[refactor] share Windows executable path helpers

apps/desktop/src/app/main.cpp

@@ -17,6 +17,7 @@
 #include <cstdio>
 
 #include "platform/windows/autostart_task.h"
+#include "platform/windows/executable_path.h"
 #include "platform/windows/gui/slint_backend.h"
 #include "platform/windows/runtime_daemon.h"
 #include "platform/windows/service/autostart_control.h"
@@ -95,23 +96,8 @@ void PrintServiceCliUsage() {
          "credentials\n";
 }
 
-std::wstring GetCurrentExecutablePathW() {
-  wchar_t path[MAX_PATH] = {0};
-  DWORD length = GetModuleFileNameW(nullptr, path, MAX_PATH);
-  if (length == 0 || length >= MAX_PATH) {
-    return L"";
-  }
-  return std::wstring(path, length);
-}
-
 std::filesystem::path GetSiblingServiceExecutablePath() {
-  std::wstring current_executable = GetCurrentExecutablePathW();
-  if (current_executable.empty()) {
-    return {};
-  }
-
-  return std::filesystem::path(current_executable).parent_path() /
-         L"crossdesk_service.exe";
+  return crossdesk::platform::SiblingExecutablePath(L"crossdesk_service.exe");
 }
 
 bool IsServiceCliCommand(const char* arg) {
@@ -286,7 +272,7 @@ static int RunApplication(int argc, char* argv[]) {
 #ifdef _WIN32
   crossdesk::get_logger()->info(
       "CrossDesk executable: {}",
-      std::filesystem::path(GetCurrentExecutablePathW()).u8string());
+      std::filesystem::path(crossdesk::platform::CurrentExecutablePath()).u8string());
 #endif
 
   if (IsDaemonChild(argc, argv)) {

apps/desktop/src/platform/windows/autostart.cpp

@@ -11,6 +11,7 @@
 #include <vector>
 
 #include "autostart_task.h"
+#include "executable_path.h"
 #include "rd_log.h"
 
 namespace crossdesk::platform {
@@ -185,11 +186,7 @@ bool RemoveLogonTask(const std::wstring& app_name) {
 }  // namespace
 
 std::string GetAutostartExecutablePath() {
-  std::vector<wchar_t> path(32768);
-  const DWORD length =
-      GetModuleFileNameW(nullptr, path.data(), static_cast<DWORD>(path.size()));
-  if (length == 0 || length >= path.size()) return {};
-  return std::filesystem::path(path.data(), path.data() + length).u8string();
+  return std::filesystem::path(CurrentExecutablePath()).u8string();
 }
 
 bool EnableAutostart(const std::string& app_name,

apps/desktop/src/platform/windows/executable_path.h

@@ -0,0 +1,30 @@
+#ifndef CROSSDESK_PLATFORM_WINDOWS_EXECUTABLE_PATH_H_
+#define CROSSDESK_PLATFORM_WINDOWS_EXECUTABLE_PATH_H_
+
+#include <windows.h>
+
+#include <filesystem>
+#include <string>
+#include <vector>
+
+namespace crossdesk::platform {
+
+// Full path of this process image, including long paths; empty on failure.
+inline std::wstring CurrentExecutablePath() {
+  std::vector<wchar_t> path(32768);
+  const DWORD length = GetModuleFileNameW(nullptr, path.data(),
+                                          static_cast<DWORD>(path.size()));
+  if (length == 0 || length >= path.size()) return {};
+  return {path.data(), length};
+}
+
+// A file installed next to this executable; empty if the path is unknown.
+inline std::filesystem::path SiblingExecutablePath(const wchar_t* name) {
+  const auto executable = CurrentExecutablePath();
+  if (executable.empty()) return {};
+  return std::filesystem::path(executable).parent_path() / name;
+}
+
+}  // namespace crossdesk::platform
+
+#endif

apps/desktop/src/platform/windows/runtime_daemon.cpp

@@ -1,5 +1,7 @@
 #include "platform/windows/runtime_daemon.h"
 
+#include "platform/windows/executable_path.h"
+
 #include <shellapi.h>
 
 #include <cerrno>
@@ -25,14 +27,6 @@ struct Arguments {
   ~Arguments() { if (values) LocalFree(values); }
 };
 
-std::wstring ExecutablePath() {
-  std::vector<wchar_t> path(32768);
-  const DWORD count = GetModuleFileNameW(nullptr, path.data(),
-                                        static_cast<DWORD>(path.size()));
-  if (!count || count >= path.size()) return {};
-  return {path.data(), count};
-}
-
 std::wstring QuoteArgument(const std::wstring& value) {
   std::wstring result = L"\"";
   size_t slashes = 0;
@@ -130,7 +124,7 @@ WindowsRuntimeDaemon::~WindowsRuntimeDaemon() { Shutdown(); }
 void WindowsRuntimeDaemon::Initialize() {
   std::lock_guard<std::mutex> lock(mutex_);
   initialized_ = true;
-  executable_ = ExecutablePath();
+  executable_ = CurrentExecutablePath();
   arguments_.clear();
   Arguments arguments;
   if (!arguments.values) {
@@ -273,7 +267,7 @@ int RunWindowsRuntimeDaemon() {
       return 1;
     }
   }
-  const auto executable = ExecutablePath();
+  const auto executable = CurrentExecutablePath();
   if (executable.empty()) return 1;
   std::wstring command = QuoteArgument(executable);
   for (int i = 5; i < arguments.count; ++i)