Add NPPM_GETNPPSETTINGSDIRPATH message to get Notepad++ settings directory path

Fix notepad-plus-plus#16944, close notepad-plus-plus#16946

Author: pryrt

PowerEditor/src/MISC/PluginsManager/Notepad_plus_msgs.h

@@ -1025,7 +1025,20 @@ enum Platform { PF_UNKNOWN, PF_X86, PF_X64, PF_IA64, PF_ARM64 };
 	// Return toolbar icon set choice as an integer value. Here are 5 possible values:
 	// 0 (Fluent UI: small), 1 (Fluent UI: large), 2 (Filled Fluent UI: small), 3 (Filled Fluent UI: large) and 4 (Standard icons: small).
 
-	// For RUNCOMMAND_USER
+	#define NPPM_GETNPPSETTINGSDIRPATH (NPPMSG + 119)
+	// int NPPM_GETNPPSETTINGSDIRPATH(size_t strLen, wchar_t *settingsDirPath)
+	// Get path for the active Notepad++ settings: it will use -settingsDir path if that's defined; if not, it will use Cloud directory if that's defined;
+	// if not, it will use the AppData settings directory, or finally the installation path. This allows plugins to have one interface to find out
+	// where the active Notepad++ settings are stored, whichever location they are currently set to.
+	// wParam[in]: strLen - size of allocated buffer "settingsDirPath"
+	// lParam[out]: settingsDirPath - Users should call it with settingsDirPath be NULL to get the required number of wchar_t (not including the terminating nul character),
+	//              allocate settingsDirPath buffer with the return value + 1, then call it again to get the path.
+	// Returns the number of wchar_t copied/to copy. If the return value is 0, then the "strLen" is not enough to copy the path, or the settings path could not be determined.
+	// 
+	// Note: This message is for the active Notepad++ configuration location.  If you are looking for the settings directory for plugins (...\Plugins\Config\),
+	// use NPPM_GETPLUGINSCONFIGDIR instead.
+
+// For RUNCOMMAND_USER
 	#define VAR_NOT_RECOGNIZED 0
 	#define FULL_CURRENT_PATH 1
 	#define CURRENT_DIRECTORY 2

PowerEditor/src/NppBigSwitch.cpp

@@ -3218,6 +3218,23 @@ LRESULT Notepad_plus::process(HWND hwnd, UINT message, WPARAM wParam, LPARAM lPa
 			return settingsOnCloudPath.length();
 		}
 
+		case NPPM_GETNPPSETTINGSDIRPATH:
+		{
+			// get the path (-settingsDir, Cloud directory, AppData or NppDir selection handled by _userPath, returned by .getUserPath())
+			wstring settingsDirPath = nppParam.getUserPath();
+
+			// if the LPARAM is a big enough non-null pointer, populate that memory with the path string
+			if (lParam != 0)
+			{
+				if (settingsDirPath.length() >= static_cast<size_t>(wParam))
+					return 0;
+				lstrcpy(reinterpret_cast<wchar_t*>(lParam), settingsDirPath.c_str());
+			}
+
+			// the message returns the string length
+			return settingsDirPath.length();
+		}
+
 		case NPPM_SETLINENUMBERWIDTHMODE:
 		{
 			if (lParam != LINENUMWIDTH_DYNAMIC && lParam != LINENUMWIDTH_CONSTANT)