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backend_car_files.go
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backend_car_files.go
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package gateway
import (
"bytes"
"context"
"fmt"
"io"
blocks "github.com/ipfs/go-block-format"
"github.com/ipfs/go-cid"
format "github.com/ipfs/go-ipld-format"
"github.com/ipfs/go-unixfsnode"
ufsData "github.com/ipfs/go-unixfsnode/data"
"github.com/ipfs/go-unixfsnode/hamt"
ufsiter "github.com/ipfs/go-unixfsnode/iter"
dagpb "github.com/ipld/go-codec-dagpb"
"github.com/ipld/go-ipld-prime"
"github.com/ipld/go-ipld-prime/datamodel"
cidlink "github.com/ipld/go-ipld-prime/linking/cid"
"github.com/ipld/go-ipld-prime/node/basicnode"
"github.com/ipld/go-ipld-prime/schema"
"github.com/littlespeechless/boxo/files"
"github.com/littlespeechless/boxo/ipld/unixfs"
"github.com/multiformats/go-multicodec"
)
type awaitCloser interface {
AwaitClose() <-chan error
}
type backpressuredFile struct {
size int64
f io.ReadSeeker
getLsys lsysGetter
ctx context.Context
fileCid cid.Cid
byteRange DagByteRange
retErr error
closed chan error
}
func (b *backpressuredFile) AwaitClose() <-chan error {
return b.closed
}
func (b *backpressuredFile) Close() error {
close(b.closed)
return nil
}
func (b *backpressuredFile) Size() (int64, error) {
return b.size, nil
}
func (b *backpressuredFile) Read(p []byte) (n int, err error) {
if b.retErr == nil {
n, err = b.f.Read(p)
if err == nil || err == io.EOF {
return n, err
}
if n > 0 {
b.retErr = err
return n, nil
}
} else {
err = b.retErr
}
from, seekErr := b.f.Seek(0, io.SeekCurrent)
if seekErr != nil {
// Return the seek error since by this point seeking failures like this should be impossible
return 0, seekErr
}
// we had an error while reading so attempt to reset the underlying reader
for {
if b.ctx.Err() != nil {
return 0, b.ctx.Err()
}
retry, processedErr := isRetryableError(err)
if !retry {
return 0, processedErr
}
var nd files.Node
nd, err = loadTerminalUnixFSElementWithRecursiveDirectories(b.ctx, b.fileCid, nil, nil, CarParams{Scope: DagScopeEntity, Range: &DagByteRange{From: from, To: b.byteRange.To}}, b.getLsys)
if err != nil {
continue
}
f, ok := nd.(files.File)
if !ok {
return 0, fmt.Errorf("not a file, should be unreachable")
}
b.f = f
break
}
// now that we've reset the reader try reading again
return b.Read(p)
}
func (b *backpressuredFile) Seek(offset int64, whence int) (int64, error) {
return b.f.Seek(offset, whence)
}
var _ files.File = (*backpressuredFile)(nil)
var _ awaitCloser = (*backpressuredFile)(nil)
type singleUseDirectory struct {
dirIter files.DirIterator
closed chan error
}
func (b *singleUseDirectory) AwaitClose() <-chan error {
return b.closed
}
func (b *singleUseDirectory) Close() error {
close(b.closed)
return nil
}
func (b *singleUseDirectory) Size() (int64, error) {
//TODO implement me
panic("implement me")
}
func (b *singleUseDirectory) Entries() files.DirIterator {
return b.dirIter
}
var _ files.Directory = (*singleUseDirectory)(nil)
var _ awaitCloser = (*singleUseDirectory)(nil)
type backpressuredFlatDirIter struct {
linksItr *dagpb.PBLinks__Itr
lsys *ipld.LinkSystem
getLsys lsysGetter
ctx context.Context
curName string
curFile files.Node
err error
}
func (it *backpressuredFlatDirIter) Name() string {
return it.curName
}
func (it *backpressuredFlatDirIter) Node() files.Node {
return it.curFile
}
func (it *backpressuredFlatDirIter) Next() bool {
if it.err != nil {
return false
}
iter := it.linksItr
if iter.Done() {
return false
}
_, v := iter.Next()
c := v.Hash.Link().(cidlink.Link).Cid
var name string
if v.Name.Exists() {
name = v.Name.Must().String()
}
var nd files.Node
var err error
params := CarParams{Scope: DagScopeAll}
for {
if it.ctx.Err() != nil {
it.err = it.ctx.Err()
return false
}
if err != nil {
it.lsys, err = it.getLsys(it.ctx, c, params)
continue
}
nd, err = loadTerminalUnixFSElementWithRecursiveDirectories(it.ctx, c, nil, it.lsys, params, it.getLsys)
if err != nil {
if ctxErr := it.ctx.Err(); ctxErr != nil {
continue
}
retry, processedErr := isRetryableError(err)
if retry {
err = processedErr
continue
}
it.err = processedErr
return false
}
break
}
it.curName = name
it.curFile = nd
return true
}
func (it *backpressuredFlatDirIter) Err() error {
return it.err
}
var _ files.DirIterator = (*backpressuredFlatDirIter)(nil)
type backpressuredHAMTDirIter struct {
linksItr ipld.MapIterator
dirCid cid.Cid
lsys *ipld.LinkSystem
getLsys lsysGetter
ctx context.Context
curName string
curFile files.Node
curProcessed int
err error
}
func (it *backpressuredHAMTDirIter) Name() string {
return it.curName
}
func (it *backpressuredHAMTDirIter) Node() files.Node {
return it.curFile
}
func (it *backpressuredHAMTDirIter) Next() bool {
if it.err != nil {
return false
}
iter := it.linksItr
if iter.Done() {
return false
}
/*
Since there is no way to make a graph request for part of a HAMT during errors we can either fill in the HAMT with
block requests, or we can re-request the HAMT and skip over the parts we already have.
Here we choose the latter, however in the event of a re-request we request the entity rather than the entire DAG as
a compromise between more requests and over-fetching data.
*/
var err error
for {
if it.ctx.Err() != nil {
it.err = it.ctx.Err()
return false
}
retry, processedErr := isRetryableError(err)
if !retry {
it.err = processedErr
return false
}
var nd ipld.Node
if err != nil {
var lsys *ipld.LinkSystem
lsys, err = it.getLsys(it.ctx, it.dirCid, CarParams{Scope: DagScopeEntity})
if err != nil {
continue
}
_, pbn, ufsFieldData, _, ufsBaseErr := loadUnixFSBase(it.ctx, it.dirCid, nil, lsys)
if ufsBaseErr != nil {
err = ufsBaseErr
continue
}
nd, err = hamt.NewUnixFSHAMTShard(it.ctx, pbn, ufsFieldData, lsys)
if err != nil {
err = fmt.Errorf("could not reify sharded directory: %w", err)
continue
}
iter = nd.MapIterator()
for i := 0; i < it.curProcessed; i++ {
_, _, err = iter.Next()
if err != nil {
continue
}
}
it.linksItr = iter
}
var k, v ipld.Node
k, v, err = iter.Next()
if err != nil {
retry, processedErr = isRetryableError(err)
if retry {
err = processedErr
continue
}
it.err = processedErr
return false
}
var name string
name, err = k.AsString()
if err != nil {
it.err = err
return false
}
var lnk ipld.Link
lnk, err = v.AsLink()
if err != nil {
it.err = err
return false
}
cl, ok := lnk.(cidlink.Link)
if !ok {
it.err = fmt.Errorf("link not a cidlink")
return false
}
c := cl.Cid
params := CarParams{Scope: DagScopeAll}
var childNd files.Node
for {
if it.ctx.Err() != nil {
it.err = it.ctx.Err()
return false
}
if err != nil {
retry, processedErr = isRetryableError(err)
if !retry {
it.err = processedErr
return false
}
it.lsys, err = it.getLsys(it.ctx, c, params)
continue
}
childNd, err = loadTerminalUnixFSElementWithRecursiveDirectories(it.ctx, c, nil, it.lsys, params, it.getLsys)
if err != nil {
continue
}
break
}
it.curName = name
it.curFile = childNd
it.curProcessed++
break
}
return true
}
func (it *backpressuredHAMTDirIter) Err() error {
return it.err
}
var _ files.DirIterator = (*backpressuredHAMTDirIter)(nil)
type backpressuredHAMTDirIterNoRecursion struct {
dagSize uint64
linksItr ipld.MapIterator
dirCid cid.Cid
lsys *ipld.LinkSystem
getLsys lsysGetter
ctx context.Context
curLnk unixfs.LinkResult
curProcessed int
closed chan error
hasClosed bool
err error
}
func (it *backpressuredHAMTDirIterNoRecursion) AwaitClose() <-chan error {
return it.closed
}
func (it *backpressuredHAMTDirIterNoRecursion) Link() unixfs.LinkResult {
return it.curLnk
}
func (it *backpressuredHAMTDirIterNoRecursion) Next() bool {
defer func() {
if it.linksItr.Done() || it.err != nil {
if !it.hasClosed {
it.hasClosed = true
close(it.closed)
}
}
}()
if it.err != nil {
return false
}
iter := it.linksItr
if iter.Done() {
return false
}
/*
Since there is no way to make a graph request for part of a HAMT during errors we can either fill in the HAMT with
block requests, or we can re-request the HAMT and skip over the parts we already have.
Here we choose the latter, however in the event of a re-request we request the entity rather than the entire DAG as
a compromise between more requests and over-fetching data.
*/
var err error
for {
if it.ctx.Err() != nil {
it.err = it.ctx.Err()
return false
}
retry, processedErr := isRetryableError(err)
if !retry {
it.err = processedErr
return false
}
var nd ipld.Node
if err != nil {
var lsys *ipld.LinkSystem
lsys, err = it.getLsys(it.ctx, it.dirCid, CarParams{Scope: DagScopeEntity})
if err != nil {
continue
}
_, pbn, ufsFieldData, _, ufsBaseErr := loadUnixFSBase(it.ctx, it.dirCid, nil, lsys)
if ufsBaseErr != nil {
err = ufsBaseErr
continue
}
nd, err = hamt.NewUnixFSHAMTShard(it.ctx, pbn, ufsFieldData, lsys)
if err != nil {
err = fmt.Errorf("could not reify sharded directory: %w", err)
continue
}
iter = nd.MapIterator()
for i := 0; i < it.curProcessed; i++ {
_, _, err = iter.Next()
if err != nil {
continue
}
}
it.linksItr = iter
}
var k, v ipld.Node
k, v, err = iter.Next()
if err != nil {
retry, processedErr = isRetryableError(err)
if retry {
err = processedErr
continue
}
it.err = processedErr
return false
}
var name string
name, err = k.AsString()
if err != nil {
it.err = err
return false
}
var lnk ipld.Link
lnk, err = v.AsLink()
if err != nil {
it.err = err
return false
}
cl, ok := lnk.(cidlink.Link)
if !ok {
it.err = fmt.Errorf("link not a cidlink")
return false
}
c := cl.Cid
pbLnk, ok := v.(*ufsiter.IterLink)
if !ok {
it.err = fmt.Errorf("HAMT value is not a dag-pb link")
return false
}
cumulativeDagSize := uint64(0)
if pbLnk.Substrate.Tsize.Exists() {
cumulativeDagSize = uint64(pbLnk.Substrate.Tsize.Must().Int())
}
it.curLnk = unixfs.LinkResult{
Link: &format.Link{
Name: name,
Size: cumulativeDagSize,
Cid: c,
},
}
it.curProcessed++
break
}
return true
}
func (it *backpressuredHAMTDirIterNoRecursion) Err() error {
return it.err
}
var _ awaitCloser = (*backpressuredHAMTDirIterNoRecursion)(nil)
/*
1. Run traversal to get the top-level response
2. Response can do a callback for another response
*/
type lsysGetter = func(ctx context.Context, c cid.Cid, params CarParams) (*ipld.LinkSystem, error)
func loadUnixFSBase(ctx context.Context, c cid.Cid, blk blocks.Block, lsys *ipld.LinkSystem) ([]byte, dagpb.PBNode, ufsData.UnixFSData, int64, error) {
lctx := ipld.LinkContext{Ctx: ctx}
pathTerminalCidLink := cidlink.Link{Cid: c}
var blockData []byte
var err error
if blk != nil {
blockData = blk.RawData()
} else {
blockData, err = lsys.LoadRaw(lctx, pathTerminalCidLink)
if err != nil {
return nil, nil, nil, 0, err
}
}
if c.Type() == uint64(multicodec.Raw) {
return blockData, nil, nil, 0, nil
}
// decode the terminal block into a node
pc := dagpb.AddSupportToChooser(func(lnk ipld.Link, lnkCtx ipld.LinkContext) (ipld.NodePrototype, error) {
if tlnkNd, ok := lnkCtx.LinkNode.(schema.TypedLinkNode); ok {
return tlnkNd.LinkTargetNodePrototype(), nil
}
return basicnode.Prototype.Any, nil
})
np, err := pc(pathTerminalCidLink, lctx)
if err != nil {
return nil, nil, nil, 0, err
}
decoder, err := lsys.DecoderChooser(pathTerminalCidLink)
if err != nil {
return nil, nil, nil, 0, err
}
nb := np.NewBuilder()
if err := decoder(nb, bytes.NewReader(blockData)); err != nil {
return nil, nil, nil, 0, err
}
lastCidNode := nb.Build()
if pbn, ok := lastCidNode.(dagpb.PBNode); !ok {
// If it's not valid dag-pb then we're done
return nil, nil, nil, 0, errNotUnixFS
} else if !pbn.FieldData().Exists() {
// If it's not valid UnixFS then we're done
return nil, nil, nil, 0, errNotUnixFS
} else if unixfsFieldData, decodeErr := ufsData.DecodeUnixFSData(pbn.Data.Must().Bytes()); decodeErr != nil {
return nil, nil, nil, 0, errNotUnixFS
} else {
switch fieldNum := unixfsFieldData.FieldDataType().Int(); fieldNum {
case ufsData.Data_Symlink, ufsData.Data_Metadata, ufsData.Data_Raw, ufsData.Data_File, ufsData.Data_Directory, ufsData.Data_HAMTShard:
return nil, pbn, unixfsFieldData, fieldNum, nil
default:
return nil, nil, nil, 0, errNotUnixFS
}
}
}
func loadTerminalUnixFSElementWithRecursiveDirectories(ctx context.Context, c cid.Cid, blk blocks.Block, lsys *ipld.LinkSystem, params CarParams, getLsys lsysGetter) (files.Node, error) {
var err error
if lsys == nil {
lsys, err = getLsys(ctx, c, params)
if err != nil {
return nil, err
}
}
lctx := ipld.LinkContext{Ctx: ctx}
blockData, pbn, ufsFieldData, fieldNum, err := loadUnixFSBase(ctx, c, blk, lsys)
if err != nil {
return nil, err
}
if c.Type() == uint64(multicodec.Raw) {
return files.NewBytesFile(blockData), nil
}
switch fieldNum {
case ufsData.Data_Symlink:
if !ufsFieldData.FieldData().Exists() {
return nil, fmt.Errorf("invalid UnixFS symlink object")
}
lnkTarget := string(ufsFieldData.FieldData().Must().Bytes())
f := files.NewLinkFile(lnkTarget, nil)
return f, nil
case ufsData.Data_Metadata:
return nil, fmt.Errorf("UnixFS Metadata unsupported")
case ufsData.Data_HAMTShard, ufsData.Data_Directory:
switch fieldNum {
case ufsData.Data_Directory:
d := &singleUseDirectory{&backpressuredFlatDirIter{
ctx: ctx,
linksItr: pbn.Links.Iterator(),
lsys: lsys,
getLsys: getLsys,
}, make(chan error)}
return d, nil
case ufsData.Data_HAMTShard:
dirNd, err := unixfsnode.Reify(lctx, pbn, lsys)
if err != nil {
return nil, fmt.Errorf("could not reify sharded directory: %w", err)
}
d := &singleUseDirectory{
&backpressuredHAMTDirIter{
linksItr: dirNd.MapIterator(),
dirCid: c,
lsys: lsys,
getLsys: getLsys,
ctx: ctx,
}, make(chan error),
}
return d, nil
default:
return nil, fmt.Errorf("not a basic or HAMT directory: should be unreachable")
}
case ufsData.Data_Raw, ufsData.Data_File:
nd, err := unixfsnode.Reify(lctx, pbn, lsys)
if err != nil {
return nil, err
}
fnd, ok := nd.(datamodel.LargeBytesNode)
if !ok {
return nil, fmt.Errorf("could not process file since it did not present as large bytes")
}
f, err := fnd.AsLargeBytes()
if err != nil {
return nil, err
}
fileSize, err := f.Seek(0, io.SeekEnd)
if err != nil {
return nil, fmt.Errorf("unable to get UnixFS file size: %w", err)
}
from := int64(0)
var byteRange DagByteRange
if params.Range != nil {
byteRange = *params.Range
from = params.Range.From
}
_, err = f.Seek(from, io.SeekStart)
if err != nil {
return nil, fmt.Errorf("unable to get reset UnixFS file reader: %w", err)
}
return &backpressuredFile{ctx: ctx, fileCid: c, byteRange: byteRange, size: fileSize, f: f, getLsys: getLsys, closed: make(chan error)}, nil
default:
return nil, fmt.Errorf("unknown UnixFS field type")
}
}