1 files changed, 89 insertions, 0 deletions
diff --git a/third_party/rust/uniffi_bindgen/src/scaffolding/templates/ObjectTemplate.rs b/third_party/rust/uniffi_bindgen/src/scaffolding/templates/ObjectTemplate.rs
new file mode 100644
index 0000000000..e2445c670d
--- /dev/null
+++ b/third_party/rust/uniffi_bindgen/src/scaffolding/templates/ObjectTemplate.rs
@@ -0,0 +1,89 @@
+// For each Object definition, we assume the caller has provided an appropriately-shaped `struct T`
+// with an `impl` for each method on the object. We create an `Arc<T>` for "safely" handing out
+// references to these structs to foreign language code, and we provide a `pub extern "C"` function
+// corresponding to each method.
+//
+// (Note that "safely" is in "scare quotes" - that's because we use functions on an `Arc` that
+// that are inherently unsafe, but the code we generate is safe in practice.)
+//
+// If the caller's implementation of the struct does not match with the methods or types specified
+// in the UDL, then the rust compiler will complain with a (hopefully at least somewhat helpful!)
+// error message when processing this generated code.
+
+{%- match obj.imp() -%}
+{%- when ObjectImpl::Trait %}
+#[::uniffi::export_for_udl]
+pub trait r#{{ obj.name() }} {
+    {%- for meth in obj.methods() %}
+    fn {{ meth.name() }}(
+        {% if meth.takes_self_by_arc()%}self: Arc<Self>{% else %}&self{% endif %},
+        {%- for arg in meth.arguments() %}
+        {{ arg.name() }}: {% if arg.by_ref() %}&{% endif %}{{ arg.as_type().borrow()|type_rs }},
+        {%- endfor %}
+    )
+    {%- match (meth.return_type(), meth.throws_type()) %}
+    {%- when (Some(return_type), None) %} -> {{ return_type|type_rs }};
+    {%- when (Some(return_type), Some(error_type)) %} -> ::std::result::Result::<{{ return_type|type_rs }}, {{ error_type|type_rs }}>;
+    {%- when (None, Some(error_type)) %} -> ::std::result::Result::<(), {{ error_type|type_rs }}>;
+    {%- when (None, None) %};
+    {%- endmatch %}
+    {% endfor %}
+}
+{% when ObjectImpl::Struct %}
+{%- for tm in obj.uniffi_traits() %}
+{%      match tm %}
+{%          when UniffiTrait::Debug { fmt }%}
+#[uniffi::export(Debug)]
+{%          when UniffiTrait::Display { fmt }%}
+#[uniffi::export(Display)]
+{%          when UniffiTrait::Hash { hash }%}
+#[uniffi::export(Hash)]
+{%          when UniffiTrait::Eq { eq, ne }%}
+#[uniffi::export(Eq)]
+{%      endmatch %}
+{% endfor %}
+#[::uniffi::derive_object_for_udl]
+struct {{ obj.rust_name() }} { }
+
+{%- for cons in obj.constructors() %}
+#[::uniffi::export_for_udl(constructor)]
+impl {{ obj.rust_name() }} {
+    pub fn r#{{ cons.name() }}(
+        {%- for arg in cons.arguments() %}
+        r#{{ arg.name() }}: {% if arg.by_ref() %}&{% endif %}{{ arg.as_type().borrow()|type_rs }},
+        {%- endfor %}
+    )
+    {%- match (cons.return_type(), cons.throws_type()) %}
+    {%- when (Some(return_type), None) %} -> {{ return_type|type_rs }}
+    {%- when (Some(return_type), Some(error_type)) %} -> ::std::result::Result::<{{ return_type|type_rs }}, {{ error_type|type_rs }}>
+    {%- when (None, Some(error_type)) %} -> ::std::result::Result::<(), {{ error_type|type_rs }}>
+    {%- when (None, None) %}
+    {%- endmatch %}
+    {
+        unreachable!()
+    }
+}
+{%- endfor %}
+
+{%- for meth in obj.methods() %}
+#[::uniffi::export_for_udl]
+impl {{ obj.rust_name() }} {
+    pub fn r#{{ meth.name() }}(
+        {% if meth.takes_self_by_arc()%}self: Arc<Self>{% else %}&self{% endif %},
+        {%- for arg in meth.arguments() %}
+        r#{{ arg.name() }}: {% if arg.by_ref() %}&{% endif %}{{ arg.as_type().borrow()|type_rs }},
+        {%- endfor %}
+    )
+    {%- match (meth.return_type(), meth.throws_type()) %}
+    {%- when (Some(return_type), None) %} -> {{ return_type|type_rs }}
+    {%- when (Some(return_type), Some(error_type)) %} -> ::std::result::Result::<{{ return_type|type_rs }}, {{ error_type|type_rs }}>
+    {%- when (None, Some(error_type)) %} -> ::std::result::Result::<(), {{ error_type|type_rs }}>
+    {%- when (None, None) %}
+    {%- endmatch %}
+    {
+        unreachable!()
+    }
+}
+{%- endfor %}
+
+{% endmatch %}