.

wcfs/wcfs.go

@@ -446,6 +446,8 @@ func (bfroot *BigFileRoot) Mkdir(name string, mode uint32, fctx *fuse.Context) (
 
 // /bigfile/<bigfileX>/head/data -> Getattr serves stat.
 func (bfdata *BigFileData) GetAttr(out *fuse.Attr, _ nodefs.File, fctx *fuse.Context) fuse.Status {
+	// XXX locking
+
 	out.Mode = fuse.S_IFREG | 0444
 	out.Size = 0	// FIXME
 	// .Blocks
@@ -461,20 +463,18 @@ func (bfdata *BigFileData) GetAttr(out *fuse.Attr, _ nodefs.File, fctx *fuse.Con
 }
 
 
-// Read implements reading from /bigfile/<bigfileX>/head/data.
-// XXX and from /bigfile/<bigfileX>/@<tidX>/data.
-/*
-func (bf *BigFileData) Read(_ nodefs.File, dest []byte, off int64, _ fuse.Context) (fuse.ReadResult, fuse.Status) {
-	.at
-	.topoid
-	// XXX
+// /bigfile/<bigfileX>/head/data -> Read serves read.
+func (bf *BigFileData) Read(_ nodefs.File, dest []byte, off int64, _ *fuse.Context) (fuse.ReadResult, fuse.Status) {
+	// XXX locking
+
+	panic("TODO")
+	//bf.zbf.blksize
 }
-*/
 
-// /bigfile/<bigfileX>/head/at -> served by readAt.
+
+// /bigfile/<bigfileX>/head/at -> readAt serves read.
 func (bf *BigFile) readAt() []byte {
 	// XXX locking
-
 	// XXX zconn -> zbf.PJar() ?
 	return []byte(bf.zconn.At().String())
 }

wcfs/wcfs_test.py

@@ -156,7 +156,7 @@ def test_bigfile_empty():
 
     # head/at = last txn of whole db
     assert readfile(fpath + "/head/at") == tid2.encode('hex')
-
+    # TODO check head/at syncs to later non-bigfile commits
 
     wc.close()
 

wcfs/zblk.go

@@ -20,6 +20,7 @@
 package main
 // ZBlk* + ZBigFile loading
 
+
 // module: "wendelin.bigfile.file_zodb"
 //
 // ZBigFile
@@ -35,8 +36,6 @@ package main
 // ZData
 //	str (chunk)
 
-
-
 import (
 	"context"
 	"fmt"
@@ -47,6 +46,7 @@ import (
 	"golang.org/x/sync/errgroup"
 
 	"lab.nexedi.com/kirr/go123/mem"
+	"lab.nexedi.com/kirr/go123/xerr"
 	"lab.nexedi.com/kirr/neo/go/zodb"
 	"lab.nexedi.com/kirr/neo/go/zodb/btree"
 	pickle "github.com/kisielk/og-rek"
@@ -54,6 +54,15 @@ import (
 	"./internal/pycompat"
 )
 
+// zBlkLoader is the interface that every ZBlk* block implements internally for
+// loading its data.
+type zBlkLoader interface {
+	// loadBlkData loads from database and returns data block stored by this ZBlk.
+	//
+	// XXX trailing \0 can be stripped.
+	loadBlkData(ctx context.Context) ([]byte, error)
+}
+
 // module of Wendelin ZODB py objects
 const zwendelin = "wendelin.bigfile.file_zodb"
 
@@ -63,6 +72,7 @@ const zwendelin = "wendelin.bigfile.file_zodb"
 type ZBlk0 struct {
 	zodb.Persistent
 
+	// XXX py source uses bytes(buf) but on python2 it still results in str
 	blkdata string
 }
 
@@ -82,7 +92,7 @@ func (zb *zBlk0State) PySetState(pystate interface{}) error {
 	return nil
 }
 
-func (zb *ZBlk0) LoadBlkData(ctx context.Context) ([]byte, error) {
+func (zb *ZBlk0) loadBlkData(ctx context.Context) ([]byte, error) {
 	// XXX err ctx
 
 	err := zb.PActivate(ctx)
@@ -100,6 +110,7 @@ func (zb *ZBlk0) LoadBlkData(ctx context.Context) ([]byte, error) {
 type ZData struct {
 	zodb.Persistent
 
+	// XXX py source uses bytes(buf) but on python2 it still results in str
 	data string
 }
 
@@ -142,7 +153,7 @@ func (zb *zBlk1State) PySetState(pystate interface{}) error {
 	return nil
 }
 
-func (zb *ZBlk1) LoadBlkData(ctx context.Context) ([]byte, error) {
+func (zb *ZBlk1) loadBlkData(ctx context.Context) ([]byte, error) {
 	// XXX errctx
 
 	err := zb.PActivate(ctx)
@@ -178,7 +189,6 @@ func (zb *ZBlk1) LoadBlkData(ctx context.Context) ([]byte, error) {
 		// no PDeactivate, zd remains live
 
 		//fmt.Printf("@%d -> zdata #%s (%d)\n", offset, zd.POid(), len(zd.data))
-
 		mu.Lock()
 		defer mu.Unlock()
 
@@ -200,6 +210,7 @@ func (zb *ZBlk1) LoadBlkData(ctx context.Context) ([]byte, error) {
 		// XXX off + len > blksize	!ok
 
 		//fmt.Printf("\nbucket: %v\n\n", b.Entryv())
+
 		for _, e := range b.Entryv() {
 			zd, ok := e.Value().(*ZData)
 			if !ok {
@@ -215,7 +226,6 @@ func (zb *ZBlk1) LoadBlkData(ctx context.Context) ([]byte, error) {
 		return nil
 	}
 
-
 	// loadBTree spawns loading of all BTree children.
 	var loadBTree func(t *btree.IOBTree) error
 	loadBTree = func(t *btree.IOBTree) error {
@@ -351,6 +361,44 @@ func (bf *zBigFileState) PySetState(pystate interface{}) (err error) {
 	return nil
 }
 
+// LoadBlk loads data for file block #blk.
+//
+// XXX better load into user-provided buf?
+func (bf *ZBigFile) LoadBlk(ctx context.Context, blk int64) (_ []byte, err error) {
+	defer xerr.Contextf(&err, "bigfile %s: loadblk %d", bf.POid(), blk)
+
+	err = bf.PActivate(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer bf.PDeactivate()
+
+	xzblk, ok, err := bf.blktab.Get(ctx, blk)
+	if err != nil {
+		return nil, err
+	}
+	if !ok {
+		return make([]byte, bf.blksize), nil
+	}
+
+	zblk, ok := xzblk.(zBlkLoader)
+	if !ok {
+		return nil, fmt.Errorf("expect ZBlk*; got %s", typeOf(xzblk))
+	}
+
+	blkdata, err := zblk.loadBlkData(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	if l := int64(len(blkdata)); l > bf.blksize {
+		return nil, fmt.Errorf("invalid blk: size = %d (> blksize = %d)", l, bf.blksize)
+	}
+
+	// XXX append trailing \0 to reach .blksize ?
+	return blkdata, nil
+}
+
 
 // ----------------------------------------
 

wcfs/zblk_test.go

@@ -86,10 +86,10 @@ func TestZBlk(t *testing.T) {
 		binary.BigEndian.PutUint32(data[i*4:], i)
 	}
 
-	z0Data, err := z0.LoadBlkData(ctx);	X(err)
+	z0Data, err := z0.loadBlkData(ctx);	X(err)
 	assert.Equal(z0Data, data, "ZBlk0 data wrong")
 
-	z1Data, err := z1.LoadBlkData(ctx);	X(err)
+	z1Data, err := z1.loadBlkData(ctx);	X(err)
 	if false {
 		fmt.Printf("%#v\n", z1Data)
 	}
@@ -113,4 +113,6 @@ func TestZBlk(t *testing.T) {
 	}
 
 	// XXX check zf.blktab.MaxKey ?
+
+	// XXX check zf.LoadBlk()
 }