refactor: 拆分 bytecode/cache crate 并模块化 counter

crates/oxide_code_cache/src/lib.rs

@@ -0,0 +1,71 @@
+#![doc = "OxideJS - Compiler-independent compiled module cache"]
+
+use std::sync::Arc;
+
+use dashmap::DashMap;
+use oxide_bytecode::CompiledModule;
+
+/// Shared compiled-module cache keyed by a caller-provided safe module hash.
+///
+/// The cache intentionally does not know how to parse or compile JavaScript.
+/// Compiler-aware callers compute the key and provide the compile callback.
+pub struct CodeForge {
+    map: DashMap<u64, Arc<CompiledModule>>,
+}
+
+impl CodeForge {
+    pub fn new() -> Self {
+        Self {
+            map: DashMap::with_shard_amount(16),
+        }
+    }
+
+    pub fn get(&self, hash: u64) -> Option<Arc<CompiledModule>> {
+        self.map.get(&hash).map(|entry| Arc::clone(&entry))
+    }
+
+    pub fn insert(&self, hash: u64, module: CompiledModule) -> Arc<CompiledModule> {
+        let module = Arc::new(module);
+        Arc::clone(self.map.entry(hash).or_insert(module).value())
+    }
+
+    pub fn get_or_insert_with<F>(&self, hash: u64, compile: F) -> Result<Arc<CompiledModule>, String>
+    where
+        F: FnOnce() -> Result<CompiledModule, String>,
+    {
+        if let Some(module) = self.get(hash) {
+            return Ok(module);
+        }
+
+        Ok(self.insert(hash, compile()?))
+    }
+}
+
+impl Default for CodeForge {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn cache_returns_same_arc_for_same_hash() {
+        let forge = CodeForge::new();
+        let first = forge.insert(1, CompiledModule::new());
+        let second = forge.get_or_insert_with(1, || Ok(CompiledModule::new())).expect("cache hit");
+
+        assert!(Arc::ptr_eq(&first, &second));
+    }
+
+    #[test]
+    fn cache_misses_for_different_hashes() {
+        let forge = CodeForge::new();
+        let first = forge.insert(1, CompiledModule::new());
+        let second = forge.insert(2, CompiledModule::new());
+
+        assert!(!Arc::ptr_eq(&first, &second));
+    }
+}