LibDevTools: Add a helper to acquire required message parameters

This is just to help make the message handlers a bit briefer. I had
considered adding a TRY-like macro to auto-return when the lookup fails,
but since statement expressions cannot return references, that would
result in a copy of all e.g. object and array lookups.

Libraries/LibDevTools/Actor.cpp

@@ -4,7 +4,6 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <AK/JsonObject.h>
 #include <LibDevTools/Actor.h>
 #include <LibDevTools/Connection.h>
 #include <LibDevTools/DevToolsServer.h>

Libraries/LibDevTools/Actor.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <AK/Badge.h>
+#include <AK/JsonObject.h>
 #include <AK/Optional.h>
 #include <AK/RefCounted.h>
 #include <AK/String.h>
@@ -55,6 +56,30 @@ protected:
 
     BlockToken block_responses();
 
+    template<typename ParameterType>
+    auto get_required_parameter(JsonObject const& message, StringView parameter)
+    {
+        auto result = [&]() {
+            if constexpr (IsIntegral<ParameterType>)
+                return message.get_integer<ParameterType>(parameter);
+            else if constexpr (IsSame<ParameterType, bool>)
+                return message.get_bool(parameter);
+            else if constexpr (IsSame<ParameterType, String>)
+                return message.get_string(parameter);
+            else if constexpr (IsSame<ParameterType, JsonObject>)
+                return message.get_object(parameter);
+            else if constexpr (IsSame<ParameterType, JsonArray>)
+                return message.get_array(parameter);
+            else
+                static_assert(DependentFalse<ParameterType>);
+        }();
+
+        if (!result.has_value())
+            send_missing_parameter_error(parameter);
+
+        return result;
+    }
+
 private:
     DevToolsServer& m_devtools;
     String m_name;

Libraries/LibDevTools/Actors/ConsoleActor.cpp

@@ -40,11 +40,9 @@ void ConsoleActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "evaluateJSAsync"sv) {
-        auto text = message.get_string("text"sv);
+        auto text = get_required_parameter<String>(message, "text"sv);
-        if (!text.has_value()) {
+        if (!text.has_value())
-            send_missing_parameter_error("text"sv);
             return;
-        }
 
         auto result_id = MUST(String::formatted("{}-{}", name(), m_execution_id++));
 

Libraries/LibDevTools/Actors/HighlighterActor.cpp

@@ -32,11 +32,9 @@ void HighlighterActor::handle_message(StringView type, JsonObject const& message
     JsonObject response;
 
     if (type == "show"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         response.set("value"sv, false);
 

Libraries/LibDevTools/Actors/InspectorActor.cpp

@@ -43,11 +43,9 @@ void InspectorActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "getHighlighterByType"sv) {
-        auto type_name = message.get_string("typeName"sv);
+        auto type_name = get_required_parameter<String>(message, "typeName"sv);
-        if (!type_name.has_value()) {
+        if (!type_name.has_value())
-            send_missing_parameter_error("typeName"sv);
             return;
-        }
 
         auto highlighter = m_highlighters.ensure(*type_name, [&]() -> NonnullRefPtr<HighlighterActor> {
             return devtools().register_actor<HighlighterActor>(*this);

Libraries/LibDevTools/Actors/NodeActor.cpp

@@ -110,11 +110,9 @@ void NodeActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "modifyAttributes"sv) {
-        auto modifications = message.get_array("modifications"sv);
+        auto modifications = get_required_parameter<JsonArray>(message, "modifications"sv);
-        if (!modifications.has_value()) {
+        if (!modifications.has_value())
-            send_missing_parameter_error("modifications"sv);
             return;
-        }
 
         auto [attribute_to_replace, replacement_attributes] = parse_attribute_modification(*modifications);
         if (!attribute_to_replace.has_value() && replacement_attributes.is_empty())
@@ -148,11 +146,9 @@ void NodeActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "setNodeValue"sv) {
-        auto value = message.get_string("value"sv);
+        auto value = get_required_parameter<String>(message, "value"sv);
-        if (!value.has_value()) {
+        if (!value.has_value())
-            send_missing_parameter_error("value"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(m_walker, name());
         if (!dom_node.has_value()) {

Libraries/LibDevTools/Actors/PageStyleActor.cpp

@@ -41,11 +41,9 @@ void PageStyleActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "getComputed"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         inspect_dom_node(*node, [](auto& self, auto const& properties, auto block_token) {
             self.received_computed_style(properties.computed_style, move(block_token));
@@ -55,11 +53,9 @@ void PageStyleActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "getLayout"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         inspect_dom_node(*node, [](auto& self, auto const& properties, auto block_token) {
             self.received_layout(properties.computed_style, properties.node_box_sizing, move(block_token));

Libraries/LibDevTools/Actors/RootActor.cpp

@@ -65,11 +65,9 @@ void RootActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "getProcess"sv) {
-        auto id = message.get_integer<u64>("id"sv);
+        auto id = get_required_parameter<u64>(message, "id"sv);
-        if (!id.has_value()) {
+        if (!id.has_value())
-            send_missing_parameter_error("id"sv);
             return;
-        }
 
         for (auto const& actor : devtools().actor_registry()) {
             auto const* process_actor = as_if<ProcessActor>(*actor.value);
@@ -87,11 +85,9 @@ void RootActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "getTab"sv) {
-        auto browser_id = message.get_integer<u64>("browserId"sv);
+        auto browser_id = get_required_parameter<u64>(message, "browserId"sv);
-        if (!browser_id.has_value()) {
+        if (!browser_id.has_value())
-            send_missing_parameter_error("browserId"sv);
             return;
-        }
 
         for (auto const& actor : devtools().actor_registry()) {
             auto const* tab_actor = as_if<TabActor>(*actor.value);

Libraries/LibDevTools/Actors/TargetConfigurationActor.cpp

@@ -27,11 +27,9 @@ void TargetConfigurationActor::handle_message(StringView type, JsonObject const&
     JsonObject response;
 
     if (type == "updateConfiguration"sv) {
-        auto configuration = message.get_object("configuration"sv);
+        auto configuration = get_required_parameter<JsonObject>(message, "configuration"sv);
-        if (!configuration.has_value()) {
+        if (!configuration.has_value())
-            send_missing_parameter_error("configuration"sv);
             return;
-        }
 
         send_message(move(response));
         return;

Libraries/LibDevTools/Actors/ThreadConfigurationActor.cpp

@@ -27,11 +27,9 @@ void ThreadConfigurationActor::handle_message(StringView type, JsonObject const&
     JsonObject response;
 
     if (type == "updateConfiguration"sv) {
-        auto configuration = message.get_object("configuration"sv);
+        auto configuration = get_required_parameter<JsonObject>(message, "configuration"sv);
-        if (!configuration.has_value()) {
+        if (!configuration.has_value())
-            send_missing_parameter_error("configuration"sv);
             return;
-        }
 
         send_message(move(response));
         return;

Libraries/LibDevTools/Actors/WalkerActor.cpp

@@ -48,11 +48,9 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     JsonObject response;
 
     if (type == "children"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         auto ancestor_node = WalkerActor::dom_node_for(*this, *node);
         if (!ancestor_node.has_value()) {
@@ -76,11 +74,9 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "duplicateNode"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(*this, *node);
         if (!dom_node.has_value()) {
@@ -106,17 +102,13 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "editTagName"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
-        auto tag_name = message.get_string("tagName"sv);
+        auto tag_name = get_required_parameter<String>(message, "tagName"sv);
-        if (!tag_name.has_value()) {
+        if (!tag_name.has_value())
-            send_missing_parameter_error("tagName"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(*this, *node);
         if (!dom_node.has_value()) {
@@ -168,11 +160,9 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "innerHTML"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(*this, *node);
         if (!dom_node.has_value()) {
@@ -204,11 +194,9 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
         // FIXME: This message also contains `value` and `position` parameters, containing the HTML to insert and the
         //        location to insert it. For the "Create New Node" action, this is always "<div></div>" and "beforeEnd",
         //        which is exactly what our WebView implementation currently supports.
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(*this, *node);
         if (!dom_node.has_value()) {
@@ -245,17 +233,13 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "insertBefore"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
-        auto parent = message.get_string("parent"sv);
+        auto parent = get_required_parameter<String>(message, "parent"sv);
-        if (!parent.has_value()) {
+        if (!parent.has_value())
-            send_missing_parameter_error("parent"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(*this, *node);
         if (!dom_node.has_value()) {
@@ -298,11 +282,9 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "isInDOMTree"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         response.set("attached"sv, m_actor_to_dom_node_map.contains(*node));
         send_message(move(response));
@@ -310,11 +292,9 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "outerHTML"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(*this, *node);
         if (!dom_node.has_value()) {
@@ -343,11 +323,9 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "previousSibling"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(*this, *node);
         if (!dom_node.has_value()) {
@@ -365,17 +343,13 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "querySelector"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
-        auto selector = message.get_string("selector"sv);
+        auto selector = get_required_parameter<String>(message, "selector"sv);
-        if (!selector.has_value()) {
+        if (!selector.has_value())
-            send_missing_parameter_error("selector"sv);
             return;
-        }
 
         auto ancestor_node = WalkerActor::dom_node_for(*this, *node);
         if (!ancestor_node.has_value()) {
@@ -400,11 +374,9 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "removeNode"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(*this, *node);
         if (!dom_node.has_value()) {
@@ -446,17 +418,13 @@ void WalkerActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "setOuterHTML"sv) {
-        auto node = message.get_string("node"sv);
+        auto node = get_required_parameter<String>(message, "node"sv);
-        if (!node.has_value()) {
+        if (!node.has_value())
-            send_missing_parameter_error("node"sv);
             return;
-        }
 
-        auto value = message.get_string("value"sv);
+        auto value = get_required_parameter<String>(message, "value"sv);
-        if (!value.has_value()) {
+        if (!value.has_value())
-            send_missing_parameter_error("value"sv);
             return;
-        }
 
         auto dom_node = WalkerActor::dom_node_for(*this, *node);
         if (!dom_node.has_value()) {

Libraries/LibDevTools/Actors/WatcherActor.cpp

@@ -38,11 +38,9 @@ void WatcherActor::handle_message(StringView type, JsonObject const& message)
     JsonObject response;
 
     if (type == "getParentBrowsingContextID"sv) {
-        auto browsing_context_id = message.get_integer<u64>("browsingContextID"sv);
+        auto browsing_context_id = get_required_parameter<u64>(message, "browsingContextID"sv);
-        if (!browsing_context_id.has_value()) {
+        if (!browsing_context_id.has_value())
-            send_missing_parameter_error("browsingContextID"sv);
             return;
-        }
 
         response.set("browsingContextID"sv, *browsing_context_id);
         send_message(move(response));
@@ -68,11 +66,9 @@ void WatcherActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "watchResources"sv) {
-        auto resource_types = message.get_array("resourceTypes"sv);
+        auto resource_types = get_required_parameter<JsonArray>(message, "resourceTypes"sv);
-        if (!resource_types.has_value()) {
+        if (!resource_types.has_value())
-            send_missing_parameter_error("resourceTypes"sv);
             return;
-        }
 
         if constexpr (DEVTOOLS_DEBUG) {
             for (auto const& resource_type : resource_types->values()) {
@@ -88,11 +84,9 @@ void WatcherActor::handle_message(StringView type, JsonObject const& message)
     }
 
     if (type == "watchTargets"sv) {
-        auto target_type = message.get_string("targetType"sv);
+        auto target_type = get_required_parameter<String>(message, "targetType"sv);
-        if (!target_type.has_value()) {
+        if (!target_type.has_value())
-            send_missing_parameter_error("targetType"sv);
             return;
-        }
 
         if (target_type == "frame"sv) {
             auto& css_properties = devtools().register_actor<CSSPropertiesActor>();