[fix] make Xfce optional with separate Linux deb packages, refs #106

apps/desktop/src/version_checker/linux_update_download.cpp

@@ -0,0 +1,55 @@
+#include "linux_update_download.h"
+
+#include <fstream>
+#include <nlohmann/json.hpp>
+
+namespace crossdesk {
+
+std::string LinuxUpdateDownloadUrl(const nlohmann::json& manifest,
+                                   const VersionInfo& latest,
+                                   const std::string& architecture,
+                                   const std::filesystem::path& executable_dir) {
+  const std::string fallback = "https://github.com/kunkundi/crossdesk/releases";
+  if ((architecture != "amd64" && architecture != "arm64") ||
+      executable_dir.empty()) {
+    return fallback;
+  }
+
+  std::string package_name = "crossdesk";
+  const auto marker = executable_dir / "package-name";
+  std::error_code error;
+  const bool has_marker = std::filesystem::exists(marker, error);
+  if (error) return fallback;
+  if (has_marker) {
+    std::ifstream file(marker);
+    if (!std::getline(file, package_name)) return fallback;
+  }
+  std::string key = "linux-" + architecture;
+  if (package_name == "crossdesk-virtual-desktop-xfce") {
+    key += "-virtual-desktop-xfce";
+  } else if (package_name != "crossdesk") {
+    return fallback;
+  }
+
+  try {
+    const auto& download = manifest.at("downloads").at(key);
+    const auto version = ParseVersionInfoJSON(download.dump());
+    // A partial release can leave older downloads in the merged manifest.
+    if (!version || version->version != latest.version ||
+        IsNewerVersionWithMetadata(version->version, latest.version,
+                                   latest.release_date, latest.patch)) {
+      return fallback;
+    }
+    const std::string filename = package_name + "-linux-" + architecture +
+                                 "-v" + latest.version + ".deb";
+    const std::string url = "https://downloads.crossdesk.cn/" + filename;
+    // Verify the variant in the asset name too, not just the manifest key.
+    if (download.at("filename") == filename && download.at("url") == url) {
+      return url;
+    }
+  } catch (const nlohmann::json::exception&) {
+  }
+  return fallback;
+}
+
+}  // namespace crossdesk

apps/desktop/src/version_checker/linux_update_download.h

@@ -0,0 +1,29 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-10-08
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _LINUX_UPDATE_DOWNLOAD_H_
+#define _LINUX_UPDATE_DOWNLOAD_H_
+
+#include <filesystem>
+#include <string>
+
+#include <nlohmann/json_fwd.hpp>
+
+#include "app_version.h"
+
+namespace crossdesk {
+
+// Uses package-name beside the executable, so source builds cannot inherit an
+// unrelated system installation's variant. Missing/invalid downloads open the
+// release list rather than silently offering a different package or old release.
+std::string LinuxUpdateDownloadUrl(const nlohmann::json& manifest,
+                                   const VersionInfo& latest,
+                                   const std::string& architecture,
+                                   const std::filesystem::path& executable_dir);
+
+}  // namespace crossdesk
+
+#endif

apps/desktop/src/version_checker/version_checker.cpp

@@ -10,6 +10,7 @@
 #include <nlohmann/json.hpp>
 
 #include "rd_log.h"
+#include "linux_update_download.h"
 
 #include <cstdlib>
 #include <filesystem>
@@ -118,8 +119,22 @@ std::optional<VersionInfo> CheckUpdate() {
   if (res) {
     if (res->status == 200) {
       try {
-        auto info = ParseVersionInfo(nlohmann::json::parse(res->body));
+        const auto manifest = nlohmann::json::parse(res->body);
+        auto info = ParseVersionInfo(manifest);
         if (info) {
+#if defined(__linux__)
+          std::string architecture;
+#if defined(__x86_64__)
+          architecture = "amd64";
+#elif defined(__aarch64__)
+          architecture = "arm64";
+#endif
+          std::error_code error;
+          const auto executable = std::filesystem::read_symlink("/proc/self/exe", error);
+          info->download_url = LinuxUpdateDownloadUrl(
+              manifest, *info, architecture,
+              error ? std::filesystem::path{} : executable.parent_path());
+#endif
           LOG_INFO("Fetched version.json: latest_version={}, releaseDate={}, patch={}",
                    info->version, info->release_date, info->patch);
         } else {