Stores: Externally tracked state and reactive collections (#4483)

* map signals mutably

* boxed signals

* remove mutable borrow type from boxed writable

* improve map mut example

* restore boxed_mut helper

* make boxed readable/writable types copy

* Move away from the ReadOnlySignal alias in examples

* automatically convert Write

* Fix some tests

* ReadSignal and WriteSignal

* move read only signal alias

* make maps copy

* store prototype

* implement derive macro

* Handle generics in the derive macro

* Make Selector boxable

* derive boxed conversion

* Get rid of store type

* Remove hardcoded type from derive macro

* selector -> store

* Refactor store implementation

* more vec methods

* todo mvc store example

* Implement Storable for HashMap

* fix write

* restore sorting logic in todomvc

* derive readable and writable

* improve todomvc store example

* Result store

* Option store

* collect dead subscribers

* fix clippy and formatting

* recognize some common foreign types automatically

* fix foreign stores in props

* slice and array selectors

* clean up store example

* writable is child owned

* box selector

* read and write to builtins

* re-use the proc macro in the derive macro

* Switch to a extension trait based approach

* switch to extension traits in the derive macro

* transposed method

* derive enums

* Expose Store::new

* remove stores from the prelude

* More consistent naming scheme for SelectorScope methods

* document hashmap methods

* document index extension

* document option ext

* document result ext

* document slice extension

* document the vec extension

* make more methods borrow the store mutably

* Move to impls to have higher priority over the builtin write extension traits

* fix deadlock

* finish stores documentation

* Document the store macro

* cleanup docs and organization

* finish derive docs

* fix typo

* fix clippy

* fix doc tests

* fix derive macro with generics

* fix clippy

* test and fix empty structs

* clean up todomvc store example

* default to a boxed store writer to make it easier to type when providing to the context api

* fix cargo doc

* fix clippy in store example

* relax generational box lifetime bounds

* relax bounds

* relax signal bounds

* fix compilation

* read store

* relax bounds on default store impls

* fix enum derive

* Convert to readsignal and writesignal automatically

* simplify type matching logic

* add write store

* unsized stores

* shrink the path vec type

* use more concrete types

* remove opaque types

* remove copy bounds

* use lens as generic name everywhere

* more consistent borrow semantics

* use a concrete type for the signal metadata and mention references in the map docs

* improve todomvc store docs

* document store derive macro internals

* refactor macro

* improve selector node documentation

* fix clippy

* add btreemap

* fix doc tests

* more option methods

* fix doc

* fix clippy

* add a bunch more result methods

* add a bunch of bounds to the iterators

* fix clippy

* remove option from subscribers

* add store macro to generate extension traits

* fix store example

* fix deadlock

* fix docs

* fix doc tests

* fix clippy

* add stores to public api

* add store macro, and then update todomvc_store example

---------

Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>

packages/signals/src/map.rs

@@ -4,7 +4,7 @@ use generational_box::{AnyStorage, BorrowResult};
 use std::ops::Deref;
 
 /// A read only signal that has been mapped to a new type.
-pub struct MappedSignal<O: ?Sized + 'static, V: Readable, F = fn(&<V as Readable>::Target) -> &O> {
+pub struct MappedSignal<O: ?Sized, V, F = fn(&<V as Readable>::Target) -> &O> {
     value: V,
     map_fn: F,
     _marker: std::marker::PhantomData<O>,
@@ -34,11 +34,9 @@ where
 impl<V, O, F> MappedSignal<O, V, F>
 where
     O: ?Sized,
-    V: Readable,
-    F: Fn(&V::Target) -> &O,
 {
     /// Create a new mapped signal.
-    pub(crate) fn new(value: V, map_fn: F) -> Self {
+    pub fn new(value: V, map_fn: F) -> Self {
         MappedSignal {
             value,
             map_fn,
@@ -51,6 +49,7 @@ impl<V, O, F> Readable for MappedSignal<O, V, F>
 where
     O: ?Sized,
     V: Readable,
+    V::Target: 'static,
     F: Fn(&V::Target) -> &O,
 {
     type Target = O;
@@ -68,15 +67,16 @@ where
         Ok(V::Storage::map(value, |v| (self.map_fn)(v)))
     }
 
-    fn subscribers(&self) -> Option<Subscribers> {
+    fn subscribers(&self) -> Subscribers {
         self.value.subscribers()
     }
 }
 
 impl<V, O, F> IntoAttributeValue for MappedSignal<O, V, F>
 where
-    O: Clone + IntoAttributeValue,
+    O: Clone + IntoAttributeValue + 'static,
     V: Readable,
+    V::Target: 'static,
     F: Fn(&V::Target) -> &O,
 {
     fn into_value(self) -> dioxus_core::AttributeValue {
@@ -100,7 +100,7 @@ where
 /// Currently only limited to clone types, though could probably specialize for string/arc/rc
 impl<V, O, F> Deref for MappedSignal<O, V, F>
 where
-    O: Clone,
+    O: Clone + 'static,
     V: Readable + 'static,
     F: Fn(&V::Target) -> &O + 'static,
 {
@@ -111,4 +111,4 @@ where
     }
 }
 
-read_impls!(MappedSignal<T, V, F> where V: Readable, F: Fn(&V::Target) -> &T);
+read_impls!(MappedSignal<T, V, F> where V: Readable<Target: 'static>, F: Fn(&V::Target) -> &T);