distribution/storagedriver/inmemory/driver.go

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package inmemory
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"regexp"
"strings"
"sync"
"github.com/docker/docker-registry/storagedriver"
"github.com/docker/docker-registry/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]string) (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 {
storage map[string][]byte
mutex sync.RWMutex
}
// New constructs a new Driver.
func New() *Driver {
return &Driver{storage: make(map[string][]byte)}
}
// Implement the storagedriver.StorageDriver interface.
// GetContent retrieves the content stored at "path" as a []byte.
func (d *Driver) GetContent(path string) ([]byte, error) {
d.mutex.RLock()
defer d.mutex.RUnlock()
contents, ok := d.storage[path]
if !ok {
return nil, storagedriver.PathNotFoundError{Path: path}
}
return contents, nil
}
// PutContent stores the []byte content at a location designated by "path".
func (d *Driver) PutContent(path string, contents []byte) error {
d.mutex.Lock()
defer d.mutex.Unlock()
d.storage[path] = contents
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) {
d.mutex.RLock()
defer d.mutex.RUnlock()
contents, err := d.GetContent(path)
if err != nil {
return nil, err
} else if len(contents) <= int(offset) {
return nil, storagedriver.InvalidOffsetError{Path: path, Offset: offset}
}
src := contents[offset:]
buf := make([]byte, len(src))
copy(buf, src)
return ioutil.NopCloser(bytes.NewReader(buf)), 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, size int64, reader io.ReadCloser) error {
defer reader.Close()
d.mutex.RLock()
defer d.mutex.RUnlock()
resumableOffset, err := d.CurrentSize(path)
if err != nil {
return err
}
if offset > int64(resumableOffset) {
return storagedriver.InvalidOffsetError{Path: path, Offset: offset}
}
contents, err := ioutil.ReadAll(reader)
if err != nil {
return err
}
if offset > 0 {
contents = append(d.storage[path][0:offset], contents...)
}
d.storage[path] = contents
return nil
}
// CurrentSize retrieves the curernt size in bytes of the object at the given
// path.
func (d *Driver) CurrentSize(path string) (uint64, error) {
d.mutex.RLock()
defer d.mutex.RUnlock()
contents, ok := d.storage[path]
if !ok {
return 0, nil
}
return uint64(len(contents)), 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 path[len(path)-1] != '/' {
path += "/"
}
subPathMatcher, err := regexp.Compile(fmt.Sprintf("^%s[^/]+", path))
if err != nil {
return nil, err
}
d.mutex.RLock()
defer d.mutex.RUnlock()
// we use map to collect unique keys
keySet := make(map[string]struct{})
for k := range d.storage {
if key := subPathMatcher.FindString(k); key != "" {
keySet[key] = struct{}{}
}
}
keys := make([]string, 0, len(keySet))
for k := range keySet {
keys = append(keys, k)
}
return keys, nil
}
// Move moves an object stored at sourcePath to destPath, removing the original
// object.
func (d *Driver) Move(sourcePath string, destPath string) error {
d.mutex.Lock()
defer d.mutex.Unlock()
contents, ok := d.storage[sourcePath]
if !ok {
return storagedriver.PathNotFoundError{Path: sourcePath}
}
d.storage[destPath] = contents
delete(d.storage, sourcePath)
return nil
}
// Delete recursively deletes all objects stored at "path" and its subpaths.
func (d *Driver) Delete(path string) error {
d.mutex.Lock()
defer d.mutex.Unlock()
var subPaths []string
for k := range d.storage {
if strings.HasPrefix(k, path) {
subPaths = append(subPaths, k)
}
}
if len(subPaths) == 0 {
return storagedriver.PathNotFoundError{Path: path}
}
for _, subPath := range subPaths {
delete(d.storage, subPath)
}
return nil
}