func TestDagModifierBasic(t *testing.T) { dserv := getMockDagServ(t) b, n := getNode(t, dserv, 50000) ctx, cancel := context.WithCancel(context.Background()) defer cancel() dagmod, err := NewDagModifier(ctx, n, dserv, sizeSplitterGen(512)) if err != nil { t.Fatal(err) } // Within zero block beg := uint64(15) length := uint64(60) t.Log("Testing mod within zero block") b = testModWrite(t, beg, length, b, dagmod) // Within bounds of existing file beg = 1000 length = 4000 t.Log("Testing mod within bounds of existing multiblock file.") b = testModWrite(t, beg, length, b, dagmod) // Extend bounds beg = 49500 length = 4000 t.Log("Testing mod that extends file.") b = testModWrite(t, beg, length, b, dagmod) // "Append" beg = uint64(len(b)) length = 3000 t.Log("Testing pure append") b = testModWrite(t, beg, length, b, dagmod) // Verify reported length node, err := dagmod.GetNode() if err != nil { t.Fatal(err) } size, err := ft.DataSize(node.Data()) if err != nil { t.Fatal(err) } expected := uint64(50000 + 3500 + 3000) if size != expected { t.Fatalf("Final reported size is incorrect [%d != %d]", size, expected) } }
// dagTruncate truncates the given node to 'size' and returns the modified Node func dagTruncate(ctx context.Context, nd *mdag.Node, size uint64, ds mdag.DAGService) (*mdag.Node, error) { if len(nd.Links) == 0 { // TODO: this can likely be done without marshaling and remarshaling pbn, err := ft.FromBytes(nd.Data) if err != nil { return nil, err } nd.Data = ft.WrapData(pbn.Data[:size]) return nd, nil } var cur uint64 end := 0 var modified *mdag.Node ndata := new(ft.FSNode) for i, lnk := range nd.Links { child, err := lnk.GetNode(ctx, ds) if err != nil { return nil, err } childsize, err := ft.DataSize(child.Data) if err != nil { return nil, err } // found the child we want to cut if size < cur+childsize { nchild, err := dagTruncate(ctx, child, size-cur, ds) if err != nil { return nil, err } ndata.AddBlockSize(size - cur) modified = nchild end = i break } cur += childsize ndata.AddBlockSize(childsize) } _, err := ds.Add(modified) if err != nil { return nil, err } nd.Links = nd.Links[:end] err = nd.AddNodeLinkClean("", modified) if err != nil { return nil, err } d, err := ndata.GetBytes() if err != nil { return nil, err } nd.Data = d // invalidate cache and recompute serialized data _, err = nd.Encoded(true) if err != nil { return nil, err } return nd, nil }