Merge pull request #3 from logos-storage/stew-bump

chore: bump stew, fix import conflict

.github/workflows/ci.yml

@@ -8,22 +8,15 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macOS-latest, windows-latest]
-        nim: [stable, 1.2.6]
+        nim: [stable, 2.0.14]
     steps:
-    - uses: actions/checkout@v2
-    - uses: iffy/install-nim@v3
+    - uses: actions/checkout@v6
       with:
-        version: ${{ matrix.nim }}
-
-    # workaround for https://github.com/iffy/install-nim/issues/11
-    - name: Workaround SSL error with choosenim
-      run: |
-          curl -fO https://curl.se/ca/cacert.pem
-          install cacert.pem ~/.nimble/bin
-          ls ~/.nimble/bin
-      shell: bash
-      if: runner.os == 'Windows'
-
+        submodules: recursive
+    - uses: jiro4989/setup-nim-action@v2
+      with:
+        nim-version: ${{matrix.nim}}
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
     - name: Build
       run: nimble install -y
     - name: Test

.gitignore

@@ -1,3 +1,6 @@
 *
 !*/
 !*.*
+nimble.develop
+nimble.paths
+nimbledeps

.tool-versions

@@ -1 +1 @@
-nim 1.4.4
+nim 1.6.2

License.md

@@ -0,0 +1,5 @@
+Licensed and distributed under either of
+[MIT license](http://opensource.org/licenses/MIT) or
+[Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
+at your option. These files may not be copied, modified, or distributed except
+according to those terms.

Readme.md

@@ -10,3 +10,11 @@ References
   - [statechannels.org](https://statechannels.org/)
   - [Nitro paper](https://magmo.com/nitro-protocol.pdf)
   - [Nitro smart contracts & Javascript code](https://github.com/statechannels/statechannels/tree/master/packages/nitro-protocol)
+
+# Installation
+
+To avoid conflicts with previous versions of `contractabi`, use the following command to install dependencies:
+
+```bash
+nimble install --maximumtaggedversions=2
+```

config.nims

@@ -0,0 +1,5 @@
+# begin Nimble config (version 2)
+--noNimblePath
+when withDir(thisDir(), system.fileExists("nimble.paths")):
+  include "nimble.paths"
+# end Nimble config

nimble.lock

@@ -0,0 +1,101 @@
+{
+  "version": 2,
+  "packages": {
+    "results": {
+      "version": "0.5.1",
+      "vcsRevision": "df8113dda4c2d74d460a8fa98252b0b771bf1f27",
+      "url": "https://github.com/arnetheduck/nim-results",
+      "downloadMethod": "git",
+      "dependencies": [],
+      "checksums": {
+        "sha1": "a9c011f74bc9ed5c91103917b9f382b12e82a9e7"
+      }
+    },
+    "unittest2": {
+      "version": "0.2.5",
+      "vcsRevision": "26f2ef3ae0ec72a2a75bfe557e02e88f6a31c189",
+      "url": "https://github.com/status-im/nim-unittest2",
+      "downloadMethod": "git",
+      "dependencies": [],
+      "checksums": {
+        "sha1": "02bb3751ba9ddc3c17bfd89f2e41cb6bfb8fc0c9"
+      }
+    },
+    "stew": {
+      "version": "0.4.2",
+      "vcsRevision": "b66168735d6f3841c5239c3169d3fe5fe98b1257",
+      "url": "https://github.com/status-im/nim-stew",
+      "downloadMethod": "git",
+      "dependencies": [
+        "results",
+        "unittest2"
+      ],
+      "checksums": {
+        "sha1": "928e82cb8d2f554e8f10feb2349ee9c32fee3a8c"
+      }
+    },
+    "stint": {
+      "version": "0.8.2",
+      "vcsRevision": "470b7892561b5179ab20bd389a69217d6213fe58",
+      "url": "https://github.com/status-im/nim-stint",
+      "downloadMethod": "git",
+      "dependencies": [
+        "stew",
+        "unittest2"
+      ],
+      "checksums": {
+        "sha1": "d8f871fd617e7857192d4609fe003b48942a8ae5"
+      }
+    },
+    "nimcrypto": {
+      "version": "0.6.4",
+      "vcsRevision": "721fb99ee099b632eb86dfad1f0d96ee87583774",
+      "url": "https://github.com/cheatfate/nimcrypto",
+      "downloadMethod": "git",
+      "dependencies": [],
+      "checksums": {
+        "sha1": "f9ab24fa940ed03d0fb09729a7303feb50b7eaec"
+      }
+    },
+    "questionable": {
+      "version": "0.10.15",
+      "vcsRevision": "82d90b67bcfb7f2e918b61dace2ff1a4ced60935",
+      "url": "https://github.com/codex-storage/questionable",
+      "downloadMethod": "git",
+      "dependencies": [],
+      "checksums": {
+        "sha1": "3238ff637c7b44d2fa8fcb839a8ded968e389de3"
+      }
+    },
+    "contractabi": {
+      "version": "0.7.3",
+      "vcsRevision": "0a7b4cecce725bcb11ad8648035a92704a8854d3",
+      "url": "https://github.com/status-im/nim-contract-abi",
+      "downloadMethod": "git",
+      "dependencies": [
+        "stint",
+        "stew",
+        "nimcrypto",
+        "questionable"
+      ],
+      "checksums": {
+        "sha1": "1bb9af15f02a77b44af02ec94b0e392b1ec88438"
+      }
+    },
+    "secp256k1": {
+      "version": "0.6.0.3.2",
+      "vcsRevision": "b526c4b436809aa1cfe650026d796cf7b8328b91",
+      "url": "https://github.com/status-im/nim-secp256k1",
+      "downloadMethod": "git",
+      "dependencies": [
+        "stew",
+        "results",
+        "nimcrypto"
+      ],
+      "checksums": {
+        "sha1": "e6e50bd4a29cb473b070eb5359d87d8946d96075"
+      }
+    }
+  },
+  "tasks": {}
+}

nitro.nimble

@@ -1,12 +1,12 @@
-version = "0.1.0"
+version = "0.6.1"
 author = "Nim Nitro developers"
 license = "MIT"
 description = "Nitro state channels"
 
-requires "nim >= 1.2.6 & < 2.0.0"
-requires "nimcrypto >= 0.5.4 & < 0.6.0"
-requires "questionable >= 0.4.3 & < 0.5.0"
-requires "upraises >= 0.1.0 & < 0.2.0"
-requires "secp256k1"
-requires "stint"
-requires "stew"
+requires "nim >= 2.0.14 & < 3.0.0"
+requires "nimcrypto >= 0.6.0 & < 0.7.0"
+requires "questionable >= 0.10.10 & < 0.11.0"
+requires "contractabi >= 0.7.1 & < 0.8.0"
+requires "secp256k1 >= 0.6.0 & < 0.7.0"
+requires "stint >= 0.8.0 & < 0.9.0"
+requires "stew >= 0.2.0"

nitro/basics.nim

@@ -1,6 +1,5 @@
 import pkg/questionable
 import pkg/questionable/results
-import pkg/upraises
 import pkg/stint
 import ./basics/uint48
 import ./basics/ethaddress
@@ -8,7 +7,6 @@ import ./basics/destination
 
 export questionable
 export results
-export upraises
 export stint
 export uint48
 export ethaddress

nitro/basics/destination.nim

@@ -1,11 +1,10 @@
 import std/hashes
 import pkg/questionable
 import pkg/questionable/results
-import pkg/upraises
 import pkg/stew/byteutils
 import ./ethaddress
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 type Destination* = distinct array[32, byte]
 

nitro/basics/ethaddress.nim

@@ -1,21 +1,12 @@
-import pkg/questionable
-import pkg/questionable/results
-import pkg/stew/byteutils
+import std/hashes
+import pkg/contractabi/address
 
-export questionable
+export address
 
-type EthAddress* = distinct array[20, byte]
+type EthAddress* = Address
 
 func zero*(_: type EthAddress): EthAddress =
   EthAddress.default
 
-func toArray*(address: EthAddress): array[20, byte] =
-  array[20, byte](address)
-
-func `$`*(a: EthAddress): string =
-  a.toArray().toHex()
-
-func parse*(_: type EthAddress, hex: string): ?EthAddress =
-  EthAddress(array[20, byte].fromHex(hex)).catch.option
-
-proc `==`*(a, b: EthAddress): bool {.borrow.}
+proc `hash`*(a: EthAddress): Hash =
+  hash(a.toArray)

nitro/json.nim

@@ -8,7 +8,7 @@ import ./wallet/signedstate
 
 export signedstate
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 func `%`(value: Outcome | Allocation): JsonNode =
   type Base = distinctBase(typeof value)
@@ -37,7 +37,7 @@ func toJson*(payment: SignedState): string =
 
 {.pop.}
 
-push: {.upraises: [ValueError].}
+{.push raises: [ValueError].}
 
 func expectKind(node: JsonNode, kind: JsonNodeKind) =
   if node.kind != kind:
@@ -46,27 +46,21 @@ func expectKind(node: JsonNode, kind: JsonNodeKind) =
 
 func initFromJson*(bytes: var seq[byte], node: JsonNode, _: var string) =
   node.expectKind(JString)
-  let parsed = seq[byte].fromHex(node.getStr)
-  if parsed.isOk:
-    bytes = parsed.get
-  else:
+  without parsed =? seq[byte].fromHex(node.getStr):
     raise newException(ValueError, "invalid hex string")
+  bytes = parsed
 
 func initFromJson*(address: var EthAddress, node: JsonNode, _: var string) =
   node.expectKind(JString)
-  let parsed = EthAddress.parse(node.getStr)
-  if parsed.isSome:
-    address = parsed.get
-  else:
+  without parsed =? EthAddress.init(node.getStr):
     raise newException(ValueError, "invalid ethereum address")
+  address = parsed
 
 func initFromJson*(dest: var Destination, node: JsonNode, _: var string) =
   node.expectKind(JString)
-  let parsed = Destination.parse(node.getStr)
-  if parsed.isSome:
-    dest = parsed.get
-  else:
+  without parsed =? Destination.parse(node.getStr):
     raise newException(ValueError, "invalid nitro destination")
+  dest = parsed
 
 func initFromJson*(number: var UInt256, node: JsonNode, _: var string) =
   node.expectKind(JString)
@@ -74,15 +68,13 @@ func initFromJson*(number: var UInt256, node: JsonNode, _: var string) =
 
 func initFromJson*(signature: var Signature, node: JsonNode, _: var string) =
   node.expectKind(JString)
-  let parsed = Signature.parse(node.getStr)
-  if parsed.isSome:
-    signature = parsed.get
-  else:
+  without parsed =? Signature.parse(node.getStr):
     raise newException(ValueError, "invalid signature")
+  signature = parsed
 
 {.pop.}
 
-push: {.upraises: [].}
+{.push raises: [].}
 
 proc fromJson*(_: type SignedState, json: string): ?SignedState =
   try:

nitro/keys.nim

@@ -5,7 +5,7 @@ import ./basics
 export basics
 export toPublicKey
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 type
   EthPrivateKey* = SkSecretKey

nitro/protocol/abi.nim

@@ -1,132 +1,10 @@
-import pkg/stew/endians2
+import pkg/contractabi
 import ../basics
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 export basics
+export contractabi
 
-type
-  AbiEncoder* = object
-    stack: seq[Tuple]
-  Tuple = object
-    bytes: seq[byte]
-    postponed: seq[Split]
-    dynamic: bool
-  Split = object
-    head: Slice[int]
-    tail: seq[byte]
-
-func write*[T](encoder: var AbiEncoder, value: T)
-func encode*[T](_: type AbiEncoder, value: T): seq[byte]
-
-func init*(_: type AbiEncoder): AbiEncoder =
-  AbiEncoder(stack: @[Tuple()])
-
-func append(tupl: var Tuple, bytes: openArray[byte]) =
-  tupl.bytes.add(bytes)
-
-func postpone(tupl: var Tuple, bytes: seq[byte]) =
-  var split: Split
-  split.head.a = tupl.bytes.len
-  tupl.append(AbiEncoder.encode(0'u64))
-  split.head.b = tupl.bytes.high
-  split.tail = bytes
-  tupl.postponed.add(split)
-
-func finish(tupl: Tuple): seq[byte] =
-  var bytes = tupl.bytes
-  for split in tupl.postponed:
-    let offset = bytes.len
-    bytes[split.head] = AbiEncoder.encode(offset.uint64)
-    bytes.add(split.tail)
-  bytes
-
-func append(encoder: var AbiEncoder, bytes: openArray[byte]) =
-  encoder.stack[^1].append(bytes)
-
-func postpone(encoder: var AbiEncoder, bytes: seq[byte]) =
-  if encoder.stack.len > 1:
-    encoder.stack[^1].postpone(bytes)
-  else:
-    encoder.stack[0].append(bytes)
-
-func setDynamic(encoder: var AbiEncoder) =
-  encoder.stack[^1].dynamic = true
-
-func startTuple*(encoder: var AbiEncoder) =
-  encoder.stack.add(Tuple())
-
-func encode(encoder: var AbiEncoder, tupl: Tuple) =
-  if tupl.dynamic:
-    encoder.postpone(tupl.finish())
-    encoder.setDynamic()
-  else:
-    encoder.append(tupl.finish())
-
-func finishTuple*(encoder: var AbiEncoder) =
-  encoder.encode(encoder.stack.pop())
-
-func pad(encoder: var AbiEncoder, len: int) =
-  let padlen = (32 - len mod 32) mod 32
-  for _ in 0..<padlen:
-    encoder.append([0'u8])
-
-func padleft(encoder: var AbiEncoder, bytes: openArray[byte]) =
-  encoder.pad(bytes.len)
-  encoder.append(bytes)
-
-func padright(encoder: var AbiEncoder, bytes: openArray[byte]) =
-  encoder.append(bytes)
-  encoder.pad(bytes.len)
-
-func encode(encoder: var AbiEncoder, value: SomeUnsignedInt | StUint) =
-  encoder.padleft(value.toBytesBE)
-
-func encode(encoder: var AbiEncoder, value: bool) =
-  encoder.encode(cast[uint8](value))
-
-func encode(encoder: var AbiEncoder, value: enum) =
-  encoder.encode(uint64(ord(value)))
-
-func encode[I](encoder: var AbiEncoder, bytes: array[I, byte]) =
-  encoder.padright(bytes)
-
-func encode(encoder: var AbiEncoder, bytes: seq[byte]) =
-  encoder.encode(bytes.len.uint64)
-  encoder.padright(bytes)
-  encoder.setDynamic()
-
-func encode(encoder: var AbiEncoder, address: EthAddress) =
-  encoder.padleft(address.toArray)
-
-func encode(encoder: var AbiEncoder, destination: Destination) =
-  encoder.encode(destination.toArray)
-
-func encode[I, T](encoder: var AbiEncoder, value: array[I, T]) =
-  encoder.startTuple()
-  for element in value:
-    encoder.write(element)
-  encoder.finishTuple()
-
-func encode[T](encoder: var AbiEncoder, value: seq[T]) =
-  encoder.encode(value.len.uint64)
-  encoder.startTuple()
-  for element in value:
-    encoder.write(element)
-  encoder.finishTuple()
-  encoder.setDynamic()
-
-func write*[T](encoder: var AbiEncoder, value: T) =
-  var writer = AbiEncoder.init()
-  writer.encode(value)
-  encoder.encode(writer.stack[0])
-
-func finish*(encoder: var AbiEncoder): seq[byte] =
-  doAssert encoder.stack.len == 1, "not all tuples were finished"
-  doAssert encoder.stack[0].bytes.len mod 32 == 0, "encoding invariant broken"
-  encoder.stack[0].bytes
-
-func encode*[T](_: type AbiEncoder, value: T): seq[byte] =
-  var encoder = AbiEncoder.init()
-  encoder.write(value)
-  encoder.finish()
+func encode*(encoder: var AbiEncoder, destination: Destination) =
+  encoder.write(destination.toArray)

nitro/protocol/channel.nim

@@ -2,7 +2,7 @@ import pkg/nimcrypto
 import ../basics
 import ./abi
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 export basics
 
@@ -13,10 +13,6 @@ type
     chainId*: UInt256
 
 func getChannelId*(channel: ChannelDefinition): Destination =
-  var encoder= AbiEncoder.init()
-  encoder.startTuple()
-  encoder.write(channel.chainId)
-  encoder.write(channel.participants)
-  encoder.write(channel.nonce)
-  encoder.finishTuple()
-  Destination(keccak256.digest(encoder.finish()).data)
+  let encoding = AbiEncoder.encode:
+     (channel.chainId, channel.participants, channel.nonce)
+  Destination(keccak256.digest(encoding).data)

nitro/protocol/outcome.nim

@@ -2,7 +2,7 @@ import pkg/nimcrypto
 import ../basics
 import ./abi
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 export basics
 
@@ -52,46 +52,25 @@ func `==`*(a, b: AssetOutcome): bool =
 proc `==`*(a, b: Outcome): bool {.borrow.}
 
 func encode*(encoder: var AbiEncoder, guarantee: Guarantee) =
-  encoder.startTuple()
-  encoder.startTuple()
-  encoder.write(guarantee.targetChannelId)
-  encoder.write(guarantee.destinations)
-  encoder.finishTuple()
-  encoder.finishTuple()
-
-func encode*(encoder: var AbiEncoder, item: AllocationItem) =
-  encoder.startTuple()
-  encoder.write(item.destination)
-  encoder.write(item.amount)
-  encoder.finishTuple()
+  encoder.write:
+    ( (guarantee.targetChannelId, guarantee.destinations), )
 
 func encode*(encoder: var AbiEncoder, allocation: Allocation) =
-  encoder.startTuple()
-  encoder.write(seq[AllocationItem](allocation))
-  encoder.finishTuple()
+  encoder.write: (seq[AllocationItem](allocation),)
 
 func encode*(encoder: var AbiEncoder, assetOutcome: AssetOutcome) =
-  var content= AbiEncoder.init()
-  content.startTuple()
-  content.startTuple()
-  content.write(assetOutcome.kind)
+  var content: seq[byte]
   case assetOutcome.kind:
   of allocationType:
-    content.write(AbiEncoder.encode(assetOutcome.allocation))
+    content = AbiEncoder.encode:
+      ( (assetOutcome.kind, ABiEncoder.encode(assetOutcome.allocation)), )
   of guaranteeType:
-    content.write(AbiEncoder.encode(assetOutcome.guarantee))
-  content.finishTuple()
-  content.finishTuple()
-
-  encoder.startTuple()
-  encoder.write(assetOutcome.assetHolder)
-  encoder.write(content.finish())
-  encoder.finishTuple()
+    content = AbiEncoder.encode:
+      ( (assetOutcome.kind, AbiEncoder.encode(assetOutcome.guarantee)), )
+  encoder.write( (assetOutcome.assetHolder, content) )
 
 func encode*(encoder: var AbiEncoder, outcome: Outcome) =
-  encoder.startTuple()
-  encoder.write(seq[AssetOutcome](outcome))
-  encoder.finishTuple()
+  encoder.write: (seq[AssetOutcome](outcome),)
 
 func hashOutcome*(outcome: Outcome): array[32, byte] =
   keccak256.digest(AbiEncoder.encode(outcome)).data

nitro/protocol/signature.nim

@@ -1,11 +1,11 @@
 import pkg/secp256k1
-import pkg/nimcrypto
+import pkg/nimcrypto/keccak
 import pkg/stew/byteutils
 import ../basics
 import ../keys
 import ./state
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 export basics
 export keys
@@ -32,7 +32,7 @@ func recover(signature: Signature, hash: array[32, byte]): ?EthPublicKey =
 
 func recover*(signature: Signature, state: State): ?EthAddress =
   let hash = hashMessage(hashState(state))
-  recover(signature, hash)?.toAddress
+  recover(signature, hash).?toAddress
 
 func verify*(signature: Signature, state: State, signer: EthAddress): bool =
   recover(signature, state) == signer.some
@@ -43,8 +43,7 @@ func `$`*(signature: Signature): string =
   bytes.toHex()
 
 func parse*(_: type Signature, s: string): ?Signature =
-  let signature = catch:
-    var bytes = array[65, byte].fromHex(s)
-    bytes[64] = bytes[64] - 27
-    SkRecoverableSignature.fromRaw(bytes).get()
-  signature.option
+  without var bytes =? array[65, byte].fromHex(s).catch:
+    return Signature.none
+  bytes[64] = bytes[64] - 27
+  SkRecoverableSignature.fromRaw(bytes).option

nitro/protocol/state.nim

@@ -4,7 +4,7 @@ import ./channel
 import ./outcome
 import ./abi
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 export basics
 export channel
@@ -45,21 +45,17 @@ func variablePart*(state: State): VariablePart =
   )
 
 func hashAppPart*(state: State): array[32, byte] =
-  var encoder= AbiEncoder.init()
-  encoder.startTuple()
-  encoder.write(state.challengeDuration)
-  encoder.write(state.appDefinition)
-  encoder.write(state.appData)
-  encoder.finishTuple()
-  keccak256.digest(encoder.finish).data
+  let encoding = AbiEncoder.encode:
+    (state.challengeDuration, state.appDefinition, state.appData)
+  keccak256.digest(encoding).data
 
 func hashState*(state: State): array[32, byte] =
-  var encoder= AbiEncoder.init()
-  encoder.startTuple()
-  encoder.write(state.turnNum)
-  encoder.write(state.isFinal)
-  encoder.write(getChannelId(state.channel))
-  encoder.write(hashAppPart(state))
-  encoder.write(hashOutcome(state.outcome))
-  encoder.finishTuple()
-  keccak256.digest(encoder.finish).data
+  let encoding = AbiEncoder.encode:
+    (
+      state.turnNum,
+      state.isFinal,
+      getChannelId(state.channel),
+      hashAppPart(state),
+      hashOutcome(state.outcome)
+    )
+  keccak256.digest(encoding).data

nitro/wallet/balances.nim

@@ -3,7 +3,7 @@ import std/sequtils
 import ../basics
 import ../protocol
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 export tables
 
@@ -31,7 +31,7 @@ func move*(balances: var Balances,
            amount: UInt256): ?!void =
   try:
     if balances[source] < amount:
-      return void.failure "insufficient funds"
+      return failure "insufficient funds"
 
     balances[source] -= amount
     if (balances.contains(destination)):
@@ -39,6 +39,6 @@ func move*(balances: var Balances,
     else:
       balances[destination] = amount
 
-    ok()
+    success()
   except KeyError:
-    void.failure "no funds"
+    failure "no funds"

nitro/wallet/deref.nim

@@ -0,0 +1,46 @@
+import std/macros
+
+func identName(identDefs: NimNode): NimNode =
+  identDefs.expectKind(nnkIdentDefs)
+  identDefs[0]
+
+func identType(identDefs: NimNode): NimNode =
+  identDefs.expectKind(nnkIdentDefs)
+  identDefs[^2]
+
+func `identType=`(identDefs: NimNode, identType: NimNode) =
+  identDefs.expectKind(nnkIdentDefs)
+  identDefs[^2] = identType
+
+func insertRef(function: NimNode) =
+  function.expectKind(nnkFuncDef)
+  var paramType = function.params[1].identType
+  if paramType.kind == nnkVarTy:
+    paramType = paramType[0]
+  function.params[1].identType = newNimNode(nnkRefTy, paramType).add(paramType)
+
+func paramNames(function: NimNode): seq[NimNode] =
+  function.expectKind(nnkFuncDef)
+  for i in 1..<function.params.len:
+    result.add(function.params[i].identName)
+
+func insertDeref(params: var seq[NimNode]) =
+  params[0] = newNimNode(nnkBracketExpr, params[0]).add(params[0])
+
+func derefOverload(function: NimNode): NimNode =
+  function.expectKind(nnkFuncDef)
+  var arguments = function.paramNames
+  arguments.insertDeref()
+  result = function.copyNimTree()
+  result.insertRef()
+  result.body = newCall(function.name, arguments)
+
+macro deref*(function: untyped{nkFuncDef}): untyped =
+  ## Creates an overload that dereferences the first argument of the function
+  ## call. Roughly equivalent to the `implicitDeref` experimental feature of
+  ## Nim.
+
+  let overload = derefOverload(function)
+  quote do:
+    `function`
+    `overload`

nitro/wallet/nonces.nim

@@ -0,0 +1,34 @@
+import std/tables
+import std/sets
+import std/hashes
+import ../basics
+
+{.push raises: [].}
+
+type
+  Nonces* = object
+    next: Table[NonceKey, UInt48]
+  NonceKey = object
+    chainId: UInt256
+    participants: HashSet[EthAddress]
+
+func hash(key: NonceKey): Hash =
+  var h: Hash
+  h = h !& key.chainId.hash
+  h = h !& key.participants.hash
+  !$h
+
+func key(chainId: UInt256, participants: openArray[EthAddress]): NonceKey =
+  NonceKey(chainId: chainId, participants: participants.toHashSet)
+
+func getNonce*(nonces: var Nonces,
+               chainId: UInt256,
+               participants: varargs[EthAddress]): UInt48 =
+  nonces.next.?[key(chainId, participants)] |? 0
+
+func incNonce*(nonces: var Nonces,
+               oldNonce: UInt48,
+               chainId: UInt256,
+               participants: varargs[EthAddress]) =
+  let next = max(oldNonce, nonces.getNonce(chainId, participants)) + 1
+  nonces.next[key(chainId, participants)] = next

nitro/wallet/signedstate.nim

@@ -1,7 +1,7 @@
 import ../basics
 import ../protocol
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 type
   SignedState* = object

nitro/wallet/wallet.nim

@@ -5,8 +5,10 @@ import ../protocol
 import ./signedstate
 import ./ledger
 import ./balances
+import ./nonces
+import ./deref
 
-push: {.upraises:[].}
+{.push raises: [].}
 
 export basics
 export keys
@@ -17,21 +19,26 @@ type
   Wallet* = object
     key: EthPrivateKey
     channels: Table[ChannelId, SignedState]
+    nonces: Nonces
+  WalletRef* = ref Wallet
   ChannelId* = Destination
   Payment* = tuple
     destination: Destination
     amount: UInt256
 
 func init*(_: type Wallet, key: EthPrivateKey): Wallet =
-  result.key = key
+  Wallet(key: key)
 
-func publicKey*(wallet: Wallet): EthPublicKey =
+func new*(_: type WalletRef, key: EthPrivateKey): WalletRef =
+  WalletRef(key: key)
+
+func publicKey*(wallet: Wallet): EthPublicKey {.deref.} =
   wallet.key.toPublicKey
 
-func address*(wallet: Wallet): EthAddress =
+func address*(wallet: Wallet): EthAddress {.deref.} =
   wallet.publicKey.toAddress
 
-func destination*(wallet: Wallet): Destination =
+func destination*(wallet: Wallet): Destination {.deref.}=
   wallet.address.toDestination
 
 func sign(wallet: Wallet, state: SignedState): SignedState =
@@ -39,12 +46,17 @@ func sign(wallet: Wallet, state: SignedState): SignedState =
   signed.signatures &= wallet.key.sign(state.state)
   signed
 
+func incNonce(wallet: var Wallet, state: SignedState) =
+  let channel = state.state.channel
+  wallet.nonces.incNonce(channel.nonce, channel.chainId, channel.participants)
+
 func createChannel(wallet: var Wallet, state: SignedState): ?!ChannelId =
   let id = getChannelId(state.state.channel)
   if wallet.channels.contains(id):
-    return ChannelId.failure("channel with id " & $id & " already exists")
+    return failure "channel with id " & $id & " already exists"
   wallet.channels[id] = wallet.sign(state)
-  ok id
+  wallet.incNonce(state)
+  success id
 
 func updateChannel(wallet: var Wallet, state: SignedState) =
   let signed = wallet.sign(state)
@@ -56,31 +68,43 @@ func openLedgerChannel*(wallet: var Wallet,
                         chainId: UInt256,
                         nonce: UInt48,
                         asset: EthAddress,
-                        amount: UInt256): ?!ChannelId =
+                        amount: UInt256): ?!ChannelId {.deref.} =
   let state = startLedger(wallet.address, hub, chainId, nonce, asset, amount)
   wallet.createChannel(state)
 
-func acceptChannel*(wallet: var Wallet, signed: SignedState): ?!ChannelId =
+func openLedgerChannel*(wallet: var Wallet,
+                        hub: EthAddress,
+                        chainId: UInt256,
+                        asset: EthAddress,
+                        amount: UInt256): ?!ChannelId {.deref.} =
+  let nonce = wallet.nonces.getNonce(chainId, wallet.address, hub)
+  openLedgerChannel(wallet, hub, chainId, nonce, asset, amount)
+
+func acceptChannel*(wallet: var Wallet,
+                    signed: SignedState): ?!ChannelId {.deref.} =
   if not signed.hasParticipant(wallet.address):
-    return ChannelId.failure "wallet owner is not a participant"
+    return failure "wallet owner is not a participant"
 
   if not verifySignatures(signed):
-    return ChannelId.failure "incorrect signatures"
+    return failure "incorrect signatures"
 
   wallet.createChannel(signed)
 
-func latestSignedState*(wallet: Wallet, channel: ChannelId): ?SignedState =
-  wallet.channels?[channel]
+func latestSignedState*(wallet: Wallet,
+                        channel: ChannelId): ?SignedState {.deref.} =
+  wallet.channels.?[channel]
 
-func state*(wallet: Wallet, channel: ChannelId): ?State =
-  wallet.latestSignedState(channel)?.state
+func state*(wallet: Wallet,
+            channel: ChannelId): ?State {.deref.} =
+  wallet.latestSignedState(channel).?state
 
-func signatures*(wallet: Wallet, channel: ChannelId): ?seq[Signature] =
-  wallet.latestSignedState(channel)?.signatures
+func signatures*(wallet: Wallet,
+                 channel: ChannelId): ?seq[Signature] {.deref.} =
+  wallet.latestSignedState(channel).?signatures
 
 func signature*(wallet: Wallet,
                 channel: ChannelId,
-                address: EthAddress): ?Signature =
+                address: EthAddress): ?Signature {.deref.} =
   if signed =? wallet.latestSignedState(channel):
     for signature in signed.signatures:
       if signer =? signature.recover(signed.state):
@@ -91,30 +115,27 @@ func signature*(wallet: Wallet,
 func balance(state: State,
              asset: EthAddress,
              destination: Destination): UInt256 =
-  if balances =? state.outcome.balances(asset):
-    if balance =? (balances?[destination]):
-      balance
-    else:
-      0.u256
-  else:
-    0.u256
+  without balance =? state.outcome.balances(asset).?[destination]:
+    return 0.u256
+  balance
 
 func balance*(wallet: Wallet,
               channel: ChannelId,
               asset: EthAddress,
-              destination: Destination): UInt256 =
-  if state =? wallet.state(channel):
-    state.balance(asset, destination)
-  else:
-    0.u256
+              destination: Destination): UInt256 {.deref.} =
+  without state =? wallet.state(channel):
+    return 0.u256
+  state.balance(asset, destination)
 
 func balance*(wallet: Wallet,
               channel: ChannelId,
               asset: EthAddress,
-              address: EthAddress): UInt256 =
+              address: EthAddress): UInt256 {.deref.} =
   wallet.balance(channel, asset, address.toDestination)
 
-func balance*(wallet: Wallet, channel: ChannelId, asset: EthAddress): UInt256 =
+func balance*(wallet: Wallet,
+              channel: ChannelId,
+              asset: EthAddress): UInt256 {.deref.} =
   wallet.balance(channel, asset, wallet.address)
 
 func total(state: State, asset: EthAddress): UInt256 =
@@ -125,65 +146,64 @@ func total(state: State, asset: EthAddress): UInt256 =
   total
 
 func total(wallet: Wallet, channel: ChannelId, asset: EthAddress): UInt256 =
-  if state =? wallet.state(channel):
-    state.total(asset)
-  else:
-    0.u256
+  without state =? wallet.state(channel):
+    return 0.u256
+  state.total(asset)
 
 func pay*(wallet: var Wallet,
           channel: ChannelId,
           asset: EthAddress,
           receiver: Destination,
-          amount: UInt256): ?!SignedState =
-  if var state =? wallet.state(channel):
-    if var balances =? state.outcome.balances(asset):
-      ?balances.move(wallet.destination, receiver, amount)
-      state.outcome.update(asset, balances)
-      wallet.updateChannel(SignedState(state: state))
-      ok(wallet.channels?[channel].get)
-    else:
-      SignedState.failure "asset not found"
-  else:
-    SignedState.failure "channel not found"
+          amount: UInt256): ?!SignedState {.deref.} =
+  without var state =? wallet.state(channel):
+    return failure "channel not found"
+
+  without var balances =? state.outcome.balances(asset):
+    return failure "asset not found"
+
+  ?balances.move(wallet.destination, receiver, amount)
+  state.outcome.update(asset, balances)
+  wallet.updateChannel(SignedState(state: state))
+  success !wallet.latestSignedState(channel)
 
 func pay*(wallet: var Wallet,
           channel: ChannelId,
           asset: EthAddress,
           receiver: EthAddress,
-          amount: UInt256): ?!SignedState =
+          amount: UInt256): ?!SignedState {.deref.} =
   wallet.pay(channel, asset, receiver.toDestination, amount)
 
 func acceptPayment*(wallet: var Wallet,
                     channel: ChannelId,
                     asset: EthAddress,
                     sender: EthAddress,
-                    payment: SignedState): ?!void =
+                    payment: SignedState): ?!void {.deref.} =
   if not wallet.channels.contains(channel):
-    return void.failure "unknown channel"
+    return failure "unknown channel"
 
   if not (getChannelId(payment.state.channel) == channel):
-    return void.failure "payment does not match channel"
+    return failure "payment does not match channel"
 
   let currentBalance = wallet.balance(channel, asset)
   let futureBalance = payment.state.balance(asset, wallet.destination)
   if futureBalance <= currentBalance:
-    return void.failure "payment should not decrease balance"
+    return failure "payment should not decrease balance"
 
   let currentTotal = wallet.total(channel, asset)
   let futureTotal = payment.state.total(asset)
   if futureTotal != currentTotal:
-    return void.failure "total supply of asset should not change"
+    return failure "total supply of asset should not change"
 
   if not payment.isSignedBy(sender):
-    return void.failure "missing signature on payment"
+    return failure "missing signature on payment"
 
-  if updatedBalances =? payment.state.outcome.balances(asset):
-    var expectedState: State = wallet.channels?[channel]?.state.get
-    expectedState.outcome.update(asset, updatedBalances)
-    if payment.state != expectedState:
-      return void.failure "payment has unexpected changes in state"
-  else:
-    return void.failure "payment misses balances for asset"
+  without updatedBalances =? payment.state.outcome.balances(asset):
+    return failure "payment misses balances for asset"
+
+  var expectedState: State = !wallet.state(channel)
+  expectedState.outcome.update(asset, updatedBalances)
+  if payment.state != expectedState:
+    return failure "payment has unexpected changes in state"
 
   wallet.channels[channel] = payment
-  ok()
+  success()

tests/nitro/examples.nim

@@ -19,10 +19,10 @@ proc example*[T](_: type seq[T], len = 0..5): seq[T] =
   newSeqWith(chosenlen, T.example)
 
 proc example*(_: type UInt256): UInt256 =
-  UInt256.fromBytes(array[32, byte].example)
+  UInt256.fromBytesBE(array[32, byte].example)
 
 proc example*(_: type UInt128): UInt128 =
-  UInt128.fromBytes(array[16, byte].example)
+  UInt128.fromBytesBE(array[16, byte].example)
 
 proc example*(_: type EthAddress): EthAddress =
   EthAddress(array[20, byte].example)

tests/nitro/protocol/testAbi.nim

@@ -6,154 +6,11 @@ suite "ABI encoding":
   proc zeroes(amount: int): seq[byte] =
     newSeq[byte](amount)
 
-  test "encodes uint8":
-    check AbiEncoder.encode(42'u8) == 31.zeroes & 42'u8
-
-  test "encodes booleans":
-    check AbiEncoder.encode(false) == 31.zeroes & 0'u8
-    check AbiEncoder.encode(true) == 31.zeroes & 1'u8
-
-  test "encodes uint16, 32, 64":
-    check AbiEncoder.encode(0xABCD'u16) ==
-      30.zeroes & 0xAB'u8 & 0xCD'u8
-    check AbiEncoder.encode(0x11223344'u32) ==
-      28.zeroes & 0x11'u8 & 0x22'u8 & 0x33'u8 & 0x44'u8
-    check AbiEncoder.encode(0x1122334455667788'u64) ==
-      24.zeroes &
-      0x11'u8 & 0x22'u8 & 0x33'u8 & 0x44'u8 &
-      0x55'u8 & 0x66'u8 & 0x77'u8 & 0x88'u8
-
-  test "encodes ranges":
-    type SomeRange = range[0x0000'u16..0xAAAA'u16]
-    check AbiEncoder.encode(SomeRange(0x1122)) == 30.zeroes & 0x11'u8 & 0x22'u8
-
-  test "encodes enums":
-    type SomeEnum = enum
-      one = 1
-      two = 2
-    check AbiEncoder.encode(one) == 31.zeroes & 1'u8
-    check AbiEncoder.encode(two) == 31.zeroes & 2'u8
-
-  test "encodes stints":
-    let uint256 = UInt256.example
-    check AbiEncoder.encode(uint256) == @(uint256.toBytesBE)
-    let uint128 = UInt128.example
-    check AbiEncoder.encode(uint128) == 16.zeroes & @(uint128.toBytesBE)
-
-  test "encodes byte arrays":
-    let bytes3 = [1'u8, 2'u8, 3'u8]
-    check AbiEncoder.encode(bytes3) == @bytes3 & 29.zeroes
-    let bytes32 = array[32, byte].example
-    check AbiEncoder.encode(bytes32) == @bytes32
-    let bytes33 = array[33, byte].example
-    check AbiEncoder.encode(bytes33) == @bytes33 & 31.zeroes
-
-  test "encodes byte sequences":
-    let bytes3 = @[1'u8, 2'u8, 3'u8]
-    let bytes3len = AbiEncoder.encode(bytes3.len.uint64)
-    check AbiEncoder.encode(bytes3) == bytes3len & bytes3 & 29.zeroes
-    let bytes32 = @(array[32, byte].example)
-    let bytes32len = AbiEncoder.encode(bytes32.len.uint64)
-    check AbiEncoder.encode(bytes32) == bytes32len & bytes32
-    let bytes33 = @(array[33, byte].example)
-    let bytes33len = AbiEncoder.encode(bytes33.len.uint64)
-    check AbiEncoder.encode(bytes33) == bytes33len & bytes33 & 31.zeroes
-
   test "encodes ethereum addresses":
     let address = EthAddress.example
     check AbiEncoder.encode(address) == 12.zeroes & @(address.toArray)
 
-  test "encodes tuples":
-    let a = true
-    let b = @[1'u8, 2'u8, 3'u8]
-    let c = 0xAABBCCDD'u32
-    let d = @[4'u8, 5'u8, 6'u8]
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(a)
-    encoder.write(b)
-    encoder.write(c)
-    encoder.write(d)
-    encoder.finishTuple()
-    check encoder.finish() ==
-      AbiEncoder.encode(a) &
-      AbiEncoder.encode(4 * 32'u8) & # offset in tuple
-      AbiEncoder.encode(c) &
-      AbiEncoder.encode(6 * 32'u8) & # offset in tuple
-      AbiEncoder.encode(b) &
-      AbiEncoder.encode(d)
-
-  test "encodes nested tuples":
-    let a = true
-    let b = @[1'u8, 2'u8, 3'u8]
-    let c = 0xAABBCCDD'u32
-    let d = @[4'u8, 5'u8, 6'u8]
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(a)
-    encoder.write(b)
-    encoder.startTuple()
-    encoder.write(c)
-    encoder.write(d)
-    encoder.finishTuple()
-    encoder.finishTuple()
-    check encoder.finish() ==
-      AbiEncoder.encode(a) &
-      AbiEncoder.encode(3 * 32'u8) & # offset of b in outer tuple
-      AbiEncoder.encode(5 * 32'u8) & # offset of inner tuple in outer tuple
-      AbiEncoder.encode(b) &
-      AbiEncoder.encode(c) &
-      AbiEncoder.encode(2 * 32'u8) & # offset of d in inner tuple
-      AbiEncoder.encode(d)
-
-  test "encodes arrays":
-    let element1 = seq[byte].example
-    let element2 = seq[byte].example
-    var expected= AbiEncoder.init()
-    expected.startTuple()
-    expected.write(element1)
-    expected.write(element2)
-    expected.finishTuple()
-    check AbiEncoder.encode([element1, element2]) == expected.finish()
-
-  test "encodes sequences":
-    let element1 = seq[byte].example
-    let element2 = seq[byte].example
-    var expected= AbiEncoder.init()
-    expected.write(2'u8)
-    expected.startTuple()
-    expected.write(element1)
-    expected.write(element2)
-    expected.finishTuple()
-    check AbiEncoder.encode(@[element1, element2]) == expected.finish()
-
-  test "encodes sequence as dynamic element":
-    let s = @[42.u256, 43.u256]
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(s)
-    encoder.finishTuple()
-    check encoder.finish() ==
-      AbiEncoder.encode(32'u8) & # offset in tuple
-      AbiEncoder.encode(s)
-
-  test "encodes array of static elements as static element":
-    let a = [[42'u8], [43'u8]]
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(a)
-    encoder.finishTuple()
-    check encoder.finish() == AbiEncoder.encode(a)
-
-  test "encodes array of dynamic elements as dynamic element":
-    let a = [@[42'u8], @[43'u8]]
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(a)
-    encoder.finishTuple()
-    check encoder.finish() ==
-      AbiEncoder.encode(32'u8) & # offset in tuple
-      AbiEncoder.encode(a)
-
-# https://medium.com/b2expand/abi-encoding-explanation-4f470927092d
-# https://docs.soliditylang.org/en/v0.8.1/abi-spec.html#formal-specification-of-the-encoding
+  test "encodes nitro destinations":
+    let destination = Destination.example
+    check:
+      AbiEncoder.encode(destination) == AbiEncoder.encode(destination.toArray)

tests/nitro/protocol/testChannel.nim

@@ -7,13 +7,8 @@ suite "channel definition":
   let channel = ChannelDefinition.example
 
   test "calculates channel id":
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(channel.chainId)
-    encoder.write(channel.participants)
-    encoder.write(channel.nonce)
-    encoder.finishTuple()
-    let encoded = encoder.finish()
+    let encoded = AbiEncoder.encode:
+      (channel.chainId, channel.participants, channel.nonce)
     let hashed = keccak256.digest(encoded).data
     check getChannelId(channel) == Destination(hashed)
 
@@ -22,10 +17,10 @@ suite "channel definition":
       chainId: 9001.u256,
       nonce: 1,
       participants: @[
-        EthAddress.parse("24b905Dcc8A11C0FE57C2592f3D25f0447402C10").get()
+        !EthAddress.init("24b905Dcc8A11C0FE57C2592f3D25f0447402C10")
       ]
     )
-    let expected = Destination.parse(
+    let expected = !Destination.parse(
       "4f8cce57e9fe88edaab05234972eaf0c2d183e4f6b175aff293375fbe4d5d7cc"
-    ).get()
+    )
     check getChannelId(channel) == expected

tests/nitro/protocol/testOutcome.nim

@@ -6,31 +6,20 @@ suite "outcome":
 
   test "encodes guarantees":
     let guarantee = Guarantee.example
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.startTuple()
-    encoder.write(guarantee.targetChannelId)
-    encoder.write(guarantee.destinations)
-    encoder.finishTuple()
-    encoder.finishTuple()
-    check AbiEncoder.encode(guarantee) == encoder.finish()
+    let expected = AbiEncoder.encode:
+      ((guarantee.targetChannelId, guarantee.destinations),)
+    check AbiEncoder.encode(guarantee) == expected
 
   test "encodes allocation items":
     let item = AllocationItem.example
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(item.destination)
-    encoder.write(item.amount)
-    encoder.finishTuple()
-    check AbiEncoder.encode(item) == encoder.finish()
+    let expected = AbiEncoder.encode: (item.destination, item.amount)
+    check AbiEncoder.encode(item) == expected
 
   test "encodes allocation":
     let allocation = Allocation.example
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(seq[AllocationItem](allocation))
-    encoder.finishTuple()
-    check AbiEncoder.encode(allocation) == encoder.finish()
+    let expected = AbiEncoder.encode:
+      (seq[AllocationItem](allocation),)
+    check AbiEncoder.encode(allocation) == expected
 
   test "encodes allocation outcome":
     let assetOutcome = AssetOutcome(
@@ -38,19 +27,11 @@ suite "outcome":
       assetHolder: EthAddress.example,
       allocation: Allocation.example
     )
-    var content= AbiEncoder.init()
-    content.startTuple()
-    content.startTuple()
-    content.write(allocationType)
-    content.write(AbiEncoder.encode(assetOutcome.allocation))
-    content.finishTuple()
-    content.finishTuple()
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(assetOutcome.assetHolder)
-    encoder.write(content.finish())
-    encoder.finishTuple()
-    check AbiEncoder.encode(assetOutcome) == encoder.finish()
+    let content = AbiEncoder.encode:
+      ((allocationType, AbiEncoder.encode(assetOutcome.allocation)),)
+    let expected = AbiEncoder.encode:
+      (assetOutcome.assetHolder, content)
+    check AbiEncoder.encode(assetOutcome) == expected
 
   test "encodes guarantee outcome":
     let assetOutcome = AssetOutcome(
@@ -58,27 +39,17 @@ suite "outcome":
       assetHolder: EthAddress.example,
       guarantee: Guarantee.example
     )
-    var content= AbiEncoder.init()
-    content.startTuple()
-    content.startTuple()
-    content.write(guaranteeType)
-    content.write(AbiEncoder.encode(assetOutcome.guarantee))
-    content.finishTuple()
-    content.finishTuple()
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(assetOutcome.assetHolder)
-    encoder.write(content.finish())
-    encoder.finishTuple()
-    check AbiEncoder.encode(assetOutcome) == encoder.finish()
+    let content = AbiEncoder.encode:
+      ((guaranteeType, AbiEncoder.encode(assetOutcome.guarantee)),)
+    let expected = AbiEncoder.encode:
+      (assetOutcome.assetHolder, content)
+    check AbiEncoder.encode(assetOutcome) == expected
 
   test "encodes outcomes":
     let outcome = Outcome.example()
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(seq[AssetOutcome](outcome))
-    encoder.finishTuple()
-    check AbiEncoder.encode(outcome) == encoder.finish()
+    let expected = AbiEncoder.encode:
+      (seq[AssetOutcome](outcome),)
+    check AbiEncoder.encode(outcome) == expected
 
   test "hashes outcomes":
     let outcome = Outcome.example
@@ -90,31 +61,31 @@ suite "outcome":
     let outcome = Outcome(@[
       AssetOutcome(
         kind: allocationType,
-        assetHolder: EthAddress.parse(
+        assetHolder: !EthAddress.init(
           "1E90B49563da16D2537CA1Ddd9b1285279103D93"
-        ).get(),
+        ),
         allocation: Allocation(@[
           (
-            destination: Destination.parse(
+            destination: !Destination.parse(
               "f1918e8562236eb17adc8502332f4c9c82bc14e19bfc0aa10ab674ff75b3d2f3"
-            ).get(),
+            ),
             amount: 0x05.u256
           )
         ])
       ),
       AssetOutcome(
         kind: guaranteeType,
-        assetHolder: EthAddress.parse(
+        assetHolder: !EthAddress.init(
           "1E90B49563da16D2537CA1Ddd9b1285279103D93"
-        ).get(),
+        ),
         guarantee: Guarantee(
-          targetChannelId: Destination.parse(
+          targetChannelId: !Destination.parse(
             "cac1bb71f0a97c8ac94ca9546b43178a9ad254c7b757ac07433aa6df35cd8089"
-          ).get(),
+          ),
           destinations: @[
-            Destination.parse(
+            !Destination.parse(
               "f1918e8562236eb17adc8502332f4c9c82bc14e19bfc0aa10ab674ff75b3d2f3"
-            ).get()
+            )
           ]
         )
       )

tests/nitro/protocol/testSignature.nim

@@ -40,7 +40,7 @@ suite "signature":
         chainId: 0x1.u256,
         nonce: 1,
         participants: @[
-          EthAddress.parse("0x8a64E10FF40Bc9C90EA5750313dB5e036495c10E").get()
+          !EthAddress.init("0x8a64E10FF40Bc9C90EA5750313dB5e036495c10E")
         ]
       ),
       outcome: Outcome(@[]),
@@ -50,12 +50,12 @@ suite "signature":
       appDefinition: EthAddress.default,
       challengeDuration: 5
     )
-    let seckey = EthPrivateKey.parse(
+    let seckey = !EthPrivateKey.parse(
       "41b0f5f91967dded8af487277874f95116094cc6004ac2b2169b5b6a87608f3e"
-    ).get()
-    let expected = Signature.parse(
+    )
+    let expected = !Signature.parse(
       "9b966cf0065586d59c8b9eb475ac763c96ad8316b81061238f32968a631f9e21" &
       "251363c193c78c89b3eb2fec23f0ea5c3c72acff7d1f27430cfb84b9da9831fb" &
       "1c"
-    ).get()
+    )
     check seckey.sign(state) == expected

tests/nitro/protocol/testState.nim

@@ -23,26 +23,20 @@ suite "state":
     )
 
   test "hashes app part of state":
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(state.challengeDuration)
-    encoder.write(state.appDefinition)
-    encoder.write(state.appData)
-    encoder.finishTuple()
-    let encoded = encoder.finish()
+    let encoded = AbiEncoder.encode:
+      (state.challengeDuration, state.appDefinition, state.appData)
     let hashed = keccak256.digest(encoded).data
     check hashAppPart(state) == hashed
 
   test "hashes state":
-    var encoder= AbiEncoder.init()
-    encoder.startTuple()
-    encoder.write(state.turnNum)
-    encoder.write(state.isFinal)
-    encoder.write(getChannelId(state.channel))
-    encoder.write(hashAppPart(state))
-    encoder.write(hashOutcome(state.outcome))
-    encoder.finishTuple()
-    let encoded = encoder.finish()
+    let encoded = AbiEncoder.encode:
+      (
+        state.turnNum,
+        state.isFinal,
+        getChannelId(state.channel),
+        hashAppPart(state),
+        hashOutcome(state.outcome)
+      )
     let hashed = keccak256.digest(encoded).data
     check hashState(state) == hashed
 
@@ -52,7 +46,7 @@ suite "state":
         chainId: 0x1.u256,
         nonce: 1,
         participants: @[
-          EthAddress.parse("DBE821484648c73C1996Da25f2355342B9803eBD").get()
+          !EthAddress.init("DBE821484648c73C1996Da25f2355342B9803eBD")
         ]
       ),
       outcome: Outcome(@[]),

tests/nitro/testWallet.nim

@@ -23,29 +23,35 @@ suite "wallet: opening ledger channel":
 
   setup:
     wallet = Wallet.init(key)
-    channel = wallet.openLedgerChannel(hub, chainId, nonce, asset, amount).get
+    channel = !wallet.openLedgerChannel(hub, chainId, nonce, asset, amount)
 
   test "sets correct channel definition":
-    let definition = wallet.state(channel).get.channel
+    let definition = (!wallet.state(channel)).channel
     check definition.chainId == chainId
     check definition.nonce == nonce
     check definition.participants == @[wallet.address, hub]
 
+  test "uses consecutive nonces when none is provided":
+    channel = !wallet.openLedgerChannel(hub, chainId, asset, amount)
+    check (!wallet.state(channel)).channel.nonce == nonce + 1
+    channel = !wallet.openLedgerChannel(hub, chainId, asset, amount)
+    check (!wallet.state(channel)).channel.nonce == nonce + 2
+
   test "provides correct outcome":
-    let outcome = wallet.state(channel).get.outcome
+    let outcome = (!wallet.state(channel)).outcome
     check outcome == Outcome.init(asset, {wallet.destination: amount})
 
   test "signs the state":
-    let state = wallet.state(channel).get
-    let signatures = wallet.signatures(channel).get
+    let state = !wallet.state(channel)
+    let signatures = !wallet.signatures(channel)
     check signatures == @[key.sign(state)]
 
   test "sets app definition and app data to zero":
-    check wallet.state(channel).get.appDefinition == EthAddress.zero
-    check wallet.state(channel).get.appData.len == 0
+    check (!wallet.state(channel)).appDefinition == EthAddress.zero
+    check (!wallet.state(channel)).appData.len == 0
 
   test "does not allow opening a channel that already exists":
-    check wallet.openLedgerChannel(hub, chainId, nonce, asset, amount).isErr
+    check wallet.openLedgerChannel(hub, chainId, nonce, asset, amount).isFailure
 
 suite "wallet: accepting incoming channel":
 
@@ -59,26 +65,26 @@ suite "wallet: accepting incoming channel":
     signed.state.channel.participants &= @[wallet.address]
 
   test "returns the new channel id":
-    let channel = wallet.acceptChannel(signed).get
-    check wallet.state(channel).get == signed.state
+    let channel = !wallet.acceptChannel(signed)
+    check !wallet.state(channel) == signed.state
 
   test "signs the channel state":
-    let channel = wallet.acceptChannel(signed).get
+    let channel = !wallet.acceptChannel(signed)
     let expectedSignatures = @[key.sign(signed.state)]
-    check wallet.signatures(channel).get == expectedSignatures
+    check !wallet.signatures(channel) == expectedSignatures
 
   test "fails when wallet address is not a participant":
     let wrongParticipants = seq[EthAddress].example
     signed.state.channel.participants = wrongParticipants
-    check wallet.acceptChannel(signed).isErr
+    check wallet.acceptChannel(signed).isFailure
 
   test "fails when signatures are incorrect":
     signed.signatures = @[key.sign(State.example)]
-    check wallet.acceptChannel(signed).isErr
+    check wallet.acceptChannel(signed).isFailure
 
   test "fails when channel with this id already exists":
-    check wallet.acceptChannel(signed).isOk
-    check wallet.acceptChannel(signed).isErr
+    check wallet.acceptChannel(signed).isSuccess
+    check wallet.acceptChannel(signed).isFailure
 
 suite "wallet: making payments":
 
@@ -93,54 +99,54 @@ suite "wallet: making payments":
 
   test "paying updates the channel state":
     wallet = Wallet.init(key)
-    channel = wallet.openLedgerChannel(hub, chainId, nonce, asset, 100.u256).get
+    channel = !wallet.openLedgerChannel(hub, chainId, nonce, asset, 100.u256)
 
-    check wallet.pay(channel, asset, hub, 1.u256).isOk
+    check wallet.pay(channel, asset, hub, 1.u256).isSuccess
     check wallet.balance(channel, asset) == 99.u256
     check wallet.balance(channel, asset, hub) == 1.u256
 
-    check wallet.pay(channel, asset, hub, 2.u256).isOk
+    check wallet.pay(channel, asset, hub, 2.u256).isSuccess
     check wallet.balance(channel, asset) == 97.u256
     check wallet.balance(channel, asset, hub) == 3.u256
 
   test "paying updates signatures":
     wallet = Wallet.init(key)
-    channel = wallet.openLedgerChannel(hub, chainId, nonce, asset, 100.u256).get
-    check wallet.pay(channel, asset, hub, 1.u256).isOk
-    let expectedSignature = key.sign(wallet.state(channel).get)
+    channel = !wallet.openLedgerChannel(hub, chainId, nonce, asset, 100.u256)
+    check wallet.pay(channel, asset, hub, 1.u256).isSuccess
+    let expectedSignature = key.sign(!wallet.state(channel))
     check wallet.signature(channel, wallet.address) == expectedSignature.some
 
   test "pay returns the updated signed state":
     wallet = Wallet.init(key)
-    channel = wallet.openLedgerChannel(hub, chainId, nonce, asset, 42.u256).get
+    channel = !wallet.openLedgerChannel(hub, chainId, nonce, asset, 42.u256)
     let updated = wallet.pay(channel, asset, hub, 1.u256).option
-    check updated?.state == wallet.state(channel)
-    check updated?.signatures == wallet.signatures(channel)
+    check updated.?state == wallet.state(channel)
+    check updated.?signatures == wallet.signatures(channel)
 
   test "payment fails when channel not found":
     wallet = Wallet.init(key)
-    check wallet.pay(channel, asset, hub, 1.u256).isErr
+    check wallet.pay(channel, asset, hub, 1.u256).isFailure
 
   test "payment fails when asset not found":
     wallet = Wallet.init(key)
     var state = State.example
     state.channel.participants &= wallet.address
-    channel = wallet.acceptChannel(SignedState(state: state)).get
-    check wallet.pay(channel, asset, hub, 1.u256).isErr
+    channel = !wallet.acceptChannel(SignedState(state: state))
+    check wallet.pay(channel, asset, hub, 1.u256).isFailure
 
   test "payment fails when payer has no allocation":
     wallet = Wallet.init(key)
     var state: State
     state.channel = ChannelDefinition(participants: @[wallet.address])
     state.outcome = Outcome.init(asset, @[])
-    channel = wallet.acceptChannel(SignedState(state: state)).get
-    check wallet.pay(channel, asset, hub, 1.u256).isErr
+    channel = !wallet.acceptChannel(SignedState(state: state))
+    check wallet.pay(channel, asset, hub, 1.u256).isFailure
 
   test "payment fails when payer has insufficient funds":
     wallet = Wallet.init(key)
-    channel = wallet.openLedgerChannel(hub, chainId, nonce, asset, 1.u256).get
-    check wallet.pay(channel, asset, hub, 1.u256).isOk
-    check wallet.pay(channel, asset, hub, 1.u256).isErr
+    channel = !wallet.openLedgerChannel(hub, chainId, nonce, asset, 1.u256)
+    check wallet.pay(channel, asset, hub, 1.u256).isSuccess
+    check wallet.pay(channel, asset, hub, 1.u256).isFailure
 
 suite "wallet: accepting payments":
 
@@ -155,55 +161,71 @@ suite "wallet: accepting payments":
   setup:
     payer = Wallet.init(payerKey)
     receiver = Wallet.init(receiverKey)
-    channel = payer.openLedgerChannel(
-      receiver.address, chainId, nonce, asset, 100.u256).get
-    let update = payer.latestSignedState(channel).get
+    channel = !payer.openLedgerChannel(
+      receiver.address, chainId, nonce, asset, 100.u256)
+    let update = !payer.latestSignedState(channel)
     discard receiver.acceptChannel(update)
 
   test "updates channel state":
-    let payment = payer.pay(channel, asset, receiver.address, 42.u256).get
-    check receiver.acceptPayment(channel, asset, payer.address, payment).isOk
+    let payment = !payer.pay(channel, asset, receiver.address, 42.u256)
+    check receiver.acceptPayment(channel, asset, payer.address, payment).isSuccess
     check receiver.balance(channel, asset) == 42.u256
 
   test "fails when receiver balance is decreased":
-    let payment1 = payer.pay(channel, asset, receiver.address, 10.u256).get
-    let payment2 = payer.pay(channel, asset, receiver.address, 10.u256).get
-    check receiver.acceptPayment(channel, asset, payer.address, payment1).isOk
-    check receiver.acceptPayment(channel, asset, payer.address, payment2).isOk
-    check receiver.acceptPayment(channel, asset, payer.address, payment1).isErr
+    let payment1 = !payer.pay(channel, asset, receiver.address, 10.u256)
+    let payment2 = !payer.pay(channel, asset, receiver.address, 10.u256)
+    check receiver.acceptPayment(channel, asset, payer.address, payment1).isSuccess
+    check receiver.acceptPayment(channel, asset, payer.address, payment2).isSuccess
+    check receiver.acceptPayment(channel, asset, payer.address, payment1).isFailure
     check receiver.balance(channel, asset) == 20
 
   test "fails when the total supply of the asset changes":
-    var payment = payer.pay(channel, asset, receiver.address, 10.u256).get
-    var balances = payment.state.outcome.balances(asset).get
+    var payment = !payer.pay(channel, asset, receiver.address, 10.u256)
+    var balances = !payment.state.outcome.balances(asset)
     balances[payer.destination] += 10.u256
     payment.state.outcome.update(asset, balances)
-    check receiver.acceptPayment(channel, asset, payer.address, payment).isErr
+    check receiver.acceptPayment(channel, asset, payer.address, payment).isFailure
 
   test "fails without a signature":
-    var payment = payer.pay(channel, asset, receiver.address, 10.u256).get
+    var payment = !payer.pay(channel, asset, receiver.address, 10.u256)
     payment.signatures = @[]
-    check receiver.acceptPayment(channel, asset, payer.address, payment).isErr
+    check receiver.acceptPayment(channel, asset, payer.address, payment).isFailure
 
   test "fails with an incorrect signature":
-    var payment = payer.pay(channel, asset, receiver.address, 10.u256).get
+    var payment = !payer.pay(channel, asset, receiver.address, 10.u256)
     payment.signatures = @[Signature.example]
-    check receiver.acceptPayment(channel, asset, payer.address, payment).isErr
+    check receiver.acceptPayment(channel, asset, payer.address, payment).isFailure
 
   test "fails when channel is unknown":
-    let newChannel = payer.openLedgerChannel(
-      receiver.address, chainId, nonce + 1, asset, 100.u256).get
-    let payment = payer.pay(newChannel, asset, receiver.address, 10.u256).get
-    check receiver.acceptPayment(newChannel, asset, payer.address, payment).isErr
+    let newChannel = !payer.openLedgerChannel(
+      receiver.address, chainId, nonce + 1, asset, 100.u256)
+    let payment = !payer.pay(newChannel, asset, receiver.address, 10.u256)
+    check receiver.acceptPayment(newChannel, asset, payer.address, payment).isFailure
 
   test "fails when payment does not match channel":
-    let newChannel = payer.openLedgerChannel(
-      receiver.address, chainId, nonce + 1, asset, 100.u256).get
-    let payment = payer.pay(newChannel, asset, receiver.address, 10.u256).get
-    check receiver.acceptPayment(channel, asset, payer.address, payment).isErr
+    let newChannel = !payer.openLedgerChannel(
+      receiver.address, chainId, nonce + 1, asset, 100.u256)
+    let payment = !payer.pay(newChannel, asset, receiver.address, 10.u256)
+    check receiver.acceptPayment(channel, asset, payer.address, payment).isFailure
 
   test "fails when state is updated in unrelated areas":
-    var payment = payer.pay(channel, asset, receiver.address, 10.u256).get
+    var payment = !payer.pay(channel, asset, receiver.address, 10.u256)
     payment.state.appDefinition = EthAddress.example
     payment.signatures = @[payerKey.sign(payment.state)]
-    check receiver.acceptPayment(channel, asset, payer.address, payment).isErr
+    check receiver.acceptPayment(channel, asset, payer.address, payment).isFailure
+
+suite "wallet reference type":
+
+  let asset = EthAddress.example
+  let amount = 42.u256
+  let chainId = UInt256.example
+
+  test "wallet can also be used as a reference type":
+    let wallet1 = WalletRef.new(EthPrivateKey.random())
+    let wallet2 = WalletRef.new(EthPrivateKey.random())
+    let address1 = wallet1.address
+    let address2 = wallet2.address
+    let channel = !wallet1.openLedgerChannel(address2, chainId, asset, amount)
+    check !wallet2.acceptChannel(!wallet1.latestSignedState(channel)) == channel
+    let payment = !wallet1.pay(channel, asset, address2, amount)
+    check wallet2.acceptPayment(channel, asset, address1, payment).isSuccess

tests/nitro/wallet/testNonces.nim

@@ -0,0 +1,37 @@
+import ../basics
+import pkg/nitro/wallet/nonces
+
+suite "nonces":
+
+  let chainId = UInt256.example
+  let participants = seq[EthAddress].example(1..5)
+
+  var nonces: Nonces
+
+  setup:
+    nonces = Nonces()
+
+  test "nonces start at 0":
+    check nonces.getNonce(chainId, participants) == 0
+
+  test "nonces increase by 1":
+    nonces.incNonce(0, chainId, participants)
+    check nonces.getNonce(chainId, participants) == 1
+    nonces.incNonce(1, chainId, participants)
+    check nonces.getNonce(chainId, participants) == 2
+
+  test "nonces do not decrease":
+    nonces.incNonce(100, chainId, participants)
+    check nonces.getNonce(chainId, participants) == 101
+    nonces.incNonce(0, chainId, participants)
+    check nonces.getNonce(chainId, participants) == 102
+
+  test "nonces are different when participants differ":
+    let otherParticipants = seq[EthAddress].example(1..5)
+    nonces.incNonce(0, chainId, participants)
+    check nonces.getNonce(chainId, otherParticipants) == 0
+
+  test "nonces are different when chain ids differ":
+    let otherChainId = UInt256.example
+    nonces.incNonce(0, chainId, participants)
+    check nonces.getNonce(otherChainId, participants) == 0

tests/testAll.nim

@@ -3,6 +3,7 @@ import ./nitro/protocol/testChannel
 import ./nitro/protocol/testOutcome
 import ./nitro/protocol/testState
 import ./nitro/protocol/testSignature
+import ./nitro/wallet/testNonces
 import ./nitro/testWallet
 import ./nitro/testJson