WIP

crates/erg_compiler/module/promise.rs

@@ -0,0 +1,56 @@
+use std::path::{Path, PathBuf};
+use std::thread::JoinHandle;
+
+use erg_common::dict::Dict;
+use erg_common::shared::Shared;
+
+use crate::artifact::ErrorArtifact;
+
+#[derive(Debug)]
+pub enum Promise {
+    Running(JoinHandle<Result<(), ErrorArtifact>>),
+    Finished,
+}
+
+impl Promise {
+    pub fn is_finished(&self) -> bool {
+        match self {
+            Self::Finished => true,
+            Self::Running(handle) => handle.is_finished(),
+        }
+    }
+
+    pub fn take(&mut self) -> Self {
+        std::mem::replace(self, Self::Finished)
+    }
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct SharedPromises(Shared<Dict<PathBuf, Promise>>);
+
+impl SharedPromises {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn insert(&self, path: PathBuf, handle: JoinHandle<Result<(), ErrorArtifact>>) {
+        self.0.borrow_mut().insert(path, Promise::Running(handle));
+    }
+
+    pub fn is_registered(&self, path: &Path) -> bool {
+        self.0.borrow_mut().get(path).is_some()
+    }
+
+    pub fn is_finished(&self, path: &Path) -> bool {
+        self.0
+            .borrow_mut()
+            .get(path)
+            .is_some_and(|promise| promise.is_finished())
+    }
+
+    pub fn join(&self, path: &Path) -> Result<(), ErrorArtifact> {
+        let promise = self.0.borrow_mut().get_mut(path).unwrap().take();
+        let Promise::Running(handle) = promise else { todo!() };
+        handle.join().unwrap()
+    }
+}