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
}