improve safety by avoiding raw pointers,improve dynamic view code a bit

lyra-engine

@@ -1 +1 @@
-Subproject commit 60ec62c55828a4ea273a10e5614e7cc589b005cf
+Subproject commit 12c8ece4183f117864bac362d181ea5906141c6f

src/main.rs

@@ -6,7 +6,7 @@ use std::ptr::NonNull;
 use async_trait::async_trait;
 use component::witguest::ecs::WasmTypeId;
 use component::witguest::{ecs as wasm_ecs, math};
-use ecs::query::dynamic::QueryDynamicType;
+use ecs::query::dynamic::{DynamicViewState, DynamicViewStateIter, QueryDynamicType};
 use lyra_ecs::Component;
 
 use lyra_ecs as ecs;
@@ -15,6 +15,8 @@ use slab::Slab;
 use thiserror::Error;
 use wasmtime_wasi::WasiView;
 
+use wasmtime::component::Resource as WasmResource;
+
 #[allow(unused_imports)]
 pub(crate) mod lyra_engine {
     pub use lyra_ecs as ecs;
@@ -69,8 +71,23 @@ struct Vec3 {
     z: f32,
 }
 
+struct WorldEntry {
+    world: lyra_ecs::World,
+    /// Indices of dynamic views that are still alive
+    views: Slab<usize>,
+}
+
+struct DynamicViewEntry {
+    /// The index of the world that this view is a part of
+    world_index: usize,
+    view: DynamicViewStateIter,
+}
+
+unsafe impl Send for DynamicViewEntry {}
+
 struct Imports {
-    world_slab: Slab<lyra_ecs::World>,
+    world_slab: Slab<WorldEntry>,
+    world_views_slab: Slab<DynamicViewEntry>,
 }
 
 impl WasiView for Imports {
@@ -96,19 +113,31 @@ impl math::Host for Imports {}
 #[derive(Error, Debug)]
 pub enum WasmError {
     #[error("an invalid '{0}' resource handle was used by the guest")]
-    InvalidResourceHandle(&'static str)
+    InvalidResourceHandle(&'static str),
 }
 
 #[async_trait]
 impl wasm_ecs::HostEcsWorld for Imports {
-    async fn new(&mut self,) ->  wasmtime::Result<wasmtime::component::Resource<wasm_ecs::EcsWorld>> {
+    async fn new(&mut self) -> wasmtime::Result<WasmResource<wasm_ecs::EcsWorld>> {
-        let world = self.world_slab.insert(lyra_ecs::World::new());
+        let entry = WorldEntry {
-        Ok(wasmtime::component::Resource::new_own(world as _))
+            world: lyra_ecs::World::new(),
+            views: Slab::new(),
+        };
+        let world = self.world_slab.insert(entry);
+        Ok(WasmResource::new_own(world as _))
     }
 
-    async fn spawn(&mut self, this: wasmtime::component::Resource<wasm_ecs::EcsWorld>, mut components: Vec<u8>, infos: Vec<wasm_ecs::ComponentInfo>) ->  wasmtime::Result<wasm_ecs::Entity> {
+    async fn spawn(
-        let world = self.world_slab.get_mut(this.rep() as _)
+        &mut self,
+        this: WasmResource<wasm_ecs::EcsWorld>,
+        mut components: Vec<u8>,
+        infos: Vec<wasm_ecs::ComponentInfo>,
+    ) -> wasmtime::Result<wasm_ecs::Entity> {
+        let world_entry = self
+            .world_slab
+            .get_mut(this.rep() as _)
             .ok_or(WasmError::InvalidResourceHandle("EcsWorld"))?;
+        let world = &mut world_entry.world;
 
         // add the components in the tightly packed `components` buffer into the dynamic bundle
         let mut bundle = ecs::DynamicBundle::new();
@@ -126,52 +155,123 @@ impl wasm_ecs::HostEcsWorld for Imports {
         Ok(en.into())
     }
 
-    async fn view(&mut self, this: wasmtime::component::Resource<wasm_ecs::EcsWorld>, infos: Vec<wasm_ecs::ComponentInfo>) -> wasmtime::Result<Vec<u8>> {
+    async fn view(
-        let world = self.world_slab.get_mut(this.rep() as _)
+        &mut self,
-            .ok_or(WasmError::InvalidResourceHandle("EcsWorld"))?;
+        this: wasmtime::component::Resource<wasm_ecs::EcsWorld>,
-
+        infos: Vec<wasm_ecs::ComponentInfo>,
-        // Create a dynamic view for querying for the components
+    ) -> wasmtime::Result<wasmtime::component::Resource<wasm_ecs::EcsDynamicView>> {
-        let mut view = world.dynamic_view();
+        <Self as wasm_ecs::HostEcsDynamicView>::new(self, this, infos).await
-        for info in infos.clone() {
-            view.push(QueryDynamicType::from_info(info.into()));
-        }
-
-        // allocate the row of components
-        let total_len = infos.iter().map(|i| i.size as usize).sum();
-        let mut components = Vec::with_capacity(total_len);
-
-        // copy each row of the query into the set of components. could get pretty big, but its a PoC so :shrug:
-        for row in view.into_iter() {
-            let first = row.iter().next().unwrap();
-
-            let mut comp = Vec::<u8>::with_capacity(first.info.layout().size());
-            unsafe {
-                std::ptr::copy_nonoverlapping(
-                    first.ptr.as_ptr(),
-                    comp.as_mut_ptr(),
-                    first.info.layout().size(),
-                );
-                comp.set_len(first.info.layout().size());
-            }
-            components.extend(comp.into_iter());
-        }
-
-        Ok(components)
     }
 
-    fn drop(&mut self, this: wasmtime::component::Resource<wasm_ecs::EcsWorld>) -> wasmtime::Result<()>  {
+    fn drop(
-        self.world_slab.try_remove(this.rep() as _)
+        &mut self,
+        this: wasmtime::component::Resource<wasm_ecs::EcsWorld>,
+    ) -> wasmtime::Result<()> {
+        let mut world_entry = self
+            .world_slab
+            .try_remove(this.rep() as _)
             .ok_or(WasmError::InvalidResourceHandle("EcsWorld"))?;
 
+        // make sure that all the world views are now dead
+        for view in world_entry.views.drain() {
+            self.world_views_slab.remove(view);
+        }
+
         Ok(())
     }
 }
 
 #[async_trait]
-impl wasm_ecs::Host for Imports {
+impl wasm_ecs::HostEcsDynamicView for Imports {
+    async fn new(
+        &mut self,
+        world: WasmResource<wasm_ecs::EcsWorld>,
+        infos: Vec<wasm_ecs::ComponentInfo>,
+    ) -> wasmtime::Result<wasmtime::component::Resource<wasm_ecs::EcsDynamicView>> {
+        // Create a dynamic view for querying for the components
+        let mut view = DynamicViewState::new();
+        for info in infos.clone() {
+            view.push(QueryDynamicType::from_info(info.into()));
+        }
 
+        let world_rep = world.rep();
+        let entry = DynamicViewEntry {
+            world_index: world_rep as _,
+            view: view.into_iter(),
+        };
+        let view_index = self.world_views_slab.insert(entry);
+
+        // link the dynamic view to the world that its a part of.
+        let world_entry = self
+            .world_slab
+            .get_mut(world.rep() as _)
+            .ok_or(WasmError::InvalidResourceHandle("EcsWorld"))?;
+        world_entry.views.insert(view_index);
+
+        Ok(WasmResource::new_own(view_index as _))
+    }
+
+    async fn next(
+        &mut self,
+        view: WasmResource<wasm_ecs::EcsDynamicView>,
+    ) -> wasmtime::Result<Option<Vec<u8>>> {
+        let view_entry = self.world_views_slab.get_mut(view.rep() as _).unwrap();
+        let world_entry = self.world_slab.get(view_entry.world_index).unwrap();
+        let view = &mut view_entry.view;
+
+        // get the next row in the view and copy the returned components into a tightly packed
+        if let Some(row) = view.next(&world_entry.world) {
+            let row_len = row.iter().map(|d| d.info.layout().size()).sum();
+            let mut row_buf = Vec::<u8>::with_capacity(row_len);
+
+            let mut offset = 0;
+            for comp in row {
+                let comp_size = comp.info.layout().size();
+                unsafe {
+                    // SAFETY: the vec has the capacity to store this component because it was
+                    // created with Vec::with_capacity.
+                    let dst = row_buf.as_mut_ptr().add(offset);
+
+                    std::ptr::copy_nonoverlapping(
+                        comp.ptr.as_ptr(),
+                        dst,
+                        comp.info.layout().size(),
+                    );
+                    
+                    // make sure to tell the vec that it now has the bytes of this component
+                    row_buf.set_len(row_buf.len() + comp_size);
+                }
+
+                offset += comp_size;
+            }
+
+            Ok(Some(row_buf))
+        } else {
+            Ok(None)
+        }
+    }
+
+    fn drop(
+        &mut self,
+        this: wasmtime::component::Resource<wasm_ecs::EcsDynamicView>,
+    ) -> wasmtime::Result<()> {
+        // first delete the actual view
+        let view_rep = this.rep() as usize;
+        let view = self.world_views_slab.get(view_rep).unwrap();
+        let view_world = view.world_index;
+
+        // now remove the link to the view inside of the world entry
+        self.world_views_slab.remove(view_rep);
+        let world = self.world_slab.get_mut(view_world).unwrap();
+        world.views.remove(view_rep);
+
+        Ok(())
+    }
 }
 
+#[async_trait]
+impl wasm_ecs::Host for Imports {}
+
 #[tokio::main]
 async fn main() -> wasmtime::Result<()> {
     // Instantiate the engine and store
@@ -192,6 +292,7 @@ async fn main() -> wasmtime::Result<()> {
             // There will likely be a world, but a slab is used in the case that the guest
             // wants another world for some reason.
             world_slab: Slab::with_capacity(1),
+            world_views_slab: Slab::with_capacity(10),
         },
     );
 

witguest/src/bindings.rs

@@ -132,6 +132,47 @@ pub mod component {
         }
       }
       
+      #[derive(Debug)]
+      #[repr(transparent)]
+      pub struct EcsDynamicView{
+        handle: wit_bindgen::rt::Resource<EcsDynamicView>,
+      }
+      
+      impl EcsDynamicView{
+        #[doc(hidden)]
+        pub unsafe fn from_handle(handle: u32) -> Self {
+          Self {
+            handle: wit_bindgen::rt::Resource::from_handle(handle),
+          }
+        }
+        
+        #[doc(hidden)]
+        pub fn handle(&self) -> u32 {
+          wit_bindgen::rt::Resource::handle(&self.handle)
+        }
+      }
+      
+      
+      unsafe impl wit_bindgen::rt::WasmResource for EcsDynamicView{
+        #[inline]
+        unsafe fn drop(_handle: u32) {
+          #[cfg(not(target_arch = "wasm32"))]
+          unreachable!();
+          
+          #[cfg(target_arch = "wasm32")]
+          {
+            #[link(wasm_import_module = "component:witguest/ecs")]
+            extern "C" {
+              #[link_name = "[resource-drop]ecs-dynamic-view"]
+              fn drop(_: u32);
+            }
+            
+            drop(_handle);
+          }
+        }
+      }
+      
+      
       #[derive(Debug)]
       #[repr(transparent)]
       pub struct EcsWorld{
@@ -172,6 +213,71 @@ pub mod component {
         }
       }
       
+      impl EcsDynamicView {
+        #[allow(unused_unsafe, clippy::all)]
+        pub fn new(wrld: &EcsWorld,component_infos: &[ComponentInfo],) -> Self{
+          
+          #[allow(unused_imports)]
+          use wit_bindgen::rt::{alloc, vec::Vec, string::String};
+          unsafe {
+            let vec0 = component_infos;
+            let ptr0 = vec0.as_ptr() as i32;
+            let len0 = vec0.len() as i32;
+            
+            #[cfg(target_arch = "wasm32")]
+            #[link(wasm_import_module = "component:witguest/ecs")]
+            extern "C" {
+              #[link_name = "[constructor]ecs-dynamic-view"]
+              fn wit_import(_: i32, _: i32, _: i32, ) -> i32;
+            }
+            
+            #[cfg(not(target_arch = "wasm32"))]
+            fn wit_import(_: i32, _: i32, _: i32, ) -> i32{ unreachable!() }
+            let ret = wit_import((wrld).handle() as i32, ptr0, len0);
+            EcsDynamicView::from_handle(ret as u32)
+          }
+        }
+      }
+      impl EcsDynamicView {
+        #[allow(unused_unsafe, clippy::all)]
+        pub fn next(&self,) -> Option<wit_bindgen::rt::vec::Vec::<u8>>{
+          
+          #[allow(unused_imports)]
+          use wit_bindgen::rt::{alloc, vec::Vec, string::String};
+          unsafe {
+            
+            #[repr(align(4))]
+            struct RetArea([u8; 12]);
+            let mut ret_area = ::core::mem::MaybeUninit::<RetArea>::uninit();
+            let ptr0 = ret_area.as_mut_ptr() as i32;
+            #[cfg(target_arch = "wasm32")]
+            #[link(wasm_import_module = "component:witguest/ecs")]
+            extern "C" {
+              #[link_name = "[method]ecs-dynamic-view.next"]
+              fn wit_import(_: i32, _: i32, );
+            }
+            
+            #[cfg(not(target_arch = "wasm32"))]
+            fn wit_import(_: i32, _: i32, ){ unreachable!() }
+            wit_import((self).handle() as i32, ptr0);
+            let l1 = i32::from(*((ptr0 + 0) as *const u8));
+            match l1 {
+              0 => None,
+              1 => {
+                let e = {
+                  let l2 = *((ptr0 + 4) as *const i32);
+                  let l3 = *((ptr0 + 8) as *const i32);
+                  let len4 = l3 as usize;
+                  
+                  Vec::from_raw_parts(l2 as *mut _, len4, len4)
+                };
+                Some(e)
+              }
+              _ => wit_bindgen::rt::invalid_enum_discriminant(),
+            }
+          }
+        }
+      }
       impl EcsWorld {
         #[allow(unused_unsafe, clippy::all)]
         pub fn new() -> Self{
@@ -196,6 +302,7 @@ pub mod component {
       }
       impl EcsWorld {
         #[allow(unused_unsafe, clippy::all)]
+        /// expects components to be tightly packed in the same order of component-infos
         pub fn spawn(&self,components: &[u8],component_infos: &[ComponentInfo],) -> Entity{
           
           #[allow(unused_imports)]
@@ -235,33 +342,26 @@ pub mod component {
       }
       impl EcsWorld {
         #[allow(unused_unsafe, clippy::all)]
-        pub fn view(&self,component_infos: &[ComponentInfo],) -> wit_bindgen::rt::vec::Vec::<u8>{
+        pub fn view(&self,component_infos: &[ComponentInfo],) -> EcsDynamicView{
           
           #[allow(unused_imports)]
           use wit_bindgen::rt::{alloc, vec::Vec, string::String};
           unsafe {
-            
-            #[repr(align(4))]
-            struct RetArea([u8; 8]);
-            let mut ret_area = ::core::mem::MaybeUninit::<RetArea>::uninit();
             let vec0 = component_infos;
             let ptr0 = vec0.as_ptr() as i32;
             let len0 = vec0.len() as i32;
-            let ptr1 = ret_area.as_mut_ptr() as i32;
+            
             #[cfg(target_arch = "wasm32")]
             #[link(wasm_import_module = "component:witguest/ecs")]
             extern "C" {
               #[link_name = "[method]ecs-world.view"]
-              fn wit_import(_: i32, _: i32, _: i32, _: i32, );
+              fn wit_import(_: i32, _: i32, _: i32, ) -> i32;
             }
             
             #[cfg(not(target_arch = "wasm32"))]
-            fn wit_import(_: i32, _: i32, _: i32, _: i32, ){ unreachable!() }
+            fn wit_import(_: i32, _: i32, _: i32, ) -> i32{ unreachable!() }
-            wit_import((self).handle() as i32, ptr0, len0, ptr1);
+            let ret = wit_import((self).handle() as i32, ptr0, len0);
-            let l2 = *((ptr1 + 0) as *const i32);
+            EcsDynamicView::from_handle(ret as u32)
-            let l3 = *((ptr1 + 4) as *const i32);
-            let len4 = l3 as usize;
-            Vec::from_raw_parts(l2 as *mut _, len4, len4)
           }
         }
       }
@@ -274,7 +374,7 @@ pub mod component {
 #[cfg(target_arch = "wasm32")]
 #[link_section = "component-type:example"]
 #[doc(hidden)]
-pub static __WIT_BINDGEN_COMPONENT_TYPE: [u8; 608] = [0, 97, 115, 109, 13, 0, 1, 0, 0, 25, 22, 119, 105, 116, 45, 99, 111, 109, 112, 111, 110, 101, 110, 116, 45, 101, 110, 99, 111, 100, 105, 110, 103, 4, 0, 7, 227, 3, 1, 65, 2, 1, 65, 9, 1, 66, 2, 1, 114, 3, 1, 120, 118, 1, 121, 118, 1, 122, 118, 4, 0, 4, 118, 101, 99, 51, 3, 0, 0, 3, 1, 23, 99, 111, 109, 112, 111, 110, 101, 110, 116, 58, 119, 105, 116, 103, 117, 101, 115, 116, 47, 109, 97, 116, 104, 5, 0, 1, 66, 20, 1, 114, 1, 2, 105, 100, 119, 4, 0, 9, 101, 110, 116, 105, 116, 121, 45, 105, 100, 3, 0, 0, 1, 114, 2, 2, 105, 100, 1, 10, 103, 101, 110, 101, 114, 97, 116, 105, 111, 110, 119, 4, 0, 6, 101, 110, 116, 105, 116, 121, 3, 0, 2, 1, 111, 2, 119, 119, 1, 114, 1, 5, 105, 110, 110, 101, 114, 4, 4, 0, 12, 119, 97, 115, 109, 45, 116, 121, 112, 101, 45, 105, 100, 3, 0, 5, 1, 114, 3, 4, 115, 105, 122, 101, 119, 9, 97, 108, 105, 103, 110, 109, 101, 110, 116, 119, 7, 116, 121, 112, 101, 45, 105, 100, 6, 4, 0, 14, 99, 111, 109, 112, 111, 110, 101, 110, 116, 45, 105, 110, 102, 111, 3, 0, 7, 4, 0, 9, 101, 99, 115, 45, 119, 111, 114, 108, 100, 3, 1, 1, 105, 9, 1, 64, 0, 0, 10, 4, 0, 22, 91, 99, 111, 110, 115, 116, 114, 117, 99, 116, 111, 114, 93, 101, 99, 115, 45, 119, 111, 114, 108, 100, 1, 11, 1, 104, 9, 1, 112, 125, 1, 112, 8, 1, 64, 3, 4, 115, 101, 108, 102, 12, 10, 99, 111, 109, 112, 111, 110, 101, 110, 116, 115, 13, 15, 99, 111, 109, 112, 111, 110, 101, 110, 116, 45, 105, 110, 102, 111, 115, 14, 0, 3, 4, 0, 23, 91, 109, 101, 116, 104, 111, 100, 93, 101, 99, 115, 45, 119, 111, 114, 108, 100, 46, 115, 112, 97, 119, 110, 1, 15, 1, 64, 2, 4, 115, 101, 108, 102, 12, 15, 99, 111, 109, 112, 111, 110, 101, 110, 116, 45, 105, 110, 102, 111, 115, 14, 0, 13, 4, 0, 22, 91, 109, 101, 116, 104, 111, 100, 93, 101, 99, 115, 45, 119, 111, 114, 108, 100, 46, 118, 105, 101, 119, 1, 16, 3, 1, 22, 99, 111, 109, 112, 111, 110, 101, 110, 116, 58, 119, 105, 116, 103, 117, 101, 115, 116, 47, 101, 99, 115, 5, 1, 1, 64, 1, 3, 109, 115, 103, 115, 1, 0, 3, 0, 10, 104, 111, 115, 116, 45, 112, 114, 105, 110, 116, 1, 2, 1, 106, 1, 125, 0, 1, 64, 0, 0, 3, 4, 0, 7, 111, 110, 45, 105, 110, 105, 116, 1, 4, 4, 1, 26, 99, 111, 109, 112, 111, 110, 101, 110, 116, 58, 119, 105, 116, 103, 117, 101, 115, 116, 47, 101, 120, 97, 109, 112, 108, 101, 4, 0, 11, 13, 1, 0, 7, 101, 120, 97, 109, 112, 108, 101, 3, 0, 0, 0, 70, 9, 112, 114, 111, 100, 117, 99, 101, 114, 115, 1, 12, 112, 114, 111, 99, 101, 115, 115, 101, 100, 45, 98, 121, 2, 13, 119, 105, 116, 45, 99, 111, 109, 112, 111, 110, 101, 110, 116, 6, 48, 46, 50, 49, 46, 48, 16, 119, 105, 116, 45, 98, 105, 110, 100, 103, 101, 110, 45, 114, 117, 115, 116, 6, 48, 46, 49, 56, 46, 48];
+pub static __WIT_BINDGEN_COMPONENT_TYPE: [u8; 745] = [0, 97, 115, 109, 13, 0, 1, 0, 0, 25, 22, 119, 105, 116, 45, 99, 111, 109, 112, 111, 110, 101, 110, 116, 45, 101, 110, 99, 111, 100, 105, 110, 103, 4, 0, 7, 236, 4, 1, 65, 2, 1, 65, 9, 1, 66, 2, 1, 114, 3, 1, 120, 118, 1, 121, 118, 1, 122, 118, 4, 0, 4, 118, 101, 99, 51, 3, 0, 0, 3, 1, 23, 99, 111, 109, 112, 111, 110, 101, 110, 116, 58, 119, 105, 116, 103, 117, 101, 115, 116, 47, 109, 97, 116, 104, 5, 0, 1, 66, 28, 1, 114, 1, 2, 105, 100, 119, 4, 0, 9, 101, 110, 116, 105, 116, 121, 45, 105, 100, 3, 0, 0, 1, 114, 2, 2, 105, 100, 1, 10, 103, 101, 110, 101, 114, 97, 116, 105, 111, 110, 119, 4, 0, 6, 101, 110, 116, 105, 116, 121, 3, 0, 2, 1, 111, 2, 119, 119, 1, 114, 1, 5, 105, 110, 110, 101, 114, 4, 4, 0, 12, 119, 97, 115, 109, 45, 116, 121, 112, 101, 45, 105, 100, 3, 0, 5, 1, 114, 3, 4, 115, 105, 122, 101, 119, 9, 97, 108, 105, 103, 110, 109, 101, 110, 116, 119, 7, 116, 121, 112, 101, 45, 105, 100, 6, 4, 0, 14, 99, 111, 109, 112, 111, 110, 101, 110, 116, 45, 105, 110, 102, 111, 3, 0, 7, 4, 0, 16, 101, 99, 115, 45, 100, 121, 110, 97, 109, 105, 99, 45, 118, 105, 101, 119, 3, 1, 4, 0, 9, 101, 99, 115, 45, 119, 111, 114, 108, 100, 3, 1, 1, 104, 10, 1, 112, 8, 1, 105, 9, 1, 64, 2, 4, 119, 114, 108, 100, 11, 15, 99, 111, 109, 112, 111, 110, 101, 110, 116, 45, 105, 110, 102, 111, 115, 12, 0, 13, 4, 0, 29, 91, 99, 111, 110, 115, 116, 114, 117, 99, 116, 111, 114, 93, 101, 99, 115, 45, 100, 121, 110, 97, 109, 105, 99, 45, 118, 105, 101, 119, 1, 14, 1, 104, 9, 1, 112, 125, 1, 107, 16, 1, 64, 1, 4, 115, 101, 108, 102, 15, 0, 17, 4, 0, 29, 91, 109, 101, 116, 104, 111, 100, 93, 101, 99, 115, 45, 100, 121, 110, 97, 109, 105, 99, 45, 118, 105, 101, 119, 46, 110, 101, 120, 116, 1, 18, 1, 105, 10, 1, 64, 0, 0, 19, 4, 0, 22, 91, 99, 111, 110, 115, 116, 114, 117, 99, 116, 111, 114, 93, 101, 99, 115, 45, 119, 111, 114, 108, 100, 1, 20, 1, 64, 3, 4, 115, 101, 108, 102, 11, 10, 99, 111, 109, 112, 111, 110, 101, 110, 116, 115, 16, 15, 99, 111, 109, 112, 111, 110, 101, 110, 116, 45, 105, 110, 102, 111, 115, 12, 0, 3, 4, 0, 23, 91, 109, 101, 116, 104, 111, 100, 93, 101, 99, 115, 45, 119, 111, 114, 108, 100, 46, 115, 112, 97, 119, 110, 1, 21, 1, 64, 2, 4, 115, 101, 108, 102, 11, 15, 99, 111, 109, 112, 111, 110, 101, 110, 116, 45, 105, 110, 102, 111, 115, 12, 0, 13, 4, 0, 22, 91, 109, 101, 116, 104, 111, 100, 93, 101, 99, 115, 45, 119, 111, 114, 108, 100, 46, 118, 105, 101, 119, 1, 22, 3, 1, 22, 99, 111, 109, 112, 111, 110, 101, 110, 116, 58, 119, 105, 116, 103, 117, 101, 115, 116, 47, 101, 99, 115, 5, 1, 1, 64, 1, 3, 109, 115, 103, 115, 1, 0, 3, 0, 10, 104, 111, 115, 116, 45, 112, 114, 105, 110, 116, 1, 2, 1, 106, 1, 125, 0, 1, 64, 0, 0, 3, 4, 0, 7, 111, 110, 45, 105, 110, 105, 116, 1, 4, 4, 1, 26, 99, 111, 109, 112, 111, 110, 101, 110, 116, 58, 119, 105, 116, 103, 117, 101, 115, 116, 47, 101, 120, 97, 109, 112, 108, 101, 4, 0, 11, 13, 1, 0, 7, 101, 120, 97, 109, 112, 108, 101, 3, 0, 0, 0, 70, 9, 112, 114, 111, 100, 117, 99, 101, 114, 115, 1, 12, 112, 114, 111, 99, 101, 115, 115, 101, 100, 45, 98, 121, 2, 13, 119, 105, 116, 45, 99, 111, 109, 112, 111, 110, 101, 110, 116, 6, 48, 46, 50, 49, 46, 48, 16, 119, 105, 116, 45, 98, 105, 110, 100, 103, 101, 110, 45, 114, 117, 115, 116, 6, 48, 46, 49, 56, 46, 48];
 
 #[inline(never)]
 #[doc(hidden)]

witguest/src/lib.rs

@@ -1,7 +1,7 @@
 #[allow(warnings)]
 mod bindings;
 
-use bindings::{component::witguest::ecs::{ComponentInfo, EcsWorld, WasmTypeId}, Guest};
+use bindings::{component::witguest::ecs::{ComponentInfo, EcsWorld, Entity, WasmTypeId}, Guest};
 
 use std::{alloc::Layout, any::TypeId, mem};
 
@@ -42,25 +42,30 @@ struct Component;
 
 impl Guest for Component {
     fn on_init() -> Result<u8, ()> {
-        let comps = &mut [Vec3::new(7.0, 30.0, 18.0),];
-        let info = &[Vec3::component_info()];
-
-        // no fucking clue if this will work, but lets try and it see
-        let comps = comps.as_mut_ptr().cast::<u8>();
-        let comps = unsafe { Vec::from_raw_parts(comps, mem::size_of::<Vec3>(), 1) };
-
         let world = EcsWorld::new();
-        let en = world.spawn(&comps, info);
+        spawn_vec3(&world, Vec3::new(7.0, 30.0, 18.0));
+        spawn_vec3(&world, Vec3::new(90.30, 65.0, 83.0));
 
-        //let en = ecs_world::spawn(&comps, info);
+        bindings::host_print("Spawned entities");
 
-        bindings::host_print(&format!("Spawned entity: {}", en.id.id));
+        let view = world.view(&[Vec3::component_info()]);
-
+        while let Some(mut buffer) = view.next() {
-        let mut buffer = world.view(&[Vec3::component_info()]);
+            bindings::host_print(&format!("Retrieved vec3 of {} bytes long", buffer.len()));
-        bindings::host_print(&format!("Retrieved vec3 of {} bytes long", buffer.len()));
+            let fetched_vec = unsafe { std::ptr::read(buffer.as_mut_ptr().cast::<Vec3>()) };
-        let fetched_vec = unsafe { std::ptr::read(buffer.as_mut_ptr().cast::<Vec3>()) };
+            bindings::host_print(&format!("Retrieved vec3: {:?}", fetched_vec));
-        bindings::host_print(&format!("Retrieved vec3: {:?}", fetched_vec));
+        }
 
         Ok(0)
     }
 }
+
+fn spawn_vec3(world: &EcsWorld, v: Vec3) -> Entity {
+    let comps = &mut [v,];
+    let info = &[Vec3::component_info()];
+
+    // no fucking clue if this will work, but lets try and it see
+    let comps = comps.as_mut_ptr().cast::<u8>();
+    let comps = unsafe { Vec::from_raw_parts(comps, mem::size_of::<Vec3>(), 1) };
+
+    world.spawn(&comps, info)
+}

witguest/wit/world.wit

@@ -30,12 +30,18 @@ interface ecs {
         type-id: wasm-type-id, // a u128
     }
 
+    resource ecs-dynamic-view {
+        constructor(wrld: borrow<ecs-world>, component-infos: list<component-info>);
+
+        next: func() -> option<list<u8>>;
+    }
+
     resource ecs-world {
         constructor();
 
         // expects components to be tightly packed in the same order of component-infos
         spawn: func(components: list<u8>, component-infos: list<component-info>) -> entity;
-        view: func(component-infos: list<component-info>) -> list<u8>;
+        view: func(component-infos: list<component-info>) -> ecs-dynamic-view;
     }
 }