Create a clap_plugin instance stub

src/wrapper/clap.rs

@@ -1,4 +1,5 @@
 mod factory;
+mod plugin;
 
 /// Re-export for the wrapper.
 pub use self::factory::Factory;

src/wrapper/clap/factory.rs

@@ -2,12 +2,13 @@ use clap_sys::host::clap_host;
 use clap_sys::plugin::{clap_plugin, clap_plugin_descriptor};
 use clap_sys::plugin_factory::clap_plugin_factory;
 use clap_sys::version::CLAP_VERSION;
-use std::ffi::CString;
+use std::ffi::{CStr, CString};
 use std::marker::PhantomData;
 use std::mem::MaybeUninit;
 use std::os::raw::c_char;
 use std::ptr;
 
+use super::plugin::Plugin;
 use crate::ClapPlugin;
 
 /// The plugin's factory. Initialized using a lazy_static from the entry poiunt's `get_factory()`
@@ -127,6 +128,12 @@ impl<P: ClapPlugin> Factory<P> {
         host: *const clap_host,
         plugin_id: *const c_char,
     ) -> *const clap_plugin {
-        todo!()
+        let factory = &*(factory as *const Self);
+
+        if !plugin_id.is_null() && CStr::from_ptr(plugin_id) == factory.clap_id.as_c_str() {
+            &Box::leak(Box::new(Plugin::<P>::new(host))).clap_plugin
+        } else {
+            ptr::null()
+        }
     }
 }

src/wrapper/clap/plugin.rs

@@ -0,0 +1,38 @@
+use clap_sys::host::clap_host;
+use clap_sys::plugin::clap_plugin;
+use parking_lot::RwLock;
+
+use crate::plugin::ClapPlugin;
+
+#[repr(C)]
+pub struct Plugin<P: ClapPlugin> {
+    // Keep the vtable as the first field so we can do a simple pointer cast
+    pub clap_plugin: clap_plugin,
+
+    /// The wrapped plugin instance.
+    plugin: RwLock<P>,
+
+    host_callback: *const clap_host,
+}
+
+impl<P: ClapPlugin> Plugin<P> {
+    pub fn new(host_callback: *const clap_host) -> Self {
+        Self {
+            clap_plugin: clap_plugin {
+                desc: todo!(),
+                plugin_data: todo!(),
+                init: todo!(),
+                destroy: todo!(),
+                activate: todo!(),
+                deactivate: todo!(),
+                start_processing: todo!(),
+                stop_processing: todo!(),
+                process: todo!(),
+                get_extension: todo!(),
+                on_main_thread: todo!(),
+            },
+            plugin: RwLock::new(P::default()),
+            host_callback,
+        }
+    }
+}