feat: implement office thumbnail provider with COM interop and fix Explorer thumbnail issues

Author: Shomnipotence

Cargo.lock

@@ -51,7 +51,11 @@ impl IClassFactory_Impl for ClassFactory {
         if punkouter.is_some() {
             return CLASS_E_NOAGGREGATION.ok();
         }
-        self.provider.create_instance(riid, ppvobject)
+        let res = self.provider.create_instance(riid, ppvobject);
+        if let Ok(mut file) = std::fs::OpenOptions::new().create(true).append(true).open(&temp_log) {
+            let _ = writeln!(file, "[DLL] [PID:{}] ClassFactory::CreateInstance result: {:?}", std::process::id(), res);
+        }
+        res
     }
 
     fn LockServer(&self, _flock: BOOL) -> windows::core::Result<()> {

crates/core/src/lib.rs

@@ -302,7 +302,7 @@ impl IThumbnailProvider_Impl for ThumbnailFileHandler {
             }
         }
 
-        // Create lock file
+        // Create lock file (with current PID initially, will be updated with child PID if spawn succeeds)
         if let Ok(mut f) = std::fs::File::create(&lock_file) {
             let _ = write!(f, "PID: {}", std::process::id());
         }
@@ -330,14 +330,14 @@ impl IThumbnailProvider_Impl for ThumbnailFileHandler {
            .arg("--api").arg("default")
            .arg("--lock-file").arg(&lock_file);
 
-        // if let Ok(mut file) = std::fs::OpenOptions::new().create(true).append(true).open(&temp_log) {
-        //    let _ = writeln!(file, "[ThumbnailFileHandler] [PID:{}] Spawning Async CLI: {:?} -> {:?}", std::process::id(), cli_path, cache_file);
-        // }
-
         // Spawn async
         match cmd.spawn() {
-            Ok(_) => {
-                log_debug("CLI process spawned successfully. Returning E_PENDING.");
+            Ok(child) => {
+                // Update lock file with CLI process PID for better liveness tracking
+                if let Ok(mut f) = std::fs::File::create(&lock_file) {
+                    let _ = write!(f, "PID: {}", child.id());
+                }
+                log_debug(&format!("CLI process spawned successfully (PID: {}). Returning E_PENDING.", child.id()));
                 return Err(windows::core::Error::from(E_PENDING));
             },
             Err(e) => {

crates/windows-dll/src/dll.rs

@@ -1,6 +1,6 @@
 @echo off
 setlocal EnableDelayedExpansion
-chcp 65001 >nul
+REM chcp 65001 >nul
 
 REM Generate a unique log file for this execution
 if defined STEP2OBJ_OUTPUT (
@@ -10,39 +10,39 @@ if defined STEP2OBJ_OUTPUT (
 )
 
 set SCRIPT_DIR=%~dp0
-echo [step2obj] Starting in %SCRIPT_DIR% > "!LOG_FILE!"
-echo [step2obj] Input: %STEP2OBJ_INPUT% >> "!LOG_FILE!"
-echo [step2obj] Output: %STEP2OBJ_OUTPUT% >> "!LOG_FILE!"
-echo [step2obj] Date: %DATE% %TIME% >> "!LOG_FILE!"
+echo [step2obj] Starting in %SCRIPT_DIR% 
+echo [step2obj] Input: %STEP2OBJ_INPUT% 
+echo [step2obj] Output: %STEP2OBJ_OUTPUT% 
+echo [step2obj] Date: %DATE% %TIME% 
 
 REM Check for python command
-where python >> "!LOG_FILE!" 2>&1
-python --version >> "!LOG_FILE!" 2>&1
+where python 
+python --version 
 
 REM Use local Embedded Python (Plan A)
 if exist "%SCRIPT_DIR%python\python.exe" (
-    echo [step2obj] Using local python >> "!LOG_FILE!"
+    echo [step2obj] Using local python 
     set PYTHONIOENCODING=utf-8
-    "%SCRIPT_DIR%python\python.exe" -u "%SCRIPT_DIR%step2obj_occ.py" %* >> "!LOG_FILE!" 2>&1
+    "%SCRIPT_DIR%python\python.exe" -u "%SCRIPT_DIR%step2obj_occ.py" %* 
     set EXIT_CODE=!ERRORLEVEL!
     goto :END
 )
 
 REM Use System Python (Plan B - Explicit Path)
 if exist "C:\Users\Shomn\AppData\Local\Programs\Python\Python311\python.exe" (
-    echo [step2obj] Using explicit python path >> "!LOG_FILE!"
+    echo [step2obj] Using explicit python path 
     set PYTHONIOENCODING=utf-8
-    "C:\Users\Shomn\AppData\Local\Programs\Python\Python311\python.exe" -u "%SCRIPT_DIR%step2obj_occ.py" %* >> "!LOG_FILE!" 2>&1
+    "C:\Users\Shomn\AppData\Local\Programs\Python\Python311\python.exe" -u "%SCRIPT_DIR%step2obj_occ.py" %* 
     set EXIT_CODE=!ERRORLEVEL!
     goto :END
 )
 
 REM Use System Python (Plan C - PATH)
 where python >nul 2>nul
 if !ERRORLEVEL! equ 0 (
-    echo [step2obj] Using system python >> "!LOG_FILE!"
+    echo [step2obj] Using system python 
     set PYTHONIOENCODING=utf-8
-    python -u "%SCRIPT_DIR%step2obj_occ.py" %* >> "!LOG_FILE!" 2>&1
+    python -u "%SCRIPT_DIR%step2obj_occ.py" %* 
     set EXIT_CODE=!ERRORLEVEL!
     goto :END
 )
@@ -51,5 +51,5 @@ echo [step2obj.bat] Error: No Python environment found! >> "!LOG_FILE!"
 set EXIT_CODE=1
 
 :END
-echo [step2obj] Exit Code: !EXIT_CODE! >> "!LOG_FILE!"
+echo [step2obj] Exit Code: !EXIT_CODE! >> "%LOG_FILE%"
 exit /b !EXIT_CODE!