1 files changed, 38 insertions, 0 deletions
diff --git a/src/config.rs b/src/config.rs
new file mode 100644
index 0000000..06aa088
--- /dev/null
+++ b/src/config.rs
@@ -0,0 +1,38 @@
+use std::path::Path;
+use std::sync::OnceLock;
+
+/// Returns the default feature name configured in the consuming crate's
+/// `Cargo.toml` under `[package.metadata.might_be_async.default_feature_name]`.
+///
+/// If the metadata key is absent or unreadable, falls back to `"async"`.
+pub(crate) fn default_feature_name() -> &'static str {
+    static DEFAULT: OnceLock<String> = OnceLock::new();
+    DEFAULT.get_or_init(read_default_feature_name)
+}
+
+fn read_default_feature_name() -> String {
+    let manifest_dir = match std::env::var("CARGO_MANIFEST_DIR") {
+        Ok(dir) => dir,
+        Err(_) => return "async".to_string(),
+    };
+
+    let cargo_toml_path = Path::new(&manifest_dir).join("Cargo.toml");
+    let content = match std::fs::read_to_string(cargo_toml_path) {
+        Ok(c) => c,
+        Err(_) => return "async".to_string(),
+    };
+
+    let value: toml::Value = match content.parse() {
+        Ok(v) => v,
+        Err(_) => return "async".to_string(),
+    };
+
+    value
+        .get("package")
+        .and_then(|p| p.get("metadata"))
+        .and_then(|m| m.get("might_be_async"))
+        .and_then(|a| a.get("default_feature_name"))
+        .and_then(|v| v.as_str())
+        .unwrap_or("async")
+        .to_string()
+}