f22029bf3d
This enables any rclone remote to be mounted and used as a filesystem with some limitations. Only supported for Linux, FreeBSD and OS X
130 lines
3.4 KiB
Go
130 lines
3.4 KiB
Go
// +build linux darwin freebsd
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package mount
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import (
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"io"
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"sync"
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"bazil.org/fuse"
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fusefs "bazil.org/fuse/fs"
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"github.com/ncw/rclone/fs"
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"golang.org/x/net/context"
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)
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// ReadFileHandle is an open for read file handle on a File
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type ReadFileHandle struct {
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mu sync.Mutex
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closed bool // set if handle has been closed
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r io.ReadCloser
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o fs.Object
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readCalled bool // set if read has been called
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}
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func newReadFileHandle(o fs.Object) (*ReadFileHandle, error) {
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r, err := o.Open()
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if err != nil {
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return nil, err
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}
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return &ReadFileHandle{
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r: r,
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o: o,
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}, nil
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}
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// Check interface satisfied
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var _ fusefs.Handle = (*ReadFileHandle)(nil)
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// Check interface satisfied
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var _ fusefs.HandleReader = (*ReadFileHandle)(nil)
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// Read from the file handle
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func (fh *ReadFileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
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fs.Debug(fh.o, "ReadFileHandle.Open")
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if fh.closed {
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fs.ErrorLog(fh.o, "ReadFileHandle.Read error: %v", errClosedFileHandle)
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return errClosedFileHandle
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}
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fh.readCalled = true
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// We don't actually enforce Offset to match where previous read
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// ended. Maybe we should, but that would mean'd we need to track
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// it. The kernel *should* do it for us, based on the
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// fuse.OpenNonSeekable flag.
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//
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// One exception to the above is if we fail to fully populate a
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// page cache page; a read into page cache is always page aligned.
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// Make sure we never serve a partial read, to avoid that.
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buf := make([]byte, req.Size)
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n, err := io.ReadFull(fh.r, buf)
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if err == io.ErrUnexpectedEOF || err == io.EOF {
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err = nil
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}
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resp.Data = buf[:n]
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if err != nil {
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fs.ErrorLog(fh.o, "ReadFileHandle.Open error: %v", err)
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} else {
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fs.Debug(fh.o, "ReadFileHandle.Open OK")
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}
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return err
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}
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// close the file handle returning errClosedFileHandle if it has been
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// closed already.
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//
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// Must be called with fh.mu held
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func (fh *ReadFileHandle) close() error {
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if fh.closed {
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return errClosedFileHandle
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}
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fh.closed = true
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return fh.r.Close()
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}
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// Check interface satisfied
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var _ fusefs.HandleFlusher = (*ReadFileHandle)(nil)
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// Flush is called each time the file or directory is closed.
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// Because there can be multiple file descriptors referring to a
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// single opened file, Flush can be called multiple times.
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func (fh *ReadFileHandle) Flush(ctx context.Context, req *fuse.FlushRequest) error {
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fh.mu.Lock()
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defer fh.mu.Unlock()
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fs.Debug(fh.o, "ReadFileHandle.Flush")
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// If Read hasn't been called then ignore the Flush - Release
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// will pick it up
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if !fh.readCalled {
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fs.Debug(fh.o, "ReadFileHandle.Flush ignoring flush on unread handle")
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return nil
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}
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err := fh.close()
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if err != nil {
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fs.ErrorLog(fh.o, "ReadFileHandle.Flush error: %v", err)
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return err
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}
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fs.Debug(fh.o, "ReadFileHandle.Flush OK")
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return nil
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}
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var _ fusefs.HandleReleaser = (*ReadFileHandle)(nil)
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// Release is called when we are finished with the file handle
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//
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// It isn't called directly from userspace so the error is ignored by
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// the kernel
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func (fh *ReadFileHandle) Release(ctx context.Context, req *fuse.ReleaseRequest) error {
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fh.mu.Lock()
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defer fh.mu.Unlock()
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if fh.closed {
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fs.Debug(fh.o, "ReadFileHandle.Release nothing to do")
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return nil
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}
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fs.Debug(fh.o, "ReadFileHandle.Release closing")
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err := fh.close()
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if err != nil {
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fs.ErrorLog(fh.o, "ReadFileHandle.Release error: %v", err)
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} else {
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fs.Debug(fh.o, "ReadFileHandle.Release OK")
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}
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return err
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}
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