ipfs: meta from core API instead of node directly

Specifically this fixes handling of CIDv1/raw nodes when fetching
their size.

internal/filesystem/ipfs/core.go

@@ -3,7 +3,6 @@ package ipfs
 import (
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"io/fs"
@@ -15,9 +14,6 @@ import (
 	files "github.com/ipfs/go-ipfs-files"
 	cbor "github.com/ipfs/go-ipld-cbor"
 	ipld "github.com/ipfs/go-ipld-format" // TODO: migrate to new standard
-	dag "github.com/ipfs/go-merkledag"
-	"github.com/ipfs/go-unixfs"
-	unixpb "github.com/ipfs/go-unixfs/pb"
 	coreiface "github.com/ipfs/interface-go-ipfs-core"
 	corepath "github.com/ipfs/interface-go-ipfs-core/path"
 )
@@ -410,15 +406,6 @@ func openIPFSFile(name string, core coreiface.CoreAPI, ipldNode ipld.Node,
 
 func openUFSNode(name string, core coreiface.CoreAPI, ipldNode ipld.Node,
 ) (fs.File, error) {
-	typedNode, ok := ipldNode.(*dag.ProtoNode)
-	if !ok {
-		return nil, errors.New("TODO")
-	}
-	ufsNode, err := unixfs.ExtractFSNode(typedNode)
-	if err != nil {
-		return nil, err
-	}
-
 	var (
 		ufsPath     = corepath.IpfsPath(ipldNode.Cid())
 		ctx, cancel = context.WithCancel(context.Background())
@@ -428,7 +415,6 @@ func openUFSNode(name string, core coreiface.CoreAPI, ipldNode ipld.Node,
 		cancel()
 		return nil, err
 	}
-
 	fileNode, ok := apiNode.(files.File)
 	if !ok {
 		cancel()
@@ -443,29 +429,20 @@ func openUFSNode(name string, core coreiface.CoreAPI, ipldNode ipld.Node,
 			),
 		)
 	}
+	size, err := fileNode.Size()
+	if err != nil {
+		cancel()
+		return nil, fserrors.New(fserrors.IO)
+	}
+
 	// TODO: store/get permissions from root.
 	const permissions = readAll | executeAll
 	// TODO: store permissions on the type and do this in the method for Mode()
-	mode := func() fs.FileMode {
-		mode := permissions
-		switch ufsNode.Type() {
-		case unixpb.Data_Directory, unixpb.Data_HAMTShard:
-			mode |= fs.ModeDir
-		case unixpb.Data_Symlink:
-			mode |= fs.ModeSymlink
-		case unixpb.Data_File, unixpb.Data_Raw:
-		// NOOP:  mode |= fs.FileMode(0)
-		default:
-			mode |= fs.ModeIrregular
-		}
-		return mode
-	}()
 	return &coreFile{
 		stat: &coreFileInfo{
-			name: name,
-			size: int64(ufsNode.FileSize()),
-			// mode:     unixfsTypeToGoType(ufsNode.Type()) | permissions,
-			mode:     mode,
+			name:     name,
+			size:     size,
+			mode:     permissions,
 			initTime: time.Now(), // TODO: from root
 		},
 		File:   fileNode,