LibWeb: Implement ModuleMap and expose it on EnvironmentSettingsObject

This patch adds the ModuleMap class used to keep track of the type and
url of a module as well as the fetching state associated. Each
environment settings object now also has a module map.

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -258,6 +258,7 @@ set(SOURCES
     HTML/Scripting/ClassicScript.cpp
     HTML/Scripting/Environments.cpp
     HTML/Scripting/ExceptionReporter.cpp
+    HTML/Scripting/ModuleMap.cpp
     HTML/Scripting/Script.cpp
     HTML/Scripting/WindowEnvironmentSettingsObject.cpp
     HTML/Storage.cpp

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

@@ -11,6 +11,7 @@
 #include <LibWeb/HTML/PromiseRejectionEvent.h>
 #include <LibWeb/HTML/Scripting/Environments.h>
 #include <LibWeb/HTML/Scripting/ExceptionReporter.h>
+#include <LibWeb/HTML/Scripting/WindowEnvironmentSettingsObject.h>
 #include <LibWeb/HTML/Window.h>
 #include <LibWeb/Page/Page.h>
 
@@ -34,6 +35,11 @@ JS::ExecutionContext& EnvironmentSettingsObject::realm_execution_context()
     return *m_realm_execution_context;
 }
 
+ModuleMap& EnvironmentSettingsObject::module_map()
+{
+    return m_module_map;
+}
+
 // https://html.spec.whatwg.org/multipage/webappapis.html#environment-settings-object%27s-realm
 JS::Realm& EnvironmentSettingsObject::realm()
 {

Userland/Libraries/LibWeb/HTML/Scripting/Environments.h

@@ -14,6 +14,7 @@
 #include <LibJS/Runtime/Realm.h>
 #include <LibWeb/HTML/EventLoop/EventLoop.h>
 #include <LibWeb/HTML/Origin.h>
+#include <LibWeb/HTML/Scripting/ModuleMap.h>
 
 namespace Web::HTML {
 
@@ -61,7 +62,8 @@ struct EnvironmentSettingsObject
     // https://html.spec.whatwg.org/multipage/webappapis.html#concept-environment-target-browsing-context
     JS::ExecutionContext& realm_execution_context();
 
-    // FIXME: A module map https://html.spec.whatwg.org/multipage/webappapis.html#concept-settings-object-module-map
+    // https://html.spec.whatwg.org/multipage/webappapis.html#concept-settings-object-module-map
+    ModuleMap& module_map();
 
     // https://html.spec.whatwg.org/multipage/webappapis.html#responsible-document
     virtual JS::GCPtr<DOM::Document> responsible_document() = 0;
@@ -113,6 +115,8 @@ protected:
 
 private:
     NonnullOwnPtr<JS::ExecutionContext> m_realm_execution_context;
+    ModuleMap m_module_map;
+
     EventLoop* m_responsible_event_loop { nullptr };
 
     // https://html.spec.whatwg.org/multipage/webappapis.html#outstanding-rejected-promises-weak-set

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

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2022, networkException <networkexception@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/HTML/Scripting/ModuleMap.h>
+
+namespace Web::HTML {
+
+bool ModuleMap::is_fetching(AK::URL const& url, String const& type) const
+{
+    return is(url, type, EntryType::Fetching);
+}
+
+bool ModuleMap::is_failed(AK::URL const& url, String const& type) const
+{
+    return is(url, type, EntryType::Failed);
+}
+
+bool ModuleMap::is(AK::URL const& url, String const& type, EntryType entry_type) const
+{
+    auto value = m_values.get({ url, type });
+    if (!value.has_value())
+        return false;
+
+    return value->type == entry_type;
+}
+
+Optional<ModuleMap::Entry> ModuleMap::get(AK::URL const& url, String const& type) const
+{
+    return m_values.get({ url, type });
+}
+
+AK::HashSetResult ModuleMap::set(AK::URL const& url, String const& type, Entry entry)
+{
+    auto callbacks = m_callbacks.get({ url, type });
+    if (callbacks.has_value())
+        for (auto const& callback : *callbacks)
+            callback(entry);
+
+    return m_values.set({ url, type }, entry);
+}
+
+void ModuleMap::wait_for_change(AK::URL const& url, String const& type, Function<void(Entry)> callback)
+{
+    m_callbacks.ensure({ url, type }).append(move(callback));
+}
+
+}

Userland/Libraries/LibWeb/HTML/Scripting/ModuleMap.h

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2022, networkException <networkexception@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/HTML/Scripting/ModuleScript.h>
+
+namespace Web::HTML {
+
+class ModuleLocationTuple {
+public:
+    ModuleLocationTuple(AK::URL url, String type)
+        : m_url(move(url))
+        , m_type(move(type))
+    {
+    }
+
+    AK::URL const& url() const { return m_url; };
+    String const& type() const { return m_type; }
+
+    bool operator==(ModuleLocationTuple const& other) const
+    {
+        return other.url() == m_url && other.type() == m_type;
+    };
+
+private:
+    AK::URL m_url;
+    String m_type;
+};
+
+// https://html.spec.whatwg.org/multipage/webappapis.html#module-map
+class ModuleMap {
+    AK_MAKE_NONCOPYABLE(ModuleMap);
+
+public:
+    ModuleMap() = default;
+    ~ModuleMap() = default;
+
+    enum class EntryType {
+        Fetching,
+        Failed,
+        ModuleScript
+    };
+
+    struct Entry {
+        EntryType type;
+        JavaScriptModuleScript* module_script;
+    };
+
+    bool is_fetching(AK::URL const& url, String const& type) const;
+    bool is_failed(AK::URL const& url, String const& type) const;
+
+    bool is(AK::URL const& url, String const& type, EntryType) const;
+
+    Optional<Entry> get(AK::URL const& url, String const& type) const;
+
+    AK::HashSetResult set(AK::URL const& url, String const& type, Entry);
+
+    void wait_for_change(AK::URL const& url, String const& type, Function<void(Entry)> callback);
+
+private:
+    HashMap<ModuleLocationTuple, Entry> m_values;
+    HashMap<ModuleLocationTuple, Vector<Function<void(Entry)>>> m_callbacks;
+};
+
+}
+
+namespace AK {
+
+template<>
+struct Traits<Web::HTML::ModuleLocationTuple> : public GenericTraits<Web::HTML::ModuleLocationTuple> {
+    static unsigned hash(Web::HTML::ModuleLocationTuple const& tuple)
+    {
+        return pair_int_hash(tuple.url().to_string().hash(), tuple.type().hash());
+    }
+};
+
+}