Fix missing session invalid error for user session & enhance NPPM_GETNBSESSIONFILES

New specs of NPPM_GETNBSESSIONFILES (which is retro-compatible):

======================
NPPM_GETNBSESSIONFILES

Retrieves the number of files to load in the session sessionFileName. sessionFileName should be a full path name of an xml file.

Parameters:

wParam [out]
BOOL* isValidXML, if this pointer is null, then this parameter will be ignored. TRUE if XML is valid, otherwise FALSE.

lParam [in]
const TCHAR * sessionFileName

Return value:
Returns 0 if sessionFileName is an empty string/NULL, or XML session file is corrupted/invalid, else the number of files.
======================

Other minor improvements:
- checking also for a possible ShellExecute errors
- removing the isAllSuccessful boolean, as it is no longer needed.

Fix #14228, close #14232

PowerEditor/src/NppBigSwitch.cpp

@@ -1295,13 +1295,22 @@ LRESULT Notepad_plus::process(HWND hwnd, UINT message, WPARAM wParam, LPARAM lPa
 
 		case NPPM_GETNBSESSIONFILES:
 		{
-			const TCHAR *sessionFileName = reinterpret_cast<const TCHAR *>(lParam);
+			size_t nbSessionFiles = 0;
-			if ((!sessionFileName) || (sessionFileName[0] == '\0'))
+			const TCHAR* sessionFileName = reinterpret_cast<const TCHAR*>(lParam);
-				return 0;
+			BOOL* pbIsValidXML = reinterpret_cast<BOOL*>(wParam);
-			Session session2Load;
+			if (pbIsValidXML)
-			if (nppParam.loadSession(session2Load, sessionFileName))
+				*pbIsValidXML = false;
-				return session2Load.nbMainFiles() + session2Load.nbSubFiles();
+			if (sessionFileName && (sessionFileName[0] != '\0'))
-			return 0;
+			{
+				Session session2Load;
+				if (nppParam.loadSession(session2Load, sessionFileName, true))
+				{
+					if (pbIsValidXML)
+						*pbIsValidXML = true;
+					nbSessionFiles = session2Load.nbMainFiles() + session2Load.nbSubFiles();
+				}
+			}
+			return nbSessionFiles;
 		}
 
 		case NPPM_GETSESSIONFILES:
@@ -1313,7 +1322,7 @@ LRESULT Notepad_plus::process(HWND hwnd, UINT message, WPARAM wParam, LPARAM lPa
 				return FALSE;
 
 			Session session2Load;
-			if (nppParam.loadSession(session2Load, sessionFileName))
+			if (nppParam.loadSession(session2Load, sessionFileName, true))
 			{
 				size_t i = 0;
 				for ( ; i < session2Load.nbMainFiles() ; )

PowerEditor/src/NppIO.cpp

@@ -2449,7 +2449,6 @@ bool Notepad_plus::fileLoadSession(const TCHAR *fn)
 			sessionFileName = fn;
 	}
 
-
 	NppParameters& nppParam = NppParameters::getInstance();
 	const NppGUI & nppGUI = nppParam.getNppGUI();
 	if (!sessionFileName.empty())
@@ -2466,36 +2465,26 @@ bool Notepad_plus::fileLoadSession(const TCHAR *fn)
 			TCHAR nppFullPath[MAX_PATH]{};
 			::GetModuleFileName(NULL, nppFullPath, MAX_PATH);
 
-
 			generic_string args = TEXT("-multiInst -nosession -openSession ");
 			args += TEXT("\"");
 			args += sessionFileName;
 			args += TEXT("\"");
-			::ShellExecute(_pPublicInterface->getHSelf(), TEXT("open"), nppFullPath, args.c_str(), TEXT("."), SW_SHOW);
+			if (::ShellExecute(_pPublicInterface->getHSelf(), TEXT("open"), nppFullPath, args.c_str(), TEXT("."), SW_SHOW) > (HINSTANCE)32)
-			result = true;
+				result = true;
 		}
 		else
 		{
-			bool isAllSuccessful = true;
 			Session session2Load;
 
 			if (nppParam.loadSession(session2Load, sessionFileName.c_str()))
 			{
 				const bool isSnapshotMode = false;
-				isAllSuccessful = loadSession(session2Load, isSnapshotMode, sessionFileName.c_str());
+				result = loadSession(session2Load, isSnapshotMode, sessionFileName.c_str());
-				result = true;
+
 				if (isEmptyNpp && nppGUI._multiInstSetting == multiInstOnSession)
 					nppParam.setLoadedSessionFilePath(sessionFileName);
 			}
 		}
-		if (result == false)
-		{
-			_nativeLangSpeaker.messageBox("SessionFileInvalidError",
-				NULL,
-				TEXT("Session file is either corrupted or not valid."),
-				TEXT("Could not Load Session"),
-				MB_OK);
-		}
 	}
 
 	return result;

PowerEditor/src/Parameters.cpp

@@ -2264,13 +2264,22 @@ void NppParameters::setWorkingDir(const TCHAR * newPath)
 	}
 }
 
-bool NppParameters::loadSession(Session & session, const TCHAR *sessionFileName)
+bool NppParameters::loadSession(Session& session, const TCHAR* sessionFileName, const bool bSuppressErrorMsg)
 {
-	TiXmlDocument *pXmlSessionDocument = new TiXmlDocument(sessionFileName);
+	TiXmlDocument* pXmlSessionDocument = new TiXmlDocument(sessionFileName);
 	bool loadOkay = pXmlSessionDocument->LoadFile();
 	if (loadOkay)
 		loadOkay = getSessionFromXmlTree(pXmlSessionDocument, session);
 
+	if (!loadOkay && !bSuppressErrorMsg)
+	{
+		_pNativeLangSpeaker->messageBox("SessionFileInvalidError",
+			NULL,
+			TEXT("Session file is either corrupted or not valid."),
+			TEXT("Could not Load Session"),
+			MB_OK);
+	}
+
 	delete pXmlSessionDocument;
 	return loadOkay;
 }

PowerEditor/src/Parameters.h

@@ -1659,7 +1659,7 @@ public:
 		return _doPrintAndExit;
 	};
 
-	bool loadSession(Session & session, const TCHAR *sessionFileName);
+	bool loadSession(Session& session, const TCHAR* sessionFileName, const bool bSuppressErrorMsg = false);
 
 	void setLoadedSessionFilePath(const std::wstring & loadedSessionFilePath) {
 		_loadedSessionFullFilePath = loadedSessionFilePath;