Add util function for boolean env vars

It's probably good to be consistent about what is recognized as "true"
without copying the same code.

src/state.rs

@@ -454,14 +454,7 @@ pub fn client_is_privileged(client: &Client) -> bool {
 }
 
 fn enable_wayland_security() -> bool {
-    std::env::var("COSMIC_ENABLE_WAYLAND_SECURITY")
-        .map(|x| {
-            x == "1"
-                || x.to_lowercase() == "true"
-                || x.to_lowercase() == "yes"
-                || x.to_lowercase() == "y"
-        })
-        .unwrap_or(false)
+    crate::utils::env::bool_var("COSMIC_ENABLE_WAYLAND_SECURITY").unwrap_or(false)
 }
 
 impl State {
@@ -524,8 +517,8 @@ impl State {
         let idle_inhibit_manager_state = IdleInhibitManagerState::new::<State>(&dh);
         let idle_inhibiting_surfaces = HashSet::new();
 
-        let data_control_state = std::env::var("COSMIC_DATA_CONTROL_ENABLED")
-            .is_ok_and(|value| value == "1")
+        let data_control_state = crate::utils::env::bool_var("COSMIC_DATA_CONTROL_ENABLED")
+            .unwrap_or(false)
             .then(|| {
                 DataControlState::new::<Self, _>(dh, Some(&primary_selection_state), |_| true)
             });

src/utils/env.rs

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-3.0-only
+
+pub fn bool_var(name: &str) -> Option<bool> {
+    let value = std::env::var(name).ok()?.to_lowercase();
+    Some(["1", "true", "yes", "y"].contains(&value.as_str()))
+}

src/utils/mod.rs

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-3.0-only
 
+pub mod env;
 mod ids;
 pub(crate) use self::ids::id_gen;
 pub mod geometry;