roezio/config: Builder pattern

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>

src/config.rs

@@ -15,13 +15,13 @@
 
 use crate::error::Error;
 
-use std::cell::LazyCell;
 use std::collections::HashMap;
 use std::fmt;
 use std::fs;
 use std::io::{BufRead, BufReader, BufWriter, Read, Seek, SeekFrom, Write};
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
+use std::sync::LazyLock;
 
 use configparser::ini::Ini;
 use jid::Jid;
@@ -102,34 +102,60 @@ fn parse_assignment(i: &str) -> IResult<&str, &str> {
     Ok((i, key))
 }
 
-pub(crate) const DEFAULT_CONFIG: LazyCell<HashMap<&str, HashMap<&str, ConfigValue>>> =
-    LazyCell::new(|| HashMap::new());
+pub(crate) static DEFAULT_CONFIG: LazyLock<HashMap<&str, HashMap<&str, ConfigValue>>> =
+    LazyLock::new(|| HashMap::new());
 
+pub(crate) struct ConfigBuilder<'a> {
+    filename: PathBuf,
+    default_section: Option<&'a str>,
+    defaults: Option<&'a HashMap<&'a str, HashMap<&'a str, ConfigValue>>>,
+}
+
+impl<'a> ConfigBuilder<'a> {
+    pub(crate) fn with_default_section(mut self, name: &'a str) -> ConfigBuilder<'a> {
+        self.default_section = Some(name);
+        self
+    }
+
+    pub(crate) fn with_defaults(
+        mut self,
+        defaults: &'a HashMap<&'a str, HashMap<&'a str, ConfigValue>>,
+    ) -> ConfigBuilder<'a> {
+        self.defaults = Some(defaults);
+        self
+    }
+
+    /// Builds the Config object
+    pub(crate) fn build(self) -> Result<Config<'a>, Error> {
+        let filename: PathBuf = self.filename;
+        let mut ini = Ini::new();
+        ini.load::<&Path>(filename.as_ref())
+            .map_err(|_| Error::UnableToOpenConfigFile(filename.clone()))?;
+
+        Ok(Config {
+            filename,
+            defaults: self.defaults.unwrap_or(&DEFAULT_CONFIG),
+            default_section: self.default_section.unwrap_or("Poezio"),
+            ini: Ini::new(),
+        })
+    }
+}
+
+#[derive(Debug)]
 pub(crate) struct Config<'a> {
     filename: PathBuf,
-    defaults: HashMap<&'a str, HashMap<&'a str, ConfigValue>>,
+    defaults: &'a HashMap<&'a str, HashMap<&'a str, ConfigValue>>,
     default_section: &'a str,
     ini: Ini,
 }
 
 impl<'a> Config<'a> {
-    /// Create a new Config object
-    pub(crate) fn new<P: Into<PathBuf>>(
-        filename: P,
-        defaults: HashMap<&'a str, HashMap<&'a str, ConfigValue>>,
-        default_section: Option<&'a str>,
-    ) -> Result<Self, Error> {
-        let filename: PathBuf = filename.into();
-        let mut ini = Ini::new();
-        ini.load(filename.clone())
-            .map_err(|_| Error::UnableToOpenConfigFile(filename.clone()))?;
-
-        Ok(Config {
-            filename,
-            defaults,
-            default_section: default_section.unwrap_or("default"),
-            ini: Ini::new(),
-        })
+    pub(crate) fn builder<P: Into<PathBuf>>(filename: P) -> ConfigBuilder<'a> {
+        ConfigBuilder {
+            filename: filename.into(),
+            default_section: None,
+            defaults: None,
+        }
     }
 
     /// Sets a key/value pair in memory and updates the config file.