flutter: check if dart is installed

Ref fzyzcjy/flutter_rust_bridge#2411

Signed-off-by: Yuki Kishimoto <[email protected]>

bindings/nostr-sdk-flutter/rust/build.rs

@@ -10,18 +10,33 @@ use lib_flutter_rust_bridge_codegen::codegen::Config;
 fn main() {
     println!("cargo:rerun-if-changed=src/api");
 
-    if is_flutter_installed() {
-        // Execute code generator with auto-detected config
-        codegen::generate(
-            Config::from_config_file("../flutter_rust_bridge.yaml")
-                .unwrap()
-                .unwrap(),
-            Default::default(),
-        )
-        .unwrap();
-    } else {
+    if !is_dart_installed() {
+        eprintln!("Warning: dart not installed.");
+        return;
+    }
+
+    if !is_flutter_installed() {
         eprintln!("Warning: flutter not installed.");
+        return;
     }
+
+    // Execute code generator with auto-detected config
+    codegen::generate(
+        Config::from_config_file("../flutter_rust_bridge.yaml")
+            .unwrap()
+            .unwrap(),
+        Default::default(),
+    )
+    .unwrap();
+}
+
+fn is_dart_installed() -> bool {
+    let output = Command::new("dart")
+        .arg("--version")
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .status();
+    matches!(output, Ok(status) if status.success())
 }
 
 fn is_flutter_installed() -> bool {