Convex MCP server

//! Provides an equivalent to the [`v8::Isolate::set_slot`] API that is //! context-local. [`v8::Context::set_slot`] doesn't work because it only offers //! access behind an Rc, which is inconvenient. use std::{ collections::HashMap, hash::{ Hash, Hasher, }, rc::Rc, }; use deno_core::v8; // size > 0 so that pointers are unique struct ContextIdSlot(#[allow(dead_code)] u8); struct ContextId(Rc<ContextIdSlot>); impl PartialEq for ContextId { fn eq(&self, other: &Self) -> bool { Rc::ptr_eq(&self.0, &other.0) } } impl Eq for ContextId {} impl Hash for ContextId { fn hash<H: Hasher>(&self, state: &mut H) { Rc::as_ptr(&self.0).hash(state); } } impl ContextId { fn of(context: &v8::Context) -> Self { if let Some(slot) = context.get_slot::<ContextIdSlot>() { return Self(slot); } let slot = Rc::new(ContextIdSlot(0)); assert!(context.set_slot(slot.clone()).is_none()); Self(slot) } } struct PerContext<T> { by_context: HashMap<ContextId, T>, } impl<T> PerContext<T> { fn new() -> Self { Self { by_context: HashMap::new(), } } fn get(&self, context: &v8::Context) -> Option<&T> { self.by_context.get(&ContextId::of(context)) } fn get_mut(&mut self, context: &v8::Context) -> Option<&mut T> { self.by_context.get_mut(&ContextId::of(context)) } fn set(&mut self, context: &v8::Context, value: T) -> bool { self.by_context .insert(ContextId::of(context), value) .is_none() } fn remove(&mut self, context: &v8::Context) -> Option<T> { self.by_context.remove(&ContextId::of(context)) } } pub(crate) trait GetContextSlot { fn get_context_slot<'a, T: 'static>(&self, isolate: &'a v8::Isolate) -> Option<&'a T>; fn get_context_slot_mut<'a, T: 'static>( &self, isolate: &'a mut v8::Isolate, ) -> Option<&'a mut T>; fn set_context_slot<T: 'static>(&self, isolate: &mut v8::Isolate, value: T) -> bool; fn remove_context_slot<T: 'static>(&self, isolate: &mut v8::Isolate) -> Option<T>; } impl GetContextSlot for v8::Context { fn get_context_slot<'a, T: 'static>(&self, isolate: &'a v8::Isolate) -> Option<&'a T> { isolate .get_slot::<PerContext<T>>() .and_then(|slot| slot.get(self)) } fn get_context_slot_mut<'a, T: 'static>( &self, isolate: &'a mut v8::Isolate, ) -> Option<&'a mut T> { isolate .get_slot_mut::<PerContext<T>>() .and_then(|slot| slot.get_mut(self)) } fn set_context_slot<T: 'static>(&self, isolate: &mut v8::Isolate, value: T) -> bool { if let Some(slot) = isolate.get_slot_mut::<PerContext<T>>() { return slot.set(self, value); } let mut slot = PerContext::<T>::new(); slot.set(self, value); assert!(isolate.set_slot(slot)); true } fn remove_context_slot<T: 'static>(&self, isolate: &mut v8::Isolate) -> Option<T> { isolate .get_slot_mut::<PerContext<T>>() .and_then(|slot| slot.remove(self)) } }