LibTimeZone+Meta: Add plumbing for an IANA Time Zone Database generator

The IANA Time Zone Database contains data needed, at least, for various
JavaScript objects. This adds plumbing for a parser and code generator
for this data. The generated data will be made available by LibTimeZone,
much like how UCD and CLDR data is available through LibUnicode.

Meta/Lagom/CMakeLists.txt

@@ -216,6 +216,11 @@ function(lagom_test source)
     )
 endfunction()
 
+if (NOT TARGET all_generated)
+    # Meta target to run all code-gen steps in the build.
+    add_custom_target(all_generated)
+endif()
+
 # AK/Core
 # Note: AK is included in LagomCore for the host build instead of LibC per the target build
 file(GLOB AK_SOURCES CONFIGURE_DEPENDS "../../AK/*.cpp")
@@ -240,6 +245,19 @@ if (APPLE)
     target_link_options(LagomMain PRIVATE -undefined dynamic_lookup)
 endif()
 
+# TimeZone
+# This is needed even if Lagom is not enabled because it is depended upon by code generators.
+if (NOT ENABLE_OSS_FUZZ AND NOT ENABLE_FUZZER_SANITIZER)
+    include(time_zone_data)
+else()
+    set(ENABLE_TIME_ZONE_DATABASE_DOWNLOAD OFF)
+endif()
+file(GLOB LIBTIMEZONE_SOURCES CONFIGURE_DEPENDS "../../Userland/Libraries/LibTimeZone/*.cpp")
+lagom_lib(TimeZone timezone
+    SOURCES ${LIBTIMEZONE_SOURCES} ${TIME_ZONE_DATA_SOURCES}
+)
+target_compile_definitions(LagomTimeZone PRIVATE ENABLE_TIME_ZONE_DATA=$<BOOL:${ENABLE_TIME_ZONE_DATABASE_DOWNLOAD}>)
+
 # Manually install AK headers
 install(
     DIRECTORY "${SERENITY_PROJECT_ROOT}/AK"
@@ -255,12 +273,6 @@ if (NOT ENABLE_OSS_FUZZ AND NOT ENABLE_FUZZER_SANITIZER)
 endif()
 
 if (BUILD_LAGOM)
-
-    if (NOT TARGET all_generated)
-        # Meta target to run all code-gen steps in the build.
-        add_custom_target(all_generated)
-    endif()
-
     # Lagom Libraries
 
     # Archive

Meta/Lagom/Tools/CodeGenerators/CMakeLists.txt

@@ -1,4 +1,5 @@
 add_subdirectory(IPCCompiler)
+add_subdirectory(LibTimeZone)
 add_subdirectory(LibUnicode)
 add_subdirectory(LibWeb)
 add_subdirectory(StateMachineGenerator)

Meta/Lagom/Tools/CodeGenerators/LibTimeZone/CMakeLists.txt

@@ -0,0 +1 @@
+lagom_tool(GenerateTimeZoneData SOURCES GenerateTimeZoneData.cpp LIBS LagomMain)

Meta/Lagom/Tools/CodeGenerators/LibTimeZone/GenerateTimeZoneData.cpp

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2022, Tim Flynn <trflynn89@pm.me>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/SourceGenerator.h>
+#include <AK/String.h>
+#include <AK/StringBuilder.h>
+#include <AK/Vector.h>
+#include <LibCore/ArgsParser.h>
+#include <LibCore/File.h>
+
+static void generate_time_zone_data_header(Core::File& file)
+{
+    StringBuilder builder;
+    SourceGenerator generator { builder };
+
+    generator.append(R"~~~(
+#pragma once
+)~~~");
+
+    VERIFY(file.write(generator.as_string_view()));
+}
+
+static void generate_time_zone_data_implementation(Core::File& file)
+{
+    StringBuilder builder;
+    SourceGenerator generator { builder };
+
+    generator.append(R"~~~(
+#include <LibTimeZone/TimeZoneData.h>
+)~~~");
+
+    VERIFY(file.write(generator.as_string_view()));
+}
+
+ErrorOr<int> serenity_main(Main::Arguments arguments)
+{
+    StringView generated_header_path;
+    StringView generated_implementation_path;
+    Vector<StringView> time_zone_paths;
+
+    Core::ArgsParser args_parser;
+    args_parser.add_option(generated_header_path, "Path to the time zone data header file to generate", "generated-header-path", 'h', "generated-header-path");
+    args_parser.add_option(generated_implementation_path, "Path to the time zone data implementation file to generate", "generated-implementation-path", 'c', "generated-implementation-path");
+    args_parser.add_positional_argument(time_zone_paths, "Paths to the time zone database files", "time-zone-paths");
+    args_parser.parse(arguments);
+
+    auto open_file = [&](StringView path) -> ErrorOr<NonnullRefPtr<Core::File>> {
+        if (path.is_empty()) {
+            args_parser.print_usage(stderr, arguments.argv[0]);
+            return Error::from_string_literal("Must provide all command line options"sv);
+        }
+
+        return Core::File::open(path, Core::OpenMode::ReadWrite);
+    };
+
+    auto generated_header_file = TRY(open_file(generated_header_path));
+    auto generated_implementation_file = TRY(open_file(generated_implementation_path));
+
+    generate_time_zone_data_header(generated_header_file);
+    generate_time_zone_data_implementation(generated_implementation_file);
+
+    return 0;
+}