beginning fuse filesystem impl

fs.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"context"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"bazil.org/fuse"
+	"bazil.org/fuse/fs"
+)
+
+var _ fs.FS = (*FS)(nil)
+
+type FS struct {
+	SourcePath string
+}
+
+// Root returns the file system root.
+func (f *FS) Root() (fs.Node, error) {
+	return &File{fs: f}, nil
+}
+
+var _ fs.Node = (*File)(nil)
+
+type File struct {
+	fs   *FS    // base filesystem
+	path string // path within file system
+}
+
+func (f *File) srcpath() string {
+	return filepath.Join(f.fs.SourcePath, f.path)
+}
+
+func (f *File) Attr(ctx context.Context, a *fuse.Attr) error {
+	fi, err := os.Stat(f.srcpath())
+	if err != nil {
+		return err
+	}
+	statt := fi.Sys().(*syscall.Stat_t)
+
+	// TODO: Cache attr w/ a.Valid?
+
+	if f.path == "" {
+		a.Inode = 1
+	} else {
+		a.Inode = statt.Ino
+	}
+	a.Size = uint64(fi.Size())
+	a.Blocks = uint64(statt.Blocks)
+	a.Atime = time.Unix(statt.Atim.Sec, statt.Atim.Nsec).UTC()
+	a.Mtime = time.Unix(statt.Mtim.Sec, statt.Mtim.Nsec).UTC()
+	a.Ctime = time.Unix(statt.Ctim.Sec, statt.Ctim.Nsec).UTC()
+	a.Mode = fi.Mode()
+	a.Nlink = uint32(statt.Nlink)
+	a.Uid = uint32(statt.Uid)
+	a.Gid = uint32(statt.Gid)
+	a.Rdev = uint32(statt.Rdev)
+	a.BlockSize = uint32(statt.Blksize)
+
+	return nil
+}
+
+func (f *File) Lookup(ctx context.Context, name string) (fs.Node, error) {
+	path := filepath.Join(f.path, name)
+	srcpath := filepath.Join(f.fs.SourcePath, path)
+	if _, err := os.Stat(srcpath); os.IsNotExist(err) {
+		return nil, syscall.ENOENT
+	}
+	return &File{fs: f.fs, path: path}, nil
+}
+
+func (f *File) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {
+	fis, err := ioutil.ReadDir(f.srcpath())
+	if err != nil {
+		return nil, err
+	}
+
+	ents := make([]fuse.Dirent, len(fis))
+	for i, fi := range fis {
+		statt := fi.Sys().(*syscall.Stat_t)
+		ents[i] = fuse.Dirent{Inode: statt.Ino, Name: fi.Name()}
+	}
+	return ents, nil
+}