build(wasm): libconfig now builds and works in wasm

build-config/yaml-cpp/meson.build

@@ -2,17 +2,41 @@ cmake = import('cmake')
 yaml_cpp_cmake_options = cmake.subproject_options()
 
 yaml_cpp_cmake_options.add_cmake_defines({
-        'BUILD_SHARED_LIBS': 'ON',
+        'BUILD_SHARED_LIBS': 'OFF',
+        'BUILD_STATIC_LIBS': 'ON',
         'YAML_CPP_BUILD_TESTS': 'OFF',
         'CMAKE_CXX_FLAGS': '-Wno-shadow',
         'CMAKE_C_FLAGS': '-Wno-shadow',
         'CMAKE_INSTALL_LIBDIR': get_option('libdir'),
         'CMAKE_INSTALL_INCLUDEDIR': get_option('includedir'),
-        'CMAKE_POLICY_VERSION_MINIMUM': '3.5'
+        'CMAKE_POLICY_VERSION_MINIMUM': '3.5',
+        'CMAKE_POSITION_INDEPENDENT_CODE': 'ON'
     })
 
 yaml_cpp_sp = cmake.subproject(
     'yaml-cpp',
     options: yaml_cpp_cmake_options,
 )
-yaml_cpp_dep = yaml_cpp_sp.dependency('yaml-cpp')
+
+
+yaml_cpp_tgt = yaml_cpp_sp.target('yaml-cpp')
+yaml_cpp_inc = yaml_cpp_sp.include_directories('yaml-cpp')
+empty_yaml_cpp_file = configure_file(
+  output: 'yaml_cpp_dummy_ar.cpp',
+  command: ['echo'],
+  capture: true
+  )
+libyaml_static = static_library(
+   'yaml_cpp-static',
+   empty_yaml_cpp_file,
+   objects: [yaml_cpp_tgt.extract_all_objects(recursive: true)],
+   include_directories: yaml_cpp_inc,
+   pic: true,
+   install: false
+)
+
+
+yaml_cpp_dep = declare_dependency(
+  link_with: libyaml_static,
+  include_directories: yaml_cpp_inc,
+)

cross/macos_arm64.ini

@@ -0,0 +1,19 @@
+[binaries]
+c = 'arm64-apple-darwin25-clang'
+cpp = 'arm64-apple-darwin25-clang++'
+ar = 'arm64-apple-darwin25-ar'
+strip = 'arm64-apple-darwin25-strip'
+pkg-config = 'pkg-config'
+ranlib = '/usr/bin/true'
+
+[host_machine]
+system = 'darwin'
+cpu_family = 'aarch64'
+cpu = 'arm64'
+endian = 'little'
+
+[built-in options]
+c_args = ['-mmacosx-version-min=15.0']
+cpp_args = ['-mmacos-version-min=15.0']
+c_link_args = ['-mmacosx-version-min=15.0']
+cpp_link_args = ['-mmacos-version-min=15.0']

cross/wasm.ini

@@ -0,0 +1,19 @@
+[binaries]
+cpp = 'em++'
+ar = 'emar'
+strip = 'emstrip'
+
+exec_wrapper = 'node'
+
+[built-in options]
+cpp_args = ['-Dpkg_config=false', '-Dbuild_tests=false', '-Dbuild_examples=true', '-fwasm-exceptions', '-s', 'MEMORY64=1']
+cpp_link_args = ['-s', 'WASM=1', '-s', 'ALLOW_MEMORY_GROWTH=1', '-s', 'MEMORY64=1', '-fwasm-exceptions', '-s', 'EXPORTED_RUNTIME_METHODS=["FS", "callMain"]', '-s', 'INVOKE_RUN=0']
+
+[host_machine]
+system = 'emscripten'
+cpu_family = 'wasm64'
+cpu = 'wasm64'
+endian = 'little'
+
+[properties]
+cmake_toolchain_file = '/home/tboudreaux/Programming/emsdk/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake'

examples/config_example.yml

@@ -0,0 +1,4 @@
+men: ["John Smith", "Bill Jones"]
+women:
+  - Karol Boudreaux
+  - Emily Boudreaux

examples/meson.build

@@ -0,0 +1,2 @@
+executable('simple_config_test', 'simple.cpp', dependencies: [config_dep])
+executable('simple_config_wasm_test', 'wasm.cpp', dependencies: [config_dep])

examples/simple.cpp

@@ -0,0 +1,35 @@
+#include "fourdst/config/config.h"
+#include <string>
+#include <vector>
+#include <iostream>
+#include <filesystem>
+
+std::string get_validated_filename(int argc, char* argv[]) {
+    if (argc != 2) {
+        std::cout << "Usage: " << argv[0] << " <input_file>" << std::endl;
+        exit(1);
+    }
+
+    std::filesystem::path const file_path{ argv[1] };
+
+    if (not std::filesystem::exists(file_path) || not std::filesystem::is_regular_file(file_path)) {
+        std::cout << "Error: File does not exist or is not a regular file." << std::endl;
+        exit(1);
+    }
+
+    return file_path.string();
+}
+
+int main(int argc, char* argv[]) {
+  fourdst::config::Config& config = fourdst::config::Config::getInstance();
+
+  std::string filename = get_validated_filename(argc, argv);
+  config.loadConfig(filename);
+
+  auto men = config.get<std::vector<std::string>>("men", {});
+
+  for (const auto& name : men) {
+    std::cout << "men are " << name << std::endl;
+  }
+
+}

examples/wasm.cpp

@@ -0,0 +1,19 @@
+#include "fourdst/config/config.h"
+#include <string>
+#include <vector>
+#include <iostream>
+#include <filesystem>
+
+
+int main(int argc, char* argv[]) {
+  fourdst::config::Config& config = fourdst::config::Config::getInstance();
+
+  config.loadConfig("/input.yaml");
+
+  auto men = config.get<std::vector<std::string>>("men", {});
+
+  for (const auto& name : men) {
+    std::cout << "men are " << name << std::endl;
+  }
+
+}

meson.build

@@ -18,7 +18,7 @@
 #   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 #
 # *********************************************************************** #
-project('libconfig', 'cpp', version: 'v1.1.3', default_options: ['cpp_std=c++23'], meson_version: '>=1.5.0')
+project('libconfig', 'cpp', version: 'v1.1.4', default_options: ['cpp_std=c++23'], meson_version: '>=1.5.0')
 
 # Add default visibility for all C++ targets
 add_project_arguments('-fvisibility=default', language: 'cpp')
@@ -26,9 +26,16 @@ add_project_arguments('-fvisibility=default', language: 'cpp')
 cpp = meson.get_compiler('cpp')
 subdir('build-config')
 subdir('src')
-subdir('tests')
 
-if get_option('pkg-config')
+if get_option('build_tests')
+  subdir('tests')
+endif
+
+if get_option('build_examples')
+  subdir('examples')
+endif
+
+if get_option('pkg_config')
     message('Generating pkg-config file for libconfig...')
     pkg = import('pkgconfig')
     pkg.generate(

meson_options.txt

@@ -1 +1,3 @@
-option('pkg-config', type: 'boolean', value: true, description: 'generate pkg-config file for libconfig (fourdst_config.pc)')
+option('pkg_config', type: 'boolean', value: true, description: 'generate pkg-config file for libconfig (fourdst_config.pc)')
+option('build_tests', type: 'boolean', value: true, description: 'Build unit and integration tests (uses gtest)')
+option('build_examples', type: 'boolean', value: true, description: 'Build simple example programs')