Refactor how InitContext works with factors

This commit is a refactoring to replace the concrete `InitContext`
structure with a generic type parameter instead. The motivation for this
is to prepare for handling bytecodealliance/wasmtime#10770. That's a big
change to how `add_to_linker` functions work, notably that the argument
to the generated functions is a `fn`, not a `F: Fn`. WASI factors
currently rely on the closure-like nature this argument which means it's
not compatible with that change. The refactoring to use a `trait
InitContext` here enables plumbing a type parameter through a function
to be able to get a function pointer without relying on closures.

Signed-off-by: Alex Crichton <[email protected]>

Author: alexcrichton

crates/factor-key-value/src/lib.rs

@@ -38,7 +38,10 @@ impl Factor for KeyValueFactor {
     type AppState = AppState;
     type InstanceBuilder = InstanceBuilder;
 
-    fn init<T: Send + 'static>(&mut self, mut ctx: InitContext<T, Self>) -> anyhow::Result<()> {
+    fn init<C>(&mut self, ctx: &mut C) -> anyhow::Result<()>
+    where
+        C: InitContext<Self>,
+    {
         ctx.link_bindings(spin_world::v1::key_value::add_to_linker)?;
         ctx.link_bindings(spin_world::v2::key_value::add_to_linker)?;
         ctx.link_bindings(spin_world::wasi::keyvalue::store::add_to_linker)?;

crates/factor-llm/src/lib.rs

@@ -36,10 +36,10 @@ impl Factor for LlmFactor {
     type AppState = AppState;
     type InstanceBuilder = InstanceState;
 
-    fn init<T: Send + 'static>(
-        &mut self,
-        mut ctx: spin_factors::InitContext<T, Self>,
-    ) -> anyhow::Result<()> {
+    fn init<C>(&mut self, ctx: &mut C) -> anyhow::Result<()>
+    where
+        C: spin_factors::InitContext<Self>,
+    {
         ctx.link_bindings(spin_world::v1::llm::add_to_linker)?;
         ctx.link_bindings(spin_world::v2::llm::add_to_linker)?;
         Ok(())

crates/factor-outbound-http/src/lib.rs

@@ -52,12 +52,12 @@ impl Factor for OutboundHttpFactor {
     type AppState = ();
     type InstanceBuilder = InstanceState;
 
-    fn init<T: Send + 'static>(
-        &mut self,
-        mut ctx: spin_factors::InitContext<T, Self>,
-    ) -> anyhow::Result<()> {
+    fn init<C>(&mut self, ctx: &mut C) -> anyhow::Result<()>
+    where
+        C: spin_factors::InitContext<Self>,
+    {
         ctx.link_bindings(spin_world::v1::http::add_to_linker)?;
-        wasi::add_to_linker::<T>(&mut ctx)?;
+        wasi::add_to_linker(ctx)?;
         Ok(())
     }
 

crates/factor-outbound-http/src/wasi.rs

@@ -23,26 +23,24 @@ use crate::{
     wasi_2023_10_18, wasi_2023_11_10, InstanceState, OutboundHttpFactor, SelfRequestOrigin,
 };
 
-pub(crate) fn add_to_linker<T: Send + 'static>(
-    ctx: &mut spin_factors::InitContext<T, OutboundHttpFactor>,
-) -> anyhow::Result<()> {
-    fn type_annotate<T, F>(f: F) -> F
+pub(crate) fn add_to_linker<C>(ctx: &mut C) -> anyhow::Result<()>
+where
+    C: spin_factors::InitContext<OutboundHttpFactor>,
+{
+    fn get_http<C>(store: &mut C::StoreData) -> WasiHttpImpl<WasiHttpImplInner<'_>>
     where
-        F: Fn(&mut T) -> WasiHttpImpl<WasiHttpImplInner>,
+        C: spin_factors::InitContext<OutboundHttpFactor>,
     {
-        f
-    }
-    let get_data_with_table = ctx.get_data_with_table_fn();
-    let closure = type_annotate(move |data| {
-        let (state, table) = get_data_with_table(data);
+        let (state, table) = C::get_data_with_table(store);
         WasiHttpImpl(IoImpl(WasiHttpImplInner { state, table }))
-    });
+    }
+    let get_http = get_http::<C> as fn(&mut C::StoreData) -> WasiHttpImpl<WasiHttpImplInner<'_>>;
     let linker = ctx.linker();
-    wasmtime_wasi_http::bindings::http::outgoing_handler::add_to_linker_get_host(linker, closure)?;
-    wasmtime_wasi_http::bindings::http::types::add_to_linker_get_host(linker, closure)?;
+    wasmtime_wasi_http::bindings::http::outgoing_handler::add_to_linker_get_host(linker, get_http)?;
+    wasmtime_wasi_http::bindings::http::types::add_to_linker_get_host(linker, get_http)?;
 
-    wasi_2023_10_18::add_to_linker(linker, closure)?;
-    wasi_2023_11_10::add_to_linker(linker, closure)?;
+    wasi_2023_10_18::add_to_linker(linker, get_http)?;
+    wasi_2023_11_10::add_to_linker(linker, get_http)?;
 
     Ok(())
 }

crates/factor-outbound-http/src/wasi_2023_10_18.rs

@@ -54,10 +54,12 @@ use wasi::io::streams::{InputStream, OutputStream};
 
 use crate::wasi::WasiHttpImplInner;
 
-pub(crate) fn add_to_linker<T, F>(linker: &mut Linker<T>, closure: F) -> Result<()>
+pub(crate) fn add_to_linker<T>(
+    linker: &mut Linker<T>,
+    closure: fn(&mut T) -> WasiHttpImpl<WasiHttpImplInner<'_>>,
+) -> Result<()>
 where
-    T: Send,
-    F: Fn(&mut T) -> WasiHttpImpl<WasiHttpImplInner> + Send + Sync + Copy + 'static,
+    T: Send + 'static,
 {
     wasi::http::types::add_to_linker_get_host(linker, closure)?;
     wasi::http::outgoing_handler::add_to_linker_get_host(linker, closure)?;

crates/factor-outbound-http/src/wasi_2023_11_10.rs

@@ -59,10 +59,12 @@ use wasi::io::streams::{Error as IoError, InputStream, OutputStream};
 
 use crate::wasi::WasiHttpImplInner;
 
-pub(crate) fn add_to_linker<T, F>(linker: &mut Linker<T>, closure: F) -> Result<()>
+pub(crate) fn add_to_linker<T>(
+    linker: &mut Linker<T>,
+    closure: fn(&mut T) -> WasiHttpImpl<WasiHttpImplInner<'_>>,
+) -> Result<()>
 where
-    T: Send,
-    F: Fn(&mut T) -> WasiHttpImpl<WasiHttpImplInner> + Send + Sync + Copy + 'static,
+    T: Send + 'static,
 {
     wasi::http::types::add_to_linker_get_host(linker, closure)?;
     wasi::http::outgoing_handler::add_to_linker_get_host(linker, closure)?;

crates/factor-outbound-mqtt/src/lib.rs

@@ -31,10 +31,10 @@ impl Factor for OutboundMqttFactor {
     type AppState = ();
     type InstanceBuilder = InstanceState;
 
-    fn init<T: Send + 'static>(
-        &mut self,
-        mut ctx: spin_factors::InitContext<T, Self>,
-    ) -> anyhow::Result<()> {
+    fn init<C>(&mut self, ctx: &mut C) -> anyhow::Result<()>
+    where
+        C: spin_factors::InitContext<Self>,
+    {
         ctx.link_bindings(spin_world::v2::mqtt::add_to_linker)?;
         Ok(())
     }

crates/factor-outbound-mysql/src/lib.rs

@@ -17,7 +17,10 @@ impl<C: Send + Sync + Client + 'static> Factor for OutboundMysqlFactor<C> {
     type AppState = ();
     type InstanceBuilder = InstanceState<C>;
 
-    fn init<T: Send + 'static>(&mut self, mut ctx: InitContext<T, Self>) -> anyhow::Result<()> {
+    fn init<I>(&mut self, ctx: &mut I) -> anyhow::Result<()>
+    where
+        I: InitContext<Self>,
+    {
         ctx.link_bindings(v1::add_to_linker)?;
         ctx.link_bindings(v2::add_to_linker)?;
         Ok(())

crates/factor-outbound-pg/src/lib.rs

@@ -17,10 +17,10 @@ impl<C: Send + Sync + Client + 'static> Factor for OutboundPgFactor<C> {
     type AppState = ();
     type InstanceBuilder = InstanceState<C>;
 
-    fn init<T: Send + 'static>(
-        &mut self,
-        mut ctx: spin_factors::InitContext<T, Self>,
-    ) -> anyhow::Result<()> {
+    fn init<I>(&mut self, ctx: &mut I) -> anyhow::Result<()>
+    where
+        I: spin_factors::InitContext<Self>,
+    {
         ctx.link_bindings(spin_world::v1::postgres::add_to_linker)?;
         ctx.link_bindings(spin_world::v2::postgres::add_to_linker)?;
         ctx.link_bindings(spin_world::spin::postgres::postgres::add_to_linker)?;

crates/factor-outbound-redis/src/lib.rs

@@ -23,10 +23,10 @@ impl Factor for OutboundRedisFactor {
     type AppState = ();
     type InstanceBuilder = InstanceState;
 
-    fn init<T: Send + 'static>(
-        &mut self,
-        mut ctx: spin_factors::InitContext<T, Self>,
-    ) -> anyhow::Result<()> {
+    fn init<C>(&mut self, ctx: &mut C) -> anyhow::Result<()>
+    where
+        C: spin_factors::InitContext<Self>,
+    {
         ctx.link_bindings(spin_world::v1::redis::add_to_linker)?;
         ctx.link_bindings(spin_world::v2::redis::add_to_linker)?;
         Ok(())