LibDevTools+LibWebView: Implement getting document style sheets

Author: https://github.com/trflynn89
Commit: 0b86bcfba7
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3920

Libraries/LibDevTools/Actors/StyleSheetsActor.cpp

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/JsonObject.h>
+#include <LibDevTools/Actors/InspectorActor.h>
+#include <LibDevTools/Actors/StyleSheetsActor.h>
+#include <LibDevTools/Actors/TabActor.h>
+#include <LibDevTools/DevToolsDelegate.h>
+#include <LibDevTools/DevToolsServer.h>
+
+namespace DevTools {
+
+NonnullRefPtr<StyleSheetsActor> StyleSheetsActor::create(DevToolsServer& devtools, String name, WeakPtr<TabActor> tab)
+{
+    return adopt_ref(*new StyleSheetsActor(devtools, move(name), move(tab)));
+}
+
+StyleSheetsActor::StyleSheetsActor(DevToolsServer& devtools, String name, WeakPtr<TabActor> tab)
+    : Actor(devtools, move(name))
+    , m_tab(move(tab))
+{
+    if (auto tab = m_tab.strong_ref()) {
+        devtools.delegate().listen_for_style_sheet_sources(
+            tab->description(),
+            [weak_self = make_weak_ptr<StyleSheetsActor>()](Web::CSS::StyleSheetIdentifier const& style_sheet, String source) {
+                if (auto self = weak_self.strong_ref())
+                    self->style_sheet_source_received(style_sheet, move(source));
+            });
+    }
+}
+
+StyleSheetsActor::~StyleSheetsActor()
+{
+    if (auto tab = m_tab.strong_ref())
+        devtools().delegate().stop_listening_for_style_sheet_sources(tab->description());
+}
+
+void StyleSheetsActor::handle_message(Message const& message)
+{
+    if (message.type == "getText"sv) {
+        auto resource_id = get_required_parameter<String>(message, "resourceId"sv);
+        if (!resource_id.has_value())
+            return;
+
+        auto index = resource_id->bytes_as_string_view().find_last_split_view(':').to_number<size_t>();
+        if (!index.has_value() || *index >= m_style_sheets.size()) {
+            send_unknown_actor_error(message, *resource_id);
+            return;
+        }
+
+        if (auto tab = m_tab.strong_ref()) {
+            devtools().delegate().retrieve_style_sheet_source(tab->description(), m_style_sheets[*index]);
+            m_pending_style_sheet_source_requests.set(*index, { .id = message.id });
+        }
+
+        return;
+    }
+
+    send_unrecognized_packet_type_error(message);
+}
+
+void StyleSheetsActor::set_style_sheets(Vector<Web::CSS::StyleSheetIdentifier> style_sheets)
+{
+    m_style_sheets = move(style_sheets);
+}
+
+void StyleSheetsActor::style_sheet_source_received(Web::CSS::StyleSheetIdentifier const& style_sheet, String source)
+{
+    auto index = m_style_sheets.find_first_index_if([&](auto const& candidate) {
+        return candidate.type == style_sheet.type && candidate.url == style_sheet.url;
+    });
+    if (!index.has_value())
+        return;
+
+    auto pending_message = m_pending_style_sheet_source_requests.take(*index);
+    if (!pending_message.has_value())
+        return;
+
+    // FIXME: Support the `longString` message type so that we don't have to send the entire style sheet
+    //        source at once for large sheets.
+    JsonObject response;
+    response.set("text"sv, move(source));
+    send_response(*pending_message, move(response));
+}
+
+}