swarm/api: FUSE read-write support (#13872)

- Moved fuse related code in a new package, swarm/fuse
- Added write support
  - Create new files
  - Delete existing files
  - Append to files (with limitations)
- More test coverage

swarm/fuse/fuse_dir.go

@@ -0,0 +1,155 @@
+// 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 linux darwin freebsd
+
+package fuse
+
+import (
+	"bazil.org/fuse"
+	"bazil.org/fuse/fs"
+	"golang.org/x/net/context"
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+var (
+	_ fs.Node                = (*SwarmDir)(nil)
+	_ fs.NodeRequestLookuper = (*SwarmDir)(nil)
+	_ fs.HandleReadDirAller  = (*SwarmDir)(nil)
+	_ fs.NodeCreater         = (*SwarmDir)(nil)
+	_ fs.NodeRemover         = (*SwarmDir)(nil)
+	_ fs.NodeMkdirer         = (*SwarmDir)(nil)
+)
+
+type SwarmDir struct {
+	inode       uint64
+	name        string
+	path        string
+	directories []*SwarmDir
+	files       []*SwarmFile
+
+	mountInfo *MountInfo
+	lock      *sync.RWMutex
+}
+
+func NewSwarmDir(fullpath string, minfo *MountInfo) *SwarmDir {
+	newdir := &SwarmDir{
+		inode:       NewInode(),
+		name:        filepath.Base(fullpath),
+		path:        fullpath,
+		directories: []*SwarmDir{},
+		files:       []*SwarmFile{},
+		mountInfo:   minfo,
+		lock:        &sync.RWMutex{},
+	}
+	return newdir
+}
+
+func (sd *SwarmDir) Attr(ctx context.Context, a *fuse.Attr) error {
+	a.Inode = sd.inode
+	a.Mode = os.ModeDir | 0700
+	a.Uid = uint32(os.Getuid())
+	a.Gid = uint32(os.Getegid())
+	return nil
+}
+
+func (sd *SwarmDir) Lookup(ctx context.Context, req *fuse.LookupRequest, resp *fuse.LookupResponse) (fs.Node, error) {
+
+	for _, n := range sd.files {
+		if n.name == req.Name {
+			return n, nil
+		}
+	}
+	for _, n := range sd.directories {
+		if n.name == req.Name {
+			return n, nil
+		}
+	}
+	return nil, fuse.ENOENT
+}
+
+func (sd *SwarmDir) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {
+	var children []fuse.Dirent
+	for _, file := range sd.files {
+		children = append(children, fuse.Dirent{Inode: file.inode, Type: fuse.DT_File, Name: file.name})
+	}
+	for _, dir := range sd.directories {
+		children = append(children, fuse.Dirent{Inode: dir.inode, Type: fuse.DT_Dir, Name: dir.name})
+	}
+	return children, nil
+}
+
+func (sd *SwarmDir) Create(ctx context.Context, req *fuse.CreateRequest, resp *fuse.CreateResponse) (fs.Node, fs.Handle, error) {
+
+	newFile := NewSwarmFile(sd.path, req.Name, sd.mountInfo)
+	newFile.fileSize = 0 // 0 means, file is not in swarm yet and it is just created
+
+	sd.lock.Lock()
+	defer sd.lock.Unlock()
+	sd.files = append(sd.files, newFile)
+
+	return newFile, newFile, nil
+}
+
+func (sd *SwarmDir) Remove(ctx context.Context, req *fuse.RemoveRequest) error {
+
+	if req.Dir && sd.directories != nil {
+		newDirs := []*SwarmDir{}
+		for _, dir := range sd.directories {
+			if dir.name == req.Name {
+				removeDirectoryFromSwarm(dir)
+			} else {
+				newDirs = append(newDirs, dir)
+			}
+		}
+		if len(sd.directories) > len(newDirs) {
+			sd.lock.Lock()
+			defer sd.lock.Unlock()
+			sd.directories = newDirs
+		}
+		return nil
+	} else if !req.Dir && sd.files != nil {
+		newFiles := []*SwarmFile{}
+		for _, f := range sd.files {
+			if f.name == req.Name {
+				removeFileFromSwarm(f)
+			} else {
+				newFiles = append(newFiles, f)
+			}
+		}
+		if len(sd.files) > len(newFiles) {
+			sd.lock.Lock()
+			defer sd.lock.Unlock()
+			sd.files = newFiles
+		}
+		return nil
+	}
+	return fuse.ENOENT
+}
+
+func (sd *SwarmDir) Mkdir(ctx context.Context, req *fuse.MkdirRequest) (fs.Node, error) {
+
+	newDir := NewSwarmDir(req.Name, sd.mountInfo)
+
+	sd.lock.Lock()
+	defer sd.lock.Unlock()
+	sd.directories = append(sd.directories, newDir)
+
+	return newDir, nil
+
+}