/
memory.go
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/
memory.go
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// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package memfs contains a in-memory Beam filesystem. Useful for testing.
package memfs
import (
"bytes"
"context"
"fmt"
"io"
"os"
"runtime"
"sort"
"strings"
"sync"
"time"
"github.com/apache/beam/sdks/v2/go/pkg/beam/io/filesystem"
)
func init() {
filesystem.Register("memfs", New)
}
var instance = &fs{m: make(map[string]file)}
type fs struct {
m map[string]file
mu sync.Mutex
}
type file struct {
Data []byte
LastModified time.Time
}
func newFile(data []byte) file {
cp := make([]byte, len(data))
copy(cp, data)
return file{
Data: data,
LastModified: time.Now(),
}
}
// New returns the global memory filesystem.
func New(_ context.Context) filesystem.Interface {
return instance
}
func (f *fs) Close() error {
return nil
}
func (f *fs) List(_ context.Context, glob string) ([]string, error) {
f.mu.Lock()
defer f.mu.Unlock()
// As with other functions, the memfs:// prefix is optional.
globNoScheme := strings.TrimPrefix(glob, "memfs://")
var ret []string
for k := range f.m {
matched, err := filesystem.Match(globNoScheme, strings.TrimPrefix(k, "memfs://"))
if err != nil {
return nil, fmt.Errorf("invalid glob pattern: %w", err)
}
if matched {
ret = append(ret, k)
}
}
sort.Strings(ret)
return ret, nil
}
func (f *fs) OpenRead(_ context.Context, filename string) (io.ReadCloser, error) {
f.mu.Lock()
defer f.mu.Unlock()
if v, ok := f.m[normalize(filename)]; ok {
return io.NopCloser(bytes.NewReader(v.Data)), nil
}
return nil, os.ErrNotExist
}
func (f *fs) OpenWrite(_ context.Context, filename string) (io.WriteCloser, error) {
return &commitWriter{key: filename, instance: f}, nil
}
func (f *fs) Size(_ context.Context, filename string) (int64, error) {
f.mu.Lock()
defer f.mu.Unlock()
if v, ok := f.m[normalize(filename)]; ok {
return int64(len(v.Data)), nil
}
return -1, os.ErrNotExist
}
// LastModified returns the time at which the file was last modified.
func (f *fs) LastModified(_ context.Context, filename string) (time.Time, error) {
f.mu.Lock()
defer f.mu.Unlock()
v, ok := f.m[normalize(filename)]
if !ok {
return time.Time{}, os.ErrNotExist
}
return v.LastModified, nil
}
// Remove the named file from the filesystem.
func (f *fs) Remove(_ context.Context, filename string) error {
f.mu.Lock()
defer f.mu.Unlock()
delete(f.m, filename)
return nil
}
// Rename the old path to the new path.
func (f *fs) Rename(_ context.Context, oldpath, newpath string) error {
f.mu.Lock()
defer f.mu.Unlock()
f.m[newpath] = f.m[oldpath]
delete(f.m, oldpath)
return nil
}
// Copy copies the old path to the new path.
func (f *fs) Copy(_ context.Context, oldpath, newpath string) error {
f.mu.Lock()
defer f.mu.Unlock()
oldFile, ok := f.m[normalize(oldpath)]
if !ok {
return os.ErrNotExist
}
f.m[normalize(newpath)] = newFile(oldFile.Data)
return nil
}
// Compile time check for interface implementations.
var (
_ filesystem.LastModifiedGetter = ((*fs)(nil))
_ filesystem.Remover = ((*fs)(nil))
_ filesystem.Renamer = ((*fs)(nil))
_ filesystem.Copier = ((*fs)(nil))
)
// write is a helper function for writing to the global store.
func (f *fs) write(key string, value []byte) error {
f.mu.Lock()
defer f.mu.Unlock()
f.m[normalize(key)] = newFile(value)
return nil
}
// Write stores the given key and value in the global store.
func Write(key string, value []byte) {
instance.write(key, value)
}
func normalize(key string) string {
if runtime.GOOS == "windows" {
key = strings.ReplaceAll(key, "\\", "/")
}
if strings.HasPrefix(key, "memfs://") {
return key
}
return "memfs://" + key
}
type commitWriter struct {
key string
buf bytes.Buffer
instance *fs
}
func (w *commitWriter) Write(p []byte) (n int, err error) {
return w.buf.Write(p)
}
func (w *commitWriter) Close() error {
return w.instance.write(w.key, w.buf.Bytes())
}