/
filelike.go
737 lines (629 loc) · 16.9 KB
/
filelike.go
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package oss
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"net/http"
"os"
"runtime"
"strings"
"time"
)
type OpenOptions struct {
Offset int64
VersionId *string
EnablePrefetch bool
PrefetchNum int
ChunkSize int64
PrefetchThreshold int64
RequestPayer *string
}
type ReadOnlyFile struct {
client OpenFileAPIClient
context context.Context
// object info
bucket string
key string
versionId *string
requestPayer *string
// file info
sizeInBytes int64
modTime string
etag string
headers http.Header
// current read position
offset int64
// read
reader io.ReadCloser
readBufOffset int64
// prefetch
enablePrefetch bool
chunkSize int64
prefetchNum int
prefetchThreshold int64
asyncReaders []*AsyncRangeReader
seqReadAmount int64 // number of sequential read
numOOORead int64 // number of out of order read
closed bool // whether we have closed the file
}
// NewReadOnlyFile OpenFile opens the named file for reading.
// If successful, methods on the returned file can be used for reading.
func NewReadOnlyFile(ctx context.Context, c OpenFileAPIClient, bucket string, key string, optFns ...func(*OpenOptions)) (*ReadOnlyFile, error) {
options := OpenOptions{
Offset: 0,
EnablePrefetch: false,
PrefetchNum: DefaultPrefetchNum,
ChunkSize: DefaultPrefetchChunkSize,
PrefetchThreshold: DefaultPrefetchThreshold,
}
for _, fn := range optFns {
fn(&options)
}
if options.EnablePrefetch {
var chunkSize int64
if options.ChunkSize > 0 {
chunkSize = (options.ChunkSize + AsyncReadeBufferSize - 1) / AsyncReadeBufferSize * AsyncReadeBufferSize
} else {
chunkSize = DefaultPrefetchChunkSize
}
options.ChunkSize = chunkSize
if options.PrefetchNum <= 0 {
options.PrefetchNum = DefaultPrefetchNum
}
}
f := &ReadOnlyFile{
client: c,
context: ctx,
bucket: bucket,
key: key,
versionId: options.VersionId,
requestPayer: options.RequestPayer,
offset: options.Offset,
enablePrefetch: options.EnablePrefetch,
prefetchNum: options.PrefetchNum,
chunkSize: options.ChunkSize,
prefetchThreshold: options.PrefetchThreshold,
}
result, err := f.client.HeadObject(f.context, &HeadObjectRequest{
Bucket: &f.bucket,
Key: &f.key,
VersionId: f.versionId,
RequestPayer: f.requestPayer,
})
if err != nil {
return nil, err
}
//File info
f.sizeInBytes = result.ContentLength
f.modTime = result.Headers.Get(HTTPHeaderLastModified)
f.etag = result.Headers.Get(HTTPHeaderETag)
f.headers = result.Headers
if f.sizeInBytes < 0 {
return nil, fmt.Errorf("file size is invaid, got %v", f.sizeInBytes)
}
if f.offset > f.sizeInBytes {
return nil, fmt.Errorf("offset is unavailable, offset:%v, file size:%v", f.offset, f.sizeInBytes)
}
return f, nil
}
// Close closes the File.
func (f *ReadOnlyFile) Close() error {
if f == nil {
return os.ErrInvalid
}
return f.close()
}
func (f *ReadOnlyFile) close() error {
if f.closed {
return nil
}
if f.reader != nil {
f.reader.Close()
f.reader = nil
}
for _, reader := range f.asyncReaders {
reader.Close()
}
f.asyncReaders = nil
f.closed = true
runtime.SetFinalizer(f, nil)
return nil
}
// Read reads up to len(b) bytes from the File and stores them in b.
// It returns the number of bytes read and any error encountered.
// At end of file, Read returns 0, io.EOF.
func (f *ReadOnlyFile) Read(p []byte) (bytesRead int, err error) {
if err := f.checkValid("read"); err != nil {
return 0, err
}
n, e := f.read(p)
return n, f.wrapErr("read", e)
}
func (f *ReadOnlyFile) read(p []byte) (bytesRead int, err error) {
defer func() {
f.offset += int64(bytesRead)
}()
nwant := len(p)
var nread int
for bytesRead < nwant && err == nil {
nread, err = f.readInternal(f.offset+int64(bytesRead), p[bytesRead:])
if nread > 0 {
bytesRead += nread
}
}
return
}
// Seek sets the offset for the next Read or Write on file to offset, interpreted
// according to whence: 0 means relative to the origin of the file, 1 means
// relative to the current offset, and 2 means relative to the end.
// It returns the new offset and an error.
func (f *ReadOnlyFile) Seek(offset int64, whence int) (int64, error) {
if err := f.checkValid("seek"); err != nil {
return 0, err
}
r, e := f.seek(offset, whence)
if e != nil {
return 0, f.wrapErr("seek", e)
}
return r, nil
}
func (f *ReadOnlyFile) seek(offset int64, whence int) (int64, error) {
var abs int64
switch whence {
case io.SeekStart:
abs = offset
case io.SeekCurrent:
abs = f.offset + offset
case io.SeekEnd:
abs = f.sizeInBytes + offset
default:
return 0, fmt.Errorf("invalid whence")
}
if abs < 0 {
return 0, fmt.Errorf("negative position")
}
if abs > f.sizeInBytes {
return offset - (abs - f.sizeInBytes), fmt.Errorf("offset is unavailable")
}
f.offset = abs
return abs, nil
}
type fileInfo struct {
name string
size int64
modTime time.Time
header http.Header
}
func (fi *fileInfo) Name() string { return fi.name }
func (fi *fileInfo) Size() int64 { return fi.size }
func (fi *fileInfo) Mode() os.FileMode { return os.FileMode(0644) }
func (fi *fileInfo) ModTime() time.Time { return fi.modTime }
func (fi *fileInfo) IsDir() bool { return false }
func (fi *fileInfo) Sys() any { return fi.header }
// Stat returns the FileInfo structure describing file.
func (f *ReadOnlyFile) Stat() (os.FileInfo, error) {
if err := f.checkValid("stat"); err != nil {
return nil, err
}
mtime, _ := http.ParseTime(f.modTime)
return &fileInfo{
name: f.name(),
size: f.sizeInBytes,
modTime: mtime,
header: f.headers,
}, nil
}
func (f *ReadOnlyFile) name() string {
var name string
if f.versionId != nil {
name = fmt.Sprintf("oss://%s/%s?versionId=%s", f.bucket, f.key, *f.versionId)
} else {
name = fmt.Sprintf("oss://%s/%s", f.bucket, f.key)
}
return name
}
func (f *ReadOnlyFile) wrapErr(op string, err error) error {
if err == nil || err == io.EOF {
return err
}
return &os.PathError{Op: op, Path: f.name(), Err: err}
}
func (f *ReadOnlyFile) checkValid(op string) error {
if f == nil {
return os.ErrInvalid
} else if f.closed {
return os.ErrClosed
}
return nil
}
func (f *ReadOnlyFile) readInternal(offset int64, p []byte) (bytesRead int, err error) {
defer func() {
if bytesRead > 0 {
f.readBufOffset += int64(bytesRead)
f.seqReadAmount += int64(bytesRead)
}
}()
if offset >= f.sizeInBytes {
err = io.EOF
return
}
if f.readBufOffset != offset {
f.readBufOffset = offset
f.seqReadAmount = 0
if f.reader != nil {
f.reader.Close()
f.reader = nil
}
if f.asyncReaders != nil {
f.numOOORead++
}
for _, ar := range f.asyncReaders {
ar.Close()
}
f.asyncReaders = nil
}
if f.enablePrefetch && f.seqReadAmount >= f.prefetchThreshold && f.numOOORead < 3 {
//swith to async reader
if f.reader != nil {
f.reader.Close()
f.reader = nil
}
err = f.prefetch(offset, len(p))
if err == nil {
bytesRead, err = f.readFromPrefetcher(offset, p)
if err == nil {
return
}
}
// fall back to read serially
f.seqReadAmount = 0
for _, ar := range f.asyncReaders {
ar.Close()
}
f.asyncReaders = nil
}
bytesRead, err = f.readDirect(offset, p)
return
}
func (f *ReadOnlyFile) readDirect(offset int64, buf []byte) (bytesRead int, err error) {
if offset >= f.sizeInBytes {
return
}
if f.reader == nil {
var result *GetObjectResult
result, err = f.client.GetObject(f.context, &GetObjectRequest{
Bucket: Ptr(f.bucket),
Key: Ptr(f.key),
VersionId: f.versionId,
Range: Ptr(fmt.Sprintf("bytes=%d-", offset)),
RangeBehavior: Ptr("standard"),
RequestPayer: f.requestPayer,
})
if err != nil {
return bytesRead, err
}
if err = f.checkResultValid(offset, result.Headers); err != nil {
if result != nil {
result.Body.Close()
}
return bytesRead, err
}
f.reader = result.Body
}
bytesRead, err = f.reader.Read(buf)
if err != nil {
f.reader.Close()
f.reader = nil
err = nil
}
return
}
func (f *ReadOnlyFile) checkResultValid(offset int64, header http.Header) error {
modTime := header.Get(HTTPHeaderLastModified)
etag := header.Get(HTTPHeaderETag)
gotOffset, _ := parseOffsetAndSizeFromHeaders(header)
if gotOffset != offset {
return fmt.Errorf("Range get fail, expect offset:%v, got offset:%v", offset, gotOffset)
}
if modTime != f.modTime || etag != f.etag {
return fmt.Errorf("Source file is changed, origin info [%v,%v], new info [%v,%v]",
f.modTime, f.etag, modTime, etag)
}
return nil
}
func (f *ReadOnlyFile) readFromPrefetcher(offset int64, buf []byte) (bytesRead int, err error) {
var nread int
for len(f.asyncReaders) != 0 {
asyncReader := f.asyncReaders[0]
//check offset
if offset != asyncReader.Offset() {
return 0, errors.New("out of order")
}
nread, err = asyncReader.Read(buf)
bytesRead += nread
if err != nil {
if err == io.EOF {
//fmt.Printf("asyncReader done\n")
asyncReader.Close()
f.asyncReaders = f.asyncReaders[1:]
err = nil
} else {
return 0, err
}
}
buf = buf[nread:]
if len(buf) == 0 {
return
}
}
return
}
func (f *ReadOnlyFile) prefetch(offset int64, needAtLeast int) (err error) {
off := offset
for _, ar := range f.asyncReaders {
off = ar.oriHttpRange.Offset + ar.oriHttpRange.Count
}
//fmt.Printf("prefetch:offset %v, needAtLeast:%v, off:%v\n", offset, needAtLeast, off)
for len(f.asyncReaders) < f.prefetchNum {
remaining := f.sizeInBytes - off
size := minInt64(remaining, f.chunkSize)
cnt := (size + (AsyncReadeBufferSize - 1)) / AsyncReadeBufferSize
//fmt.Printf("f.sizeInBytes:%v, off:%v, size:%v, cnt:%v\n", f.sizeInBytes, off, size, cnt)
//NewAsyncRangeReader support softStartInitial, add more buffer count to prevent connections from not being released
if size > softStartInitial {
acnt := (AsyncReadeBufferSize+(softStartInitial-1))/softStartInitial - 1
cnt += int64(acnt)
}
if size != 0 {
getFn := func(ctx context.Context, httpRange HTTPRange) (output *ReaderRangeGetOutput, err error) {
request := &GetObjectRequest{
Bucket: Ptr(f.bucket),
Key: Ptr(f.key),
VersionId: f.versionId,
RequestPayer: f.requestPayer,
}
rangeStr := httpRange.FormatHTTPRange()
if rangeStr != nil {
request.Range = rangeStr
request.RangeBehavior = Ptr("standard")
}
var result *GetObjectResult
result, err = f.client.GetObject(f.context, request)
if err != nil {
return nil, err
}
return &ReaderRangeGetOutput{
Body: result.Body,
ETag: result.ETag,
ContentLength: result.ContentLength,
ContentRange: result.ContentRange,
}, nil
//fmt.Printf("result.Headers:%#v\n", result.Headers)
}
ar, err := NewAsyncRangeReader(f.context, getFn, &HTTPRange{off, size}, f.etag, int(cnt))
if err != nil {
break
}
f.asyncReaders = append(f.asyncReaders, ar)
off += size
}
if size != f.chunkSize {
break
}
}
return nil
}
type AppendOptions struct {
// To indicate that the requester is aware that the request and data download will incur costs
RequestPayer *string
}
type AppendOnlyFile struct {
client AppendFileAPIClient
context context.Context
// object info
bucket string
key string
requestPayer *string
info os.FileInfo
// current write position
offset int64
hashCRC64 *string
closed bool
}
// NewAppendFile AppendFile opens or creates the named file for appending.
// If successful, methods on the returned file can be used for appending.
func NewAppendFile(ctx context.Context, c AppendFileAPIClient, bucket string, key string, optFns ...func(*AppendOptions)) (*AppendOnlyFile, error) {
options := AppendOptions{}
for _, fn := range optFns {
fn(&options)
}
f := &AppendOnlyFile{
client: c,
context: ctx,
bucket: bucket,
key: key,
requestPayer: options.RequestPayer,
}
result, err := f.client.HeadObject(f.context, &HeadObjectRequest{Bucket: &f.bucket, Key: &f.key, RequestPayer: f.requestPayer})
if err != nil {
var serr *ServiceError
if errors.As(err, &serr) && serr.StatusCode == 404 {
// not found
} else {
return nil, err
}
} else {
if !strings.EqualFold(ToString(result.ObjectType), "Appendable") {
return nil, errors.New("Not a appendable file")
}
f.offset = result.ContentLength
f.hashCRC64 = result.HashCRC64
}
return f, nil
}
// Write writes len(b) bytes from b to the AppendOnlyFile.
// It returns the number of bytes written and an error, if any.
// Write returns a non-nil error when n != len(b).
func (f *AppendOnlyFile) Write(b []byte) (n int, err error) {
if err := f.checkValid("write"); err != nil {
return 0, err
}
n, e := f.write(b)
if n < 0 {
n = 0
}
if e == nil && n != len(b) {
err = io.ErrShortWrite
}
if e != nil {
err = f.wrapErr("write", e)
}
return n, err
}
// write writes len(b) bytes to the File.
// It returns the number of bytes written and an error, if any.
func (f *AppendOnlyFile) write(b []byte) (n int, err error) {
offset := f.offset
request := &AppendObjectRequest{
Bucket: &f.bucket,
Key: &f.key,
Position: Ptr(f.offset),
Body: bytes.NewReader(b),
InitHashCRC64: f.hashCRC64,
RequestPayer: f.requestPayer,
}
if f.offset == 0 {
request.InitHashCRC64 = Ptr("0")
}
var result *AppendObjectResult
if result, err = f.client.AppendObject(f.context, request); err == nil {
f.offset = result.NextPosition
f.hashCRC64 = result.HashCRC64
} else {
var serr *ServiceError
if errors.As(err, &serr) && serr.Code == "PositionNotEqualToLength" {
if position, hashcrc, ok := f.nextAppendPosition(); ok {
if offset+int64(len(b)) == position {
f.offset = position
f.hashCRC64 = hashcrc
err = nil
}
}
}
}
return int(f.offset - offset), err
}
// WriteFrom writes io.Reader to the File.
// It returns the number of bytes written and an error, if any.
func (f *AppendOnlyFile) WriteFrom(r io.Reader) (n int64, err error) {
if err := f.checkValid("write"); err != nil {
return 0, err
}
n, err = f.writeFrom(r)
if err != nil {
err = f.wrapErr("write", err)
}
return n, err
}
func (f *AppendOnlyFile) writeFrom(r io.Reader) (n int64, err error) {
offset := f.offset
request := &AppendObjectRequest{
Bucket: &f.bucket,
Key: &f.key,
Position: Ptr(f.offset),
Body: r,
RequestPayer: f.requestPayer,
}
var roffset int64
var rs io.Seeker
rs, ok := r.(io.Seeker)
if ok {
roffset, _ = rs.Seek(0, io.SeekCurrent)
}
var result *AppendObjectResult
if result, err = f.client.AppendObject(f.context, request); err == nil {
f.offset = result.NextPosition
f.hashCRC64 = result.HashCRC64
} else {
var serr *ServiceError
if errors.As(err, &serr) && serr.Code == "PositionNotEqualToLength" {
if position, hashcrc, ok := f.nextAppendPosition(); ok {
if rs != nil {
if curr, e := rs.Seek(0, io.SeekCurrent); e == nil {
if offset+(curr-roffset) == position {
f.offset = position
f.hashCRC64 = hashcrc
err = nil
}
}
}
}
}
}
return f.offset - offset, err
}
func (f *AppendOnlyFile) nextAppendPosition() (int64, *string, bool) {
if h, e := f.client.HeadObject(f.context, &HeadObjectRequest{Bucket: &f.bucket, Key: &f.key, RequestPayer: f.requestPayer}); e == nil {
return h.ContentLength, h.HashCRC64, true
}
return 0, nil, false
}
// wrapErr wraps an error that occurred during an operation on an open file.
// It passes io.EOF through unchanged, otherwise converts
// Wraps the error in a PathError.
func (f *AppendOnlyFile) wrapErr(op string, err error) error {
if err == nil || err == io.EOF {
return err
}
return &os.PathError{Op: op, Path: f.name(), Err: err}
}
func (f *AppendOnlyFile) checkValid(op string) error {
if f == nil {
return os.ErrInvalid
} else if f.closed {
return os.ErrClosed
}
return nil
}
func (f *AppendOnlyFile) name() string {
return fmt.Sprintf("oss://%s/%s", f.bucket, f.key)
}
// Stat returns the FileInfo structure describing file.
func (f *AppendOnlyFile) Stat() (os.FileInfo, error) {
if err := f.checkValid("stat"); err != nil {
return nil, err
}
info, err := f.stat()
if err != nil {
return nil, f.wrapErr("stat", err)
}
return info, nil
}
func (f *AppendOnlyFile) stat() (os.FileInfo, error) {
var err error
if f.info == nil || f.info.Size() != f.offset {
f.info = nil
if result, err := f.client.HeadObject(f.context, &HeadObjectRequest{Bucket: &f.bucket, Key: &f.key, RequestPayer: f.requestPayer}); err == nil {
f.info = &fileInfo{
name: f.name(),
size: result.ContentLength,
modTime: ToTime(result.LastModified),
header: result.Headers,
}
}
}
return f.info, err
}
// Close closes the File.
func (f *AppendOnlyFile) Close() error {
if f == nil {
return os.ErrInvalid
}
return f.close()
}
func (f *AppendOnlyFile) close() error {
f.closed = true
return nil
}