reflector.go/store/disk.go
Alex Grintsvayg e70b9af3e4
dont overallocate ram when reading blobs from disk
ReadFile checks the file size and allocates a bit more space than we
expect we'll need. ReadAll uses Go's standard resizing algo, which
doubles the underlying array each time you hit the end. So ReadAll
ends up allocating 4MB for a full blob, while ReadFile allocates
slightly over 2MB.
2020-11-27 16:18:26 -05:00

149 lines
3 KiB
Go

package store
import (
"io/ioutil"
"os"
"path"
"github.com/lbryio/lbry.go/v2/extras/errors"
"github.com/lbryio/lbry.go/v2/stream"
"github.com/lbryio/reflector.go/store/speedwalk"
)
// DiskStore stores blobs on a local disk
type DiskStore struct {
// the location of blobs on disk
blobDir string
// store files in subdirectories based on the first N chars in the filename. 0 = don't create subdirectories.
prefixLength int
// true if initOnce ran, false otherwise
initialized bool
}
// NewDiskStore returns an initialized file disk store pointer.
func NewDiskStore(dir string, prefixLength int) *DiskStore {
return &DiskStore{
blobDir: dir,
prefixLength: prefixLength,
}
}
const nameDisk = "disk"
// Name is the cache type name
func (d *DiskStore) Name() string { return nameDisk }
// Has returns T/F or Error if it the blob stored already. It will error with any IO disk error.
func (d *DiskStore) Has(hash string) (bool, error) {
err := d.initOnce()
if err != nil {
return false, err
}
_, err = os.Stat(d.path(hash))
if err != nil {
if os.IsNotExist(err) {
return false, nil
}
return false, errors.Err(err)
}
return true, nil
}
// Get returns the blob or an error if the blob doesn't exist.
func (d *DiskStore) Get(hash string) (stream.Blob, error) {
err := d.initOnce()
if err != nil {
return nil, err
}
blob, err := ioutil.ReadFile(d.path(hash))
if err != nil {
if os.IsNotExist(err) {
return nil, errors.Err(ErrBlobNotFound)
}
return nil, errors.Err(err)
}
return blob, nil
}
// Put stores the blob on disk
func (d *DiskStore) Put(hash string, blob stream.Blob) error {
err := d.initOnce()
if err != nil {
return err
}
err = d.ensureDirExists(d.dir(hash))
if err != nil {
return err
}
err = ioutil.WriteFile(d.path(hash), blob, 0644)
return errors.Err(err)
}
// PutSD stores the sd blob on the disk
func (d *DiskStore) PutSD(hash string, blob stream.Blob) error {
return d.Put(hash, blob)
}
// Delete deletes the blob from the store
func (d *DiskStore) Delete(hash string) error {
err := d.initOnce()
if err != nil {
return err
}
has, err := d.Has(hash)
if err != nil {
return err
}
if !has {
return nil
}
err = os.Remove(d.path(hash))
return errors.Err(err)
}
// list returns the hashes of blobs that already exist in the blobDir
func (d *DiskStore) list() ([]string, error) {
err := d.initOnce()
if err != nil {
return nil, err
}
return speedwalk.AllFiles(d.blobDir, true)
}
func (d *DiskStore) dir(hash string) string {
if d.prefixLength <= 0 || len(hash) < d.prefixLength {
return d.blobDir
}
return path.Join(d.blobDir, hash[:d.prefixLength])
}
func (d *DiskStore) path(hash string) string {
return path.Join(d.dir(hash), hash)
}
func (d *DiskStore) ensureDirExists(dir string) error {
return errors.Err(os.MkdirAll(dir, 0755))
}
func (d *DiskStore) initOnce() error {
if d.initialized {
return nil
}
err := d.ensureDirExists(d.blobDir)
if err != nil {
return err
}
d.initialized = true
return nil
}