make true color support bool a static

paves the way for a Default implementation for Theme

helix-term/src/main.rs

@@ -83,14 +83,15 @@ async fn main_impl() -> Result<i32> {
             }
         }
     };
+    Theme::set_true_color_support(true_color_support);
     let theme: Theme = match config.theme.as_deref() {
-        Some(theme_name) => Theme::new(theme_name, true_color_support).unwrap_or_else(|err| {
+        Some(theme_name) => Theme::new(theme_name).unwrap_or_else(|err| {
             eprintln!("Bad theme config: {}", err);
             eprintln!("Press <ENTER> to continue with default theme config");
             let _wait_for_enter = std::io::Read::read(&mut std::io::stdin(), &mut []);
-            Theme::default(true_color_support)
+            Theme::default()
         }),
-        None => Theme::default(true_color_support),
+        None => Theme::default(),
     };
 
     // TODO: use the thread local executor to spawn the application task separately from the work pool

helix-term/tests/test/helpers.rs

@@ -123,7 +123,7 @@ pub async fn test_key_sequence_with_input_text<T: Into<TestCase>>(
         None => Application::new(
             Args::default(),
             test_config(),
-            Theme::default(true),
+            Theme::default(),
             test_syntax_conf(None),
         )?,
     };
@@ -178,7 +178,7 @@ pub async fn test_with_config<T: Into<TestCase>>(
     test_case: T,
 ) -> anyhow::Result<()> {
     let test_case = test_case.into();
-    let app = Application::new(args, config, Theme::default(true), syn_conf)?;
+    let app = Application::new(args, config, Theme::default(), syn_conf)?;
 
     test_key_sequence_with_input_text(
         Some(app),
@@ -309,8 +309,7 @@ impl AppBuilder {
     }
 
     pub fn build(self) -> anyhow::Result<Application> {
-        let mut app =
-            Application::new(self.args, self.config, Theme::default(true), self.syn_conf)?;
+        let mut app = Application::new(self.args, self.config, Theme::default(), self.syn_conf)?;
 
         if let Some((text, selection)) = self.input {
             let (view, doc) = helix_view::current!(app.editor);

helix-view/src/theme.rs

@@ -35,10 +35,11 @@ pub static BASE16_DEFAULT_THEME: Lazy<Theme> = Lazy::new(|| Theme {
     ..Theme::from(BASE16_DEFAULT_THEME_DATA.clone())
 });
 
+static TRUE_COLOR_SUPPORT: once_cell::sync::OnceCell<bool> = once_cell::sync::OnceCell::new();
+
 #[derive(Clone, Debug, Default)]
 pub struct Theme {
     name: String,
-    true_color_support: bool,
     // UI styles are stored in a HashMap
     styles: HashMap<String, Style>,
     // tree-sitter highlight styles are stored in a Vec to optimize lookups
@@ -47,32 +48,35 @@ pub struct Theme {
 }
 
 impl Theme {
-    pub fn new(theme_name: &str, true_color_support: bool) -> Result<Theme> {
+    pub fn set_true_color_support(true_color_support: bool) {
+        TRUE_COLOR_SUPPORT
+            .set(true_color_support)
+            .expect("method should only be called once on program startup.");
+    }
+
+    fn get_true_color_support() -> bool {
+        *TRUE_COLOR_SUPPORT
+            .get()
+            .expect("true color support should have been set on program startup.")
+    }
+
+    pub fn new(theme_name: &str) -> Result<Theme> {
         let theme = Self::load(theme_name)?;
-        if !true_color_support && !theme.is_16_color() {
+        if !Self::get_true_color_support() && !theme.is_16_color() {
             anyhow::bail!("Unsupported theme: theme requires true color support")
         }
-        Ok(Self {
-            true_color_support,
-            ..theme
-        })
+        Ok(theme)
     }
 
     pub fn update(&self, theme_name: &str) -> Result<Theme> {
-        Self::new(theme_name, self.true_color_support)
+        Self::new(theme_name)
     }
 
-    pub fn default(true_color_support: bool) -> Theme {
-        if true_color_support {
-            Self {
-                true_color_support,
-                ..DEFAULT_THEME.clone()
-            }
+    pub fn default() -> Theme {
+        if Self::get_true_color_support() {
+            DEFAULT_THEME.clone()
         } else {
-            Self {
-                true_color_support,
-                ..BASE16_DEFAULT_THEME.clone()
-            }
+            BASE16_DEFAULT_THEME.clone()
         }
     }