feat(dojo-core): add support to read/write the same member from multiple models

crates/dojo/core-cairo-test/src/tests/model/model.cairo

@@ -194,3 +194,52 @@ fn test_model_ptr_from_entity_id() {
     let v1 = world.read_member(ptr, selector!("v1"));
     assert!(foo.v1 == v1);
 }
+
+#[test]
+fn test_read_member() {
+    let mut world = spawn_foo_world();
+    let foo = Foo { k1: 1, k2: 2, v1: 3, v2: 4 };
+    world.write_model(@foo);
+    let v1: u128 = world.read_member(foo.ptr(), selector!("v1"));
+    let v2: u32 = world.read_member(foo.ptr(), selector!("v2"));
+    assert!(foo.v1 == v1);
+    assert!(foo.v2 == v2);
+}
+
+#[test]
+fn test_read_members() {
+    let mut world = spawn_foo_world();
+    let foo = Foo { k1: 1, k2: 2, v1: 3, v2: 4 };
+    let foo2 = Foo { k1: 5, k2: 6, v1: 7, v2: 8 };
+    world.write_models([@foo, @foo2].span());
+    let ptrs = [foo.ptr(), foo2.ptr()].span();
+    let v1s: Array<u128> = world.read_members(ptrs, selector!("v1"));
+    let v2s: Array<u32> = world.read_members(ptrs, selector!("v2"));
+    assert!(v1s == array![foo.v1, foo2.v1]);
+    assert!(v2s == array![foo.v2, foo2.v2]);
+}
+
+#[test]
+fn test_write_member() {
+    let mut world = spawn_foo_world();
+    let foo = Foo { k1: 1, k2: 2, v1: 3, v2: 4 };
+    world.write_model(@foo);
+    world.write_member(foo.ptr(), selector!("v1"), 42);
+    let foo_read: Foo = world.read_model((foo.k1, foo.k2));
+    assert!(foo_read.v1 == 42 && foo_read.v2 == foo.v2);
+}
+#[test]
+fn test_write_members() {
+    let mut world = spawn_foo_world();
+    let foo = Foo { k1: 1, k2: 2, v1: 3, v2: 4 };
+    let foo2 = Foo { k1: 5, k2: 6, v1: 7, v2: 8 };
+    world.write_models([@foo, @foo2].span());
+    let ptrs = [foo.ptr(), foo2.ptr()].span();
+    let v1s = array![42, 43];
+    world.write_members(ptrs, selector!("v1"), v1s.span());
+    let v1s_read: Array<u128> = world.read_members(ptrs, selector!("v1"));
+    let v2s_read: Array<u32> = world.read_members(ptrs, selector!("v2"));
+    assert!(v1s_read == v1s);
+    assert!(v2s_read == array![foo.v2, foo2.v2]);
+}
+

crates/dojo/core/src/lib.cairo

@@ -42,7 +42,7 @@ pub mod model {
     pub use definition::{ModelIndex, ModelDefinition, ModelDef};
 
     pub mod model;
-    pub use model::{Model, KeyParser, ModelPtr};
+    pub use model::{Model, KeyParser, ModelPtr, ModelPtrsTrait};
 
     pub mod model_value;
     pub use model_value::{ModelValue, ModelValueKey};

crates/dojo/core/src/model/model.cairo

@@ -3,7 +3,7 @@ use dojo::{
     utils::{entity_id_from_serialized_keys, find_model_field_layout, entity_id_from_keys},
 };
 
-use super::{ModelDefinition, ModelDef};
+use super::{ModelDefinition, ModelDef, ModelIndex};
 /// Trait `KeyParser` defines a trait for parsing keys from a given model.
 ///
 /// A pointer to a model, which can be expressed by an entity id.
@@ -12,6 +12,29 @@ pub struct ModelPtr<M> {
     pub id: felt252,
 }
 
+pub trait ModelPtrsTrait<M> {
+    fn to_indexes(self: Span<ModelPtr<M>>) -> Span<ModelIndex>;
+    fn to_member_indexes(self: Span<ModelPtr<M>>, field_selector: felt252) -> Span<ModelIndex>;
+}
+
+pub impl ModelPtrsImpl<M> of ModelPtrsTrait<M> {
+    fn to_indexes(self: Span<ModelPtr<M>>) -> Span<ModelIndex> {
+        let mut ids = ArrayTrait::<ModelIndex>::new();
+        for ptr in self {
+            ids.append(ModelIndex::Id(*ptr.id));
+        };
+        ids.span()
+    }
+
+    fn to_member_indexes(self: Span<ModelPtr<M>>, field_selector: felt252) -> Span<ModelIndex> {
+        let mut ids = ArrayTrait::<ModelIndex>::new();
+        for ptr in self {
+            ids.append(ModelIndex::MemberId((*ptr.id, field_selector)));
+        };
+        ids.span()
+    }
+}
+
 pub trait KeyParser<M, K> {
     /// Parses the key from the given model.
     fn parse_key(self: @M) -> K;

crates/dojo/core/src/model/storage.cairo

@@ -35,14 +35,24 @@ pub trait ModelStorage<S, M> {
     /// The ptr is mostly used for type inferrence.
     fn erase_models_ptrs(ref self: S, ptrs: Span<ModelPtr<M>>);
 
-    /// Retrieves a model of type `M` using the provided entity idref .
+    /// Retrieves a model of type `M` using the provided entity id.
     fn read_member<T, +Serde<T>>(self: @S, ptr: ModelPtr<M>, field_selector: felt252) -> T;
 
-    /// Retrieves a model of type `M` using the provided entity id.
+    /// Retrieves a single member from multiple models.
+    fn read_members<T, +Serde<T>, +Drop<T>>(
+        self: @S, ptrs: Span<ModelPtr<M>>, field_selector: felt252,
+    ) -> Array<T>;
+
+    /// Updates a member of a model.
     fn write_member<T, +Serde<T>, +Drop<T>>(
         ref self: S, ptr: ModelPtr<M>, field_selector: felt252, value: T,
     );
 
+    /// Updates a member of multiple models.
+    fn write_members<T, +Serde<T>, +Drop<T>>(
+        ref self: S, ptrs: Span<ModelPtr<M>>, field_selector: felt252, values: Span<T>,
+    );
+
     /// Returns the current namespace hash.
     fn namespace_hash(self: @S) -> felt252;
 }

crates/dojo/core/src/world/storage.cairo

@@ -2,7 +2,9 @@
 
 use core::panic_with_felt252;
 use dojo::world::{IWorldDispatcher, IWorldDispatcherTrait, Resource};
-use dojo::model::{Model, ModelIndex, ModelValueKey, ModelValue, ModelStorage, ModelPtr};
+use dojo::model::{
+    Model, ModelIndex, ModelValueKey, ModelValue, ModelStorage, ModelPtr, ModelPtrsTrait,
+};
 use dojo::event::{Event, EventStorage};
 use dojo::meta::Layout;
 use dojo::utils::{
@@ -192,6 +194,22 @@ pub impl ModelStorageWorldStorageImpl<M, +Model<M>, +Drop<M>> of ModelStorage<Wo
             ),
         )
     }
+
+    fn read_members<T, +Serde<T>, +Drop<T>>(
+        self: @WorldStorage, ptrs: Span<ModelPtr<M>>, field_selector: felt252,
+    ) -> Array<T> {
+        let mut values: Array<T> = array![];
+        for entity in IWorldDispatcherTrait::entities(
+            *self.dispatcher,
+            Model::<M>::selector(*self.namespace_hash),
+            ptrs.to_member_indexes(field_selector),
+            field_layout_unwrap::<M>(field_selector),
+        ) {
+            values.append(deserialize_unwrap(*entity));
+        };
+        values
+    }
+
     fn write_member<T, +Serde<T>, +Drop<T>>(
         ref self: WorldStorage, ptr: ModelPtr<M>, field_selector: felt252, value: T,
     ) {
@@ -204,6 +222,22 @@ pub impl ModelStorageWorldStorageImpl<M, +Model<M>, +Drop<M>> of ModelStorage<Wo
         );
     }
 
+    fn write_members<T, +Serde<T>, +Drop<T>>(
+        ref self: WorldStorage, ptrs: Span<ModelPtr<M>>, field_selector: felt252, values: Span<T>,
+    ) {
+        let mut serialized_values = ArrayTrait::<Span<felt252>>::new();
+        for value in values {
+            serialized_values.append(serialize_inline(value));
+        };
+        IWorldDispatcherTrait::set_entities(
+            self.dispatcher,
+            Model::<M>::selector(self.namespace_hash),
+            ptrs.to_member_indexes(field_selector),
+            serialized_values.span(),
+            field_layout_unwrap::<M>(field_selector),
+        );
+    }
+
     fn erase_models_ptrs(ref self: WorldStorage, ptrs: Span<ModelPtr<M>>) {
         let mut indexes: Array<ModelIndex> = array![];
         for ptr in ptrs {