From 95cc2bd81076facbd839e3303e4d2815a0c13955 Mon Sep 17 00:00:00 2001
From: Ali Mohammad Pur <ali.mpfard@gmail.com>
Date: Tue, 22 Apr 2025 11:00:50 +0200
Subject: [PATCH] LibWeb/WebAssembly: Implement Module::exports(module)

---
 Libraries/LibWeb/WebAssembly/Module.cpp | 29 +++++++++++++++++++++++++
 Libraries/LibWeb/WebAssembly/Module.h   |  6 +++++
 Libraries/LibWeb/WebAssembly/Module.idl |  2 +-
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/Libraries/LibWeb/WebAssembly/Module.cpp b/Libraries/LibWeb/WebAssembly/Module.cpp
index 63f5e79b69b..16c3a487af9 100644
--- a/Libraries/LibWeb/WebAssembly/Module.cpp
+++ b/Libraries/LibWeb/WebAssembly/Module.cpp
@@ -66,6 +66,35 @@ WebIDL::ExceptionOr<Vector<ModuleImportDescriptor>> Module::imports(JS::VM&, GC:
     return import_objects;
 }
 
+// https://webassembly.github.io/threads/js-api/index.html#dom-module-exports
+WebIDL::ExceptionOr<Vector<ModuleExportDescriptor>> Module::exports(JS::VM&, GC::Ref<Module> module_object)
+{
+    // 1. Let module be moduleObject.[[Module]].
+    // 2. Let exports be « ».
+    Vector<ModuleExportDescriptor> export_objects;
+
+    // 3. For each (name, type) of module_exports(module),
+    auto& exports = module_object->m_compiled_module->module->export_section().entries();
+    export_objects.ensure_capacity(exports.size());
+    for (auto& entry : exports) {
+        // 3.1. Let kind be the string value of the extern type type.
+        auto const kind = entry.description().visit(
+            [](Wasm::FunctionIndex) { return Bindings::ImportExportKind::Function; },
+            [](Wasm::TableIndex) { return Bindings::ImportExportKind::Table; },
+            [](Wasm::MemoryIndex) { return Bindings::ImportExportKind::Memory; },
+            [](Wasm::GlobalIndex) { return Bindings::ImportExportKind::Global; });
+        // 3.2. Let obj be «[ "name" → name, "kind" → kind ]».
+        ModuleExportDescriptor descriptor {
+            .name = String::from_utf8_with_replacement_character(entry.name()),
+            .kind = kind,
+        };
+        // 3.3. Append obj to exports.
+        export_objects.append(move(descriptor));
+    }
+    // 4. Return exports.
+    return export_objects;
+}
+
 Module::Module(JS::Realm& realm, NonnullRefPtr<Detail::CompiledWebAssemblyModule> compiled_module)
     : Bindings::PlatformObject(realm)
     , m_compiled_module(move(compiled_module))
diff --git a/Libraries/LibWeb/WebAssembly/Module.h b/Libraries/LibWeb/WebAssembly/Module.h
index d7072fce792..347fa2deb77 100644
--- a/Libraries/LibWeb/WebAssembly/Module.h
+++ b/Libraries/LibWeb/WebAssembly/Module.h
@@ -29,6 +29,11 @@ struct ModuleImportDescriptor {
     Bindings::ImportExportKind kind;
 };
 
+struct ModuleExportDescriptor {
+    String name;
+    Bindings::ImportExportKind kind;
+};
+
 class Module : public Bindings::PlatformObject {
     WEB_PLATFORM_OBJECT(Module, Bindings::PlatformObject);
     GC_DECLARE_ALLOCATOR(Module);
@@ -36,6 +41,7 @@ class Module : public Bindings::PlatformObject {
 public:
     static WebIDL::ExceptionOr<GC::Ref<Module>> construct_impl(JS::Realm&, GC::Root<WebIDL::BufferSource>& bytes);
     static WebIDL::ExceptionOr<Vector<ModuleImportDescriptor>> imports(JS::VM&, GC::Ref<Module>);
+    static WebIDL::ExceptionOr<Vector<ModuleExportDescriptor>> exports(JS::VM&, GC::Ref<Module>);
 
     NonnullRefPtr<Detail::CompiledWebAssemblyModule> compiled_module() const { return m_compiled_module; }
 
diff --git a/Libraries/LibWeb/WebAssembly/Module.idl b/Libraries/LibWeb/WebAssembly/Module.idl
index dc7035c9727..77d5e49a690 100644
--- a/Libraries/LibWeb/WebAssembly/Module.idl
+++ b/Libraries/LibWeb/WebAssembly/Module.idl
@@ -21,7 +21,7 @@ dictionary ModuleImportDescriptor {
 interface Module {
     constructor(BufferSource bytes);
 
-    [FIXME] static sequence<ModuleExportDescriptor> exports(Module moduleObject);
+    static sequence<ModuleExportDescriptor> exports(Module moduleObject);
     static sequence<ModuleImportDescriptor> imports(Module moduleObject);
     [FIXME] static sequence<ArrayBuffer> customSections(Module moduleObject, DOMString sectionName);
 };