nim-json-rpc/eth-rpc/client/jsonmarshal.nim
2018-05-29 13:20:07 +03:00

125 lines
5.0 KiB
Nim

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`))
)