Add panel_send_message and PanelAbi

src/backend/mod.rs

@@ -8,6 +8,8 @@
 //! implemented, but in the future, [wasm3](https://github.com/wasm3/wasm3)
 //! will also be provided.
 
+use std::collections::VecDeque;
+
 use super::*;
 
 pub mod wasmtime;
@@ -22,7 +24,7 @@ pub fn make_default_backend() -> anyhow::Result<Box<dyn Backend>> {
 
 /// A WebAssembly runtime backend.
 pub trait Backend {
-    fn load_module(&self, abi: ScriptAbi, module: &[u8]) -> anyhow::Result<Arc<dyn Instance>>;
+    fn load_module(&self, abi: Arc<ScriptAbi>, module: &[u8]) -> anyhow::Result<Arc<dyn Instance>>;
 }
 
 /// An instance of a WebAssembly module.
@@ -69,6 +71,7 @@ pub struct ScriptAbi {
     loaded_fonts: RwLock<Vec<Arc<text::Font>>>,
     text_layouts: RwLock<Slab<text::TextLayout>>,
     message_store: RwLock<Slab<Vec<u8>>>,
+    panels: RwLock<Slab<PanelAbi>>,
 }
 
 impl ScriptAbi {
@@ -79,6 +82,13 @@ impl ScriptAbi {
         }
     }
 
+    /// Allocates a new ID and host-side storage for a panel.
+    pub fn create_panel(&self) -> PanelId {
+        let abi = PanelAbi::default();
+        let id = self.panels.write().insert(abi);
+        PanelId(id)
+    }
+
     pub fn start_draw(&self) {
         let mut lock = self.draw_cmds.lock();
         lock.clear();
@@ -157,4 +167,23 @@ impl ScriptAbi {
         let src = store.get(id as usize).unwrap();
         dst.copy_from_slice(src);
     }
+
+    pub fn panel_send_message(&self, id: u32, message: Vec<u8>) {
+        if let Some(panel) = self.panels.read().get(id as usize) {
+            panel.outgoing_messages.write().push_back(message);
+        }
+    }
+
+    pub fn recv_panel_messages(&self, id: PanelId) -> Vec<Vec<u8>> {
+        if let Some(panel) = self.panels.read().get(id.0) {
+            panel.outgoing_messages.write().drain(..).collect()
+        } else {
+            Vec::new()
+        }
+    }
+}
+
+#[derive(Default)]
+pub struct PanelAbi {
+    outgoing_messages: RwLock<VecDeque<Vec<u8>>>,
 }

src/backend/wasmtime.rs

@@ -9,9 +9,9 @@ use crate::DrawCommand;
 use canary_script::{Color, CursorEventKind, Rect, Vec2};
 use parking_lot::Mutex;
 
-type Caller<'a> = wasmtime::Caller<'a, ScriptAbi>;
-type Store = wasmtime::Store<ScriptAbi>;
-type Linker = wasmtime::Linker<ScriptAbi>;
+type Caller<'a> = wasmtime::Caller<'a, Arc<ScriptAbi>>;
+type Store = wasmtime::Store<Arc<ScriptAbi>>;
+type Linker = wasmtime::Linker<Arc<ScriptAbi>>;
 
 pub struct WasmtimeBackend {
     engine: wasmtime::Engine,
@@ -30,7 +30,7 @@ impl WasmtimeBackend {
 }
 
 impl Backend for WasmtimeBackend {
-    fn load_module(&self, abi: ScriptAbi, module: &[u8]) -> anyhow::Result<Arc<dyn Instance>> {
+    fn load_module(&self, abi: Arc<ScriptAbi>, module: &[u8]) -> anyhow::Result<Arc<dyn Instance>> {
         let module = wasmtime::Module::new(&self.engine, module)?;
         let mut store = wasmtime::Store::new(&self.engine, abi);
         let mut linker = Linker::new(&self.engine);
@@ -147,6 +147,15 @@ impl WasmtimeInstance {
             },
         )?;
 
+        linker.func_wrap(
+            module,
+            "panel_send_message",
+            |mut caller: Caller<'_>, id: u32, ptr: u32, len: u32| {
+                let message = Self::get_memory_slice_bytes(&mut caller, ptr as usize, len as usize);
+                caller.data().panel_send_message(id, message.to_vec())
+            },
+        )?;
+
         Ok(())
     }
 

src/lib.rs

@@ -29,11 +29,12 @@ impl Runtime {
 
     pub fn load_module(&self, module: &[u8]) -> anyhow::Result<Script> {
         let abi = ScriptAbi::new(self.font_store.to_owned());
-        let instance = self.backend.load_module(abi, module)?;
+        let abi = Arc::new(abi);
+        let instance = self.backend.load_module(abi.to_owned(), module)?;
 
         Ok(Script {
             instance,
-            next_panel: 0,
+            abi,
         })
     }
 }
@@ -41,16 +42,16 @@ impl Runtime {
 /// A loaded instance of a Canary script.
 pub struct Script {
     instance: Arc<dyn Instance>,
-    next_panel: usize,
+    abi: Arc<ScriptAbi>,
 }
 
 impl Script {
     pub fn create_panel(&mut self, protocol: &str, msg: Vec<u8>) -> anyhow::Result<Panel> {
-        let id = PanelId(self.next_panel);
-        self.next_panel += 1;
+        let id = self.abi.create_panel();
         let userdata = self.instance.bind_panel(id, protocol, msg);
         Ok(Panel {
             instance: self.instance.clone(),
+            abi: self.abi.clone(),
             id,
             userdata,
         })
@@ -60,6 +61,7 @@ impl Script {
 /// A Canary panel.
 pub struct Panel {
     instance: Arc<dyn Instance>,
+    abi: Arc<ScriptAbi>,
     id: PanelId,
     userdata: u32,
 }
@@ -84,6 +86,10 @@ impl Panel {
     pub fn on_message(&self, msg: Vec<u8>) {
         self.instance.on_message(self.userdata, msg);
     }
+
+    pub fn recv_messages(&self) -> Vec<Vec<u8>> {
+        self.abi.recv_panel_messages(self.id)
+    }
 }
 
 /// Proportion constant between pixels (at 96dpi) to millimeters (Canary's unit measurement).