nimbus-eth2/ncli/e2store.nim
Jacek Sieka a7a65bce42
disentangle eth2 types from the ssz library (#2785)
* reorganize ssz dependencies

This PR continues the work in
https://github.com/status-im/nimbus-eth2/pull/2646,
https://github.com/status-im/nimbus-eth2/pull/2779 as well as past
issues with serialization and type, to disentangle SSZ from eth2 and at
the same time simplify imports and exports with a structured approach.

The principal idea here is that when a library wants to introduce SSZ
support, they do so via 3 files:

* `ssz_codecs` which imports and reexports `codecs` - this covers the
basic byte conversions and ensures no overloads get lost
* `xxx_merkleization` imports and exports `merkleization` to specialize
and get access to `hash_tree_root` and friends
* `xxx_ssz_serialization` imports and exports `ssz_serialization` to
specialize ssz for a specific library

Those that need to interact with SSZ always import the `xxx_` versions
of the modules and never `ssz` itself so as to keep imports simple and
safe.

This is similar to how the REST / JSON-RPC serializers are structured in
that someone wanting to serialize spec types to REST-JSON will import
`eth2_rest_serialization` and nothing else.

* split up ssz into a core library that is independendent of eth2 types
* rename `bytes_reader` to `codec` to highlight that it contains coding
and decoding of bytes and native ssz types
* remove tricky List init overload that causes compile issues
* get rid of top-level ssz import
* reenable merkleization tests
* move some "standard" json serializers to spec
* remove `ValidatorIndex` serialization for now
* remove test_ssz_merkleization
* add tests for over/underlong byte sequences
* fix broken seq[byte] test - seq[byte] is not an SSZ type

There are a few things this PR doesn't solve:

* like #2646 this PR is weak on how to handle root and other
dontSerialize fields that "sometimes" should be computed - the same
problem appears in REST / JSON-RPC etc

* Fix a build problem on macOS

* Another way to fix the macOS builds

Co-authored-by: Zahary Karadjov <zahary@gmail.com>
2021-08-18 20:57:58 +02:00

97 lines
2.7 KiB
Nim

{.push raises: [Defect].}
import
stew/[endians2, results],
snappy, snappy/framing,
../beacon_chain/spec/datatypes/phase0,
../beacon_chain/spec/eth2_ssz_serialization
const
E2Version = [byte 0x65, 0x32]
E2Index = [byte 0x69, 0x32]
SnappyBeaconBlock = [byte 0x01, 0x00]
SnappyBeaconState = [byte 0x02, 0x00]
type
E2Store* = object
data: File
index: File
slot: Slot
Header* = object
typ*: array[2, byte]
len*: uint64
proc append(f: File, data: openArray[byte]): Result[void, string] =
try:
if writeBytes(f, data, 0, data.len()) != data.len:
err("Cannot write to file")
else:
ok()
except CatchableError as exc:
err(exc.msg)
proc readHeader(f: File): Result[Header, string] =
try:
var buf: array[8, byte]
if system.readBuffer(f, addr buf[0], 8) != 8:
return err("Not enough bytes for header")
except CatchableError as e:
return err("Cannot read header")
proc appendRecord(f: File, typ: array[2, byte], data: openArray[byte]): Result[int64, string] =
try:
let start = getFilePos(f)
let dlen = toBytesLE(data.len().uint64)
? append(f, typ)
? append(f, dlen.toOpenArray(0, 5))
? append(f, data)
ok(start)
except CatchableError as e:
err(e.msg)
proc open*(T: type E2Store, path: string, name: string, firstSlot: Slot): Result[E2Store, string] =
let
data =
try: open(path / name & ".e2s", fmWrite)
except CatchableError as e: return err(e.msg)
index =
try: system.open(path / name & ".e2i", fmWrite)
except CatchableError as e:
close(data)
return err(e.msg)
discard ? appendRecord(data, E2Version, [])
discard ? appendRecord(index, E2Index, [])
? append(index, toBytesLE(firstSlot.uint64))
ok(E2Store(data: data, index: index, slot: firstSlot))
proc close*(store: var E2Store) =
store.data.close()
store.index.close()
proc toCompressedBytes(item: auto): seq[byte] =
try:
let
payload = SSZ.encode(item)
framingFormatCompress(payload)
except CatchableError as exc:
raiseAssert exc.msg # shouldn't happen
proc appendRecord*(store: var E2Store, v: phase0.TrustedSignedBeaconBlock): Result[void, string] =
if v.message.slot < store.slot:
return err("Blocks must be written in order")
let start = store.data.appendRecord(SnappyBeaconBlock, toCompressedBytes(v)).get()
while store.slot < v.message.slot:
? append(store.index, toBytesLE(0'u64))
store.slot += 1
? append(store.index, toBytesLE(start.uint64))
store.slot += 1
ok()
proc appendRecord*(store: var E2Store, v: phase0.BeaconState): Result[void, string] =
discard ? store.data.appendRecord(SnappyBeaconState, toCompressedBytes(v))
ok()