fixes winreg Option[T] decoder

confutils/winreg/reader.nim

@@ -30,8 +30,6 @@ proc init*(T: type WinregReader,
   result.hKey = hKey
   result.path = path
 
-template getUnderlyingType*[T](_: Option[T]): untyped = T
-
 proc readValue*[T](r: var WinregReader, value: var T) =
   mixin readValue
   # TODO: reduce allocation
@@ -40,10 +38,11 @@ proc readValue*[T](r: var WinregReader, value: var T) =
     let path = constructPath(r.path, r.key)
     discard getValue(r.hKey, path, r.key[^1], value)
   elif T is Option:
+    template getUnderlyingType[T](_: Option[T]): untyped = T
+    type UT = getUnderlyingType(value)
     let path = constructPath(r.path, r.key)
-    var outVal: getUnderlyingType(value)
-    if getValue(r.hKey, path, r.key[^1], outVal):
-      value = some(outVal)
+    if pathExists(r.hKey, path, r.key[^1]):
+      value = some(r.readValue(UT))
   elif T is (seq or array):
     when uTypeIsPrimitives(T):
       let path = constructPath(r.path, r.key)

confutils/winreg/utils.nim

@@ -1,5 +1,5 @@
 import
-  strutils,
+  strutils, os,
   ./types
 
 type
@@ -17,6 +17,8 @@ const
   RT_QWORD*  = 0x00000040
   RT_ANY*    = 0x0000ffff
 
+  MAX_ELEM_SIZE = 16_383'i32
+
 proc regGetValue(hKey: HKEY, lpSubKey, lpValue: cstring,
                  dwFlags: int32, pdwType: ptr RegType,
                  pvData: pointer, pcbData: ptr int32): int32 {.
@@ -77,6 +79,9 @@ proc getValue*(hKey: HKEY, path, key: string, outVal: var SomePrimitives): bool
     call regGetValue(hKey, path, key, RT_QWORD, nil, outVal.addr, valSize.addr)
   result = true
 
+proc pathExists*(hKey: HKEY, path, key: string): bool {.inline.} =
+  result = regGetValue(hKey, path, key, RT_ANY, nil, nil, nil) == 0
+
 proc parseWinregPath*(input: string): (HKEY, string) =
   let pos = input.find('\\')
   if pos < 0: return

confutils/winreg/winreg_serialization.nim

@@ -49,7 +49,7 @@ template loadFile*(_: type Winreg,
   var reader = unpackArgs(init, [WinregReader, hKey, path, params])
   reader.readValue(RecordType)
 
-template saveFile*(Format: type, filename: string, value: auto, params: varargs[untyped]) =
+template saveFile*(_: type Winreg, filename: string, value: auto, params: varargs[untyped]) =
   mixin init, WriterType, writeValue
 
   # filename should be a Windows Registry path

tests/test_winreg.nim

@@ -1,5 +1,5 @@
 import
-  unittest, options,
+  unittest, options, os,
   ../confutils/winreg/winreg_serialization,
   ../confutils/winreg/utils
 
@@ -95,5 +95,29 @@ proc testEncoder() =
       check x.antennae.isNone
       check x.bumper.get() == "Chromium"
 
+type
+  ValidIpAddress {.requiresInit.} = object
+    value: string
+
+  TestObject = object
+    address: Option[ValidIpAddress]
+
+proc readValue(r: var WinregReader, value: var ValidIpAddress) =
+  r.readValue(value.value)
+
+proc writeValue(w: var WinregWriter, value: ValidIpAddress) =
+  w.writeValue(value.value)
+
+proc testOptionalFields() =
+  suite "optional fields test suite":
+    test "optional field with requiresInit pragma":
+
+      var z = TestObject(address: some(ValidIpAddress(value: "1.2.3.4")))
+      Winreg.saveFile("HKCU" / commonPath, z)
+      var x = Winreg.loadFile("HKCU" / commonPath, TestObject)
+      check x.address.isSome
+      check x.address.get().value == "1.2.3.4"
+
 testUtils()
 testEncoder()
+testOptionalFields()