LibWeb+LibJS: Implement support for module scripts

Userland/Libraries/LibJS/CyclicModule.cpp

@@ -11,8 +11,8 @@
 
 namespace JS {
 
-CyclicModule::CyclicModule(Realm& realm, StringView filename, bool has_top_level_await, Vector<ModuleRequest> requested_modules)
-    : Module(realm, filename)
+CyclicModule::CyclicModule(Realm& realm, StringView filename, bool has_top_level_await, Vector<ModuleRequest> requested_modules, Script::HostDefined* host_defined)
+    : Module(realm, filename, host_defined)
     , m_requested_modules(move(requested_modules))
     , m_has_top_level_await(has_top_level_await)
 {

Userland/Libraries/LibJS/CyclicModule.h

@@ -33,8 +33,10 @@ class CyclicModule : public Module {
     virtual ThrowCompletionOr<void> link(VM& vm) override;
     virtual ThrowCompletionOr<Promise*> evaluate(VM& vm) override;
 
+    Vector<ModuleRequest> const& requested_modules() const { return m_requested_modules; }
+
 protected:
-    CyclicModule(Realm& realm, StringView filename, bool has_top_level_await, Vector<ModuleRequest> requested_modules);
+    CyclicModule(Realm& realm, StringView filename, bool has_top_level_await, Vector<ModuleRequest> requested_modules, Script::HostDefined* host_defined);
 
     virtual void visit_edges(Cell::Visitor&) override;
 

Userland/Libraries/LibJS/Module.cpp

@@ -11,8 +11,9 @@
 
 namespace JS {
 
-Module::Module(Realm& realm, String filename)
+Module::Module(Realm& realm, String filename, Script::HostDefined* host_defined)
     : m_realm(realm)
+    , m_host_defined(host_defined)
     , m_filename(move(filename))
 {
 }
@@ -25,6 +26,8 @@ void Module::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_realm);
     visitor.visit(m_environment);
     visitor.visit(m_namespace);
+    if (m_host_defined)
+        m_host_defined->visit_host_defined_self(visitor);
 }
 
 // 16.2.1.5.1.1 InnerModuleLinking ( module, stack, index ), https://tc39.es/ecma262/#sec-InnerModuleLinking

Userland/Libraries/LibJS/Module.h

@@ -11,6 +11,7 @@
 #include <LibJS/Heap/GCPtr.h>
 #include <LibJS/Runtime/Environment.h>
 #include <LibJS/Runtime/Realm.h>
+#include <LibJS/Script.h>
 
 namespace JS {
 
@@ -68,6 +69,8 @@ class Module : public Cell {
 
     Environment* environment() { return m_environment; }
 
+    Script::HostDefined* host_defined() const { return m_host_defined; }
+
     ThrowCompletionOr<Object*> get_module_namespace(VM& vm);
 
     virtual ThrowCompletionOr<void> link(VM& vm) = 0;
@@ -80,7 +83,7 @@ class Module : public Cell {
     virtual ThrowCompletionOr<u32> inner_module_evaluation(VM& vm, Vector<Module*>& stack, u32 index);
 
 protected:
-    Module(Realm&, String filename);
+    Module(Realm&, String filename, Script::HostDefined* host_defined = nullptr);
 
     virtual void visit_edges(Cell::Visitor&) override;
 
@@ -97,9 +100,10 @@ class Module : public Cell {
     // destroy the VM but keep the modules this should not happen. Because VM
     // stores modules with a RefPtr we cannot just store the VM as that leads to
     // cycles.
-    GCPtr<Realm> m_realm;             // [[Realm]]
-    GCPtr<Environment> m_environment; // [[Environment]]
-    GCPtr<Object> m_namespace;        // [[Namespace]]
+    GCPtr<Realm> m_realm;                            // [[Realm]]
+    GCPtr<Environment> m_environment;                // [[Environment]]
+    GCPtr<Object> m_namespace;                       // [[Namespace]]
+    Script::HostDefined* m_host_defined { nullptr }; // [[HostDefined]]
 
     // Needed for potential lookups of modules.
     String m_filename;

Userland/Libraries/LibJS/Runtime/ModuleEnvironment.cpp

@@ -126,4 +126,11 @@ Optional<ModuleEnvironment::BindingAndIndex> ModuleEnvironment::find_binding_and
     return DeclarativeEnvironment::find_binding_and_index(name);
 }
 
+void ModuleEnvironment::visit_edges(Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    for (auto& indirect_binding : m_indirect_bindings)
+        visitor.visit(indirect_binding.module);
+}
+
 }

Userland/Libraries/LibJS/Runtime/ModuleEnvironment.h

@@ -30,6 +30,8 @@ class ModuleEnvironment final : public DeclarativeEnvironment {
 private:
     explicit ModuleEnvironment(Environment* outer_environment);
 
+    virtual void visit_edges(Visitor&) override;
+
     struct IndirectBinding {
         FlyString name;
         Module* module;

Userland/Libraries/LibJS/Script.h

@@ -32,7 +32,7 @@ class Script final : public Cell {
     Realm& realm() { return *m_realm; }
     Program const& parse_node() const { return *m_parse_node; }
 
-    HostDefined* host_defined() { return m_host_defined; }
+    HostDefined* host_defined() const { return m_host_defined; }
     StringView filename() const { return m_filename; }
 
 private:

Userland/Libraries/LibJS/SourceTextModule.cpp

@@ -98,11 +98,11 @@ static Vector<ModuleRequest> module_requests(Program& program, Vector<String> co
     return requested_modules_in_source_order;
 }
 
-SourceTextModule::SourceTextModule(Realm& realm, StringView filename, bool has_top_level_await, NonnullRefPtr<Program> body, Vector<ModuleRequest> requested_modules,
+SourceTextModule::SourceTextModule(Realm& realm, StringView filename, Script::HostDefined* host_defined, bool has_top_level_await, NonnullRefPtr<Program> body, Vector<ModuleRequest> requested_modules,
     Vector<ImportEntry> import_entries, Vector<ExportEntry> local_export_entries,
     Vector<ExportEntry> indirect_export_entries, Vector<ExportEntry> star_export_entries,
     RefPtr<ExportStatement> default_export)
-    : CyclicModule(realm, filename, has_top_level_await, move(requested_modules))
+    : CyclicModule(realm, filename, has_top_level_await, move(requested_modules), host_defined)
     , m_ecmascript_code(move(body))
     , m_execution_context(realm.heap())
     , m_import_entries(move(import_entries))
@@ -120,7 +120,7 @@ void SourceTextModule::visit_edges(Cell::Visitor& visitor)
 }
 
 // 16.2.1.6.1 ParseModule ( sourceText, realm, hostDefined ), https://tc39.es/ecma262/#sec-parsemodule
-Result<NonnullGCPtr<SourceTextModule>, Vector<Parser::Error>> SourceTextModule::parse(StringView source_text, Realm& realm, StringView filename)
+Result<NonnullGCPtr<SourceTextModule>, Vector<Parser::Error>> SourceTextModule::parse(StringView source_text, Realm& realm, StringView filename, Script::HostDefined* host_defined)
 {
     // 1. Let body be ParseText(sourceText, Module).
     auto parser = Parser(Lexer(source_text, filename), Program::Type::Module);
@@ -248,6 +248,7 @@ Result<NonnullGCPtr<SourceTextModule>, Vector<Parser::Error>> SourceTextModule::
     return NonnullGCPtr(*realm.heap().allocate_without_realm<SourceTextModule>(
         realm,
         filename,
+        host_defined,
         async,
         move(body),
         move(requested_modules),

Userland/Libraries/LibJS/SourceTextModule.h

@@ -22,7 +22,7 @@ class SourceTextModule final : public CyclicModule {
     using ImportEntry = ImportStatement::ImportEntry;
     using ExportEntry = ExportStatement::ExportEntry;
 
-    static Result<NonnullGCPtr<SourceTextModule>, Vector<Parser::Error>> parse(StringView source_text, Realm&, StringView filename = {});
+    static Result<NonnullGCPtr<SourceTextModule>, Vector<Parser::Error>> parse(StringView source_text, Realm&, StringView filename = {}, Script::HostDefined* host_defined = nullptr);
 
     Program const& parse_node() const { return *m_ecmascript_code; }
 
@@ -37,7 +37,7 @@ class SourceTextModule final : public CyclicModule {
     virtual ThrowCompletionOr<void> execute_module(VM& vm, GCPtr<PromiseCapability> capability) override;
 
 private:
-    SourceTextModule(Realm&, StringView filename, bool has_top_level_await, NonnullRefPtr<Program> body, Vector<ModuleRequest> requested_modules,
+    SourceTextModule(Realm&, StringView filename, Script::HostDefined* host_defined, bool has_top_level_await, NonnullRefPtr<Program> body, Vector<ModuleRequest> requested_modules,
         Vector<ImportEntry> import_entries, Vector<ExportEntry> local_export_entries,
         Vector<ExportEntry> indirect_export_entries, Vector<ExportEntry> star_export_entries,
         RefPtr<ExportStatement> default_export);

Userland/Libraries/LibWeb/Bindings/MainThreadVM.cpp

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2021-2022, Andreas Kling <[email protected]>
  * Copyright (c) 2021, Luke Wilde <[email protected]>
+ * Copyright (c) 2022, networkException <[email protected]>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -20,6 +21,7 @@
 #include <LibWeb/HTML/Scripting/ClassicScript.h>
 #include <LibWeb/HTML/Scripting/Environments.h>
 #include <LibWeb/HTML/Scripting/ExceptionReporter.h>
+#include <LibWeb/HTML/Scripting/Fetching.h>
 #include <LibWeb/HTML/Window.h>
 #include <LibWeb/HTML/WindowProxy.h>
 #include <LibWeb/Platform/EventLoopPlugin.h>
@@ -306,10 +308,60 @@ JS::VM& main_thread_vm()
         // FIXME: Implement 8.1.5.5.1 HostGetImportMetaProperties(moduleRecord), https://html.spec.whatwg.org/multipage/webappapis.html#hostgetimportmetaproperties
         // FIXME: Implement 8.1.5.5.2 HostImportModuleDynamically(referencingScriptOrModule, moduleRequest, promiseCapability), https://html.spec.whatwg.org/multipage/webappapis.html#hostimportmoduledynamically(referencingscriptormodule,-modulerequest,-promisecapability)
         // FIXME: Implement 8.1.5.5.3 HostResolveImportedModule(referencingScriptOrModule, moduleRequest), https://html.spec.whatwg.org/multipage/webappapis.html#hostresolveimportedmodule(referencingscriptormodule,-modulerequest)
-        // FIXME: Implement 8.1.5.5.4 HostGetSupportedImportAssertions(), https://html.spec.whatwg.org/multipage/webappapis.html#hostgetsupportedimportassertions
 
-        vm->host_resolve_imported_module = [](JS::ScriptOrModule, JS::ModuleRequest const&) -> JS::ThrowCompletionOr<JS::NonnullGCPtr<JS::Module>> {
-            return vm->throw_completion<JS::InternalError>(JS::ErrorType::NotImplemented, "Modules in the browser");
+        // 8.1.5.5.4 HostGetSupportedImportAssertions(), https://html.spec.whatwg.org/multipage/webappapis.html#hostgetsupportedimportassertions
+        vm->host_get_supported_import_assertions = []() -> Vector<String> {
+            // 1. Return « "type" ».
+            return { "type"sv };
+        };
+
+        // 8.1.5.5.3 HostResolveImportedModule(referencingScriptOrModule, moduleRequest), https://html.spec.whatwg.org/multipage/webappapis.html#hostresolveimportedmodule(referencingscriptormodule,-modulerequest)
+        vm->host_resolve_imported_module = [](JS::ScriptOrModule const& referencing_string_or_module, JS::ModuleRequest const& module_request) -> JS::ThrowCompletionOr<JS::NonnullGCPtr<JS::Module>> {
+            // 1. Let settings object be the current settings object.
+            auto* settings_object = &HTML::current_settings_object();
+
+            // 2. Let base URL be settings object's API base URL.
+            auto base_url = settings_object->api_base_url();
+
+            // 3. If referencingScriptOrModule is not null, then:
+            if (!referencing_string_or_module.has<Empty>()) {
+                // 1. Let referencing script be referencingScriptOrModule.[[HostDefined]].
+                auto const& referencing_script = verify_cast<HTML::Script>(referencing_string_or_module.has<JS::NonnullGCPtr<JS::Script>>() ? referencing_string_or_module.get<JS::NonnullGCPtr<JS::Script>>()->host_defined() : referencing_string_or_module.get<JS::NonnullGCPtr<JS::Module>>()->host_defined());
+
+                // 2. Set settings object to referencing script's settings object.
+                settings_object = &referencing_script->settings_object();
+
+                // 3. Set base URL to referencing script's base URL.
+                base_url = referencing_script->base_url();
+
+                // 4. Assert: base URL is not null, as referencing script is a classic script or a JavaScript module script.
+                VERIFY(base_url.is_valid());
+            }
+
+            // 4. Let moduleMap be settings object's module map.
+            auto& module_map = settings_object->module_map();
+
+            // 5. Let url be the result of resolving a module specifier given base URL and moduleRequest.[[Specifier]].
+            auto url = HTML::resolve_module_specifier(module_request, base_url);
+
+            // 6. Assert: url is never failure, because resolving a module specifier must have been previously successful
+            //    with these same two arguments (either while creating the corresponding module script, or in fetch an import() module script graph).
+            VERIFY(url.is_valid());
+
+            // 7. Let moduleType be the result of running the module type from module request steps given moduleRequest.
+            auto module_type = HTML::module_type_from_module_request(module_request);
+
+            // 8. Let resolved module script be moduleMap[(url, moduleType)]. (This entry must exist for us to have gotten to this point.)
+            auto resolved_module = module_map.get(url, module_type).value();
+
+            // 9. Assert: resolved module script is a module script (i.e., is not null or "fetching").
+            VERIFY(resolved_module.type == HTML::ModuleMap::EntryType::ModuleScript);
+
+            // 10. Assert: resolved module script's record is not null.
+            VERIFY(resolved_module.module_script->record());
+
+            // 11. Return resolved module script's record.
+            return JS::NonnullGCPtr(*resolved_module.module_script->record());
         };
 
         // NOTE: We push a dummy execution context onto the JS execution context stack,

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -258,6 +258,9 @@ set(SOURCES
     HTML/Scripting/ClassicScript.cpp
     HTML/Scripting/Environments.cpp
     HTML/Scripting/ExceptionReporter.cpp
+    HTML/Scripting/Fetching.cpp
+    HTML/Scripting/ModuleMap.cpp
+    HTML/Scripting/ModuleScript.cpp
     HTML/Scripting/Script.cpp
     HTML/Scripting/WindowEnvironmentSettingsObject.cpp
     HTML/Storage.cpp

Userland/Libraries/LibWeb/HTML/HTMLScriptElement.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2021, Andreas Kling <[email protected]>
+ * Copyright (c) 2022, networkException <[email protected]>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -15,8 +16,10 @@
 #include <LibWeb/HTML/EventNames.h>
 #include <LibWeb/HTML/HTMLScriptElement.h>
 #include <LibWeb/HTML/Scripting/ClassicScript.h>
+#include <LibWeb/HTML/Scripting/Fetching.h>
 #include <LibWeb/Infra/CharacterTypes.h>
 #include <LibWeb/Loader/ResourceLoader.h>
+#include <LibWeb/MimeSniff/MimeType.h>
 
 namespace Web::HTML {
 
@@ -46,6 +49,8 @@ void HTMLScriptElement::begin_delaying_document_load_event(DOM::Document& docume
 // https://html.spec.whatwg.org/multipage/scripting.html#execute-the-script-block
 void HTMLScriptElement::execute_script()
 {
+    // FIXME: Update the steps to match current spec.
+
     // 1. Let document be scriptElement's node document.
     JS::NonnullGCPtr<DOM::Document> node_document = document();
 
@@ -95,8 +100,8 @@ void HTMLScriptElement::execute_script()
         // 1. Assert: document's currentScript attribute is null.
         VERIFY(!document().current_script());
 
-        // FIXME: 2. Run the module script given by the script's script for scriptElement.
-        TODO();
+        // 2. Run the module script given by the script's script for scriptElement.
+        (void)verify_cast<JavaScriptModuleScript>(*m_script).run();
     }
 
     // 6. Decrement the ignore-destructive-writes counter of document, if it was incremented in the earlier step.
@@ -108,16 +113,11 @@ void HTMLScriptElement::execute_script()
         dispatch_event(*DOM::Event::create(realm(), HTML::EventNames::load));
 }
 
-// https://mimesniff.spec.whatwg.org/#javascript-mime-type-essence-match
-static bool is_javascript_mime_type_essence_match(String const& string)
-{
-    auto lowercase_string = string.to_lowercase();
-    return lowercase_string.is_one_of("application/ecmascript", "application/javascript", "application/x-ecmascript", "application/x-javascript", "text/ecmascript", "text/javascript", "text/javascript1.0", "text/javascript1.1", "text/javascript1.2", "text/javascript1.3", "text/javascript1.4", "text/javascript1.5", "text/jscript", "text/livescript", "text/x-ecmascript", "text/x-javascript");
-}
-
 // https://html.spec.whatwg.org/multipage/scripting.html#prepare-a-script
 void HTMLScriptElement::prepare_script()
 {
+    // FIXME: Update the steps to match current spec.
+
     // 1. If the script element is marked as having "already started", then return. The script is not executed.
     if (m_already_started) {
         dbgln("HTMLScriptElement: Refusing to run script because it has already started.");
@@ -169,7 +169,7 @@ void HTMLScriptElement::prepare_script()
     }
 
     // Determine the script's type as follows:
-    if (is_javascript_mime_type_essence_match(script_block_type.trim(Infra::ASCII_WHITESPACE))) {
+    if (MimeSniff::is_javascript_mime_type_essence_match(script_block_type.trim(Infra::ASCII_WHITESPACE))) {
         // - If the script block's type string with leading and trailing ASCII whitespace stripped is a JavaScript MIME type essence match, the script's type is "classic".
         m_script_type = ScriptType::Classic;
     } else if (script_block_type.equals_ignoring_case("module"sv)) {
@@ -299,32 +299,42 @@ void HTMLScriptElement::prepare_script()
             auto resource = ResourceLoader::the().load_resource(Resource::Type::Generic, request);
             set_resource(resource);
         } else if (m_script_type == ScriptType::Module) {
-            // FIXME: -> "module"
-            //        Fetch an external module script graph given url, settings object, and options.
+            // Fetch an external module script graph given url, settings object, options, and onComplete.
+            // FIXME: Pass options.
+            fetch_external_module_script_graph(url, document().relevant_settings_object(), [this](auto const* result) {
+                // 1. Mark as ready el given result.
+                m_script = result;
+                script_became_ready();
+            });
         }
     } else {
         // 27. If the element does not have a src content attribute, run these substeps:
 
-        // FIXME: 1. Let base URL be the script element's node document's document base URL.
+        // 1. Let base URL be the script element's node document's document base URL.
+        auto base_url = m_document->base_url();
 
         // 2. Switch on the script's type:
         if (m_script_type == ScriptType::Classic) {
             // -> "classic"
             // 1. Let script be the result of creating a classic script using source text, settings object, base URL, and options.
-
-            // FIXME: Pass settings, base URL and options.
-            auto script = ClassicScript::create(m_document->url().to_string(), source_text, document().relevant_settings_object(), AK::URL(), m_source_line_number);
+            // FIXME: Pass options.
+            auto script = ClassicScript::create(m_document->url().to_string(), source_text, document().relevant_settings_object(), base_url, m_source_line_number);
 
             // 2. Set the script's script to script.
             m_script = script;
 
             // 3. The script is ready.
             script_became_ready();
         } else if (m_script_type == ScriptType::Module) {
-            // FIXME: -> "module"
-            // 1. Fetch an inline module script graph, given source text, base URL, settings object, and options.
-            //    When this asynchronously completes, set the script's script to the result. At that time, the script is ready.
-            TODO();
+            // FIXME: 1. Set el's delaying the load event to true.
+
+            // 2. Fetch an inline module script graph, given source text, base URL, settings object, options, and with the following steps given result:
+            // FIXME: Pass options
+            fetch_inline_module_script_graph(m_document->url().to_string(), source_text, base_url, document().relevant_settings_object(), [this](auto const* result) {
+                // 1. Mark as ready el given result.
+                m_script = result;
+                script_became_ready();
+            });
         }
     }
 

Userland/Libraries/LibWeb/HTML/Scripting/ClassicScript.cpp

@@ -166,9 +166,4 @@ void ClassicScript::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_script_record);
 }
 
-void ClassicScript::visit_host_defined_self(Cell::Visitor& visitor)
-{
-    visitor.visit(this);
-}
-
 }