Regexp
+}
+
+func NewFS(fs provider.FS, re *regexp.Regexp) (*FS, error) {
+	return &FS{
+		FS: fs,
+		re: re,
+	}, nil
+}
+
+func (fs *FS) match(p string) error {
+	if fs.re.MatchString(p) {
+		return nil
+	}
+	return stdfs.ErrNotExist
+}
+
+func (fs *FS) Stat(p string) (stdfs.FileInfo, error) {
+	err := fs.match(p)
+	if err != nil {
+		return nil, err
+	}
+	return fs.FS.Stat(p)
+}
+
+func (fs *FS) Remove(p string) error {
+	err := fs.match(p)
+	if err != nil {
+		return err
+	}
+	return fs.FS.Remove(p)
+}
+
+func (fs *FS) Open(p string) (provider.File, error) {
+	err := fs.match(p)
+	if err != nil {
+		return nil, err
+	}
+	f, err := fs.FS.Open(p)
+	if err != nil {
+		return nil, err
+	}
+	return newFile(f, fs, p)
+}
+
+func (fs *FS) OpenFile(p string, flags int, mode os.FileMode) (provider.File, error) {
+	err := fs.match(p)
+	if err != nil {
+		return nil, err
+	}
+	f, err := fs.FS.OpenFile(p, flags, mode)
+	if err != nil {
+		return nil, err
+	}
+	return newFile(f, fs, p)
+}
+
+func (fs *FS) MkdirAll(p string, mode os.FileMode) error {
+	err := fs.match(p)
+	if err != nil {
+		return err
+	}
+	return fs.FS.MkdirAll(p, mode)
+}