container: split into reader+writer

pkg/container/writer.go

@@ -0,0 +1,107 @@
+package container
+
+import (
+	"compress/flate"
+	"compress/gzip"
+	"encoding/base64"
+	"io"
+
+	"github.com/ipfs/go-cid"
+	cbor "github.com/ipfs/go-ipld-cbor"
+	"github.com/ipld/go-ipld-prime"
+	"github.com/ipld/go-ipld-prime/codec/dagcbor"
+	"github.com/ipld/go-ipld-prime/datamodel"
+	"github.com/ipld/go-ipld-prime/fluent/qp"
+	"github.com/ipld/go-ipld-prime/node/basicnode"
+)
+
+type Writer map[cid.Cid][]byte
+
+func NewWriter() Writer {
+	return make(Writer)
+}
+
+func (ctn Writer) AddSealed(cid cid.Cid, data []byte) {
+	ctn[cid] = data
+}
+
+func (ctn Writer) ToCar(w io.Writer) error {
+	return writeCar(w, nil, func(yield func(carBlock) bool) {
+		for c, bytes := range ctn {
+			if !yield(carBlock{c: c, data: bytes}) {
+				return
+			}
+		}
+	})
+}
+
+func (ctn Writer) ToCarBase64(w io.Writer) error {
+	w2 := base64.NewEncoder(base64.StdEncoding, w)
+	defer w2.Close()
+	return ctn.ToCar(w2)
+}
+
+func (ctn Writer) ToCarGzip(w io.Writer) error {
+	w2 := gzip.NewWriter(w)
+	defer w2.Close()
+	return ctn.ToCar(w2)
+}
+
+func (ctn Writer) ToCarGzipBase64(w io.Writer) error {
+	w2 := base64.NewEncoder(base64.StdEncoding, w)
+	defer w2.Close()
+	return ctn.ToCarGzip(w2)
+}
+
+func (ctn Writer) ToCbor2(w io.Writer) error {
+	node, err := qp.BuildList(basicnode.Prototype.Any, int64(len(ctn)), func(la datamodel.ListAssembler) {
+		for _, bytes := range ctn {
+			qp.ListEntry(la, qp.Bytes(bytes))
+		}
+	})
+	if err != nil {
+		return err
+	}
+	return ipld.EncodeStreaming(w, node, dagcbor.Encode)
+}
+
+func (ctn Writer) ToCbor(w io.Writer) error {
+	raw := make([][]byte, 0, len(ctn))
+	for _, bytes := range ctn {
+		raw = append(raw, bytes)
+	}
+	return cbor.EncodeWriter(raw, w)
+}
+
+func (ctn Writer) ToCborBase64(w io.Writer) error {
+	w2 := base64.NewEncoder(base64.StdEncoding, w)
+	defer w2.Close()
+	return ctn.ToCbor(w2)
+}
+
+func (ctn Writer) ToCborGzip(w io.Writer) error {
+	w2 := gzip.NewWriter(w)
+	defer w2.Close()
+	return ctn.ToCbor(w2)
+}
+
+func (ctn Writer) ToCborGzipBase64(w io.Writer) error {
+	w2 := base64.NewEncoder(base64.StdEncoding, w)
+	defer w2.Close()
+	return ctn.ToCborGzip(w2)
+}
+
+func (ctn Writer) ToCborFlate(w io.Writer) error {
+	w2, err := flate.NewWriter(w, flate.DefaultCompression)
+	if err != nil {
+		return err
+	}
+	defer w2.Close()
+	return ctn.ToCbor(w2)
+}
+
+func (ctn Writer) ToCborFlateBase64(w io.Writer) error {
+	w2 := base64.NewEncoder(base64.StdEncoding, w)
+	defer w2.Close()
+	return ctn.ToCborFlate(w2)
+}