package inmemory import ( "bytes" "fmt" "io" "io/ioutil" "sync" "time" "github.com/docker/distribution/storagedriver" "github.com/docker/distribution/storagedriver/factory" ) const driverName = "inmemory" func init() { factory.Register(driverName, &inMemoryDriverFactory{}) } // inMemoryDriverFacotry implements the factory.StorageDriverFactory interface. type inMemoryDriverFactory struct{} func (factory *inMemoryDriverFactory) Create(parameters map[string]interface{}) (storagedriver.StorageDriver, error) { return New(), nil } // Driver is a storagedriver.StorageDriver implementation backed by a local map. // Intended solely for example and testing purposes. type Driver struct { root *dir mutex sync.RWMutex } // New constructs a new Driver. func New() *Driver { return &Driver{root: &dir{ common: common{ p: "/", mod: time.Now(), }, }} } // Implement the storagedriver.StorageDriver interface. // GetContent retrieves the content stored at "path" as a []byte. func (d *Driver) GetContent(path string) ([]byte, error) { if !storagedriver.PathRegexp.MatchString(path) { return nil, storagedriver.InvalidPathError{Path: path} } d.mutex.RLock() defer d.mutex.RUnlock() rc, err := d.ReadStream(path, 0) if err != nil { return nil, err } defer rc.Close() return ioutil.ReadAll(rc) } // PutContent stores the []byte content at a location designated by "path". func (d *Driver) PutContent(p string, contents []byte) error { if !storagedriver.PathRegexp.MatchString(p) { return storagedriver.InvalidPathError{Path: p} } d.mutex.Lock() defer d.mutex.Unlock() f, err := d.root.mkfile(p) if err != nil { // TODO(stevvooe): Again, we need to clarify when this is not a // directory in StorageDriver API. return fmt.Errorf("not a file") } f.truncate() f.WriteAt(contents, 0) return nil } // ReadStream retrieves an io.ReadCloser for the content stored at "path" with a // given byte offset. func (d *Driver) ReadStream(path string, offset int64) (io.ReadCloser, error) { if !storagedriver.PathRegexp.MatchString(path) { return nil, storagedriver.InvalidPathError{Path: path} } d.mutex.RLock() defer d.mutex.RUnlock() if offset < 0 { return nil, storagedriver.InvalidOffsetError{Path: path, Offset: offset} } path = normalize(path) found := d.root.find(path) if found.path() != path { return nil, storagedriver.PathNotFoundError{Path: path} } if found.isdir() { return nil, fmt.Errorf("%q is a directory", path) } return ioutil.NopCloser(found.(*file).sectionReader(offset)), nil } // WriteStream stores the contents of the provided io.ReadCloser at a location // designated by the given path. func (d *Driver) WriteStream(path string, offset int64, reader io.Reader) (nn int64, err error) { if !storagedriver.PathRegexp.MatchString(path) { return 0, storagedriver.InvalidPathError{Path: path} } d.mutex.Lock() defer d.mutex.Unlock() if offset < 0 { return 0, storagedriver.InvalidOffsetError{Path: path, Offset: offset} } normalized := normalize(path) f, err := d.root.mkfile(normalized) if err != nil { return 0, fmt.Errorf("not a file") } // Unlock while we are reading from the source, in case we are reading // from the same mfs instance. This can be fixed by a more granular // locking model. d.mutex.Unlock() d.mutex.RLock() // Take the readlock to block other writers. var buf bytes.Buffer nn, err = buf.ReadFrom(reader) if err != nil { // TODO(stevvooe): This condition is odd and we may need to clarify: // we've read nn bytes from reader but have written nothing to the // backend. What is the correct return value? Really, the caller needs // to know that the reader has been advanced and reattempting the // operation is incorrect. d.mutex.RUnlock() d.mutex.Lock() return nn, err } d.mutex.RUnlock() d.mutex.Lock() f.WriteAt(buf.Bytes(), offset) return nn, err } // Stat returns info about the provided path. func (d *Driver) Stat(path string) (storagedriver.FileInfo, error) { if !storagedriver.PathRegexp.MatchString(path) { return nil, storagedriver.InvalidPathError{Path: path} } d.mutex.RLock() defer d.mutex.RUnlock() normalized := normalize(path) found := d.root.find(path) if found.path() != normalized { return nil, storagedriver.PathNotFoundError{Path: path} } fi := storagedriver.FileInfoFields{ Path: path, IsDir: found.isdir(), ModTime: found.modtime(), } if !fi.IsDir { fi.Size = int64(len(found.(*file).data)) } return storagedriver.FileInfoInternal{FileInfoFields: fi}, nil } // List returns a list of the objects that are direct descendants of the given // path. func (d *Driver) List(path string) ([]string, error) { if !storagedriver.PathRegexp.MatchString(path) && path != "/" { return nil, storagedriver.InvalidPathError{Path: path} } normalized := normalize(path) found := d.root.find(normalized) if !found.isdir() { return nil, fmt.Errorf("not a directory") // TODO(stevvooe): Need error type for this... } entries, err := found.(*dir).list(normalized) if err != nil { switch err { case errNotExists: return nil, storagedriver.PathNotFoundError{Path: path} case errIsNotDir: return nil, fmt.Errorf("not a directory") default: return nil, err } } return entries, nil } // Move moves an object stored at sourcePath to destPath, removing the original // object. func (d *Driver) Move(sourcePath string, destPath string) error { if !storagedriver.PathRegexp.MatchString(sourcePath) { return storagedriver.InvalidPathError{Path: sourcePath} } else if !storagedriver.PathRegexp.MatchString(destPath) { return storagedriver.InvalidPathError{Path: destPath} } d.mutex.Lock() defer d.mutex.Unlock() normalizedSrc, normalizedDst := normalize(sourcePath), normalize(destPath) err := d.root.move(normalizedSrc, normalizedDst) switch err { case errNotExists: return storagedriver.PathNotFoundError{Path: destPath} default: return err } } // Delete recursively deletes all objects stored at "path" and its subpaths. func (d *Driver) Delete(path string) error { if !storagedriver.PathRegexp.MatchString(path) { return storagedriver.InvalidPathError{Path: path} } d.mutex.Lock() defer d.mutex.Unlock() normalized := normalize(path) err := d.root.delete(normalized) switch err { case errNotExists: return storagedriver.PathNotFoundError{Path: path} default: return err } } // URLFor returns a URL which may be used to retrieve the content stored at the given path. // May return an UnsupportedMethodErr in certain StorageDriver implementations. func (d *Driver) URLFor(path string, options map[string]interface{}) (string, error) { return "", storagedriver.ErrUnsupportedMethod }