Rename settings::BoolValue => ConfigValue; refactor/cleanup (#272)

Renames the type used for storing a configuration setting.

Also changes the internal functions to use `Option<ConfigValue>` as the
return value, rather than comparing to a default value, which makes them
slightly more idiomatic.

src/key.rs

@@ -473,7 +473,7 @@ pub fn generate(
     const SZ_ROCA_BLOCK_ADMIN: &str = "was blocked due to an administrator configuration setting.";
     const SZ_ROCA_DEFAULT: &str = "was permitted by default, but is not recommended.  The default behavior will change in a future Yubico release.";
 
-    let setting_roca: settings::BoolValue;
+    let setting_roca: settings::ConfigValue;
 
     match algorithm {
         AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => {
@@ -481,7 +481,7 @@ pub fn generate(
                 && (yubikey.version.minor < 3
                     || yubikey.version.minor == 3 && (yubikey.version.patch < 5))
             {
-                setting_roca = settings::BoolValue::get(SZ_SETTING_ROCA, true);
+                setting_roca = settings::ConfigValue::get(SZ_SETTING_ROCA, true);
 
                 let psz_msg = match setting_roca.source {
                     settings::Source::User => {

src/settings.rs

@@ -53,45 +53,36 @@ pub enum Source {
     Default,
 }
 
+impl Default for Source {
+    fn default() -> Self {
+        Self::Default
+    }
+}
+
 /// Setting booleans
 #[derive(Copy, Clone, Debug)]
-pub struct BoolValue {
+pub struct ConfigValue {
     /// Boolean value
     pub value: bool,
 
-    /// Source of the configuration setting (user/admin/default)
+    /// Source of the configuration setting (user, admin, or default)
     pub source: Source,
 }
 
-impl BoolValue {
-    /// Get a [`BoolValue`] value
-    pub fn get(key: &str, def: bool) -> Self {
-        let mut setting = get_setting_from_file(key);
-
-        if setting.source == Source::Default {
-            setting = get_setting_from_env(key);
-        }
-
-        if setting.source == Source::Default {
-            setting.value = def;
-        }
-
-        setting
-    }
-}
-
-/// Get a boolean config value
-fn get_setting_from_file(key: &str) -> BoolValue {
-    let mut setting: BoolValue = BoolValue {
-        value: false,
+impl ConfigValue {
+    /// Get a [`BoolValue`] value by name.
+    pub fn get(key: &str, default: bool) -> Self {
+        Self::from_file(key)
+            .or_else(|| Self::from_env(key))
+            .unwrap_or(Self {
+                value: default,
                 source: Source::Default,
-    };
-
-    let file = match File::open(DEFAULT_CONFIG_FILE) {
-        Ok(f) => f,
-        Err(_) => return setting,
-    };
+            })
+    }
 
+    /// Get a boolean config value from the provided config file
+    fn from_file(key: &str) -> Option<Self> {
+        if let Ok(file) = File::open(DEFAULT_CONFIG_FILE) {
             for line in BufReader::new(file).lines() {
                 let line = match line {
                     Ok(line) => line,
@@ -113,26 +104,33 @@ fn get_setting_from_file(key: &str) -> BoolValue {
                 };
 
                 if name == key {
-            setting.source = Source::Admin;
-            setting.value = value == "1" || value == "true";
-            break;
+                    return Some(ConfigValue {
+                        source: Source::Admin,
+                        value: value == "1" || value == "true",
+                    });
+                }
             }
         }
 
-    setting
+        None
+    }
+
+    /// Get a setting boolean from an environment variable
+    fn from_env(key: &str) -> Option<Self> {
+        env::var(format!("YUBIKEY_PIV_{}", key))
+            .ok()
+            .map(|value| ConfigValue {
+                source: Source::User,
+                value: value == "1" || value == "true",
+            })
+    }
 }
 
-/// Get a setting boolean from an environment variable
-fn get_setting_from_env(key: &str) -> BoolValue {
-    let mut setting: BoolValue = BoolValue {
+impl Default for ConfigValue {
+    fn default() -> Self {
+        Self {
             value: false,
-        source: Source::Default,
-    };
-
-    if let Ok(value) = env::var(format!("YUBIKEY_PIV_{}", key)) {
-        setting.source = Source::User;
-        setting.value = value == "1" || value == "true";
+            source: Source::default(),
+        }
     }
-
-    setting
 }