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package sftpd
import (
"fmt"
"io"
"sync"
"github.com/seaweedfs/seaweedfs/weed/filer"
filer_pb "github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
"github.com/seaweedfs/seaweedfs/weed/sftpd/utils"
)
type SeaweedFileReaderAt struct {
fs *SftpServer
entry *filer_pb.Entry
reader io.ReadSeeker
mu sync.Mutex
bufferSize int
cache *utils.LruCache
fileSize int64
}
func NewSeaweedFileReaderAt(fs *SftpServer, entry *filer_pb.Entry) *SeaweedFileReaderAt {
return &SeaweedFileReaderAt{
fs: fs,
entry: entry,
bufferSize: 5 * 1024 * 1024, // 5MB
cache: utils.NewLRUCache(10), // Max 10 chunks = ~50MB
fileSize: int64(entry.Attributes.FileSize),
}
}
func (ra *SeaweedFileReaderAt) ReadAt(p []byte, off int64) (n int, err error) {
ra.mu.Lock()
defer ra.mu.Unlock()
if off >= ra.fileSize {
return 0, io.EOF
}
remaining := len(p)
readOffset := off
totalRead := 0
for remaining > 0 && readOffset < ra.fileSize {
bufferKey := (readOffset / int64(ra.bufferSize)) * int64(ra.bufferSize)
bufferOffset := int(readOffset - bufferKey)
buffer, ok := ra.cache.Get(bufferKey)
if !ok {
readSize := ra.bufferSize
if bufferKey+int64(readSize) > ra.fileSize {
readSize = int(ra.fileSize - bufferKey)
}
if ra.reader == nil {
r := filer.NewFileReader(ra.fs, ra.entry)
if rs, ok := r.(io.ReadSeeker); ok {
ra.reader = rs
} else {
return 0, fmt.Errorf("reader is not seekable")
}
}
if _, err := ra.reader.Seek(bufferKey, io.SeekStart); err != nil {
return 0, fmt.Errorf("seek error: %w", err)
}
buffer = make([]byte, readSize)
readBytes, err := io.ReadFull(ra.reader, buffer)
if err != nil && err != io.ErrUnexpectedEOF {
return 0, fmt.Errorf("read error: %w", err)
}
buffer = buffer[:readBytes]
ra.cache.Put(bufferKey, buffer)
}
toCopy := len(buffer) - bufferOffset
if toCopy > remaining {
toCopy = remaining
}
if toCopy <= 0 {
break
}
copy(p[totalRead:], buffer[bufferOffset:bufferOffset+toCopy])
totalRead += toCopy
readOffset += int64(toCopy)
remaining -= toCopy
}
if totalRead == 0 {
return 0, io.EOF
}
if totalRead < len(p) {
return totalRead, io.EOF
}
return totalRead, nil
}
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