Add support for optional args with default text

parity/cli/mod.rs

@@ -91,8 +91,6 @@ usage! {
 		flag_no_download: bool = false, or |c: &Config| otry!(c.parity).no_download.clone(),
 		flag_no_consensus: bool = false, or |c: &Config| otry!(c.parity).no_consensus.clone(),
 		flag_chain: String = "homestead", or |c: &Config| otry!(c.parity).chain.clone(),
-		flag_base_path: String = dir::default_data_path(), or |c: &Config| otry!(c.parity).base_path.clone(),
-		flag_db_path: String = dir::CHAINS_PATH, or |c: &Config| otry!(c.parity).db_path.clone(),
 		flag_keys_path: String = "$BASE/keys", or |c: &Config| otry!(c.parity).keys_path.clone(),
 		flag_identity: String = "", or |c: &Config| otry!(c.parity).identity.clone(),
 
@@ -289,6 +287,11 @@ usage! {
 		flag_no_color: bool = false,
 			or |c: &Config| otry!(c.misc).color.map(|c| !c).clone(),
 	}
+	{
+		// Values with optional default value.
+		flag_base_path: Option<String>, display dir::default_data_path(), or |c: &Config| otry!(c.parity).base_path.clone().map(Some),
+		flag_db_path: Option<String>, display dir::CHAINS_PATH, or |c: &Config| otry!(c.parity).db_path.clone().map(Some),
+	}
 }
 
 
@@ -547,8 +550,8 @@ mod tests {
 			flag_no_download: false,
 			flag_no_consensus: false,
 			flag_chain: "xyz".into(),
-			flag_base_path: "$HOME/.parity".into(),
-			flag_db_path: "$HOME/.parity/chains".into(),
+			flag_base_path: Some("$HOME/.parity".into()),
+			flag_db_path: Some("$HOME/.parity/chains".into()),
 			flag_keys_path: "$HOME/.parity/keys".into(),
 			flag_identity: "".into(),
 

parity/cli/usage.rs

@@ -43,6 +43,11 @@ macro_rules! usage {
 				$field:ident : $typ:ty = $default:expr, or $from_config:expr,
 			)*
 		}
+		{
+			$(
+				$field_s:ident : $typ_s:ty, display $default_s:expr, or $from_config_s:expr,
+			)*
+		}
 	) => {
 		use toml;
 		use std::{fs, io, process};
@@ -108,6 +113,10 @@ macro_rules! usage {
 			$(
 				pub $field: $typ,
 			)*
+
+			$(
+				pub $field_s: $typ_s,
+			)*
 		}
 
 		impl Default for Args {
@@ -120,6 +129,10 @@ macro_rules! usage {
 					$(
 						$field: $default.into(),
 					)*
+
+					$(
+						$field_s: Default::default(),
+					)*
 				}
 			}
 		}
@@ -132,6 +145,9 @@ macro_rules! usage {
 			$(
 				$field: Option<$typ>,
 			)*
+			$(
+				$field_s: Option<$typ_s>,
+			)*
 		}
 
 		impl Args {
@@ -206,6 +222,9 @@ macro_rules! usage {
 				$(
 					args.$field = self.$field.or_else(|| $from_config(&config)).unwrap_or_else(|| $default.into());
 				)*
+				$(
+					args.$field_s = self.$field_s.or_else(|| $from_config_s(&config)).unwrap_or(None);
+				)*
 				args
 			}
 
@@ -222,6 +241,9 @@ macro_rules! usage {
 						// "named argument never used" error
 						// $field = $default,
 					)*
+					$(
+						$field_s = $default_s,
+					)*
 				)
 			}
 		}

parity/configuration.rs

@@ -734,10 +734,14 @@ impl Configuration {
 		use util::path;
 
 		let local_path = default_local_path();
-		let data_path = replace_home("", self.args.flag_datadir.as_ref().unwrap_or(&self.args.flag_base_path));
-
-		//TODO: refactor this for better detection if base_path is custom.
-		let base_db_path = if data_path != default_data_path() && self.args.flag_db_path == dir::CHAINS_PATH { "$BASE/chains".to_owned() } else { self.args.flag_db_path.clone() };
+		let base_path = self.args.flag_base_path.as_ref().map_or_else(|| default_data_path(), |s| s.clone());
+		let data_path = replace_home("", self.args.flag_datadir.as_ref().unwrap_or(&base_path));
+		let base_db_path = if self.args.flag_base_path.is_some() && self.args.flag_db_path.is_none() {
+			// If base_path is set and db_path is not we default to base path subdir instead of LOCAL.
+			"$BASE/chains"
+		} else {
+			self.args.flag_db_path.as_ref().map_or(dir::CHAINS_PATH, |s| &s)
+		};
 
 		let db_path = replace_home_for_db(&data_path, &local_path, &base_db_path);
 		let keys_path = replace_home(&data_path, &self.args.flag_keys_path);