Fix TestLib::slurp_file() with offset on windows.

anarazel · anarazel · commit cd1b2334b8a2 · 2021-10-04T13:33:08.000-07:00
3c5b068 used setFilePointer() to set the position of the filehandle, but passed the wrong filehandle, always leaving the position at 0. Instead of just fixing that, remove use of setFilePointer(), we have a perl fd at this point, so we can just use perl's seek(). Additionally, the perl filehandle wasn't closed, just the windows filehandle. Reviewed-By: Andrew Dunstan <andrew@dunslane.net> Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20211003173038.64mmhgxctfqn7wl6@alap3.anarazel.de Backpatch: 9.6-, like 3c5b068
diff --git a/src/test/perl/TestLib.pm b/src/test/perl/TestLib.pm
@@ -99,7 +99,7 @@ BEGIN
 	if ($windows_os)
 	{
 		require Win32API::File;
-		Win32API::File->import(qw(createFile OsFHandleOpen CloseHandle setFilePointer));
+		Win32API::File->import(qw(createFile OsFHandleOpen CloseHandle));
 	}
 }
 
@@ -280,33 +280,33 @@ sub slurp_file
 	my ($filename, $offset) = @_;
 	local $/;
 	my $contents;
+	my $fh;
+
+	# On windows open file using win32 APIs, to allow us to set the
+	# FILE_SHARE_DELETE flag ("d" below), otherwise other accesses to the file
+	# may fail.
 	if ($Config{osname} ne 'MSWin32')
 	{
-		open(my $in, '<', $filename)
+		open($fh, '<', $filename)
 		  or die "could not read \"$filename\": $!";
-		if (defined($offset))
-		{
-			seek($in, $offset, SEEK_SET)
-			  or die "could not seek \"$filename\": $!";
-		}
-		$contents = <$in>;
-		close $in;
 	}
 	else
 	{
 		my $fHandle = createFile($filename, "r", "rwd")
 		  or die "could not open \"$filename\": $^E";
-		OsFHandleOpen(my $fh = IO::Handle->new(), $fHandle, 'r')
+		OsFHandleOpen($fh = IO::Handle->new(), $fHandle, 'r')
 		  or die "could not read \"$filename\": $^E\n";
-		if (defined($offset))
-		{
-			setFilePointer($fh, $offset, qw(FILE_BEGIN))
-			  or die "could not seek \"$filename\": $^E\n";
-		}
-		$contents = <$fh>;
-		CloseHandle($fHandle)
-		  or die "could not close \"$filename\": $^E\n";
 	}
+
+	if (defined($offset))
+	{
+		seek($fh, $offset, SEEK_SET)
+		  or die "could not seek \"$filename\": $!";
+	}
+
+	$contents = <$fh>;
+	close $fh;
+
 	$contents =~ s/\r\n/\n/g if $Config{osname} eq 'msys';
 	return $contents;
 }
