112 lines
3.4 KiB
Nim
112 lines
3.4 KiB
Nim
# Nimbus
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# Copyright (c) 2018 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
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# * MIT license ([LICENSE-MIT](LICENSE-MIT))
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# at your option.
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# This file may not be copied, modified, or distributed except according to
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# those terms.
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## This module implements the Ethereum hexadecimal string formats for JSON
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## See: https://github.com/ethereum/wiki/wiki/JSON-RPC#hex-value-encoding
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type
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HexQuantityStr* = distinct string
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HexDataStr* = distinct string
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# Hex validation
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template stripLeadingZeros(value: string): string =
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var cidx = 0
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# ignore the last character so we retain '0' on zero value
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while cidx < value.len - 1 and value[cidx] == '0':
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cidx.inc
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value[cidx .. ^1]
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proc encodeQuantity*(value: SomeUnsignedInt): string =
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var hValue = value.toHex.stripLeadingZeros
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result = "0x" & hValue
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template hasHexHeader*(value: string): bool =
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if value != "" and value[0] == '0' and value[1] in {'x', 'X'} and value.len > 2: true
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else: false
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template isHexChar*(c: char): bool =
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if c notin {'0'..'9'} and
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c notin {'a'..'f'} and
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c notin {'A'..'F'}: false
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else: true
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proc validateHexQuantity*(value: string): bool =
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if value.len < 3 or not value.hasHexHeader:
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return false
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# No leading zeros (but allow 0x0)
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if value.len > 3 and value[2] == '0': return false
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for i in 2 ..< value.len:
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let c = value[i]
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if not c.isHexChar:
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return false
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return true
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proc validateHexData*(value: string): bool =
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if value.len < 3 or not value.hasHexHeader:
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return false
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# Must be even number of digits
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if value.len mod 2 != 0: return false
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# Leading zeros are allowed
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for i in 2 ..< value.len:
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let c = value[i]
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if not c.isHexChar:
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return false
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return true
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const
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SInvalidQuantity = "Invalid hex quantity format for Ethereum"
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SInvalidData = "Invalid hex data format for Ethereum"
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proc validateRaiseHexQuantity*(value: string) =
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if not value.validateHexQuantity:
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raise newException(ValueError, SInvalidQuantity & ": " & value)
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proc validateRaiseHexData*(value: string) =
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if not value.validateHexData:
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raise newException(ValueError, SInvalidData & ": " & value)
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# Initialisation
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proc hexQuantityStr*(value: string): HexQuantityStr =
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value.validateRaiseHexQuantity
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result = value.HexQuantityStr
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proc hexDataStr*(value: string): HexDataStr =
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value.validateRaiseHexData
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result = value.HexDataStr
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# Converters for use in RPC
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import json
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from json_rpc/rpcserver import expect
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proc `%`*(value: HexQuantityStr): JsonNode =
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result = %(value.string)
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proc `%`*(value: HexDataStr): JsonNode =
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result = %(value.string)
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proc fromJson*(n: JsonNode, argName: string, result: var HexQuantityStr) =
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# Note that '0x' is stripped after validation
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n.kind.expect(JString, argName)
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let hexStr = n.getStr()
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if not hexStr.validateHexQuantity:
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raise newException(ValueError, "Parameter \"" & argName & "\" is not valid as an Ethereum hex quantity \"" & hexStr & "\"")
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result = hexStr.hexQuantityStr
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proc fromJson*(n: JsonNode, argName: string, result: var HexDataStr) =
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# Note that '0x' is stripped after validation
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n.kind.expect(JString, argName)
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let hexStr = n.getStr()
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if not hexStr.validateHexData:
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raise newException(ValueError, "Parameter \"" & argName & "\" is not valid as a Ethereum data \"" & hexStr & "\"")
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result = hexStr.hexDataStr
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