port unionFs from filters to filesystems
diff --git a/union.go b/union.go index 828cf0c..7cce83e 100644 --- a/union.go +++ b/union.go
@@ -7,63 +7,6 @@ "syscall" ) -type UnionFs func(Fs) FilterFs - -// Create a new UnionFs: -// -// ufs := NewUnionFs(baseFs, layerFs, NewCoWUnionFs()) -// cfs := NewUnionFs(baseFs, layerFs, NewCacheUnionFs(cacheTime)) -func NewUnionFs(base Fs, overlay Fs, impl UnionFs) Fs { - ufs := impl(overlay) - ufs.SetSource(base) - return ufs -} - -func copyToLayer(base Fs, layer Fs, name string) error { - bfh, err := base.Open(name) - if err != nil { - return err - } - defer bfh.Close() - - exists, err := Exists(layer, filepath.Dir(name)) - if err != nil { - return err - } - if !exists { - err = layer.MkdirAll(filepath.Dir(name), 0777) // FIXME? - if err != nil { - return err - } - } - - lfh, err := layer.Create(name) - if err != nil { - return err - } - n, err := io.Copy(lfh, bfh) - if err != nil { - layer.Remove(name) - lfh.Close() - return err - } - - bfi, err := bfh.Stat() - if err != nil || bfi.Size() != n { - layer.Remove(name) - lfh.Close() - return syscall.EIO - } - - err = lfh.Close() - if err != nil { - layer.Remove(name) - lfh.Close() - return err - } - return layer.Chtimes(name, bfi.ModTime(), bfi.ModTime()) -} - // The UnionFile implements the afero.File interface and will be returned // when reading a directory present at least in the overlay or opening a file // for writing. @@ -278,3 +221,48 @@ } return 0, BADFD } + +func copyToLayer(base Fs, layer Fs, name string) error { + bfh, err := base.Open(name) + if err != nil { + return err + } + defer bfh.Close() + + exists, err := Exists(layer, filepath.Dir(name)) + if err != nil { + return err + } + if !exists { + err = layer.MkdirAll(filepath.Dir(name), 0777) // FIXME? + if err != nil { + return err + } + } + + lfh, err := layer.Create(name) + if err != nil { + return err + } + n, err := io.Copy(lfh, bfh) + if err != nil { + layer.Remove(name) + lfh.Close() + return err + } + + bfi, err := bfh.Stat() + if err != nil || bfi.Size() != n { + layer.Remove(name) + lfh.Close() + return syscall.EIO + } + + err = lfh.Close() + if err != nil { + layer.Remove(name) + lfh.Close() + return err + } + return layer.Chtimes(name, bfi.ModTime(), bfi.ModTime()) +}
diff --git a/union_cache.go b/union_cache.go index bae895b..aa227f0 100644 --- a/union_cache.go +++ b/union_cache.go
@@ -25,21 +25,6 @@ cacheTime time.Duration } -func NewCacheUnionFs(t time.Duration) UnionFs { - return func(layer Fs) FilterFs { - return &CacheUnionFs{cacheTime: t, layer: layer} - } -} - -func (u *CacheUnionFs) AddFilter(fs FilterFs) { - fs.SetSource(u.base) - u.base = fs -} - -func (u *CacheUnionFs) SetSource(fs Fs) { - u.base = fs -} - type cacheState int const (
diff --git a/union_cow.go b/union_cow.go index 0c75e2b..8c9d9dc 100644 --- a/union_cow.go +++ b/union_cow.go
@@ -6,7 +6,7 @@ "time" ) -// The CoWUnionFs is a union filesystem: a read only base file system with +// The CopyOnWriteUnionFs is a union filesystem: a read only base file system with // a possibly writeable layer on top. Changes to the file system will only // be made in the overlay: Changing an existing file in the base layer which // is not present in the overlay will copy the file to the overlay ("changing" @@ -17,28 +17,12 @@ // can handle this). // // Reading directories is currently only supported via Open(), not OpenFile(). -type CoWUnionFs struct { +type CopyOnWriteUnionFs struct { base Fs layer Fs } -func NewCoWUnionFs() UnionFs { - // returns a function to have it the same as other implemtations - return func(layer Fs) FilterFs { - return &CoWUnionFs{layer: layer} - } -} - -func (u *CoWUnionFs) AddFilter(fs FilterFs) { - fs.SetSource(u.base) - u.base = fs -} - -func (u *CoWUnionFs) SetSource(fs Fs) { - u.base = fs -} - -func (u *CoWUnionFs) isBaseFile(name string) (bool, error) { +func (u *CopyOnWriteUnionFs) isBaseFile(name string) (bool, error) { if _, err := u.layer.Stat(name); err == nil { return false, nil } @@ -46,11 +30,11 @@ return true, err } -func (u *CoWUnionFs) copyToLayer(name string) error { +func (u *CopyOnWriteUnionFs) copyToLayer(name string) error { return copyToLayer(u.base, u.layer, name) } -func (u *CoWUnionFs) Chtimes(name string, atime, mtime time.Time) error { +func (u *CopyOnWriteUnionFs) Chtimes(name string, atime, mtime time.Time) error { b, err := u.isBaseFile(name) if err != nil { return err @@ -63,7 +47,7 @@ return u.layer.Chtimes(name, atime, mtime) } -func (u *CoWUnionFs) Chmod(name string, mode os.FileMode) error { +func (u *CopyOnWriteUnionFs) Chmod(name string, mode os.FileMode) error { b, err := u.isBaseFile(name) if err != nil { return err @@ -76,7 +60,7 @@ return u.layer.Chmod(name, mode) } -func (u *CoWUnionFs) Stat(name string) (os.FileInfo, error) { +func (u *CopyOnWriteUnionFs) Stat(name string) (os.FileInfo, error) { fi, err := u.layer.Stat(name) switch err { case nil: @@ -89,7 +73,7 @@ } // Renaming files present only in the base layer is not permitted -func (u *CoWUnionFs) Rename(oldname, newname string) error { +func (u *CopyOnWriteUnionFs) Rename(oldname, newname string) error { b, err := u.isBaseFile(oldname) if err != nil { return err @@ -103,7 +87,7 @@ // Removing files present only in the base layer is not permitted. If // a file is present in the base layer and the overlay, only the overlay // will be removed. -func (u *CoWUnionFs) Remove(name string) error { +func (u *CopyOnWriteUnionFs) Remove(name string) error { err := u.layer.Remove(name) switch err { case syscall.ENOENT: @@ -117,7 +101,7 @@ } } -func (u *CoWUnionFs) RemoveAll(name string) error { +func (u *CopyOnWriteUnionFs) RemoveAll(name string) error { err := u.layer.RemoveAll(name) switch err { case syscall.ENOENT: @@ -131,7 +115,7 @@ } } -func (u *CoWUnionFs) OpenFile(name string, flag int, perm os.FileMode) (File, error) { +func (u *CopyOnWriteUnionFs) OpenFile(name string, flag int, perm os.FileMode) (File, error) { b, err := u.isBaseFile(name) if err != nil { return nil, err @@ -151,7 +135,7 @@ return u.layer.OpenFile(name, flag, perm) } -func (u *CoWUnionFs) Open(name string) (File, error) { +func (u *CopyOnWriteUnionFs) Open(name string) (File, error) { b, err := u.isBaseFile(name) if err != nil { return nil, err @@ -176,7 +160,7 @@ return &UnionFile{base: bfile, layer: lfile}, nil } -func (u *CoWUnionFs) Mkdir(name string, perm os.FileMode) error { +func (u *CopyOnWriteUnionFs) Mkdir(name string, perm os.FileMode) error { dir, err := IsDir(u.base, name) if err != nil { return u.layer.MkdirAll(name, perm) @@ -187,11 +171,11 @@ return u.layer.MkdirAll(name, perm) } -func (u *CoWUnionFs) Name() string { - return "CoWUnionFs" +func (u *CopyOnWriteUnionFs) Name() string { + return "CopyOnWriteUnionFs" } -func (u *CoWUnionFs) MkdirAll(name string, perm os.FileMode) error { +func (u *CopyOnWriteUnionFs) MkdirAll(name string, perm os.FileMode) error { dir, err := IsDir(u.base, name) if err != nil { return u.layer.MkdirAll(name, perm) @@ -202,7 +186,7 @@ return u.layer.MkdirAll(name, perm) } -func (u *CoWUnionFs) Create(name string) (File, error) { +func (u *CopyOnWriteUnionFs) Create(name string) (File, error) { b, err := u.isBaseFile(name) if err == nil && b { if err = u.copyToLayer(name); err != nil {
diff --git a/union_test.go b/union_test.go index 24f93cd..9c3fb0d 100644 --- a/union_test.go +++ b/union_test.go
@@ -11,7 +11,7 @@ base := &MemMapFs{} roBase := &ReadOnlyFs{source: base} - ufs := NewUnionFs(roBase, &MemMapFs{}, NewCoWUnionFs()) + ufs := &CopyOnWriteUnionFs{base: roBase, layer: &MemMapFs{}} base.MkdirAll("/home/test", 0777) fh, _ := base.Create("/home/test/file.txt") @@ -61,7 +61,7 @@ base := &MemMapFs{} roBase := &ReadOnlyFs{source: base} - ufs := NewUnionFs(roBase, &MemMapFs{}, NewCoWUnionFs()) + ufs := &CopyOnWriteUnionFs{base: roBase, layer: &MemMapFs{}} base.MkdirAll("/home/test", 0777) fh, _ := base.Create("/home/test/file.txt") @@ -85,7 +85,8 @@ func TestUnionCacheWrite(t *testing.T) { base := &MemMapFs{} layer := &MemMapFs{} - ufs := NewUnionFs(base, layer, NewCacheUnionFs(0)) + + ufs := &CacheUnionFs{base: base, layer: layer, cacheTime: 0} base.Mkdir("/data", 0777) @@ -114,7 +115,7 @@ func TestUnionCacheExpire(t *testing.T) { base := &MemMapFs{} layer := &MemMapFs{} - ufs := NewUnionFs(base, layer, NewCacheUnionFs(1*time.Second)) + ufs := &CacheUnionFs{base: base, layer: layer, cacheTime: 1 * time.Second} base.Mkdir("/data", 0777)