Method ParseLoopFilePattern

source/script.cpp:10965–11089

bool Line::ParseLoopFilePattern(LPTSTR aFilePattern, LoopFilesStruct &lfs, ResultType &aResult)
// Parse aFilePattern and initialize lfs.
{
	if (!*aFilePattern) // Some checks below may rely on empty aFilePattern having been excluded.
		// FindFirstFile() would find nothing in this case, but continuing may cause unnecessary
		// rescursion through all subdirectories of the working directory.
		return false;
	// Note: Even if aFilePattern is just a directory (i.e. with no wildcard pattern), it seems best
	// not to append "\\*.*" to it because the pattern might be a script variable that the user wants
	// to conditionally resolve to various things at runtime.  In other words, it's valid to have
	// only a single directory be the target of the loop.
	
	// v1.1.31.00: This function was revised.
	//  - Resolve aFilePattern to a full path immediately so that changing the working directory
	//    does not disrupt recursion or A_LoopFileLongPath/ShortPath.
	//  - Take care that path lengths are not limited to below what the system allows.
	//    That is, directory+pattern can be up to MAX_PATH on ANSI and 32767 on Unicode,
	//    although the latter requires the \\?\ prefix or Windows 10 long path awareness.
	//  - Optimize A_LoopFileLongPath and A_LoopFileShortPath by resolving the path prefix
	//    up-front and utilizing the names returned by FindFirstFile() during the loop.
	//    This can be much faster because file system access is minimized.  Benchmarks
	//    showed improvement even for single-iteration loops which use A_LoopFileLongPath.
	
	// Prior to v1.1.31.00, A_LoopFileLongPath worked as follows:
	//  - Each reference to A_LoopFileLongPath results in two BIV_LoopFileLongPath calls.
	//  - BIV_LoopFileLongPath calls GetFullPathName() and ConvertFilespecToCorrectCase().
	//  - CFTCC() calls FindFirstFile() once for each slash-delimited name.
	//  - For example, with "c:\foo\bar\baz.txt", A_LoopFileLongPath results in SIX calls to
	//    FindFirstFile().

	// Find the final name or pattern component of aFilePattern.
	LPTSTR name_part, cp;
	for (name_part = cp = aFilePattern; *cp; cp++)
		if (*cp == '\\' || *cp == '/')
			name_part = cp + 1;

	if (name_part == aFilePattern && *name_part && name_part[1] == ':') // Single character followed by ':' but not '\\' or '/'.
		name_part += 2;
	
	size_t pattern_length = cp - name_part;
	if (pattern_length > _countof(lfs.pattern)) // Most likely too long to match a real path/filename.
		return false; 
	tmemcpy(lfs.pattern, name_part, pattern_length + 1);
	lfs.pattern_length = pattern_length;

	size_t orig_dir_length = name_part - aFilePattern;
	if (orig_dir_length)
	{
		if (  !(lfs.orig_dir = tmalloc(orig_dir_length + 1))  )
		{
			aResult = MemoryError();
			return false;
		}
		tmemcpy(lfs.orig_dir, aFilePattern, orig_dir_length);
		lfs.orig_dir[orig_dir_length] = '\0';
		lfs.orig_dir_length = orig_dir_length;
	}
	else