add configuration

premix/configuration.nim

@@ -0,0 +1,83 @@
+import stint, os, parseopt, strutils
+from ../nimbus/config import getDefaultDataDir, ConfigStatus, processInteger
+
+export ConfigStatus
+
+type
+  PremixConfiguration* = ref object
+    dataDir*: string
+    head*: Uint256
+    maxBlocks*: int
+    numCommits*: int
+
+var premixConfig {.threadvar.}: PremixConfiguration
+
+proc getConfiguration*(): PremixConfiguration {.gcsafe.}
+
+proc initConfiguration(): PremixConfiguration =
+  result = new PremixConfiguration
+
+  const dataDir = getDefaultDataDir()
+
+  result.dataDir = getHomeDir() / dataDir
+  result.head = 0.u256
+  result.maxBlocks = 0
+  result.numCommits = 128
+
+proc getConfiguration*(): PremixConfiguration =
+  if isNil(premixConfig):
+    premixConfig = initConfiguration()
+  result = premixConfig
+
+proc processU256(val: string, o: var Uint256): ConfigStatus =
+  if val.len > 2 and val[0] == '0' and val[1] == 'x':
+    o = Uint256.fromHex(val)
+  else:
+    o = parse(val, Uint256)
+  result = Success
+
+template checkArgument(fun, o: untyped) =
+  ## Checks if arguments got processed successfully
+  var res = (fun)(value, o)
+  if res == Success:
+    continue
+  elif res == ErrorParseOption:
+    msg = "Error processing option [" & key & "] with value [" & value & "]"
+    result = res
+    break
+  elif res == ErrorIncorrectOption:
+    msg = "Incorrect value for option [" & key & "] value [" & value & "]"
+    result = res
+    break
+
+proc processArguments*(msg: var string): ConfigStatus =
+  var
+    opt = initOptParser()
+    length = 0
+    config = getConfiguration()
+
+  result = Success
+  for kind, key, value in opt.getopt():
+    case kind
+    of cmdArgument:
+      discard
+    of cmdLongOption, cmdShortOption:
+      inc(length)
+      case key.toLowerAscii()
+      of "datadir": config.dataDir = value
+      of "maxblocks":
+        checkArgument processInteger, config.maxBlocks
+      of "head":
+        checkArgument processU256, config.head
+      of "numcommits":
+        checkArgument processInteger, config.numCommits
+        config.numCommits = max(config.numCommits, 512)
+      else:
+        msg = "Unknown option " & key
+        if value.len > 0: msg = msg & " : " & value
+        result = ErrorUnknownOption
+        break
+    of cmdEnd:
+      msg = "Error processing option [" & key & "]"
+      result = ErrorParseOption
+      break