woodpecker/vendor/github.com/djherbis/fscache/memfs.go

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2016-04-13 00:27:24 +00:00
package fscache
import (
"bytes"
"errors"
"io"
"sync"
"time"
"gopkg.in/djherbis/stream.v1"
)
type memFS struct {
mu sync.RWMutex
files map[string]*memFile
}
// NewMemFs creates an in-memory FileSystem.
// It does not support persistence (Reload is a nop).
func NewMemFs() FileSystem {
return &memFS{
files: make(map[string]*memFile),
}
}
func (fs *memFS) Reload(add func(key, name string)) error {
return nil
}
func (fs *memFS) AccessTimes(name string) (rt, wt time.Time, err error) {
fs.mu.RLock()
defer fs.mu.RUnlock()
f, ok := fs.files[name]
if ok {
return f.rt, f.wt, nil
}
return rt, wt, errors.New("file has not been read")
}
func (fs *memFS) Create(key string) (stream.File, error) {
fs.mu.Lock()
defer fs.mu.Unlock()
if _, ok := fs.files[key]; ok {
return nil, errors.New("file exists")
}
file := &memFile{
name: key,
r: bytes.NewBuffer(nil),
wt: time.Now(),
}
file.memReader.memFile = file
fs.files[key] = file
return file, nil
}
func (fs *memFS) Open(name string) (stream.File, error) {
fs.mu.Lock()
defer fs.mu.Unlock()
if f, ok := fs.files[name]; ok {
f.rt = time.Now()
return &memReader{memFile: f}, nil
}
return nil, errors.New("file does not exist")
}
func (fs *memFS) Remove(key string) error {
fs.mu.Lock()
defer fs.mu.Unlock()
delete(fs.files, key)
return nil
}
func (fs *memFS) RemoveAll() error {
fs.mu.Lock()
defer fs.mu.Unlock()
fs.files = make(map[string]*memFile)
return nil
}
type memFile struct {
mu sync.RWMutex
name string
r *bytes.Buffer
memReader
rt, wt time.Time
}
func (f *memFile) Name() string {
return f.name
}
func (f *memFile) Write(p []byte) (int, error) {
if len(p) > 0 {
f.mu.Lock()
defer f.mu.Unlock()
return f.r.Write(p)
}
return len(p), nil
}
func (f *memFile) Bytes() []byte {
f.mu.RLock()
defer f.mu.RUnlock()
return f.r.Bytes()
}
func (f *memFile) Close() error {
return nil
}
type memReader struct {
*memFile
n int
}
func (r *memReader) ReadAt(p []byte, off int64) (n int, err error) {
data := r.Bytes()
if int64(len(data)) < off {
return 0, io.EOF
}
n, err = bytes.NewReader(data[off:]).ReadAt(p, 0)
return n, err
}
func (r *memReader) Read(p []byte) (n int, err error) {
n, err = bytes.NewReader(r.Bytes()[r.n:]).Read(p)
r.n += n
return n, err
}
func (r *memReader) Close() error {
return nil
}