Single file instance sometimes fails

[zufuliu]

Currently it doesn't work for using Notepad2 as external tool for Cppcheck (see wiki https://github.com/zufuliu/notepad2/wiki/Command-Line-Switches#cppcheck). Enable argument dump in ParseCommandLine() shows following arguments are parsed by Cppcheck (note the double slashes):

 -g 4610 D:\\notepad2\\scite\\src\\SciTEBase.cxx

In EnumWndProc2() the passed file path is compared against final path name (GetFinalPathNameByHandle() in EditLoadFile()), which is then diffs.

Following is a quick fix for ActivatePrevInst():

diff --git a/src/Notepad2.c b/src/Notepad2.c
index f3550510..e4564d74 100644
--- a/src/Notepad2.c
+++ b/src/Notepad2.c
@@ -7769,6 +7769,11 @@ BOOL ActivatePrevInst(void) {
 		}
 
 		GetLongPathNameEx(lpFileArg, MAX_PATH);
+		{
+			WCHAR tchTmp[MAX_PATH];
+			GetFullPathName(lpFileArg, MAX_PATH, tchTmp, NULL);
+			lstrcpy(lpFileArg, tchTmp);
+		}
 
 		HWND hwnd = NULL;
 		EnumWindows(EnumWndProc2, (LPARAM)&hwnd);

There maybe other cases where the name diffs, a better solution is needed, possible just open the file and get the final path.

[zufuliu]

GetFullPathName() does not fix \\?\ prefixed path (see https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#win32-file-namespaces).

[zufuliu]

Based on https://stackoverflow.com/questions/562701/best-way-to-determine-if-two-path-reference-to-same-file-in-windows (and similar questions), we need to use GetFileInformationByHandle() (or GetFileInformationByHandleEx() for Win8+), which is how C++20's std::filesystem::equivalent() is implemented (see https://github.com/microsoft/STL/blob/main/stl/src/filesys.cpp#L329).

[zufuliu]

Fixed by 2c3b8d6.
Cppcheck bug reported to https://sourceforge.net/p/cppcheck/discussion/general/thread/b548fc603b/.