Merge branch 'feat/no-temp-files' of ../pieceio

Author: hannahhoward

pieceio/README.md

@@ -0,0 +1,54 @@
+# pieceio
+
+The pieceio module is a collection of structs for generating piece commitments (a.k.a. CommP) and 
+storing pieces for storage market deals. It is used by the 
+[`storagemarket`](../storagemarket) module.
+
+## Installation
+```bash
+go get github.com/filecoin-project/go-fil-markets/pieceio
+```
+
+## PieceIO
+`PieceIO` is used by [`storagemarket`](../storagemarket) client for proposing deals. 
+
+**To initialize a PieceIO:**
+```go
+package pieceio
+
+func NewPieceIO(carIO CarIO, bs blockstore.Blockstore) PieceIO
+```
+**Parameters**
+* `carIO` is a [CarIO](#CarIO) from this module
+* `bs` is an IPFS blockstore for storing and retrieving data for deals. See
+ [github.com/ipfs/go-ipfs-blockstore](github.com/ipfs/go-ipfs-blockstore).
+
+## PieceIOWithStore
+`PieceIOWithStore` is `PieceIO` with a [`filestore`](../filestore). It is used by 
+[`storagemarket`](../storagemarket) provider to store pieces, and to generate and store piece commitments
+ and piece metadata for deals. 
+ 
+**To initialize a PieceIOWithStore:**
+
+```go
+package pieceio
+
+func NewPieceIOWithStore(carIO CarIO, store filestore.FileStore, bs blockstore.Blockstore) PieceIOWithStore
+```
+**Parameters**
+* `carIO` is a [CarIO](#CarIO) from this module
+* `store` is a [FileStore](../filestore) from this go-fil-markets repo.
+* `bs` is an IPFS blockstore for storing and retrieving data for deals. See
+ [github.com/ipfs/go-ipfs-blockstore](github.com/ipfs/go-ipfs-blockstore).
+
+## CarIO
+CarIO is a utility module that wraps [github.com/ipld/go-car](https://github.com/ipld/go-car) for use by storagemarket.
+
+**To initialize a CarIO:**
+```go
+package cario
+
+func NewCarIO() pieceio.CarIO
+```
+
+Please the [tests](pieceio_test.go) for more information about expected behavior.

pieceio/cario/cario.go

@@ -0,0 +1,46 @@
+package cario
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"github.com/ipfs/go-cid"
+	"github.com/ipld/go-car"
+	"github.com/ipld/go-ipld-prime"
+
+	"github.com/filecoin-project/go-fil-markets/pieceio"
+)
+
+type carIO struct {
+}
+
+// NewCarIO returns a new CarIO utility module that wraps go-car
+func NewCarIO() pieceio.CarIO {
+	return &carIO{}
+}
+
+func (c carIO) WriteCar(ctx context.Context, bs pieceio.ReadStore, payloadCid cid.Cid, selector ipld.Node, w io.Writer, userOnNewCarBlocks ...car.OnNewCarBlockFunc) error {
+	sc := car.NewSelectiveCar(ctx, bs, []car.Dag{{Root: payloadCid, Selector: selector}})
+	return sc.Write(w, userOnNewCarBlocks...)
+}
+
+func (c carIO) PrepareCar(ctx context.Context, bs pieceio.ReadStore, payloadCid cid.Cid, selector ipld.Node, userOnNewCarBlocks ...car.OnNewCarBlockFunc) (pieceio.PreparedCar, error) {
+	sc := car.NewSelectiveCar(ctx, bs, []car.Dag{{Root: payloadCid, Selector: selector}})
+	return sc.Prepare(userOnNewCarBlocks...)
+}
+
+func (c carIO) LoadCar(bs pieceio.WriteStore, r io.Reader) (cid.Cid, error) {
+	header, err := car.LoadCar(bs, r)
+	if err != nil {
+		return cid.Undef, err
+	}
+	l := len(header.Roots)
+	if l == 0 {
+		return cid.Undef, fmt.Errorf("invalid header: missing root")
+	}
+	if l > 1 {
+		return cid.Undef, fmt.Errorf("invalid header: contains %d roots (expecting 1)", l)
+	}
+	return header.Roots[0], nil
+}