Refactored processing of params for client

eth-rpc/client/jsonmarshal.nim

@@ -0,0 +1,125 @@
+import macros, json, ../ jsonconverters, stint
+
+template expect*(actual, expected: JsonNodeKind, argName: string) =
+  if actual != expected: raise newException(ValueError, "Parameter \"" & argName & "\" expected " & $expected & " but got " & $actual)
+
+proc fromJson(n: JsonNode, argName: string, result: var bool) =
+  n.kind.expect(JBool, argName)
+  result = n.getBool()
+
+proc fromJson(n: JsonNode, argName: string, result: var int) =
+  n.kind.expect(JInt, argName)
+  result = n.getInt()
+
+# TODO: Why does compiler complain that result cannot be assigned to when using result: var int|var int64
+# TODO: Compiler requires forward decl when processing out of module
+proc fromJson(n: JsonNode, argName: string, result: var byte)
+proc fromJson(n: JsonNode, argName: string, result: var float)
+proc fromJson(n: JsonNode, argName: string, result: var string)
+proc fromJson[T](n: JsonNode, argName: string, result: var seq[T])
+proc fromJson[N, T](n: JsonNode, argName: string, result: var array[N, T])
+proc fromJson(n: JsonNode, argName: string, result: var UInt256)
+proc fromJson(n: JsonNode, argName: string, result: var int64)
+proc fromJson(n: JsonNode, argName: string, result: var ref int64)
+proc fromJson(n: JsonNode, argName: string, result: var ref int)
+proc fromJson(n: JsonNode, argName: string, result: var ref UInt256)
+
+# TODO: Why can't this be forward declared? Complains of lack of definition
+proc fromJson[T: enum](n: JsonNode, argName: string, result: var T) =
+  n.kind.expect(JInt, argName)
+  result = n.getInt().T
+
+# TODO: Why can't this be forward declared? Complains of lack of definition
+proc fromJson[T: object](n: JsonNode, argName: string, result: var T) =
+  n.kind.expect(JObject, argName)
+  for k, v in fieldpairs(result):
+    fromJson(n[k], k, v)
+
+proc fromJson[T: ref object](n: JsonNode, argName: string, result: var T) =
+  n.kind.expect(JObject, argName)
+  result = new T
+  for k, v in fieldpairs(result[]):
+    fromJson(n[k], k, v)
+
+proc fromJson(n: JsonNode, argName: string, result: var int64) =
+  n.kind.expect(JInt, argName)
+  result = n.getInt()
+
+proc fromJson(n: JsonNode, argName: string, result: var ref int64) =
+  n.kind.expect(JInt, argName)
+  new result
+  result[] = n.getInt()
+
+proc fromJson(n: JsonNode, argName: string, result: var ref int) =
+  n.kind.expect(JInt, argName)
+  new result
+  result[] = n.getInt()
+
+proc fromJson(n: JsonNode, argName: string, result: var byte) =
+  n.kind.expect(JInt, argName)
+  let v = n.getInt()
+  if v > 255 or v < 0: raise newException(ValueError, "Parameter \"" & argName & "\" value out of range for byte: " & $v)
+  result = byte(v)
+
+proc fromJson(n: JsonNode, argName: string, result: var UInt256) =
+  # expects base 16 string, starting with "0x"
+  n.kind.expect(JString, argName)
+  let hexStr = n.getStr()
+  if hexStr.len > 64 + 2: # including "0x"
+    raise newException(ValueError, "Parameter \"" & argName & "\" value too long for UInt256: " & $hexStr.len)
+  result = hexStr.parse(StUint[256], 16) # TODO: Handle errors
+
+proc fromJson(n: JsonNode, argName: string, result: var ref UInt256) =
+  # expects base 16 string, starting with "0x"
+  n.kind.expect(JString, argName)
+  let hexStr = n.getStr()
+  if hexStr.len > 64 + 2: # including "0x"
+    raise newException(ValueError, "Parameter \"" & argName & "\" value too long for UInt256: " & $hexStr.len)
+  new result
+  result[] = hexStr.parse(StUint[256], 16) # TODO: Handle errors
+
+proc fromJson(n: JsonNode, argName: string, result: var float) =
+  n.kind.expect(JFloat, argName)
+  result = n.getFloat()
+
+proc fromJson(n: JsonNode, argName: string, result: var string) =
+  n.kind.expect(JString, argName)
+  result = n.getStr()
+
+proc fromJson[T](n: JsonNode, argName: string, result: var seq[T]) =
+  n.kind.expect(JArray, argName)
+  result = newSeq[T](n.len)
+  for i in 0 ..< n.len:
+    fromJson(n[i], argName, result[i])
+
+proc fromJson[N, T](n: JsonNode, argName: string, result: var array[N, T]) =
+  n.kind.expect(JArray, argName)
+  if n.len > result.len: raise newException(ValueError, "Parameter \"" & argName & "\" item count is too big for array")
+  for i in 0 ..< n.len:
+    fromJson(n[i], argName, result[i])
+
+import typetraits
+proc unpackArg[T](args: JsonNode, argName: string, argtype: typedesc[T]): T =
+  fromJson(args, argName, result)
+
+proc expectArrayLen(node: NimNode, paramsIdent: untyped, length: int) =
+  let
+    identStr = paramsIdent.repr
+    expectedStr = "Expected " & $length & " Json parameter(s) but got "
+  node.add(quote do:
+    `paramsIdent`.kind.expect(JArray, `identStr`)
+    if `paramsIdent`.len != `length`:
+      raise newException(ValueError, `expectedStr` & $`paramsIdent`.len)
+  )
+
+proc setupParamFromJson*(assignIdent, paramType, jsonIdent: NimNode): NimNode =
+  # Add code to verify input and load json parameters into provided Nim type
+  result = newStmtList()
+  # initial parameter array length check
+  # TODO: do this higher up
+  #result.expectArrayLen(jsonIdent, nimParameters.len - 1)
+  # unpack each parameter and provide assignments
+  let paramNameStr = $assignIdent
+  result.add(quote do:
+    `assignIdent` = `unpackArg`(`jsonIdent`, `paramNameStr`, type(`paramType`))
+  )