LibWeb/IDB: Add internal Index object

Author: https://github.com/stelar7
Commit: 9321ad04c0
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4178
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/AtkinsSJ

Libraries/LibWeb/CMakeLists.txt

@@ -567,6 +567,7 @@ set(SOURCES
     IndexedDB/IDBVersionChangeEvent.cpp
     IndexedDB/Internal/Algorithms.cpp
     IndexedDB/Internal/Database.cpp
+    IndexedDB/Internal/Index.cpp
     IndexedDB/Internal/Key.cpp
     IndexedDB/Internal/ObjectStore.cpp
     IndexedDB/Internal/RequestList.cpp

Libraries/LibWeb/Forward.h

@@ -625,6 +625,7 @@ class IDBOpenDBRequest;
 class IDBRequest;
 class IDBTransaction;
 class IDBVersionChangeEvent;
+class Index;
 class ObjectStore;
 class RequestList;
 }

Libraries/LibWeb/IndexedDB/Internal/Index.cpp

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2025, stelar7 <dudedbz@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/IndexedDB/Internal/Index.h>
+#include <LibWeb/IndexedDB/Internal/ObjectStore.h>
+
+namespace Web::IndexedDB {
+
+GC_DEFINE_ALLOCATOR(Index);
+
+Index::~Index() = default;
+
+GC::Ref<Index> Index::create(JS::Realm& realm, GC::Ref<ObjectStore> store, String name, KeyPath const& key_path, bool unique, bool multi_entry)
+{
+    return realm.create<Index>(store, name, key_path, unique, multi_entry);
+}
+
+Index::Index(GC::Ref<ObjectStore> store, String name, KeyPath const& key_path, bool unique, bool multi_entry)
+    : m_object_store(store)
+    , m_name(move(name))
+    , m_unique(unique)
+    , m_multi_entry(multi_entry)
+    , m_key_path(key_path)
+{
+    store->add_index(*this);
+}
+
+void Index::visit_edges(Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_object_store);
+
+    for (auto& record : m_records) {
+        visitor.visit(record.key);
+        visitor.visit(record.value);
+    }
+}
+
+}

Libraries/LibWeb/IndexedDB/Internal/Index.h

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2025, stelar7 <dudedbz@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Vector.h>
+#include <LibGC/Ptr.h>
+#include <LibJS/Heap/Cell.h>
+#include <LibJS/Runtime/Realm.h>
+#include <LibWeb/IndexedDB/Internal/ObjectStore.h>
+
+namespace Web::IndexedDB {
+
+using KeyPath = Variant<String, Vector<String>>;
+
+// https://w3c.github.io/IndexedDB/#index-list-of-records
+struct IndexRecord {
+    GC::Ref<Key> key;
+    GC::Ref<Key> value;
+};
+
+// https://w3c.github.io/IndexedDB/#index-construct
+class Index : public JS::Cell {
+    GC_CELL(Index, JS::Cell);
+    GC_DECLARE_ALLOCATOR(Index);
+
+public:
+    [[nodiscard]] static GC::Ref<Index> create(JS::Realm&, GC::Ref<ObjectStore>, String, KeyPath const&, bool, bool);
+    virtual ~Index();
+
+    void set_name(String name) { m_name = move(name); }
+    [[nodiscard]] String name() const { return m_name; }
+    [[nodiscard]] bool unique() const { return m_unique; }
+    [[nodiscard]] bool multi_entry() const { return m_multi_entry; }
+    [[nodiscard]] GC::Ref<ObjectStore> object_store() const { return m_object_store; }
+    [[nodiscard]] AK::ReadonlySpan<IndexRecord> records() const { return m_records; }
+    [[nodiscard]] KeyPath const& key_path() const { return m_key_path; }
+
+protected:
+    virtual void visit_edges(Visitor&) override;
+
+private:
+    Index(GC::Ref<ObjectStore>, String, KeyPath const&, bool, bool);
+
+    // An index [...] has a referenced object store.
+    GC::Ref<ObjectStore> m_object_store;
+
+    // The index has a list of records which hold the data stored in the index.
+    Vector<IndexRecord> m_records;
+
+    // An index has a name, which is a name. At any one time, the name is unique within index’s referenced object store.
+    String m_name;
+
+    // An index has a unique flag. When true, the index enforces that no two records in the index has the same key.
+    bool m_unique { false };
+
+    // An index has a multiEntry flag. This flag affects how the index behaves when the result of evaluating the index’s key path yields an array key.
+    bool m_multi_entry { false };
+
+    // The keys are derived from the referenced object store’s values using a key path.
+    KeyPath m_key_path;
+};
+
+}

Libraries/LibWeb/IndexedDB/Internal/ObjectStore.cpp

@@ -32,6 +32,7 @@ void ObjectStore::visit_edges(Visitor& visitor)
 {
     Base::visit_edges(visitor);
     visitor.visit(m_database);
+    visitor.visit(m_indexes);
 }
 
 }

Libraries/LibWeb/IndexedDB/Internal/ObjectStore.h

@@ -15,6 +15,7 @@
 #include <LibJS/Runtime/Realm.h>
 #include <LibWeb/IndexedDB/Internal/Algorithms.h>
 #include <LibWeb/IndexedDB/Internal/Database.h>
+#include <LibWeb/IndexedDB/Internal/Index.h>
 #include <LibWeb/IndexedDB/Internal/KeyGenerator.h>
 
 namespace Web::IndexedDB {
@@ -39,6 +40,9 @@ public:
 
     GC::Ref<Database> database() const { return m_database; }
 
+    void add_index(GC::Ref<Index> index) { m_indexes.append(index); }
+    ReadonlySpan<GC::Ref<Index>> index_set() const { return m_indexes; }
+
 protected:
     virtual void visit_edges(Visitor&) override;
 
@@ -48,6 +52,9 @@ private:
     // AD-HOC: An ObjectStore needs to know what Database it belongs to...
     GC::Ref<Database> m_database;
 
+    // AD-HOC: An Index has referenced ObjectStores, we also need the reverse mapping
+    Vector<GC::Ref<Index>> m_indexes;
+
     // An object store has a name, which is a name. At any one time, the name is unique within the database to which it belongs.
     String m_name;