[refactor] reorganize platform and wire sources

apps/desktop/src/platform/macos/path_backend.cpp

@@ -0,0 +1,48 @@
+#include "platform/path_backend.h"
+
+#include <mach-o/dyld.h>
+
+#include <cstdlib>
+#include <vector>
+
+namespace crossdesk::platform {
+namespace {
+
+std::filesystem::path Home() {
+  const char* value = std::getenv("HOME");
+  return value ? std::filesystem::path(value) : std::filesystem::path();
+}
+
+std::filesystem::path EnvOrDefault(const char* name,
+                                   const std::filesystem::path& fallback) {
+  const char* value = std::getenv(name);
+  return value ? std::filesystem::path(value) : fallback;
+}
+
+}  // namespace
+
+std::filesystem::path GetExecutableDirectory() {
+  uint32_t size = 0;
+  _NSGetExecutablePath(nullptr, &size);
+  std::vector<char> buffer(size + 1);
+  if (_NSGetExecutablePath(buffer.data(), &size) != 0) return {};
+  std::error_code error;
+  std::filesystem::path executable =
+      std::filesystem::weakly_canonical(buffer.data(), error);
+  if (error) executable = buffer.data();
+  return executable.parent_path();
+}
+
+std::filesystem::path GetConfigPath(const std::string& app_name) {
+  return EnvOrDefault("XDG_CONFIG_HOME", Home() / ".config") / app_name;
+}
+
+std::filesystem::path GetCachePath(const std::string& app_name) {
+  return EnvOrDefault("XDG_CACHE_HOME", Home() / ".cache") / app_name;
+}
+
+std::filesystem::path GetLogPath(const std::string& app_name) {
+  return Home() / "Library" / "Logs" / app_name;
+}
+
+}  // namespace crossdesk::platform