thumbnail preview fixes windows (Stirling-Tools#6074)

Author: Frooodle

app/common/src/main/java/stirling/software/common/util/ProcessExecutor.java

@@ -282,8 +282,9 @@ public ProcessExecutorResult runCommandWithOutputHandling(
             boolean finished = process.waitFor(timeoutDuration, TimeUnit.MINUTES);
 
             if (!finished) {
-                // Terminate the process
-                process.destroy();
+                // Kill the entire process tree (descendants first, then the process itself)
+                process.descendants().forEach(ProcessHandle::destroyForcibly);
+                process.destroyForcibly();
                 // Interrupt the reader threads
                 errorReaderThread.interrupt();
                 outputReaderThread.interrupt();

docker/embedded/compose/test_cicd.yml

@@ -5,10 +5,6 @@ services:
     build:
       context: ../../../
       dockerfile: docker/embedded/Dockerfile.fat
-    deploy:
-      resources:
-        limits:
-          memory: 4G
     healthcheck:
       test: ["CMD-SHELL", "curl -f -H 'X-API-KEY: 123456789' http://localhost:8080${SYSTEM_ROOTURIPATH:-''}/api/v1/info/status | grep -q 'UP'"]
       interval: 5s

frontend/scripts/build-provisioner.mjs

@@ -22,3 +22,15 @@ mkdirSync(wixDir, { recursive: true });
 
 const destExe = join(wixDir, "stirling-provision.exe");
 copyFileSync(provisionerExe, destExe);
+
+// --- Thumbnail handler DLL ---
+const thumbManifest = join(tauriDir, "thumbnail-handler", "Cargo.toml");
+
+execFileSync("cargo", ["build", "--release", "--manifest-path", thumbManifest], { stdio: "inherit" });
+
+const thumbDll = join(tauriDir, "thumbnail-handler", "target", "release", "stirling_thumbnail_handler.dll");
+if (!existsSync(thumbDll)) {
+  throw new Error(`Thumbnail handler DLL not found at ${thumbDll}`);
+}
+
+copyFileSync(thumbDll, join(wixDir, "stirling_thumbnail_handler.dll"));

frontend/src-tauri/thumbnail-handler/.gitignore

@@ -0,0 +1 @@
+/target

frontend/src-tauri/thumbnail-handler/Cargo.lock

@@ -0,0 +1,26 @@
+[package]
+name = "stirling-thumbnail-handler"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies.windows]
+version = "0.58"
+features = [
+    "implement",
+    "Win32_Foundation",
+    "Win32_System_Com",
+    "Win32_System_Com_StructuredStorage",
+    "Win32_Graphics_Gdi",
+    "Win32_Graphics_Imaging",
+    "Win32_UI_Shell",
+    "Win32_UI_Shell_PropertiesSystem",
+    "Storage_Streams",
+    "Data_Pdf",
+    "Foundation",
+]
+
+[dependencies]
+windows-core = "0.58"

frontend/src-tauri/thumbnail-handler/Cargo.toml

@@ -0,0 +1,61 @@
+# Windows PDF Thumbnail Handler
+
+A lightweight COM DLL that provides PDF page-preview thumbnails in Windows Explorer when Stirling-PDF is the default PDF application.
+
+## Why this exists
+
+When Stirling-PDF registers as the default PDF handler, Windows associates `.pdf` files with Stirling's ProgID. Without a thumbnail handler on that ProgID, Explorer falls back to showing the application icon (the big S logo) instead of a page preview. This DLL restores thumbnail previews by implementing the Windows Shell `IThumbnailProvider` COM interface.
+
+## How it works
+
+1. **Explorer requests a thumbnail** — when a folder with PDFs is opened in Medium/Large icon view, Explorer loads the DLL via the registered COM CLSID.
+2. **Shell calls `IInitializeWithStream`** — passes the PDF file content as an `IStream`.
+3. **Shell calls `IThumbnailProvider::GetThumbnail(cx)`** — requests a bitmap of size `cx × cx`.
+4. **The DLL renders page 1** using the built-in `Windows.Data.Pdf` WinRT API (the same engine Edge uses), preserving aspect ratio.
+5. **WIC decodes the rendered PNG** into BGRA pixels, which are copied into an `HBITMAP` via `CreateDIBSection`.
+6. **Explorer displays the bitmap** as the file's thumbnail.
+
+All COM methods are wrapped in `catch_unwind` so a malformed PDF cannot crash Explorer.
+
+## Technical details
+
+| | |
+|---|---|
+| **Language** | Rust (cdylib) |
+| **DLL size** | ~156 KB |
+| **External deps** | None — uses only Windows built-in APIs |
+| **PDF renderer** | `Windows.Data.Pdf` (WinRT, Windows 10+) |
+| **Image decode** | WIC (`IWICImagingFactory`) with BGRA32 format conversion |
+| **COM CLSID** | `{2D2FBE3A-9A88-4308-A52E-7EF63CA7CF48}` |
+| **Threading model** | Apartment (STA — standard for shell extensions) |
+| **Min Windows** | Windows 10 |
+
+## Registry entries (managed by MSI)
+
+The WiX installer (`provisioning.wxs`) registers:
+
+- **CLSID** at `HKLM\SOFTWARE\Classes\CLSID\{2D2FBE3A-...}\InprocServer32` pointing to the DLL
+- **Shellex** at `HKLM\SOFTWARE\Classes\.pdf\shellex\{E357FCCD-...}` linking `.pdf` thumbnails to our CLSID
+
+Both are automatically removed on uninstall.
+
+## Building
+
+The DLL is built automatically as part of the Tauri build pipeline via `build-provisioner.mjs`:
+
+```bash
+cd frontend
+npm run tauri-build
+```
+
+To build the DLL standalone:
+
+```bash
+cd frontend/src-tauri/thumbnail-handler
+cargo build --release
+# Output: target/release/stirling_thumbnail_handler.dll
+```
+
+## Linux / macOS
+
+This DLL is Windows-only. Linux and macOS don't need it — their thumbnail systems (thumbnailers on Linux, Quick Look on macOS) are decoupled from the default app association and continue working regardless of which app is set as default.