Everywhere: Implement persistence of localStorage using sqlite

This change follows the pattern of our cookies persistence
implementation: the "browser" process is responsible for interacting
with the sqlite database, and WebContent communicates all storage
operations via IPC.

The new database table uses (storage_endpoint, storage_key, bottle_key)
as the primary key. This design follows concepts from the
https://storage.spec.whatwg.org/ and is intended to support reuse of the
persistence layer for other APIs (e.g., CacheStorage, IndexedDB). For
now, `storage_endpoint` is always "localStorage", `storage_key` is the
website's origin, and `bottle_key` is the name of the localStorage key.

Libraries/LibWeb/StorageAPI/StorageBottle.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2024-2025, Shannon Booth <shannon@serenityos.org>
+ * Copyright (c) 2025, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -13,16 +14,18 @@
 
 namespace Web::StorageAPI {
 
-GC_DEFINE_ALLOCATOR(StorageBottle);
+GC_DEFINE_ALLOCATOR(LocalStorageBottle);
+GC_DEFINE_ALLOCATOR(SessionStorageBottle);
 GC_DEFINE_ALLOCATOR(StorageBucket);
 
 void StorageBucket::visit_edges(GC::Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
-    visitor.visit(m_bottle_map);
+    for (auto& entry : m_bottle_map)
+        visitor.visit(entry);
 }
 
-StorageBucket::StorageBucket(StorageType type)
+StorageBucket::StorageBucket(GC::Ref<Page> page, StorageKey key, StorageType type)
 {
     // 1. Let bucket be null.
     // 2. If type is "local", then set bucket to a new local storage bucket.
@@ -33,21 +36,23 @@ StorageBucket::StorageBucket(StorageType type)
     // 4. For each endpoint of registered storage endpoints whose types contain type, set bucket’s bottle map[endpoint’s identifier] to a new storage bottle whose quota is endpoint’s quota.
     for (auto const& endpoint : StorageEndpoint::registered_endpoints()) {
         if (endpoint.type == type)
-            m_bottle_map.set(endpoint.identifier, StorageBottle::create(heap(), endpoint.quota));
+            m_bottle_map[to_underlying(endpoint.identifier)] = StorageBottle::create(heap(), page, type, key, endpoint.quota);
     }
 
     // 5. Return bucket.
 }
 
 // https://storage.spec.whatwg.org/#obtain-a-storage-bottle-map
-GC::Ptr<StorageBottle> obtain_a_storage_bottle_map(StorageType type, HTML::EnvironmentSettingsObject& environment, StringView identifier)
+GC::Ptr<StorageBottle> obtain_a_storage_bottle_map(StorageType type, HTML::EnvironmentSettingsObject& environment, StorageEndpointType endpoint_type)
 {
     // 1. Let shed be null.
-    GC::Ptr<StorageShed> shed = nullptr;
+    GC::Ptr<StorageShed> shed;
 
     // 2. If type is "local", then set shed to the user agent’s storage shed.
     if (type == StorageType::Local) {
-        shed = user_agent_storage_shed(environment.heap());
+        // NOTE: Bottle for local storage is constructed directly, bypassing this function, because
+        //       in that case StorageJar located on browser process side is used as a shed.
+        VERIFY_NOT_REACHED();
     }
     // 3. Otherwise:
     else {
@@ -67,10 +72,10 @@ GC::Ptr<StorageBottle> obtain_a_storage_bottle_map(StorageType type, HTML::Envir
         return {};
 
     // 6. Let bucket be shelf’s bucket map["default"].
-    auto& bucket = shelf->bucket_map().get("default"sv).value();
+    auto bucket = shelf->bucket_map().get("default"sv).value();
 
     // 7. Let bottle be bucket’s bottle map[identifier].
-    auto bottle = bucket->bottle_map().get(identifier).value();
+    auto bottle = bucket->bottle_map()[to_underlying(endpoint_type)];
 
     // 8. Let proxyMap be a new storage proxy map whose backing map is bottle’s map.
     // 9. Append proxyMap to bottle’s proxy map reference set.
@@ -79,19 +84,100 @@ GC::Ptr<StorageBottle> obtain_a_storage_bottle_map(StorageType type, HTML::Envir
 }
 
 // https://storage.spec.whatwg.org/#obtain-a-session-storage-bottle-map
-GC::Ptr<StorageBottle> obtain_a_session_storage_bottle_map(HTML::EnvironmentSettingsObject& environment, StringView identifier)
+GC::Ptr<StorageBottle> obtain_a_session_storage_bottle_map(HTML::EnvironmentSettingsObject& environment, StorageEndpointType identifier)
 {
     // To obtain a session storage bottle map, given an environment settings object environment and storage identifier identifier,
     // return the result of running obtain a storage bottle map with "session", environment, and identifier.
     return obtain_a_storage_bottle_map(StorageType::Session, environment, identifier);
 }
 
-// https://storage.spec.whatwg.org/#obtain-a-local-storage-bottle-map
-GC::Ptr<StorageBottle> obtain_a_local_storage_bottle_map(HTML::EnvironmentSettingsObject& environment, StringView identifier)
+GC::Ref<StorageBottle> StorageBottle::create(GC::Heap& heap, GC::Ref<Page> page, StorageType type, StorageKey key, Optional<u64> quota)
 {
-    // To obtain a local storage bottle map, given an environment settings object environment and storage identifier identifier,
-    // return the result of running obtain a storage bottle map with "local", environment, and identifier.
-    return obtain_a_storage_bottle_map(StorageType::Local, environment, identifier);
+    if (type == StorageType::Local)
+        return LocalStorageBottle::create(heap, page, key, quota);
+    return SessionStorageBottle::create(heap, quota);
+}
+
+void LocalStorageBottle::visit_edges(GC::Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_page);
+}
+
+size_t LocalStorageBottle::size() const
+{
+    return m_page->client().page_did_request_storage_keys(Web::StorageAPI::StorageEndpointType::LocalStorage, m_storage_key.to_string()).size();
+}
+
+Vector<String> LocalStorageBottle::keys() const
+{
+    return m_page->client().page_did_request_storage_keys(Web::StorageAPI::StorageEndpointType::LocalStorage, m_storage_key.to_string());
+}
+
+Optional<String> LocalStorageBottle::get(String const& key) const
+{
+    return m_page->client().page_did_request_storage_item(Web::StorageAPI::StorageEndpointType::LocalStorage, m_storage_key.to_string(), key);
+}
+
+WebView::StorageOperationError LocalStorageBottle::set(String const& key, String const& value)
+{
+    return m_page->client().page_did_set_storage_item(Web::StorageAPI::StorageEndpointType::LocalStorage, m_storage_key.to_string(), key, value);
+}
+
+void LocalStorageBottle::clear()
+{
+    m_page->client().page_did_clear_storage(Web::StorageAPI::StorageEndpointType::LocalStorage, m_storage_key.to_string());
+}
+
+void LocalStorageBottle::remove(String const& key)
+{
+    m_page->client().page_did_remove_storage_item(Web::StorageAPI::StorageEndpointType::LocalStorage, m_storage_key.to_string(), key);
+}
+
+size_t SessionStorageBottle::size() const
+{
+    return m_map.size();
+}
+
+Vector<String> SessionStorageBottle::keys() const
+{
+    return m_map.keys();
+}
+
+Optional<String> SessionStorageBottle::get(String const& key) const
+{
+    if (auto value = m_map.get(key); value.has_value())
+        return value.value();
+    return OptionalNone {};
+}
+
+WebView::StorageOperationError SessionStorageBottle::set(String const& key, String const& value)
+{
+    if (m_quota.has_value()) {
+        size_t current_size = 0;
+        for (auto const& [existing_key, existing_value] : m_map) {
+            if (existing_key != key) {
+                current_size += existing_key.bytes().size();
+                current_size += existing_value.bytes().size();
+            }
+        }
+        size_t new_size = key.bytes().size() + value.bytes().size();
+        if (current_size + new_size > m_quota.value())
+            return WebView::StorageOperationError::QuotaExceededError;
+    }
+
+    m_map.set(key, value);
+    return WebView::StorageOperationError::None;
+}
+
+void SessionStorageBottle::clear()
+{
+    m_map.clear();
+}
+
+void SessionStorageBottle::remove(String const& key)
+{
+    m_map.remove(key);
 }
 
 }

Libraries/LibWeb/StorageAPI/StorageBottle.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2024-2025, Shannon Booth <shannon@serenityos.org>
+ * Copyright (c) 2025, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -8,36 +9,105 @@
 
 #include <AK/HashMap.h>
 #include <AK/String.h>
+#include <LibGC/Ptr.h>
 #include <LibWeb/Forward.h>
+#include <LibWeb/Page/Page.h>
+#include <LibWeb/StorageAPI/StorageEndpoint.h>
+#include <LibWeb/StorageAPI/StorageKey.h>
 #include <LibWeb/StorageAPI/StorageType.h>
+#include <LibWebView/StorageOperationError.h>
 
 namespace Web::StorageAPI {
 
 // https://storage.spec.whatwg.org/#storage-bottle
 class StorageBottle : public GC::Cell {
     GC_CELL(StorageBottle, GC::Cell);
-    GC_DECLARE_ALLOCATOR(StorageBottle);
 
-    static GC::Ref<StorageBottle> create(GC::Heap& heap, Optional<u64> quota) { return heap.allocate<StorageBottle>(quota); }
+public:
+    static GC::Ref<StorageBottle> create(GC::Heap& heap, GC::Ref<Page> page, StorageType type, StorageKey key, Optional<u64> quota);
 
-    // A storage bottle has a map, which is initially an empty map
-    OrderedHashMap<String, String> map;
+    virtual ~StorageBottle() = default;
 
     // A storage bottle also has a proxy map reference set, which is initially an empty set
     GC::Ref<StorageBottle> proxy() { return *this; }
 
-    // A storage bottle also has a quota, which is null or a number representing a conservative estimate of
-    // the total amount of bytes it can hold. Null indicates the lack of a limit.
-    Optional<u64> quota;
+    virtual size_t size() const = 0;
+    virtual Vector<String> keys() const = 0;
+    virtual Optional<String> get(String const&) const = 0;
+    virtual WebView::StorageOperationError set(String const& key, String const& value) = 0;
+    virtual void clear() = 0;
+    virtual void remove(String const&) = 0;
 
-private:
-    explicit StorageBottle(Optional<u64> quota_)
-        : quota(quota_)
+    Optional<u64> quota() const { return m_quota; }
+
+protected:
+    explicit StorageBottle(Optional<u64> quota)
+        : m_quota(quota)
     {
     }
+
+    Optional<u64> m_quota;
 };
 
-using BottleMap = OrderedHashMap<String, GC::Ref<StorageBottle>>;
+class LocalStorageBottle final : public StorageBottle {
+    GC_CELL(LocalStorageBottle, StorageBottle);
+    GC_DECLARE_ALLOCATOR(LocalStorageBottle);
+
+public:
+    static GC::Ref<LocalStorageBottle> create(GC::Heap& heap, GC::Ref<Page> page, StorageKey key, Optional<u64> quota)
+    {
+        return heap.allocate<LocalStorageBottle>(page, key, quota);
+    }
+
+    virtual size_t size() const override;
+    virtual Vector<String> keys() const override;
+    virtual Optional<String> get(String const&) const override;
+    virtual WebView::StorageOperationError set(String const& key, String const& value) override;
+    virtual void clear() override;
+    virtual void remove(String const&) override;
+
+    virtual void visit_edges(GC::Cell::Visitor& visitor) override;
+
+private:
+    explicit LocalStorageBottle(GC::Ref<Page> page, StorageKey key, Optional<u64> quota)
+        : StorageBottle(quota)
+        , m_page(move(page))
+        , m_storage_key(move(key))
+    {
+    }
+
+    GC::Ref<Page> m_page;
+    StorageKey m_storage_key;
+};
+
+class SessionStorageBottle final : public StorageBottle {
+    GC_CELL(SessionStorageBottle, StorageBottle);
+    GC_DECLARE_ALLOCATOR(SessionStorageBottle);
+
+public:
+    static GC::Ref<SessionStorageBottle> create(GC::Heap& heap, Optional<u64> quota)
+    {
+        return heap.allocate<SessionStorageBottle>(quota);
+    }
+
+    virtual size_t size() const override;
+    virtual Vector<String> keys() const override;
+    virtual Optional<String> get(String const&) const override;
+    virtual WebView::StorageOperationError set(String const& key, String const& value) override;
+    virtual void clear() override;
+    virtual void remove(String const&) override;
+
+private:
+    explicit SessionStorageBottle(Optional<u64> quota)
+        : StorageBottle(quota)
+    {
+    }
+
+    // A storage bottle has a map, which is initially an empty map
+    OrderedHashMap<String, String> m_map;
+};
+
+using BottleMap = Array<GC::Ptr<StorageBottle>, to_underlying(StorageEndpointType::Count)>;
 
 // https://storage.spec.whatwg.org/#storage-bucket
 // A storage bucket is a place for storage endpoints to store data.
@@ -46,7 +116,7 @@ class StorageBucket : public GC::Cell {
     GC_DECLARE_ALLOCATOR(StorageBucket);
 
 public:
-    static GC::Ref<StorageBucket> create(GC::Heap& heap, StorageType type) { return heap.allocate<StorageBucket>(type); }
+    static GC::Ref<StorageBucket> create(GC::Heap& heap, GC::Ref<Page> page, StorageKey key, StorageType type) { return heap.allocate<StorageBucket>(page, key, type); }
 
     BottleMap& bottle_map() { return m_bottle_map; }
     BottleMap const& bottle_map() const { return m_bottle_map; }
@@ -54,14 +124,13 @@ public:
     virtual void visit_edges(GC::Cell::Visitor& visitor) override;
 
 private:
-    explicit StorageBucket(StorageType);
+    explicit StorageBucket(GC::Ref<Page> page, StorageKey key, StorageType type);
 
     // A storage bucket has a bottle map of storage identifiers to storage bottles.
     BottleMap m_bottle_map;
 };
 
-GC::Ptr<StorageBottle> obtain_a_session_storage_bottle_map(HTML::EnvironmentSettingsObject&, StringView storage_identifier);
-GC::Ptr<StorageBottle> obtain_a_local_storage_bottle_map(HTML::EnvironmentSettingsObject&, StringView storage_identifier);
-GC::Ptr<StorageBottle> obtain_a_storage_bottle_map(StorageType, HTML::EnvironmentSettingsObject&, StringView storage_identifier);
+GC::Ptr<StorageBottle> obtain_a_session_storage_bottle_map(HTML::EnvironmentSettingsObject&, StorageEndpointType endpoint_type);
+GC::Ptr<StorageBottle> obtain_a_storage_bottle_map(StorageType, HTML::EnvironmentSettingsObject&, StorageEndpointType endpoint_type);
 
 }

Libraries/LibWeb/StorageAPI/StorageEndpoint.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2024-2025, Shannon Booth <shannon@serenityos.org>
+ * Copyright (c) 2025, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -12,11 +13,11 @@ ReadonlySpan<StorageEndpoint> StorageEndpoint::registered_endpoints()
 {
     // https://storage.spec.whatwg.org/#registered-storage-endpoints
     static auto const endpoints = to_array<StorageEndpoint>({
-        { "caches"_string, StorageType::Local, {} },
-        { "indexedDB"_string, StorageType::Local, {} },
-        { "localStorage"_string, StorageType::Local, 5 * MiB },
-        { "serviceWorkerRegistrations"_string, StorageType::Local, {} },
-        { "sessionStorage"_string, StorageType::Session, 5 * MiB },
+        { StorageEndpointType::Caches, StorageType::Local, {} },
+        { StorageEndpointType::IndexedDB, StorageType::Local, {} },
+        { StorageEndpointType::LocalStorage, StorageType::Local, LOCAL_STORAGE_QUOTA },
+        { StorageEndpointType::ServiceWorkerRegistrations, StorageType::Local, {} },
+        { StorageEndpointType::SessionStorage, StorageType::Session, SESSION_STORAGE_QUOTA },
     });
     return endpoints;
 }

Libraries/LibWeb/StorageAPI/StorageEndpoint.h

@@ -1,12 +1,12 @@
 /*
  * Copyright (c) 2024-2025, Shannon Booth <shannon@serenityos.org>
+ * Copyright (c) 2025, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #pragma once
 
-#include <AK/Array.h>
 #include <AK/Optional.h>
 #include <AK/String.h>
 #include <AK/Types.h>
@@ -14,14 +14,27 @@
 
 namespace Web::StorageAPI {
 
+enum class StorageEndpointType : u8 {
+    Caches = 0,
+    IndexedDB = 1,
+    LocalStorage = 2,
+    ServiceWorkerRegistrations = 3,
+    SessionStorage = 4,
+
+    Count = 5 // This should always be the last value in the enum.
+};
+
 // https://storage.spec.whatwg.org/#storage-endpoint
 //
 // A storage endpoint is a local or session storage API that uses the infrastructure defined by this
 // standard, most notably storage bottles, to keep track of its storage needs.
 struct StorageEndpoint {
+    static constexpr u64 LOCAL_STORAGE_QUOTA = 5 * MiB;
+    static constexpr u64 SESSION_STORAGE_QUOTA = 5 * MiB;
+
     // https://storage.spec.whatwg.org/#storage-endpoint-identifier
     // A storage endpoint has an identifier, which is a storage identifier.
-    String identifier;
+    StorageEndpointType identifier;
 
     // https://storage.spec.whatwg.org/#storage-endpoint-types
     // A storage endpoint also has types, which is a set of storage types.

Libraries/LibWeb/StorageAPI/StorageKey.h

@@ -20,6 +20,11 @@ struct StorageKey {
     // NOTE: This is expected to change; see Client-Side Storage Partitioning https://privacycg.github.io/storage-partitioning/.
     URL::Origin origin;
 
+    String to_string() const
+    {
+        return origin.serialize();
+    }
+
     friend bool operator==(StorageKey const& a, StorageKey const& b)
     {
         // To determine whether a storage key A equals storage key B, run these steps:

Libraries/LibWeb/StorageAPI/StorageShed.cpp

@@ -6,6 +6,7 @@
 
 #include <LibGC/Heap.h>
 #include <LibWeb/HTML/Scripting/Environments.h>
+#include <LibWeb/HTML/Window.h>
 #include <LibWeb/StorageAPI/StorageShed.h>
 
 namespace Web::StorageAPI {
@@ -19,29 +20,22 @@ void StorageShed::visit_edges(GC::Cell::Visitor& visitor)
 }
 
 // https://storage.spec.whatwg.org/#obtain-a-storage-shelf
-GC::Ptr<StorageShelf> StorageShed::obtain_a_storage_shelf(HTML::EnvironmentSettingsObject const& environment, StorageType type)
+GC::Ptr<StorageShelf> StorageShed::obtain_a_storage_shelf(HTML::EnvironmentSettingsObject& environment, StorageType type)
 {
     // 1. Let key be the result of running obtain a storage key with environment.
     auto key = obtain_a_storage_key(environment);
 
+    auto& page = as<HTML::Window>(environment.global_object()).page();
+
     // 2. If key is failure, then return failure.
     if (!key.has_value())
         return {};
 
     // 3. If shed[key] does not exist, then set shed[key] to the result of running create a storage shelf with type.
     // 4. Return shed[key].
-    return m_data.ensure(key.value(), [type, &heap = this->heap()] {
-        return StorageShelf::create(heap, type);
+    return m_data.ensure(key.value(), [&page, key, type, &heap = this->heap()] {
+        return StorageShelf::create(heap, page, *key, type);
     });
 }
 
-// https://storage.spec.whatwg.org/#user-agent-storage-shed
-GC::Ref<StorageShed> user_agent_storage_shed(GC::Heap& heap)
-{
-    // A user agent holds a storage shed, which is a storage shed. A user agent’s storage shed holds all local storage data.
-    // FIXME: Storing this statically in memory is not the correct place or way of doing this!
-    static GC::Root<StorageShed> storage_shed = GC::make_root(StorageShed::create(heap));
-    return *storage_shed;
-}
-
 }

Libraries/LibWeb/StorageAPI/StorageShed.h

@@ -24,7 +24,7 @@ class StorageShed : public GC::Cell {
 public:
     static GC::Ref<StorageShed> create(GC::Heap& heap) { return heap.allocate<StorageShed>(); }
 
-    GC::Ptr<StorageShelf> obtain_a_storage_shelf(HTML::EnvironmentSettingsObject const&, StorageType);
+    GC::Ptr<StorageShelf> obtain_a_storage_shelf(HTML::EnvironmentSettingsObject&, StorageType);
 
     virtual void visit_edges(GC::Cell::Visitor& visitor) override;
 
@@ -34,6 +34,4 @@ private:
     OrderedHashMap<StorageKey, GC::Ref<StorageShelf>> m_data;
 };
 
-GC::Ref<StorageShed> user_agent_storage_shed(GC::Heap&);
-
 }

Libraries/LibWeb/StorageAPI/StorageShelf.cpp

@@ -18,11 +18,11 @@ void StorageShelf::visit_edges(GC::Cell::Visitor& visitor)
 }
 
 // https://storage.spec.whatwg.org/#create-a-storage-shelf
-StorageShelf::StorageShelf(StorageType type)
+StorageShelf::StorageShelf(GC::Ref<Page> page, StorageKey key, StorageType type)
 {
     // 1. Let shelf be a new storage shelf.
     // 2. Set shelf’s bucket map["default"] to the result of running create a storage bucket with type.
-    m_bucket_map.set("default"_string, StorageBucket::create(heap(), type));
+    m_bucket_map.set("default"_string, StorageBucket::create(heap(), page, key, type));
     // 3. Return shelf.
 }
 

Libraries/LibWeb/StorageAPI/StorageShelf.h

@@ -23,7 +23,7 @@ class StorageShelf : public GC::Cell {
     GC_DECLARE_ALLOCATOR(StorageShelf);
 
 public:
-    static GC::Ref<StorageShelf> create(GC::Heap& heap, StorageType type) { return heap.allocate<StorageShelf>(type); }
+    static GC::Ref<StorageShelf> create(GC::Heap& heap, GC::Ref<Page> page, StorageKey key, StorageType type) { return heap.allocate<StorageShelf>(page, key, type); }
 
     BucketMap& bucket_map() { return m_bucket_map; }
     BucketMap const& bucket_map() const { return m_bucket_map; }
@@ -31,7 +31,7 @@ public:
     virtual void visit_edges(GC::Cell::Visitor& visitor) override;
 
 private:
-    explicit StorageShelf(StorageType);
+    explicit StorageShelf(GC::Ref<Page>, StorageKey, StorageType);
 
     BucketMap m_bucket_map;
 };