Add type collection pass to get more info about External types (#66)

According to [The Big O of Code
Reviews](https://www.egorand.dev/the-big-o-of-code-reviews/), this is a
O(_n_) change.

This is a large diff, but most of the work is mechanical.

1. Allow the test-runner to initialize more than one C++ file. 
2. Adding a lookup for `External` types so the templates have more
detail about what the `External` (imported) types actually are.
3. Adding a `ext-types` fixture.

The most interesting of these is the second:

Before rendering any files, a pass is taken of all
`ComponentInterface`s.

Each type is collected, and added to a type map, keyed by module-path
and name.

When an external type is encountered later, the type map is consulted,
and the actual type
is used.

This is to remove a deficiency in `Type::External`: the `ExternalKind`
enum did not map completely onto a `Type`:
before this change, it wasn't clear what sort of type was being
imported, and so it was difficult/impossible
to work out __how__ to import (`import { X }` vs `import { type X }`),
or __what__ to import: `X` vs `XInterface`.

This meant changing the `type_name`, `ffi_converter_name` and some other
filter methods, necessitating __many__ template files. These changes can
be largely skimmed over.

The test also caught a runtime bug, which is also fixed in this PR: when
a Rust trait is implemented by Rust, but exposed (as a typescript
`interface`), this was erroring at runtime with a
`UniffiStaleHandleError`. This is now fixed.

.cargo/config.toml

@@ -1,2 +1,2 @@
 [alias]
-xtask = "run --package xtask --"
+xtask = "--quiet run --package xtask --"

cpp/hermes-extension/CMakeLists.txt

@@ -46,5 +46,4 @@ link_directories("${HERMES_BUILD_DIR}/API/hermes")
 link_directories("${HERMES_BUILD_DIR}/jsi")
 link_libraries(jsi)
 
-add_definitions(-DUNIFFI_ENABLE_TEST_HOOKS)
 add_library(${HERMES_EXTENSION_NAME} SHARED ${HERMES_EXTENSION_CPP})

cpp/hermes-rust-extension/CMakeLists.txt

@@ -56,6 +56,5 @@ link_directories("${HERMES_BUILD_DIR}/jsi")
 link_libraries(jsi)
 link_directories("${RUST_TARGET_DIR}")
 
-add_definitions(-DUNIFFI_ENABLE_TEST_HOOKS)
 add_library(${HERMES_EXTENSION_NAME} SHARED ${HERMES_EXTENSION_CPP})
 target_link_libraries(${HERMES_EXTENSION_NAME} ${RUST_LIB_NAME})

crates/ubrn_bindgen/src/bindings/mod.rs

@@ -6,10 +6,12 @@
 
 pub mod metadata;
 pub(crate) mod react_native;
+pub(crate) mod type_map;
 
-use std::str::FromStr;
+use std::{fs, str::FromStr};
 
 use anyhow::Result;
+use askama::Template;
 use camino::{Utf8Path, Utf8PathBuf};
 use clap::{command, Args};
 use ubrn_common::mk_dir;
@@ -150,4 +152,17 @@ impl BindingsArgs {
 
         Ok(configs)
     }
+
+    pub fn render_entrypoint(&self, path: &Utf8Path, modules: &Vec<ModuleMetadata>) -> Result<()> {
+        let index = EntrypointCpp { modules };
+        let string = index.render()?;
+        fs::write(path, string)?;
+        Ok(())
+    }
+}
+
+#[derive(Template)]
+#[template(path = "entrypoint.cpp", escape = "none")]
+struct EntrypointCpp<'a> {
+    modules: &'a Vec<ModuleMetadata>,
 }

crates/ubrn_bindgen/src/bindings/react_native/gen_cpp/templates/entrypoint.cpp

@@ -0,0 +1,21 @@
+// This file was autogenerated by some hot garbage in the `uniffi-bindgen-react-native` crate.
+// Trust me, you don't want to mess with it!
+
+// This template is only used when running `cargo xtask run`, i.e. when running `./scripts/run-tests.sh`.
+// It is an implementation of the `registerNatives` function which is used by the test-runner to dynamically
+// load the native modules without re-compiling the test-runner.
+//
+// Files generated with this template appear in the fixtures/{fixture}/generated/cpp directory, always called
+// `Entrypoint.cpp`, with a captilized `E` to ensure it does not collide with namespaces called "entrypoint".
+
+#include "registerNatives.h"
+
+{%- for m in modules %}
+#include "{{ m.hpp_filename() }}";
+{%- endfor %}
+
+extern "C" void registerNatives(jsi::Runtime &rt, std::shared_ptr<react::CallInvoker> callInvoker) {
+    {%- for m in modules %}
+    {{ m.cpp_module() }}::registerModule(rt, callInvoker);
+    {%- endfor %}
+}

crates/ubrn_bindgen/src/bindings/react_native/gen_cpp/templates/wrapper.cpp

@@ -1,7 +1,7 @@
-{%- let namespace = ci.namespace() %}
-{%- let module_name = module.cpp_module() %}
 // This file was autogenerated by some hot garbage in the `uniffi-bindgen-react-native` crate.
 // Trust me, you don't want to mess with it!
+{%- let namespace = ci.namespace() %}
+{%- let module_name = module.cpp_module() %}
 #include "{{ module.hpp_filename() }}"
 
 #include "UniffiJsiTypes.h"
@@ -14,14 +14,6 @@
 namespace react = facebook::react;
 namespace jsi = facebook::jsi;
 
-#ifdef UNIFFI_ENABLE_TEST_HOOKS
-// Initialization into the Hermes Runtime
-#include "registerNatives.h"
-extern "C" void registerNatives(jsi::Runtime &rt, std::shared_ptr<react::CallInvoker> callInvoker) {
-    {{ module_name }}::registerModule(rt, callInvoker);
-}
-#endif
-
 // Calling into Rust.
 extern "C" {
     {%- for definition in ci.ffi_definitions() %}

crates/ubrn_bindgen/src/bindings/react_native/gen_cpp/templates/wrapper.hpp

@@ -1,7 +1,7 @@
-{%- let namespace = ci.namespace() %}
-{%- let module_name = module.cpp_module() %}
 // This file was autogenerated by some hot garbage in the `uniffi-bindgen-react-native` crate.
 // Trust me, you don't want to mess with it!
+{%- let namespace = ci.namespace() %}
+{%- let module_name = module.cpp_module() %}
 #pragma once
 #include <jsi/jsi.h>
 #include <iostream>

crates/ubrn_bindgen/src/bindings/react_native/gen_typescript/filters.rs

@@ -3,7 +3,10 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/
  */
-use super::oracle::{AsCodeType, CodeOracle};
+use super::{
+    oracle::{AsCodeType, CodeOracle},
+    TypeRenderer,
+};
 pub(crate) use uniffi_bindgen::backend::filters::*;
 use uniffi_bindgen::{
     backend::{Literal, Type},
@@ -12,47 +15,72 @@ use uniffi_bindgen::{
 };
 
 pub(super) fn type_name(
-    as_ct: &impl AsCodeType,
-    ci: &ComponentInterface,
+    as_type: &impl AsType,
+    types: &TypeRenderer,
 ) -> Result<String, askama::Error> {
-    Ok(as_ct.as_codetype().type_label(ci))
+    let type_ = types.as_type(as_type);
+    Ok(type_.as_codetype().type_label(types.ci))
 }
 
 pub(super) fn decl_type_name(
-    as_ct: &impl AsCodeType,
-    ci: &ComponentInterface,
+    as_type: &impl AsType,
+    types: &TypeRenderer,
 ) -> Result<String, askama::Error> {
-    Ok(as_ct.as_codetype().decl_type_label(ci))
-}
-
-pub(super) fn canonical_name(as_ct: &impl AsCodeType) -> Result<String, askama::Error> {
-    Ok(as_ct.as_codetype().canonical_name())
+    let type_ = types.as_type(as_type);
+    Ok(type_.as_codetype().decl_type_label(types.ci))
 }
 
-pub(super) fn ffi_converter_name(as_ct: &impl AsCodeType) -> Result<String, askama::Error> {
-    Ok(as_ct.as_codetype().ffi_converter_name())
+pub(super) fn ffi_converter_name(
+    as_type: &impl AsType,
+    types: &TypeRenderer,
+) -> Result<String, askama::Error> {
+    let type_ = types.as_type(as_type);
+    Ok(type_.as_codetype().ffi_converter_name())
 }
 
-pub(super) fn ffi_error_converter_name(as_type: &impl AsType) -> Result<String, askama::Error> {
+pub(super) fn ffi_error_converter_name(
+    as_type: &impl AsType,
+    types: &TypeRenderer,
+) -> Result<String, askama::Error> {
     // special handling for types used as errors.
-    let mut name = ffi_converter_name(as_type)?;
-    if matches!(&as_type.as_type(), Type::Object { .. }) {
+    let type_ = types.as_type(as_type);
+    let mut name = type_.as_codetype().ffi_converter_name();
+    if matches!(type_, Type::Object { .. }) {
         name.push_str("__as_error")
     }
+    if let Type::External { namespace, .. } = as_type.as_type() {
+        types.import_converter(name.clone(), &namespace);
+    }
     Ok(name)
 }
 
-pub(super) fn lower_fn(as_ct: &impl AsCodeType) -> Result<String, askama::Error> {
+pub(super) fn lower_error_fn(
+    as_type: &impl AsType,
+    types: &TypeRenderer,
+) -> Result<String, askama::Error> {
     Ok(format!(
         "{ct}.lower.bind({ct})",
-        ct = as_ct.as_codetype().ffi_converter_name()
+        ct = ffi_error_converter_name(as_type, types)?
+    ))
+}
+
+pub(super) fn lift_error_fn(
+    as_type: &impl AsType,
+    types: &TypeRenderer,
+) -> Result<String, askama::Error> {
+    Ok(format!(
+        "{ct}.lift.bind({ct})",
+        ct = ffi_error_converter_name(as_type, types)?
     ))
 }
 
-pub(super) fn lift_fn(as_ct: &impl AsCodeType) -> Result<String, askama::Error> {
+pub(super) fn lift_fn(
+    as_type: &impl AsType,
+    types: &TypeRenderer,
+) -> Result<String, askama::Error> {
     Ok(format!(
         "{ct}.lift.bind({ct})",
-        ct = as_ct.as_codetype().ffi_converter_name()
+        ct = ffi_converter_name(as_type, types)?
     ))
 }