Add support for import assertions (#598)

This commit adds support for import assertions.

Major changes include:
- removal of "ResolveCallback" (deprecated in V8) 
in favor of "ModuleResolveCallback"
- removal of "HostImportModuleDynamicallyCallback" (deprecated in V8)
in favor of "HostImportModuleDynamicallyWithImportAssertionsCallback"

src/binding.cc

@@ -73,19 +73,24 @@ enum InternalSlots {
   (isolate->GetNumberOfDataSlots() - 1 - slot)
 
 // This is an extern C calling convention compatible version of
-// v8::HostImportModuleDynamicallyCallback
-typedef v8::Promise* (*v8__HostImportModuleDynamicallyCallback)(
+// v8::HostImportModuleDynamicallyWithImportAssertionsCallback
+typedef v8::Promise* (
+    *v8__HostImportModuleDynamicallyWithImportAssertionsCallback)(
     v8::Local<v8::Context> context, v8::Local<v8::ScriptOrModule> referrer,
-    v8::Local<v8::String> specifier);
+    v8::Local<v8::String> specifier,
+    v8::Local<v8::FixedArray> import_assertions);
 
-v8::MaybeLocal<v8::Promise> HostImportModuleDynamicallyCallback(
+v8::MaybeLocal<v8::Promise>
+HostImportModuleDynamicallyWithImportAssertionsCallback(
     v8::Local<v8::Context> context, v8::Local<v8::ScriptOrModule> referrer,
-    v8::Local<v8::String> specifier) {
+    v8::Local<v8::String> specifier,
+    v8::Local<v8::FixedArray> import_assertions) {
   auto* isolate = context->GetIsolate();
   void* d = isolate->GetData(SLOT_INTERNAL(isolate, kSlotDynamicImport));
-  auto* callback = reinterpret_cast<v8__HostImportModuleDynamicallyCallback>(d);
+  auto* callback = reinterpret_cast<
+      v8__HostImportModuleDynamicallyWithImportAssertionsCallback>(d);
   assert(callback != nullptr);
-  auto* promise_ptr = callback(context, referrer, specifier);
+  auto* promise_ptr = callback(context, referrer, specifier, import_assertions);
   if (promise_ptr == nullptr) {
     return v8::MaybeLocal<v8::Promise>();
   } else {
@@ -221,11 +226,12 @@ void v8__Isolate__SetHostInitializeImportMetaObjectCallback(
 }
 
 void v8__Isolate__SetHostImportModuleDynamicallyCallback(
-    v8::Isolate* isolate, v8__HostImportModuleDynamicallyCallback callback) {
+    v8::Isolate* isolate,
+    v8__HostImportModuleDynamicallyWithImportAssertionsCallback callback) {
   isolate->SetData(SLOT_INTERNAL(isolate, kSlotDynamicImport),
                    reinterpret_cast<void*>(callback));
   isolate->SetHostImportModuleDynamicallyCallback(
-      HostImportModuleDynamicallyCallback);
+      HostImportModuleDynamicallyWithImportAssertionsCallback);
 }
 
 bool v8__Isolate__AddMessageListener(v8::Isolate* isolate,
@@ -614,6 +620,13 @@ const v8::Boolean* v8__Boolean__New(v8::Isolate* isolate, bool value) {
   return local_to_ptr(v8::Boolean::New(isolate, value));
 }
 
+int v8__FixedArray__Length(const v8::FixedArray& self) { return self.Length(); }
+
+const v8::Data* v8__FixedArray__Get(const v8::FixedArray& self,
+                                    const v8::Context& context, int index) {
+  return local_to_ptr(ptr_to_local(&self)->Get(ptr_to_local(&context), index));
+}
+
 const v8::PrimitiveArray* v8__PrimitiveArray__New(v8::Isolate* isolate,
                                                   int length) {
   return local_to_ptr(v8::PrimitiveArray::New(isolate, length));
@@ -1560,18 +1573,15 @@ const v8::Value* v8__Script__Run(const v8::Script& script,
 }
 
 void v8__ScriptOrigin__CONSTRUCT(
-    v8::Isolate* isolate,
-    uninit_t<v8::ScriptOrigin>* buf, const v8::Value& resource_name,
-    int resource_line_offset, int resource_column_offset,
-    bool resource_is_shared_cross_origin, int script_id,
-    const v8::Value& source_map_url,
-    bool resource_is_opaque, bool is_wasm, bool is_module) {
+    v8::Isolate* isolate, uninit_t<v8::ScriptOrigin>* buf,
+    const v8::Value& resource_name, int resource_line_offset,
+    int resource_column_offset, bool resource_is_shared_cross_origin,
+    int script_id, const v8::Value& source_map_url, bool resource_is_opaque,
+    bool is_wasm, bool is_module) {
   construct_in_place<v8::ScriptOrigin>(
-      buf, isolate, ptr_to_local(&resource_name),
-      resource_line_offset, resource_column_offset,
-      resource_is_shared_cross_origin, script_id,
-      ptr_to_local(&source_map_url),
-      resource_is_opaque, is_wasm, is_module);
+      buf, isolate, ptr_to_local(&resource_name), resource_line_offset,
+      resource_column_offset, resource_is_shared_cross_origin, script_id,
+      ptr_to_local(&source_map_url), resource_is_opaque, is_wasm, is_module);
 }
 
 const v8::Value* v8__ScriptOrModule__GetResourceName(
@@ -2055,7 +2065,7 @@ int v8__Module__ScriptId(const v8::Module& self) {
 
 MaybeBool v8__Module__InstantiateModule(const v8::Module& self,
                                         const v8::Context& context,
-                                        v8::Module::ResolveCallback cb) {
+                                        v8::Module::ResolveModuleCallback cb) {
   return maybe_to_maybe_bool(
       ptr_to_local(&self)->InstantiateModule(ptr_to_local(&context), cb));
 }

src/data.rs

@@ -356,6 +356,17 @@ impl_eq! { for Module }
 impl_partial_eq! { Data for Module use identity }
 impl_partial_eq! { Module for Module use identity }
 
+/// A fixed-sized array with elements of type Data.
+#[repr(C)]
+#[derive(Debug)]
+pub struct FixedArray(Opaque);
+
+impl_deref! { Data for FixedArray }
+impl_eq! { for FixedArray }
+impl_hash! { for FixedArray }
+impl_partial_eq! { Data for FixedArray use identity }
+impl_partial_eq! { FixedArray for FixedArray use identity }
+
 /// An array to hold Primitive values. This is used by the embedder to
 /// pass host defined options to the ScriptOptions during compilation.
 ///

src/fixed_array.rs

@@ -0,0 +1,39 @@
+// Copyright 2019-2020 the Deno authors. All rights reserved. MIT license.
+use crate::support::int;
+use crate::Context;
+use crate::Data;
+use crate::FixedArray;
+use crate::HandleScope;
+use crate::Local;
+
+extern "C" {
+  fn v8__FixedArray__Length(this: *const FixedArray) -> int;
+
+  fn v8__FixedArray__Get(
+    this: *const FixedArray,
+    context: *const Context,
+    index: int,
+  ) -> *const Data;
+}
+
+impl FixedArray {
+  pub fn length(&self) -> usize {
+    unsafe { v8__FixedArray__Length(self) as usize }
+  }
+
+  pub fn get<'s>(
+    &self,
+    scope: &mut HandleScope<'s>,
+    index: usize,
+  ) -> Option<Local<'s, Data>> {
+    if index >= self.length() {
+      return None;
+    }
+
+    unsafe {
+      scope.cast_local(|sd| {
+        v8__FixedArray__Get(self, &*sd.get_current_context(), index as int)
+      })
+    }
+  }
+}

src/isolate.rs

@@ -11,6 +11,7 @@ use crate::support::UnitType;
 use crate::wasm::trampoline;
 use crate::wasm::WasmStreaming;
 use crate::Context;
+use crate::FixedArray;
 use crate::Function;
 use crate::Local;
 use crate::Message;
@@ -90,7 +91,7 @@ pub type PromiseRejectCallback = extern "C" fn(PromiseRejectMessage);
 pub type HostInitializeImportMetaObjectCallback =
   extern "C" fn(Local<Context>, Local<Module>, Local<Object>);
 
-/// HostImportModuleDynamicallyCallback is called when we require the
+/// HostImportModuleDynamicallyWithImportAssertionsCallback is called when we require the
 /// embedder to load a module. This is used as part of the dynamic
 /// import syntax.
 ///
@@ -108,11 +109,13 @@ pub type HostInitializeImportMetaObjectCallback =
 /// this promise with the exception. If the promise creation itself
 /// fails (e.g. due to stack overflow), the embedder must propagate
 /// that exception by returning an empty MaybeLocal.
-pub type HostImportModuleDynamicallyCallback = extern "C" fn(
+pub type HostImportModuleDynamicallyWithImportAssertionsCallback =
+  extern "C" fn(
     Local<Context>,
     Local<ScriptOrModule>,
     Local<String>,
-) -> *mut Promise;
+    Local<FixedArray>,
+  ) -> *mut Promise;
 
 pub type InterruptCallback =
   extern "C" fn(isolate: &mut Isolate, data: *mut c_void);
@@ -180,7 +183,7 @@ extern "C" {
   );
   fn v8__Isolate__SetHostImportModuleDynamicallyCallback(
     isolate: *mut Isolate,
-    callback: HostImportModuleDynamicallyCallback,
+    callback: HostImportModuleDynamicallyWithImportAssertionsCallback,
   );
   fn v8__Isolate__RequestInterrupt(
     isolate: *const Isolate,
@@ -507,7 +510,7 @@ impl Isolate {
   /// import() language feature to load modules.
   pub fn set_host_import_module_dynamically_callback(
     &mut self,
-    callback: HostImportModuleDynamicallyCallback,
+    callback: HostImportModuleDynamicallyWithImportAssertionsCallback,
   ) {
     unsafe {
       v8__Isolate__SetHostImportModuleDynamicallyCallback(self, callback)

src/isolate_create_params.rs

@@ -192,6 +192,7 @@ pub(crate) mod raw {
     pub embedder_wrapper_type_index: int,
     pub embedder_wrapper_object_index: int,
     pub cpp_heap_params: SharedPtr<CppHeapCreateParams>,
+    // NOTE(bartlomieju): this field is deprecated in V8 API.
     // This is an std::vector<std::string>. It's usually no bigger
     // than three or four words but let's take a generous upper bound.
     pub supported_import_assertions: [usize; 8],

src/lib.rs

@@ -42,6 +42,7 @@ mod date;
 mod exception;
 mod external;
 mod external_references;
+mod fixed_array;
 mod function;
 mod handle;
 mod isolate;
@@ -92,7 +93,7 @@ pub use handle::Global;
 pub use handle::Handle;
 pub use handle::Local;
 pub use isolate::HeapStatistics;
-pub use isolate::HostImportModuleDynamicallyCallback;
+pub use isolate::HostImportModuleDynamicallyWithImportAssertionsCallback;
 pub use isolate::HostInitializeImportMetaObjectCallback;
 pub use isolate::Isolate;
 pub use isolate::IsolateHandle;

src/module.rs

@@ -11,6 +11,7 @@ use crate::support::MaybeBool;
 use crate::support::ToCFn;
 use crate::support::UnitType;
 use crate::Context;
+use crate::FixedArray;
 use crate::HandleScope;
 use crate::Isolate;
 use crate::Local;
@@ -19,7 +20,7 @@ use crate::String;
 use crate::Value;
 
 /// Called during Module::instantiate_module. Provided with arguments:
-/// (context, specifier, referrer). Return None on error.
+/// (context, specifier, import_assertions, referrer). Return None on error.
 ///
 /// Note: this callback has an unusual signature due to ABI incompatibilities
 /// between Rust and C++. However end users can implement the callback as
@@ -29,6 +30,7 @@ use crate::Value;
 ///   fn my_resolve_callback<'a>(
 ///      context: v8::Local<'a, v8::Context>,
 ///      specifier: v8::Local<'a, v8::String>,
+///      import_assertions: v8::Local<'a, v8::FixedArray>,
 ///      referrer: v8::Local<'a, v8::Module>,
 ///   ) -> Option<v8::Local<'a, v8::Module>> {
 ///      // ...
@@ -38,34 +40,37 @@ use crate::Value;
 
 // System V AMD64 ABI: Local<Module> returned in a register.
 #[cfg(not(target_os = "windows"))]
-pub type ResolveCallback<'a> = extern "C" fn(
+pub type ResolveModuleCallback<'a> = extern "C" fn(
   Local<'a, Context>,
   Local<'a, String>,
+  Local<'a, FixedArray>,
   Local<'a, Module>,
 ) -> *const Module;
 
 // Windows x64 ABI: Local<Module> returned on the stack.
 #[cfg(target_os = "windows")]
-pub type ResolveCallback<'a> = extern "C" fn(
+pub type ResolveModuleCallback<'a> = extern "C" fn(
   *mut *const Module,
   Local<'a, Context>,
   Local<'a, String>,
+  Local<'a, FixedArray>,
   Local<'a, Module>,
 ) -> *mut *const Module;
 
-impl<'a, F> MapFnFrom<F> for ResolveCallback<'a>
+impl<'a, F> MapFnFrom<F> for ResolveModuleCallback<'a>
 where
   F: UnitType
     + Fn(
       Local<'a, Context>,
       Local<'a, String>,
+      Local<'a, FixedArray>,
       Local<'a, Module>,
     ) -> Option<Local<'a, Module>>,
 {
   #[cfg(not(target_os = "windows"))]
   fn mapping() -> Self {
-    let f = |context, specifier, referrer| {
-      (F::get())(context, specifier, referrer)
+    let f = |context, specifier, import_assertions, referrer| {
+      (F::get())(context, specifier, import_assertions, referrer)
         .map(|r| -> *const Module { &*r })
         .unwrap_or(null())
     };
@@ -74,8 +79,8 @@ where
 
   #[cfg(target_os = "windows")]
   fn mapping() -> Self {
-    let f = |ret_ptr, context, specifier, referrer| {
-      let r = (F::get())(context, specifier, referrer)
+    let f = |ret_ptr, context, specifier, import_assertions, referrer| {
+      let r = (F::get())(context, specifier, import_assertions, referrer)
         .map(|r| -> *const Module { &*r })
         .unwrap_or(null());
       unsafe { std::ptr::write(ret_ptr, r) }; // Write result to stack.
@@ -144,7 +149,7 @@ extern "C" {
   fn v8__Module__InstantiateModule(
     this: *const Module,
     context: *const Context,
-    cb: ResolveCallback,
+    cb: ResolveModuleCallback,
   ) -> MaybeBool;
   fn v8__Module__Evaluate(
     this: *const Module,
@@ -283,7 +288,7 @@ impl Module {
   pub fn instantiate_module<'a>(
     &self,
     scope: &mut HandleScope,
-    callback: impl MapFnTo<ResolveCallback<'a>>,
+    callback: impl MapFnTo<ResolveModuleCallback<'a>>,
   ) -> Option<bool> {
     unsafe {
       v8__Module__InstantiateModule(

tests/test_api.rs

@@ -34,7 +34,7 @@ fn setup() -> SetupGuard {
   let mut g = INIT_LOCK.lock().unwrap();
   *g += 1;
   if *g == 1 {
-    v8::V8::set_flags_from_string("--expose_gc");
+    v8::V8::set_flags_from_string("--expose_gc --harmony-import-assertions");
     v8::V8::initialize_platform(v8::new_default_platform().unwrap());
     v8::V8::initialize();
   }
@@ -913,6 +913,7 @@ fn add_message_listener() {
 fn unexpected_module_resolve_callback<'a>(
   _context: v8::Local<'a, v8::Context>,
   _specifier: v8::Local<'a, v8::String>,
+  _import_assertions: v8::Local<'a, v8::FixedArray>,
   _referrer: v8::Local<'a, v8::Module>,
 ) -> Option<v8::Local<'a, v8::Module>> {
   unreachable!()
@@ -1980,6 +1981,7 @@ fn module_instantiation_failures1() {
       fn resolve_callback<'a>(
         context: v8::Local<'a, v8::Context>,
         _specifier: v8::Local<'a, v8::String>,
+        _import_assertions: v8::Local<'a, v8::FixedArray>,
         _referrer: v8::Local<'a, v8::Module>,
       ) -> Option<v8::Local<'a, v8::Module>> {
         let scope = &mut unsafe { v8::CallbackScope::new(context) };
@@ -2003,6 +2005,7 @@ fn module_instantiation_failures1() {
 fn compile_specifier_as_module_resolve_callback<'a>(
   context: v8::Local<'a, v8::Context>,
   specifier: v8::Local<'a, v8::String>,
+  _import_assertions: v8::Local<'a, v8::FixedArray>,
   _referrer: v8::Local<'a, v8::Module>,
 ) -> Option<v8::Local<'a, v8::Module>> {
   let scope = &mut unsafe { v8::CallbackScope::new(context) };
@@ -2053,6 +2056,85 @@ fn module_evaluation() {
   }
 }
 
+#[test]
+fn import_assertions() {
+  let _setup_guard = setup();
+  let isolate = &mut v8::Isolate::new(Default::default());
+
+  fn module_resolve_callback<'a>(
+    context: v8::Local<'a, v8::Context>,
+    _specifier: v8::Local<'a, v8::String>,
+    import_assertions: v8::Local<'a, v8::FixedArray>,
+    _referrer: v8::Local<'a, v8::Module>,
+  ) -> Option<v8::Local<'a, v8::Module>> {
+    let scope = &mut unsafe { v8::CallbackScope::new(context) };
+
+    // "type" keyword, value and source offset of assertion
+    assert_eq!(import_assertions.length(), 3);
+    let assert1 = import_assertions.get(scope, 0).unwrap();
+    let assert1_val = v8::Local::<v8::Value>::try_from(assert1).unwrap();
+    assert_eq!(assert1_val.to_rust_string_lossy(scope), "type");
+    let assert2 = import_assertions.get(scope, 1).unwrap();
+    let assert2_val = v8::Local::<v8::Value>::try_from(assert2).unwrap();
+    assert_eq!(assert2_val.to_rust_string_lossy(scope), "json");
+    let assert3 = import_assertions.get(scope, 2).unwrap();
+    let assert3_val = v8::Local::<v8::Value>::try_from(assert3).unwrap();
+    assert_eq!(assert3_val.to_rust_string_lossy(scope), "27");
+
+    let origin = mock_script_origin(scope, "module.js");
+    let src = v8::String::new(scope, "export const a = 'a';").unwrap();
+    let source = v8::script_compiler::Source::new(src, &origin);
+    let module = v8::script_compiler::compile_module(scope, source).unwrap();
+    Some(module)
+  }
+
+  extern "C" fn dynamic_import_cb(
+    context: v8::Local<v8::Context>,
+    _referrer: v8::Local<v8::ScriptOrModule>,
+    _specifier: v8::Local<v8::String>,
+    import_assertions: v8::Local<v8::FixedArray>,
+  ) -> *mut v8::Promise {
+    let scope = &mut unsafe { v8::CallbackScope::new(context) };
+    let scope = &mut v8::HandleScope::new(scope);
+    // "type" keyword, value
+    assert_eq!(import_assertions.length(), 2);
+    let assert1 = import_assertions.get(scope, 0).unwrap();
+    let assert1_val = v8::Local::<v8::Value>::try_from(assert1).unwrap();
+    assert_eq!(assert1_val.to_rust_string_lossy(scope), "type");
+    let assert2 = import_assertions.get(scope, 1).unwrap();
+    let assert2_val = v8::Local::<v8::Value>::try_from(assert2).unwrap();
+    assert_eq!(assert2_val.to_rust_string_lossy(scope), "json");
+    std::ptr::null_mut()
+  }
+  isolate.set_host_import_module_dynamically_callback(dynamic_import_cb);
+
+  {
+    let scope = &mut v8::HandleScope::new(isolate);
+    let context = v8::Context::new(scope);
+    let scope = &mut v8::ContextScope::new(scope, context);
+
+    let source_text = v8::String::new(
+      scope,
+      "import 'foo.json' assert { type: \"json\" };\n\
+        import('foo.json', { assert: { type: 'json' } });",
+    )
+    .unwrap();
+    let origin = mock_script_origin(scope, "foo.js");
+    let source = v8::script_compiler::Source::new(source_text, &origin);
+
+    let module = v8::script_compiler::compile_module(scope, source).unwrap();
+    assert!(module.script_id().is_some());
+    assert!(module.is_source_text_module());
+    assert!(!module.is_synthetic_module());
+    assert_eq!(v8::ModuleStatus::Uninstantiated, module.get_status());
+    module.hash(&mut DefaultHasher::new()); // Should not crash.
+
+    let result = module.instantiate_module(scope, module_resolve_callback);
+    assert!(result.unwrap());
+    assert_eq!(v8::ModuleStatus::Instantiated, module.get_status());
+  }
+}
+
 #[test]
 fn primitive_array() {
   let _setup_guard = setup();
@@ -2550,6 +2632,7 @@ fn dynamic_import() {
     context: v8::Local<v8::Context>,
     _referrer: v8::Local<v8::ScriptOrModule>,
     specifier: v8::Local<v8::String>,
+    _import_assertions: v8::Local<v8::FixedArray>,
   ) -> *mut v8::Promise {
     let scope = &mut unsafe { v8::CallbackScope::new(context) };
     let scope = &mut v8::HandleScope::new(scope);