swarm/api: support mounting manifests via FUSE (#3690)

swarm/api/fuse.go

@@ -0,0 +1,139 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// +build !windows
+
+package api
+
+import (
+	"io"
+	"os"
+
+	"bazil.org/fuse"
+	"bazil.org/fuse/fs"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/swarm/storage"
+	"golang.org/x/net/context"
+)
+
+
+
+
+// Data structures used for Fuse filesystem, serving directories and serving files to Fuse driver
+type FS struct {
+	root *Dir
+}
+
+type Dir struct {
+	inode       uint64
+	name        string
+	path        string
+	directories []*Dir
+	files       []*File
+}
+
+type File struct {
+	inode    uint64
+	name     string
+	path     string
+	key      storage.Key
+	swarmApi *Api
+	fileSize uint64
+	reader   storage.LazySectionReader
+}
+
+
+// Functions which satisfy the Fuse File System requests
+func (filesystem *FS) Root() (fs.Node, error) {
+	return filesystem.root, nil
+}
+
+func (directory *Dir) Attr(ctx context.Context, a *fuse.Attr) error {
+	a.Inode = directory.inode
+	//TODO: need to get permission as argument
+	a.Mode = os.ModeDir | 0500
+	a.Uid = uint32(os.Getuid())
+	a.Gid = uint32(os.Getegid())
+	return nil
+}
+
+func (directory *Dir) Lookup(ctx context.Context, name string) (fs.Node, error) {
+	if directory.files != nil {
+		for _, n := range directory.files {
+			if n.name == name {
+				return n, nil
+			}
+		}
+	}
+	if directory.directories != nil {
+		for _, n := range directory.directories {
+			if n.name == name {
+				return n, nil
+			}
+		}
+	}
+	return nil, fuse.ENOENT
+}
+
+func (d *Dir) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {
+	var children []fuse.Dirent
+	if d.files != nil {
+		for _, file := range d.files {
+			children = append(children, fuse.Dirent{Inode: file.inode, Type: fuse.DT_File, Name: file.name})
+		}
+	}
+	if d.directories != nil {
+		for _, dir := range d.directories {
+			children = append(children, fuse.Dirent{Inode: dir.inode, Type: fuse.DT_Dir, Name: dir.name})
+		}
+	}
+	return children, nil
+}
+
+func (file *File) Attr(ctx context.Context, a *fuse.Attr) error {
+
+	a.Inode = file.inode
+	//TODO: need to get permission as argument
+	a.Mode = 0500
+	a.Uid = uint32(os.Getuid())
+	a.Gid = uint32(os.Getegid())
+
+
+	reader := file.swarmApi.Retrieve(file.key)
+	quitC := make(chan bool)
+	size, err := reader.Size(quitC)
+	if err != nil {
+		log.Warn("Couldnt file size of file %s : %v", file.path, err)
+		a.Size = uint64(0)
+	}
+	a.Size = uint64(size)
+	file.fileSize = a.Size
+	return nil
+}
+
+var _ = fs.HandleReader(&File{})
+
+func (file *File) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
+	buf := make([]byte, req.Size)
+	reader := file.swarmApi.Retrieve(file.key)
+	n, err := reader.ReadAt(buf, req.Offset)
+	if err == io.ErrUnexpectedEOF || err == io.EOF {
+		err = nil
+	}
+	resp.Data = buf[:n]
+	return err
+
+}