Fix preview handlers failing when PowerToys is installed in AppData\Local directory

src/common/utils/modulesRegistry.h

@@ -8,6 +8,9 @@
 
 namespace fs = std::filesystem;
 
+// Import path normalization function from registry namespace
+using registry::shellex::normalizePathForComRegistration;
+
 namespace NonLocalizable
 {
     const static wchar_t* MONACO_LANGUAGES_FILE_NAME = L"Assets\\Monaco\\monaco_languages.json";
@@ -240,10 +243,11 @@ inline registry::ChangeSet getRegistryPreviewSetDefaultAppChangeSet(const std::w
     std::wstring registryKeyPrefix = L"Software\\Classes\\";
 
     std::wstring appPath = installationDir + L"\\WinUI3Apps\\PowerToys.RegistryPreview.exe";
-    std::wstring command = appPath + L" \"----ms-protocol:ms-encodedlaunch:App?ContractId=Windows.File&Verb=open&File=%1\"";
+    std::wstring normalizedAppPath = normalizePathForComRegistration(appPath);
+    std::wstring command = normalizedAppPath + L" \"----ms-protocol:ms-encodedlaunch:App?ContractId=Windows.File&Verb=open&File=%1\"";
 
     changes.push_back({ scope, registryKeyPrefix + fullAppName + L"\\" + L"Application", L"ApplicationName", appName });
-    changes.push_back({ scope, registryKeyPrefix + fullAppName + L"\\" + L"DefaultIcon", std::nullopt, appPath });
+    changes.push_back({ scope, registryKeyPrefix + fullAppName + L"\\" + L"DefaultIcon", std::nullopt, normalizedAppPath });
     changes.push_back({ scope, registryKeyPrefix + fullAppName + L"\\" + L"shell\\open\\command", std::nullopt, command });
     changes.push_back({ scope, registryKeyPrefix + L".reg\\OpenWithProgIDs", fullAppName, L"" });
 
@@ -257,13 +261,15 @@ inline registry::ChangeSet getRegistryPreviewChangeSet(const std::wstring instal
     using vec_t = std::vector<registry::ValueChange>;
     vec_t changes;
 
-    std::wstring command = installationDir;
-    command.append(L"\\WinUI3Apps\\PowerToys.RegistryPreview.exe \"%1\"");
+    std::wstring exePath = installationDir + L"\\WinUI3Apps\\PowerToys.RegistryPreview.exe";
+    std::wstring normalizedExePath = normalizePathForComRegistration(exePath);
+    std::wstring command = normalizedExePath + L" \"%1\"";
     changes.push_back({ scope, L"Software\\Classes\\regfile\\shell\\preview\\command", std::nullopt, command });
 
     std::wstring icon_path = installationDir;
     icon_path.append(L"\\WinUI3Apps\\Assets\\RegistryPreview\\RegistryPreview.ico");
-    changes.push_back({ scope, L"Software\\Classes\\regfile\\shell\\preview", L"icon", icon_path });
+    std::wstring normalizedIconPath = normalizePathForComRegistration(icon_path);
+    changes.push_back({ scope, L"Software\\Classes\\regfile\\shell\\preview", L"icon", normalizedIconPath });
 
     return { changes };
 }

src/common/utils/registry.h

@@ -387,6 +387,37 @@ namespace registry
             thumbnail
         };
 
+        // Helper function to properly quote DLL paths for COM registration
+        inline std::wstring quotePathIfNeeded(const std::wstring& path)
+        {
+            // If path contains spaces, it should be quoted for proper COM registration
+            if (path.find(L' ') != std::wstring::npos)
+            {
+                return L"\"" + path + L"\"";
+            }
+            return path;
+        }
+
+        // Helper function to normalize and resolve DLL paths for COM registration
+        inline std::wstring normalizePathForComRegistration(const std::wstring& path)
+        {
+            try 
+            {
+                // Normalize the path to handle any relative components or inconsistencies
+                auto normalizedPath = std::filesystem::canonical(std::filesystem::path(path));
+                auto pathStr = normalizedPath.wstring();
+
+                // Quote if needed and return
+                return quotePathIfNeeded(pathStr);
+            }
+            catch (const std::filesystem::filesystem_error&)
+            {
+                // If canonicalization fails (file doesn't exist), fall back to the original path
+                // This can happen during installation when files aren't copied yet
+                return quotePathIfNeeded(path);
+            }
+        }
+
         inline registry::ChangeSet generatePreviewHandler(const PreviewHandlerType handlerType,
                                                           const bool perUser,
                                                           std::wstring handlerClsid,
@@ -426,11 +457,17 @@ namespace registry
             versionPath += L'\\';
             versionPath += powertoysVersion;
 
+            // Normalize and quote the DLL path to ensure proper COM registration
+            std::wstring normalizedPathToHandler = normalizePathForComRegistration(fullPathToHandler);
+
+            // Log the path transformation for debugging
+            Logger::info(L"Registering preview handler: {} -> {}", fullPathToHandler, normalizedPathToHandler);
+
             using vec_t = std::vector<registry::ValueChange>;
             // TODO: verify that we actually need all of those
             vec_t changes = { { scope, clsidPath, L"DisplayName", displayName },
                               { scope, clsidPath, std::nullopt, className },
-                              { scope, inprocServerPath, std::nullopt, fullPathToHandler },
+                              { scope, inprocServerPath, std::nullopt, normalizedPathToHandler },
                               { scope, inprocServerPath, L"Assembly", assemblyKeyValue },
                               { scope, inprocServerPath, L"Class", className },
                               { scope, inprocServerPath, L"ThreadingModel", L"Apartment" } };
@@ -467,6 +504,20 @@ namespace registry
 
                 changes.push_back({ scope, clsidPath, L"AppID", previewHostClsid });
                 changes.push_back({ scope, previewHandlerListPath, handlerClsid, displayName });
+
+                // For user-directory installations, add additional AppID configuration to ensure proper COM activation
+                if (perUser)
+                {
+                    std::wstring appIdPath = L"Software\\Classes\\AppID\\" + previewHostClsid;
+                    // These settings help ensure the preview handler can be activated properly from different security contexts
+                    changes.push_back({ scope, appIdPath, L"DllSurrogate", L"" }); // Use default surrogate (prevhost.exe)
+                    changes.push_back({ scope, appIdPath, L"AppIDFlags", DWORD(0x4) }); // APPIDREGFLAGS_ACTIVATE_IUSERVER_INDESKTOP
+
+                    // Add authentication level to ensure proper security context
+                    changes.push_back({ scope, appIdPath, L"AuthenticationLevel", DWORD(1) }); // RPC_C_AUTHN_LEVEL_NONE
+
+                    Logger::info(L"Added per-user AppID configuration for preview handler in: {}", normalizedPathToHandler);
+                }
             }
 
             return registry::ChangeSet{ .changes = std::move(changes) };