refactor!: make UserData more generic

runtime/examples/readme.rs

@@ -1,7 +1,7 @@
 use extism::*;
 
 // pretend this is redis or something :)
-type KVStore = std::collections::BTreeMap<String, Vec<u8>>;
+type KVStore = std::sync::Arc<std::sync::Mutex<std::collections::BTreeMap<String, Vec<u8>>>>;
 
 // When a first argument separated with a semicolon is provided to `host_fn` it is used as the
 // variable name and type for the `UserData` parameter

runtime/src/function.rs

@@ -81,18 +81,18 @@ pub(crate) enum UserDataHandle {
 /// using `UserData::get`. The `C` data is stored as a pointer and cleanup function and isn't usable from Rust. The cleanup function
 /// will be called when the inner `CPtr` is dropped.
 #[derive(Debug)]
-pub enum UserData<T: Sized> {
+pub enum UserData<T: Sync + Clone + Sized> {
     C(Arc<CPtr>),
-    Rust(Arc<std::sync::Mutex<T>>),
+    Rust(T),
 }
 
-impl<T: Default> Default for UserData<T> {
+impl<T: Default + Sync + Clone> Default for UserData<T> {
     fn default() -> Self {
         UserData::new(T::default())
     }
 }
 
-impl<T> Clone for UserData<T> {
+impl<T: Sync + Clone> Clone for UserData<T> {
     fn clone(&self) -> Self {
         match self {
             UserData::C(ptr) => UserData::C(ptr.clone()),
@@ -101,7 +101,7 @@ impl<T> Clone for UserData<T> {
     }
 }
 
-impl<T> UserData<T> {
+impl<T: Sync + Clone> UserData<T> {
     /// Create a new `UserData` from an existing pointer and free function, this is used
     /// by the C API to wrap C pointers into user data
     pub(crate) fn new_pointer(
@@ -126,12 +126,11 @@ impl<T> UserData<T> {
     ///
     /// This will wrap the provided value in a reference-counted mutex
     pub fn new(x: T) -> Self {
-        let data = Arc::new(std::sync::Mutex::new(x));
-        UserData::Rust(data)
+        UserData::Rust(x)
     }
 
     /// Get a copy of the inner value
-    pub fn get(&self) -> Result<Arc<std::sync::Mutex<T>>, Error> {
+    pub fn get(&self) -> Result<T, Error> {
         match self {
             UserData::C { .. } => anyhow::bail!("C UserData should not be used from Rust"),
             UserData::Rust(data) => Ok(data.clone()),
@@ -150,8 +149,8 @@ impl Drop for CPtr {
     }
 }
 
-unsafe impl<T> Send for UserData<T> {}
-unsafe impl<T> Sync for UserData<T> {}
+unsafe impl<T: Sync + Clone> Send for UserData<T> {}
+unsafe impl<T: Sync + Clone> Sync for UserData<T> {}
 unsafe impl Send for CPtr {}
 unsafe impl Sync for CPtr {}
 
@@ -180,7 +179,7 @@ pub struct Function {
 
 impl Function {
     /// Create a new host function
-    pub fn new<T: 'static, F>(
+    pub fn new<T: 'static + Sync + Clone, F>(
         name: impl Into<String>,
         args: impl IntoIterator<Item = ValType>,
         returns: impl IntoIterator<Item = ValType>,
@@ -211,7 +210,9 @@ impl Function {
             namespace: None,
             _user_data: match &user_data {
                 UserData::C(ptr) => UserDataHandle::C(ptr.clone()),
-                UserData::Rust(x) => UserDataHandle::Rust(x.clone()),
+                UserData::Rust(x) => {
+                    UserDataHandle::Rust(std::sync::Arc::new(std::sync::Mutex::new(x.clone())))
+                }
             },
         }
     }

runtime/src/plugin_builder.rs

@@ -60,7 +60,7 @@ impl<'a> PluginBuilder<'a> {
     }
 
     /// Add a single host function
-    pub fn with_function<T: 'static, F>(
+    pub fn with_function<T: Sync + Clone + 'static, F>(
         mut self,
         name: impl Into<String>,
         args: impl IntoIterator<Item = ValType>,
@@ -80,7 +80,7 @@ impl<'a> PluginBuilder<'a> {
     }
 
     /// Add a single host function in a specific namespace
-    pub fn with_function_in_namespace<T: 'static, F>(
+    pub fn with_function_in_namespace<T: Sync + Clone + 'static, F>(
         mut self,
         namespace: impl Into<String>,
         name: impl Into<String>,

runtime/src/tests/runtime.rs

@@ -453,7 +453,7 @@ fn hello_world_user_data(
     _plugin: &mut CurrentPlugin,
     inputs: &[Val],
     outputs: &mut [Val],
-    user_data: UserData<std::fs::File>,
+    user_data: UserData<std::sync::Arc<std::sync::Mutex<std::fs::File>>>,
 ) -> Result<(), Error> {
     let data = user_data.get()?;
     let mut data = data.lock().unwrap();
@@ -470,7 +470,8 @@ fn test_userdata() {
         if path.exists() {
             std::fs::remove_file(&path).unwrap();
         }
-        let file = std::fs::File::create(&path).unwrap();
+        let file =
+            std::sync::Arc::new(std::sync::Mutex::new(std::fs::File::create(&path).unwrap()));
         let f = Function::new(
             "hello_world",
             [PTR],