Refactor repo

cmd/litestream/main.go

@@ -11,6 +11,7 @@ import (
 
 	"bazil.org/fuse"
 	"bazil.org/fuse/fs"
+	"github.com/middlemost/litestream"
 )
 
 func main() {
@@ -43,6 +44,8 @@ func (m *Main) Run(args []string) (err error) {
 	if err := flagSet.Parse(args); err != nil {
 		return err
 	}
+
+	// Ensure src & mount paths are specified.
 	if m.SourcePath = flagSet.Arg(0); m.SourcePath == "" {
 		return errors.New("source path required")
 	} else if m.MountPath = flagSet.Arg(1); m.MountPath == "" {
@@ -50,7 +53,9 @@ func (m *Main) Run(args []string) (err error) {
 	}
 
 	// Setup logging, if verbose specified.
+	var config fs.Config
 	if *verbose {
+		config.Debug = debug
 		m.logger = log.New(os.Stderr, "", log.LstdFlags)
 	}
 
@@ -64,10 +69,8 @@ func (m *Main) Run(args []string) (err error) {
 
 	m.logger.Printf("mounted")
 
-	s := fs.New(conn, &fs.Config{
+	s := fs.New(conn, &config)
-		Debug: debug,
+	return s.Serve(&litestream.FileSystem{SourcePath: m.SourcePath})
-	})
-	return s.Serve(&FS{SourcePath: m.SourcePath})
 }
 
 func (m *Main) usage() {

file_system.go

@@ -0,0 +1,18 @@
+package litestream
+
+import (
+	"bazil.org/fuse/fs"
+)
+
+var _ fs.FS = (*FileSystem)(nil)
+
+// FileSystem represents the file system that is mounted.
+// It returns a root node that represents the root directory.
+type FileSystem struct {
+	SourcePath string
+}
+
+// Root returns the file system root node.
+func (f *FileSystem) Root() (fs.Node, error) {
+	return &Node{fs: f}, nil
+}

fs.go

@@ -1,58 +0,0 @@
-package main
-
-import (
-	"context"
-
-	"bazil.org/fuse"
-	"bazil.org/fuse/fs"
-)
-
-var _ fs.FS = (*FS)(nil)
-var _ fs.FSDestroyer = (*FS)(nil)
-var _ fs.FSStatfser = (*FS)(nil)
-
-// var _ fs.FSInodeGenerator = (*FS)(nil)
-
-type FS struct {
-	SourcePath string
-}
-
-// Root returns the file system root.
-func (f *FS) Root() (fs.Node, error) {
-	return &Node{fs: f}, nil
-}
-
-// Destroy is called when the file system is shutting down.
-//
-// Linux only sends this request for block device backed (fuseblk)
-// filesystems, to allow them to flush writes to disk before the
-// unmount completes.
-func (f *FS) Destroy() {
-	// TODO: Flush writes?
-}
-
-// Statfs is called to obtain file system metadata.
-// It should write that data to resp.
-func (f *FS) Statfs(ctx context.Context, req *fuse.StatfsRequest, resp *fuse.StatfsResponse) error {
-	panic("TODO")
-}
-
-// GenerateInode is called to pick a dynamic inode number when it
-// would otherwise be 0.
-//
-// Not all filesystems bother tracking inodes, but FUSE requires
-// the inode to be set, and fewer duplicates in general makes UNIX
-// tools work better.
-//
-// Operations where the nodes may return 0 inodes include Getattr,
-// Setattr and ReadDir.
-//
-// If FS does not implement FSInodeGenerator, GenerateDynamicInode
-// is used.
-//
-// Implementing this is useful to e.g. constrain the range of
-// inode values used for dynamic inodes.
-//
-// Non-zero return values should be greater than 1, as that is
-// always used for the root inode.
-// func (f *FS) GenerateInode(parentInode uint64, name string) uint64 {}

handle.go

@@ -1,4 +1,4 @@
-package main
+package litestream
 
 import (
 	"context"
@@ -11,11 +11,16 @@ import (
 	"bazil.org/fuse/fs"
 )
 
+const (
+	F_OFD_GETLK  = 0x24
+	F_OFD_SETLK  = 0x25
+	F_OFD_SETLKW = 0x26
+)
+
 var _ fs.HandleFlockLocker = (*Handle)(nil)
 var _ fs.HandleFlusher = (*Handle)(nil)
 var _ fs.HandleLocker = (*Handle)(nil)
 var _ fs.HandlePOSIXLocker = (*Handle)(nil)
-var _ fs.HandlePoller = (*Handle)(nil)
 var _ fs.HandleReadDirAller = (*Handle)(nil)
 var _ fs.HandleReader = (*Handle)(nil)
 var _ fs.HandleReleaser = (*Handle)(nil)
@@ -23,17 +28,39 @@ var _ fs.HandleWriter = (*Handle)(nil)
 
 // var _ fs.HandleReadAller = (*Handle)(nil)
 
+// Handle represents a FUSE file handle.
 type Handle struct {
 	f *os.File
 }
 
-// Flush is called each time the file or directory is closed.
+// Release closes the underlying file descriptor.
-// Because there can be multiple file descriptors referring to a
+func (h *Handle) Release(ctx context.Context, req *fuse.ReleaseRequest) (err error) {
-// single opened file, Flush can be called multiple times.
+	return h.f.Close()
+}
+
+// Read reads data from a given offset in the underlying file.
+func (h *Handle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) (err error) {
+	buf := make([]byte, req.Size)
+	n, err := h.f.ReadAt(buf, req.Offset)
+	if err != nil && err != io.EOF {
+		return err
+	}
+	resp.Data = buf[:n]
+	return nil
+}
+
+// Write writes data at a given offset to the underlying file.
+func (h *Handle) Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) (err error) {
+	resp.Size, err = h.f.WriteAt(req.Data, req.Offset)
+	return err
+}
+
+// Flush is called when a file handle is synced to disk. Implements fs.HandleFlusher.
 func (h *Handle) Flush(ctx context.Context, req *fuse.FlushRequest) (err error) {
 	return h.f.Sync()
 }
 
+// ReadDirAll returns a list of all entries in a directory. Implements fs.HandleReadDirAller.
 func (h *Handle) ReadDirAll(ctx context.Context) (ents []fuse.Dirent, err error) {
 	fis, err := h.f.Readdir(-1)
 	if err != nil {
@@ -51,124 +78,33 @@ func (h *Handle) ReadDirAll(ctx context.Context) (ents []fuse.Dirent, err error)
 	return ents, nil
 }
 
-// Read requests to read data from the handle.
-//
-// There is a page cache in the kernel that normally submits only
-// page-aligned reads spanning one or more pages. However, you
-// should not rely on this. To see individual requests as
-// submitted by the file system clients, set OpenDirectIO.
-//
-// Note that reads beyond the size of the file as reported by Attr
-// are not even attempted (except in OpenDirectIO mode).
-func (h *Handle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) (err error) {
-	// TODO: Flags     ReadFlags
-	// TODO: LockOwner
-	// TODO: FileFlags OpenFlags
-
-	buf := make([]byte, req.Size)
-	n, err := h.f.ReadAt(buf, req.Offset)
-	if err != nil && err != io.EOF {
-		return err
-	}
-	resp.Data = buf[:n]
-
-	return nil
-}
-
-// Write requests to write data into the handle at the given offset.
-// Store the amount of data written in resp.Size.
-//
-// There is a writeback page cache in the kernel that normally submits
-// only page-aligned writes spanning one or more pages. However,
-// you should not rely on this. To see individual requests as
-// submitted by the file system clients, set OpenDirectIO.
-//
-// Writes that grow the file are expected to update the file size
-// (as seen through Attr). Note that file size changes are
-// communicated also through Setattr.
-func (h *Handle) Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) (err error) {
-	// Offset    int64
-	// Data      []byte
-	// Flags     WriteFlags
-	// LockOwner LockOwner
-	// FileFlags OpenFlags
-
-	resp.Size, err = h.f.WriteAt(req.Data, req.Offset)
-	println("dbg/write!")
-	return err
-}
-
-func (h *Handle) Release(ctx context.Context, req *fuse.ReleaseRequest) (err error) {
-	return h.f.Close()
-}
-
-// Poll checks whether the handle is currently ready for I/O, and
-// may request a wakeup when it is.
-//
-// Poll should always return quickly. Clients waiting for
-// readiness can be woken up by passing the return value of
-// PollRequest.Wakeup to fs.Server.NotifyPollWakeup or
-// fuse.Conn.NotifyPollWakeup.
-//
-// To allow supporting poll for only some of your Nodes/Handles,
-// the default behavior is to report immediate readiness. If your
-// FS does not support polling and you want to minimize needless
-// requests and log noise, implement NodePoller and return
-// syscall.ENOSYS.
-//
-// The Go runtime uses epoll-based I/O whenever possible, even for
-// regular files.
-func (h *Handle) Poll(ctx context.Context, req *fuse.PollRequest, resp *fuse.PollResponse) error {
-	//type PollRequest struct {
-	//    Header `json:"-"`
-	//    Handle HandleID
-	//
-	//    Flags PollFlags
-	//    Events PollEvents
-	//}
-
-	//type PollResponse struct {
-	//    REvents PollEvents
-	//}
-
-	panic("TODO")
-}
-
 // Lock tries to acquire a lock on a byte range of the node. If a
 // conflicting lock is already held, returns syscall.EAGAIN.
-//
-// LockRequest.LockOwner is a file-unique identifier for this
-// lock, and will be seen in calls releasing this lock
-// (UnlockRequest, ReleaseRequest, FlushRequest) and also
-// in e.g. ReadRequest, WriteRequest.
 func (h *Handle) Lock(ctx context.Context, req *fuse.LockRequest) error {
-	// type LockRequest struct {
+	return h.lock(ctx, req)
-	//     Header
-	//     Handle HandleID
-	//     // LockOwner is a unique identifier for the originating client, to identify locks.
-	//     LockOwner LockOwner
-	//     Lock      FileLock
-	//     LockFlags LockFlags
-	// }
-
-	panic("TODO")
 }
 
 // LockWait acquires a lock on a byte range of the node, waiting
 // until the lock can be obtained (or context is canceled).
 func (h *Handle) LockWait(ctx context.Context, req *fuse.LockWaitRequest) error {
-	// type LockWaitRequest LockRequest
+	return h.lock(ctx, (*fuse.LockRequest)(req))
-
-	panic("TODO")
 }
 
 // Unlock releases the lock on a byte range of the node. Locks can
 // be released also implicitly, see HandleFlockLocker and
 // HandlePOSIXLocker.
 func (h *Handle) Unlock(ctx context.Context, req *fuse.UnlockRequest) error {
-	// type UnlockRequest LockRequest
+	return h.lock(ctx, (*fuse.LockRequest)(req))
 
-	panic("TODO")
+}
+
+func (h *Handle) lock(ctx context.Context, req *fuse.LockRequest) error {
+	return syscall.FcntlFlock(h.f.Fd(), F_OFD_SETLK, &syscall.Flock_t{
+		Type:   int16(req.Lock.Type),
+		Whence: io.SeekStart,
+		Start:  int64(req.Lock.Start),
+		Len:    int64(req.Lock.End) - int64(req.Lock.Start),
+	})
 }
 
 // QueryLock returns the current state of locks held for the byte

node.go

@@ -1,4 +1,4 @@
-package main
+package litestream
 
 import (
 	"context"
@@ -31,16 +31,13 @@ var _ fs.NodeSetxattrer = (*Node)(nil)
 var _ fs.NodeStringLookuper = (*Node)(nil)
 var _ fs.NodeSymlinker = (*Node)(nil)
 
-// var _ fs.NodeRequestLookuper = (*Node)(nil)
+// Node represents a file or directory in the file system.
-// var _ fs.NodeForgetter = (*Node)(nil)
-// var _ fs.NodePoller = (*Node)(nil)
-
 type Node struct {
-	fs   *FS    // base filesystem
+	fs   *FileSystem // base filesystem
 	path string      // path within file system
 }
 
-func NewNode(fs *FS, path string) *Node {
+func NewNode(fs *FileSystem, path string) *Node {
 	return &Node{fs: fs, path: path}
 }
 
@@ -106,15 +103,6 @@ func (n *Node) ReadDirAll(ctx context.Context) (ents []fuse.Dirent, err error) {
 	return ents, nil
 }
 
-// Getattr obtains the standard metadata for the receiver.
-// It should store that metadata in resp.
-//
-// If this method is not implemented, the attributes will be
-// generated based on Attr(), with zero values filled in.
-// func (n *Node) Getattr(ctx context.Context, req *fuse.GetattrRequest, resp *fuse.GetattrResponse) error {
-// 	panic("TODO")
-// }
-
 // Setattr sets the standard metadata for the receiver.
 //
 // Note, this is also used to communicate changes in the size of
@@ -249,12 +237,6 @@ func (n *Node) Access(ctx context.Context, req *fuse.AccessRequest) (err error)
 	return syscall.Access(n.srcpath(), req.Mask)
 }
 
-//type NodeRequestLookuper interface {
-//	// Lookup looks up a specific entry in the receiver.
-//	// See NodeStringLookuper for more.
-//	Lookup(ctx context.Context, req *fuse.LookupRequest, resp *fuse.LookupResponse) (Node, error)
-//}
-
 func (n *Node) Mkdir(ctx context.Context, req *fuse.MkdirRequest) (_ fs.Node, err error) {
 	if err := syscall.Mkdir(filepath.Join(n.srcpath(), req.Name), uint32(req.Mode^req.Umask)); err != nil {
 		return nil, err
@@ -264,14 +246,6 @@ func (n *Node) Mkdir(ctx context.Context, req *fuse.MkdirRequest) (_ fs.Node, er
 
 // Open opens the receiver. After a successful open, a client
 // process has a file descriptor referring to this Handle.
-//
-// Open can also be also called on non-files. For example,
-// directories are Opened for ReadDir or fchdir(2).
-//
-// If this method is not implemented, the open will always
-// succeed, and the Node itself will be used as the Handle.
-//
-// XXX note about access.  XXX OpenFlags.
 func (n *Node) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenResponse) (_ fs.Handle, err error) {
 	// TODO(bbj): Where does mode come from?
 	f, err := os.OpenFile(n.srcpath(), int(req.Flags), 0777)
@@ -290,13 +264,6 @@ func (n *Node) Create(ctx context.Context, req *fuse.CreateRequest, resp *fuse.C
 	return NewNode(n.fs, filepath.Join(n.path, req.Name)), &Handle{f: f}, nil
 }
 
-// Forget about this node. This node will not receive further
-// method calls.
-//
-// Forget is not necessarily seen on unmount, as all nodes are
-// implicitly forgotten as part of the unmount.
-// func (n *Node) Forget() { panic("TODO") }
-
 func (n *Node) Rename(ctx context.Context, req *fuse.RenameRequest, _newDir fs.Node) (err error) {
 	newDir := _newDir.(*Node)
 	return os.Rename(filepath.Join(n.srcpath(), req.OldName), filepath.Join(newDir.srcpath(), req.NewName))
@@ -320,10 +287,7 @@ func (n *Node) Fsync(ctx context.Context, req *fuse.FsyncRequest) (err error) {
 	return f.Sync()
 }
 
-// Getxattr gets an extended attribute by the given name from the
+// Getxattr gets an extended attribute by the given name from the node.
-// node.
-//
-// If there is no xattr by that name, returns fuse.ErrNoXattr.
 func (n *Node) Getxattr(ctx context.Context, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) (err error) {
 	// TODO(bbj): Handle req.Size & returned syscall.Getxattr() size.
 	if _, err = syscall.Getxattr(n.srcpath(), req.Name, resp.Xattr); err == syscall.ENODATA {
@@ -351,9 +315,3 @@ func (n *Node) Setxattr(ctx context.Context, req *fuse.SetxattrRequest) (err err
 func (n *Node) Removexattr(ctx context.Context, req *fuse.RemovexattrRequest) (err error) {
 	return syscall.Removexattr(n.srcpath(), req.Name)
 }
-
-// Poll checks whether the node is currently ready for I/O, and
-// may request a wakeup when it is. See HandlePoller.
-// func (n *Node) Poll(ctx context.Context, req *fuse.PollRequest, resp *fuse.PollResponse) error {
-// 	panic("TODO")
-// }

server.go

@@ -1,4 +1,4 @@
-package main
+package litestream
 
 /*
 import (