12483: Enable rename via webdav.

[arvados.git] / services / keep-web / webdav.go

diff --git a/services/keep-web/webdav.go b/services/keep-web/webdav.go
index 57f3f53a99ef6a73944c6cb600c1672c67cb6696..4a9476dc990bf5ff50519a61e00872c2e62a5b66 100644 (file)
--- a/services/keep-web/webdav.go
+++ b/services/keep-web/webdav.go
@@ -9,9 +9,7 @@ import (
        "errors"
        "fmt"
        prand "math/rand"
-       "net/http"
        "os"
-       "sync"
        "sync/atomic"
        "time"
 
@@ -27,24 +25,27 @@ var (
        errReadOnly           = errors.New("read-only filesystem")
 )
 
-// webdavFS implements a read-only webdav.FileSystem by wrapping an
+// webdavFS implements a webdav.FileSystem by wrapping an
 // arvados.CollectionFilesystem.
 type webdavFS struct {
        collfs arvados.CollectionFileSystem
+       update func() error
 }
 
-var _ webdav.FileSystem = &webdavFS{}
-
 func (fs *webdavFS) Mkdir(ctx context.Context, name string, perm os.FileMode) error {
-       return errReadOnly
+       return fs.collfs.Mkdir(name, 0755)
 }
 
-func (fs *webdavFS) OpenFile(ctx context.Context, name string, flag int, perm os.FileMode) (webdav.File, error) {
-       fi, err := fs.collfs.Stat(name)
-       if err != nil {
-               return nil, err
+func (fs *webdavFS) OpenFile(ctx context.Context, name string, flag int, perm os.FileMode) (f webdav.File, err error) {
+       writing := flag&(os.O_WRONLY|os.O_RDWR) != 0
+       if writing && fs.update == nil {
+               return nil, errReadOnly
+       }
+       f, err = fs.collfs.OpenFile(name, flag, perm)
+       if writing && err == nil {
+               f = writingFile{File: f, update: fs.update}
        }
-       return &webdavFile{collfs: fs.collfs, fileInfo: fi, name: name}, nil
+       return
 }
 
 func (fs *webdavFS) RemoveAll(ctx context.Context, name string) error {
@@ -52,78 +53,26 @@ func (fs *webdavFS) RemoveAll(ctx context.Context, name string) error {
 }
 
 func (fs *webdavFS) Rename(ctx context.Context, oldName, newName string) error {
-       return errReadOnly
+       if fs.update == nil {
+               return errReadOnly
+       }
+       return fs.Rename(oldName, newName)
 }
 
 func (fs *webdavFS) Stat(ctx context.Context, name string) (os.FileInfo, error) {
        return fs.collfs.Stat(name)
 }
 
-// webdavFile implements a read-only webdav.File by wrapping
-// http.File.
-//
-// The http.File is opened from an arvados.CollectionFileSystem, but
-// not until Seek, Read, or Readdir is called. This deferred-open
-// strategy makes webdav's OpenFile-Stat-Close cycle fast even though
-// the collfs's Open method is slow. This is relevant because webdav
-// does OpenFile-Stat-Close on each file when preparing directory
-// listings.
-//
-// Writes to a webdavFile always fail.
-type webdavFile struct {
-       // fields populated by (*webdavFS).OpenFile()
-       collfs   http.FileSystem
-       fileInfo os.FileInfo
-       name     string
-
-       // internal fields
-       file     http.File
-       loadOnce sync.Once
-       err      error
-}
-
-func (f *webdavFile) load() {
-       f.file, f.err = f.collfs.Open(f.name)
-}
-
-func (f *webdavFile) Write([]byte) (int, error) {
-       return 0, errReadOnly
+type writingFile struct {
+       webdav.File
+       update func() error
 }
 
-func (f *webdavFile) Seek(offset int64, whence int) (int64, error) {
-       f.loadOnce.Do(f.load)
-       if f.err != nil {
-               return 0, f.err
+func (f writingFile) Close() error {
+       if err := f.File.Close(); err != nil || f.update == nil {
+               return err
        }
-       return f.file.Seek(offset, whence)
-}
-
-func (f *webdavFile) Read(buf []byte) (int, error) {
-       f.loadOnce.Do(f.load)
-       if f.err != nil {
-               return 0, f.err
-       }
-       return f.file.Read(buf)
-}
-
-func (f *webdavFile) Close() error {
-       if f.file == nil {
-               // We never called load(), or load() failed
-               return f.err
-       }
-       return f.file.Close()
-}
-
-func (f *webdavFile) Readdir(n int) ([]os.FileInfo, error) {
-       f.loadOnce.Do(f.load)
-       if f.err != nil {
-               return nil, f.err
-       }
-       return f.file.Readdir(n)
-}
-
-func (f *webdavFile) Stat() (os.FileInfo, error) {
-       return f.fileInfo, nil
+       return f.update()
 }
 
 // noLockSystem implements webdav.LockSystem by returning success for