Integrate change #15879 from maint-5.6;

Win32::GetLongPathName() did not return valid results if there
were "." and ".." components in the path; also fix a potential
buffer overflow if the long path happens to be longer than
MAX_PATH (this can presumably happen if they use \\?\... style
paths); add a rather limited testsuite that exercises just the
edge cases
p4raw-link: @15879 on //depot/maint-5.6/perl: a15439704ef1059bf178ec4b1820fee7b2af7173

p4raw-id: //depot/perl@15880
p4raw-branched: from //depot/maint-5.6/perl@15877 'branch in'
	t/win32/longpath.t
p4raw-integrated: from //depot/maint-5.6/perl@15877 'ignore' MANIFEST
	(@12747..) 'merge in' t/harness (@11427..) win32/win32.c
	(@13145..)

1 files changed, 52 insertions, 0 deletions

diff --git a/t/win32/longpath.t b/t/win32/longpath.t
new file mode 100755
index 0000000000..d31a5b4dce
--- /dev/null
+++ b/t/win32/longpath.t
@@ -0,0 +1,52 @@
+#!perl -w
+
+# tests for Win32::GetLongPathName()
+
+$^O =~ /^MSWin/ or print("1..0 # not win32\n" ), exit;
+
+my @paths = qw(
+    /
+    //
+    .
+    ..
+    c:
+    c:/
+    c:./
+    c:/.
+    c:/..
+    c:./..
+    //./
+    //.
+    //..
+    //./..
+);
+push @paths, map { my $x = $_; $x =~ s,/,\\,g; $x } @paths;
+push @paths, qw(
+    ../\
+    c:.\\../\
+    c:/\..//
+    c://.\/./\
+    \\.\\../\
+    //\..//
+    //.\/./\
+);
+
+my $drive = $ENV{SystemDrive};
+if ($drive) {
+    for (@paths) {
+	s/^c:/$drive/;
+    }
+    push @paths, $ENV{SystemRoot} if $ENV{SystemRoot};
+}
+my %expect;
+@expect{@paths} = map { my $x = $_; $x =~ s,(.[/\\])[/\\]+,$1,g; $x } @paths;
+
+print "1.." . @paths . "\n";
+my $i = 1;
+for (@paths) {
+    my $got = Win32::GetLongPathName($_);
+    print "# '$_' => expect '$expect{$_}' => got '$got'\n";
+    print "not " unless $expect{$_} eq $got;
+    print "ok $i\n";
+    ++$i;
+}