AK+Everywhere: Convert JSON value serialization to String

This removes the use of StringBuilder::OutputType (which was ByteString,
and only used by the JSON classes). And it removes the StringBuilder
template parameter from the serialization methods; this was only ever
used with StringBuilder, so a template is pretty overkill here.

AK/CMakeLists.txt

@@ -13,6 +13,7 @@ set(SOURCES
     Format.cpp
     GenericLexer.cpp
     Hex.cpp
+    JsonArray.cpp
     JsonObject.cpp
     JsonParser.cpp
     JsonValue.cpp

AK/JsonArray.cpp

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/JsonArray.h>
+#include <AK/JsonArraySerializer.h>
+#include <AK/StringBuilder.h>
+
+namespace AK {
+
+String JsonArray::serialized() const
+{
+    StringBuilder builder;
+    serialize(builder);
+
+    return MUST(builder.to_string());
+}
+
+void JsonArray::serialize(StringBuilder& builder) const
+{
+    auto serializer = MUST(JsonArraySerializer<>::try_create(builder));
+    for_each([&](auto const& value) {
+        MUST(serializer.add(value));
+    });
+    MUST(serializer.finish());
+}
+
+}

AK/JsonArray.h

@@ -8,8 +8,8 @@
 
 #include <AK/Concepts.h>
 #include <AK/Error.h>
-#include <AK/JsonArraySerializer.h>
 #include <AK/JsonValue.h>
+#include <AK/String.h>
 #include <AK/Vector.h>
 
 namespace AK {
@@ -72,11 +72,8 @@ public:
     ErrorOr<void> append(JsonValue value) { return m_values.try_append(move(value)); }
     void set(size_t index, JsonValue value) { m_values.at(index) = move(value); }
 
-    template<typename Builder>
-    typename Builder::OutputType serialized() const;
-
-    template<typename Builder>
-    void serialize(Builder&) const;
+    String serialized() const;
+    void serialize(StringBuilder&) const;
 
     template<typename Callback>
     void for_each(Callback callback)
@@ -118,22 +115,6 @@ private:
     Vector<JsonValue> m_values;
 };
 
-template<typename Builder>
-inline void JsonArray::serialize(Builder& builder) const
-{
-    auto serializer = MUST(JsonArraySerializer<>::try_create(builder));
-    for_each([&](auto& value) { MUST(serializer.add(value)); });
-    MUST(serializer.finish());
-}
-
-template<typename Builder>
-inline typename Builder::OutputType JsonArray::serialized() const
-{
-    Builder builder;
-    serialize(builder);
-    return builder.to_byte_string();
-}
-
 }
 
 #if USING_AK_GLOBALLY

AK/JsonObject.cpp

@@ -6,7 +6,9 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include "JsonObject.h"
+#include <AK/JsonObject.h>
+#include <AK/JsonObjectSerializer.h>
+#include <AK/StringBuilder.h>
 
 namespace AK {
 
@@ -275,4 +277,21 @@ bool JsonObject::remove(StringView key)
     return m_members.remove(key);
 }
 
+String JsonObject::serialized() const
+{
+    StringBuilder builder;
+    serialize(builder);
+
+    return MUST(builder.to_string());
+}
+
+void JsonObject::serialize(StringBuilder& builder) const
+{
+    auto serializer = MUST(JsonObjectSerializer<>::try_create(builder));
+    for_each_member([&](auto& key, auto& value) {
+        MUST(serializer.add(key, value));
+    });
+    MUST(serializer.finish());
+}
+
 }

AK/JsonObject.h

@@ -8,12 +8,10 @@
 
 #pragma once
 
-#include <AK/ByteString.h>
 #include <AK/Concepts.h>
 #include <AK/Error.h>
 #include <AK/HashMap.h>
 #include <AK/JsonArray.h>
-#include <AK/JsonObjectSerializer.h>
 #include <AK/JsonValue.h>
 #include <AK/String.h>
 
@@ -107,59 +105,13 @@ public:
 
     bool remove(StringView key);
 
-    template<typename Builder>
-    typename Builder::OutputType serialized() const;
-
-    template<typename Builder>
-    void serialize(Builder&) const;
+    String serialized() const;
+    void serialize(StringBuilder&) const;
 
 private:
     OrderedHashMap<String, JsonValue> m_members;
 };
 
-template<typename Builder>
-inline void JsonObject::serialize(Builder& builder) const
-{
-    auto serializer = MUST(JsonObjectSerializer<>::try_create(builder));
-    for_each_member([&](auto& key, auto& value) {
-        MUST(serializer.add(key, value));
-    });
-    MUST(serializer.finish());
-}
-
-template<typename Builder>
-inline typename Builder::OutputType JsonObject::serialized() const
-{
-    Builder builder;
-    serialize(builder);
-    return builder.to_byte_string();
-}
-
-template<typename Builder>
-inline void JsonValue::serialize(Builder& builder) const
-{
-    m_value.visit(
-        [&](Empty const&) { builder.append("null"sv); },
-        [&](bool const& value) { builder.append(value ? "true"sv : "false"sv); },
-        [&](Arithmetic auto const& value) { builder.appendff("{}", value); },
-        [&](String const& value) {
-            builder.append('\"');
-            builder.append_escaped_for_json(value.bytes());
-            builder.append('\"');
-        },
-        [&](auto const& array_or_object) {
-            array_or_object->serialize(builder);
-        });
-}
-
-template<typename Builder>
-inline typename Builder::OutputType JsonValue::serialized() const
-{
-    Builder builder;
-    serialize(builder);
-    return builder.to_byte_string();
-}
-
 }
 
 #if USING_AK_GLOBALLY

AK/JsonValue.cpp

@@ -9,6 +9,7 @@
 #include <AK/JsonObject.h>
 #include <AK/JsonParser.h>
 #include <AK/JsonValue.h>
+#include <AK/StringBuilder.h>
 #include <AK/StringView.h>
 
 namespace AK {
@@ -192,4 +193,28 @@ ErrorOr<JsonValue> JsonValue::from_string(StringView input)
     return JsonParser(input).parse();
 }
 
+String JsonValue::serialized() const
+{
+    StringBuilder builder;
+    serialize(builder);
+
+    return MUST(builder.to_string());
+}
+
+void JsonValue::serialize(StringBuilder& builder) const
+{
+    m_value.visit(
+        [&](Empty const&) { builder.append("null"sv); },
+        [&](bool const& value) { builder.append(value ? "true"sv : "false"sv); },
+        [&](Arithmetic auto const& value) { builder.appendff("{}", value); },
+        [&](String const& value) {
+            builder.append('\"');
+            builder.append_escaped_for_json(value.bytes());
+            builder.append('\"');
+        },
+        [&](auto const& array_or_object) {
+            array_or_object->serialize(builder);
+        });
+}
+
 }

AK/JsonValue.h

@@ -11,7 +11,6 @@
 #include <AK/NonnullOwnPtr.h>
 #include <AK/Optional.h>
 #include <AK/String.h>
-#include <AK/StringBuilder.h>
 
 namespace AK {
 
@@ -77,10 +76,8 @@ public:
     JsonValue& operator=(JsonArray&&);
     JsonValue& operator=(JsonObject&&);
 
-    template<typename Builder>
-    typename Builder::OutputType serialized() const;
-    template<typename Builder>
-    void serialize(Builder&) const;
+    String serialized() const;
+    void serialize(StringBuilder&) const;
 
     Optional<int> get_int() const { return get_integer<int>(); }
     Optional<i32> get_i32() const { return get_integer<i32>(); }
@@ -224,7 +221,7 @@ template<>
 struct Formatter<JsonValue> : Formatter<StringView> {
     ErrorOr<void> format(FormatBuilder& builder, JsonValue const& value)
     {
-        return Formatter<StringView>::format(builder, value.serialized<StringBuilder>());
+        return Formatter<StringView>::format(builder, value.serialized());
     }
 };
 

AK/StringBuilder.h

@@ -19,7 +19,6 @@ public:
     static constexpr size_t inline_capacity = 256;
 
     using Buffer = Detail::ByteBuffer<inline_capacity>;
-    using OutputType = ByteString;
 
     static ErrorOr<StringBuilder> create(size_t initial_capacity = inline_capacity);
 

Libraries/LibCore/ArgsParser.cpp

@@ -754,7 +754,7 @@ void ArgsParser::autocomplete(FILE* file, StringView program_name, ReadonlySpan<
         object.set("invariant_offset"sv, has_invariant ? option_to_complete.length() : 0u);
         object.set("display_trivia"sv, StringView { option.help_string, strlen(option.help_string) });
         object.set("trailing_trivia"sv, option.argument_mode == OptionArgumentMode::Required ? " "sv : ""sv);
-        outln(file, "{}", object.serialized<StringBuilder>());
+        outln(file, "{}", object.serialized());
     };
 
     if (option_to_complete.starts_with("--"sv)) {

Libraries/LibDevTools/Connection.cpp

@@ -7,7 +7,6 @@
 #include <AK/Debug.h>
 #include <AK/JsonObject.h>
 #include <AK/JsonValue.h>
-#include <AK/StringBuilder.h>
 #include <LibCore/EventLoop.h>
 #include <LibDevTools/Connection.h>
 
@@ -34,7 +33,7 @@ Connection::~Connection() = default;
 // https://firefox-source-docs.mozilla.org/devtools/backend/protocol.html#packets
 void Connection::send_message(JsonValue const& message)
 {
-    auto serialized = message.serialized<StringBuilder>();
+    auto serialized = message.serialized();
 
     if constexpr (DEVTOOLS_DEBUG) {
         if (message.is_object() && message.as_object().get("error"sv).has_value())
@@ -43,7 +42,7 @@ void Connection::send_message(JsonValue const& message)
             dbgln("\x1b[1;32m<<\x1b[0m {}", serialized);
     }
 
-    if (m_socket->write_formatted("{}:{}", serialized.length(), serialized).is_error()) {
+    if (m_socket->write_formatted("{}:{}", serialized.byte_count(), serialized).is_error()) {
         if (on_connection_closed)
             on_connection_closed();
     }

Libraries/LibIPC/Encoder.cpp

@@ -82,7 +82,7 @@ ErrorOr<void> encode(Encoder& encoder, ByteBuffer const& value)
 template<>
 ErrorOr<void> encode(Encoder& encoder, JsonValue const& value)
 {
-    return encoder.encode(value.serialized<StringBuilder>());
+    return encoder.encode(value.serialized());
 }
 
 template<>

Libraries/LibTest/TestRunner.h

@@ -274,7 +274,7 @@ inline void TestRunner::print_test_results_as_json() const
         root.set("files_total"sv, m_counts.files_total);
         root.set("duration"sv, m_total_elapsed_time_in_ms / 1000.0);
     }
-    outln("{}", root.serialized<StringBuilder>());
+    outln("{}", root.serialized());
 }
 
 }

Libraries/LibWeb/WebDriver/Client.cpp

@@ -298,7 +298,7 @@ ErrorOr<void, Client::WrappedError> Client::send_success_response(HTTP::HttpRequ
         keep_alive = it->value.trim_whitespace().equals_ignoring_ascii_case("keep-alive"sv);
 
     result = make_success_response(move(result));
-    auto content = result.serialized<StringBuilder>();
+    auto content = result.serialized();
 
     StringBuilder builder;
     builder.append("HTTP/1.1 200 OK\r\n"sv);
@@ -309,7 +309,7 @@ ErrorOr<void, Client::WrappedError> Client::send_success_response(HTTP::HttpRequ
         builder.append("Connection: keep-alive\r\n"sv);
     builder.append("Cache-Control: no-cache\r\n"sv);
     builder.append("Content-Type: application/json; charset=utf-8\r\n"sv);
-    builder.appendff("Content-Length: {}\r\n", content.length());
+    builder.appendff("Content-Length: {}\r\n", content.byte_count());
     builder.append("\r\n"sv);
     builder.append(content);
 
@@ -338,13 +338,13 @@ ErrorOr<void, Client::WrappedError> Client::send_error_response(HTTP::HttpReques
     JsonObject result;
     result.set("value"sv, move(error_response));
 
-    auto content = result.serialized<StringBuilder>();
+    auto content = result.serialized();
 
     StringBuilder builder;
     builder.appendff("HTTP/1.1 {} {}\r\n", error.http_status, reason);
     builder.append("Cache-Control: no-cache\r\n"sv);
     builder.append("Content-Type: application/json; charset=utf-8\r\n"sv);
-    builder.appendff("Content-Length: {}\r\n", content.length());
+    builder.appendff("Content-Length: {}\r\n", content.byte_count());
     builder.append("\r\n"sv);
     builder.append(content);
 

Tests/AK/TestJSON.cpp

@@ -160,13 +160,13 @@ TEST_CASE(json_duplicate_keys)
     json.set("test"sv, "foo"sv);
     json.set("test"sv, "bar"sv);
     json.set("test"sv, "baz"sv);
-    EXPECT_EQ(json.serialized<StringBuilder>(), "{\"test\":\"baz\"}");
+    EXPECT_EQ(json.serialized(), "{\"test\":\"baz\"}");
 }
 
 TEST_CASE(json_u64_roundtrip)
 {
     auto big_value = 0xffffffffffffffffull;
-    auto json = JsonValue(big_value).serialized<StringBuilder>();
+    auto json = JsonValue(big_value).serialized();
     auto value = JsonValue::from_string(json);
     EXPECT_EQ_FORCE(value.is_error(), false);
     EXPECT_EQ(value.value().as_integer<u64>(), big_value);
@@ -531,7 +531,7 @@ TEST_CASE(json_array_serialized)
     auto raw_json = R"(["Hello",2,3.14,4,"World"])"sv;
     auto json_value = MUST(JsonValue::from_string(raw_json));
     auto array = json_value.as_array();
-    auto const& serialized_json = array.serialized<StringBuilder>();
+    auto const& serialized_json = array.serialized();
     EXPECT_EQ(serialized_json, raw_json);
 }
 

Tests/LibJS/test262-runner.cpp

@@ -532,7 +532,7 @@ static bool g_in_assert = false;
         assert_fail_result.set("assert_fail"sv, true);
         assert_fail_result.set("result"sv, "assert_fail"sv);
         assert_fail_result.set("output"sv, StringView { assert_failed_message, strlen(assert_failed_message) });
-        outln(saved_stdout_fd, "RESULT {}{}", assert_fail_result.serialized<StringBuilder>(), '\0');
+        outln(saved_stdout_fd, "RESULT {}{}", assert_fail_result.serialized(), '\0');
         // (Attempt to) Ensure that messages are written before quitting.
         fflush(saved_stdout_fd);
         fflush(stderr);
@@ -733,7 +733,7 @@ int main(int argc, char** argv)
         result_object.set("test"sv, path);
 
         ScopeGuard output_guard = [&] {
-            outln(saved_stdout_fd, "RESULT {}{}", result_object.serialized<StringBuilder>(), '\0');
+            outln(saved_stdout_fd, "RESULT {}{}", result_object.serialized(), '\0');
             fflush(saved_stdout_fd);
         };