lib9p

commit 42c5456c307858ab7a7a6693cfe41764a9d9006a
parent 287a65746ba4a3ad22b9c48ee3293e9ddde96fbc
Author: Matsuda Kenji <info@mtkn.jp>
Date:   Fri,  8 Sep 2023 14:26:36 +0900

implement diskfs

Diffstat:
M
diskfs/file.go
 | 
94
++++++++++++++++++++++++++++++++++++++++---------------------------------------

1 file changed, 48 insertions(+), 46 deletions(-)
diff --git a/diskfs/file.go b/diskfs/file.go
@@ -13,10 +13,11 @@ import (
 )
 
 type File struct {
-	fs   *FS      // file system to which this file belongs
-	file *os.File // underlying file
-	path string   // absolute path from the root of the fs.
-	children []lib9p.File
+	fs         *FS      // file system to which this file belongs
+	file       *os.File // underlying file
+	path       string   // absolute path from the root of the fs.
+	childEntry []*lib9p.DirEntry
+	diroff     int // directory offset for ReadDir()
 }
 
 func openFile(fsys *FS, fpath string) (*File, error) {
@@ -24,10 +25,38 @@ func openFile(fsys *FS, fpath string) (*File, error) {
 	if err != nil {
 		return nil, fmt.Errorf("open fs: %v", err)
 	}
+
+	fi, err := file.Stat()
+	if err != nil {
+		return nil, fmt.Errorf("stat: %v", err)
+	}
+	var childEntry []*lib9p.DirEntry
+	if fi.IsDir() {
+		dir := file.(fs.ReadDirFile)
+		de, err := dir.ReadDir(-1)
+		if err != nil {
+			return nil, fmt.Errorf("read dir: %v", err)
+		}
+		childEntry = make([]*lib9p.DirEntry, len(de))
+		for i := 0; i < len(de); i++ {
+			info, err := de[i].Info()
+			if err != nil {
+				return nil, fmt.Errorf("info: %v", err)
+			}
+			sys := info.Sys().(*syscall.Stat_t)
+			id := fileID{
+				device: sys.Dev,
+				inode:  sys.Ino,
+			}
+			stat := fiStat(fsys.qidPool, id, info)
+			childEntry[i] = &lib9p.DirEntry{Stat: *stat}
+		}
+	}
 	f := &File{
-		fs:   fsys,
-		file: file.(*os.File),
-		path: fpath,
+		fs:         fsys,
+		file:       file.(*os.File),
+		path:       fpath,
+		childEntry: childEntry,
 	}
 	return f, nil
 }
@@ -89,13 +118,16 @@ func (f *File) Parent() (lib9p.File, error) {
 }
 
 func (f *File) Child() ([]lib9p.File, error) {
-	if f.children == nil {
-		_, err := f.ReadDir(-1)
+	files := make([]lib9p.File, len(f.childEntry))
+	for i := 0; i < len(f.childEntry); i++ {
+		cpath := path.Join(f.path, f.childEntry[i].Name())
+		child, err := f.fs.Open(cpath)
 		if err != nil {
-			return f.children, fmt.Errorf("read dir: %v")
+			return files, fmt.Errorf("open child unko: %v", err)
 		}
+		files[i] = child
 	}
-	return f.children, nil
+	return files, nil
 }
 
 func (f *File) ReadAt(p []byte, off int64) (int, error) {
@@ -103,41 +135,11 @@ func (f *File) ReadAt(p []byte, off int64) (int, error) {
 }
 
 func (f *File) ReadDir(n int) ([]*lib9p.DirEntry, error) {
-	fsde, err := f.file.ReadDir(n)
-	if err != nil {
-		return nil, err
-	}
-	if len(fsde) == 0 {
-		if f.children == nil {
-			f.children = make([]lib9p.File, 0)
-		}
-		de := make([]*lib9p.DirEntry, len(f.children))
-		for i := 0; i < len(f.children); i++ {
-			fi, err := f.children[i].Stat()
-			if err != nil {
-				return de, fmt.Errorf("stat: %v", err)
-			}
-			de[i] = &lib9p.FileInfo{*fi.Sys().(*lib9p.Stat)}
-		}
-		return de, nil
+	childEntry := f.childEntry[f.diroff:]
+	if n < 0 || len(childEntry) < n {
+		n = len(childEntry)
 	}
-	de := make([]*lib9p.DirEntry, len(fsde))
-	children := make([]lib9p.File, len(fsde))
-	for i := 0; i < len(de); i++ {
-		info, err := fsde[i].Info()
-		if err != nil {
-			return de, err
-		}
-		id := idFromInfo(info)
-		de[i] = &lib9p.FileInfo{*fiStat(f.fs.qidPool, id, info)}
 
-		childPath := path.Join(f.PathName(), info.Name())
-		child, err := f.fs.Open(childPath)
-		if err != nil {
-			return de, fmt.Errorf("open: %v", err)
-		}
-		children[i] = child
-	}
-	f.children = append(f.children, children...)
-	return de, nil
+	f.diroff += n
+	return childEntry[:n], nil
 }