In commit f9e572595b I claimed that I'd removed very nearly all
the global and static variables from windows/window.c. It turns out
that this was wildly overoptimistic - I missed quite a few of them!
I'm not quite sure how I managed that; my best guess is that I used an
underpowered 'nm' command that failed to find some classes of
variable.
Some of the remaining function-scope statics were removed completely
by commit afb3dab1e9 just now. In this commit, I've swept up some
more and turn them into fields of WinGuiSeat, where they should have
been moved last September.
The (hopefully complete this time) list of remaining variables,
generated by running this rune in the Windows build directory:
nm windows/CMakeFiles/putty.dir/window.c.obj |
grep -E '^([^ ]+)? *[bBcCdDgGsS] [^\.]'
consists of the following variables which are legitimately global
across the whole process and not related to a particular window:
- 'hinst' and 'hprev', instance handles for Windows loadable modules
- 'classname' in the terminal_window_class_a() and
terminal_window_class_w() functions, which allocate a window class
reusably
- some pointers to Windows API functions retrieved via the
DECL_WINDOWS_FUNCTION / GET_WINDOWS_FUNCTION system, such as
p_AdjustWindowRectExForDpi and p_FlashWindowEx
- some pointers to Windows API functions set up by assigning them at
startup to the right one of the ANSI or Unicode version depending on
the Windows version, e.g. sw_DefWindowProc and sw_DispatchMessage
- 'unicode_window', a boolean flag set at the same time as those
sw_Foo function pointers
- 'sesslist', storing the last-retrieved version of the saved
sessions menu
- 'cursor_visible' in show_mouseptr() and 'forced_visible' in
update_mouse_pointer(), each of which tracks the cumulative number
of times that function has shown or hidden the mouse pointer, so as
to manage its effect on the global state updated by ShowCursor
- 'trust_icon', loaded from the executable's resources
- 'wgslisthead', the list of all active WinGuiSeats
- 'wm_mousewheel', the window-message id we use for mouse wheel
events
and the following which are nothing to do with our code:
- '_OptionsStorage' in __local_stdio_printf_options() and
__local_stdio_scanf_options(), which I'd never noticed before, but
apparently are internal to a standard library header.
This is a piece of refactoring that's been overdue forever. In the
Unix front end, all the variables specific to a particular SSH session
live in a big 'inst' structure, and calls to any of the trait APIs
like Seat or TermWin can recover the right 'inst' from their input
context pointer. But the Windows frontend was written before that kind
of thing became habitual to me, and all its variables have been just
lying around at the top level of window.c, and most of those context
pointers were just ignored.
Now I've swept them all up and put them where they ought to be, in a
big context structure. This was made immeasurably easier by the very
nifty 'clang-rename' tool, which can rename a single variable in a C
source file, and find just the right set of identifiers to change even
if other variables in the file have the same name, even in sub-scopes.
So I started by clang-renaming all the top-level variables in question
to have names beginning with a prefix that didn't previously appear
anywhere in the code; checked that still worked; and then moved all
the declarations into the struct type and did a purely textual
search-and-replace of the prefix with 'wgs->'.
One potential benefit of this change is that it allows more than one
instance of the WinGuiSeat structure to exist in the same process. I
don't have any immediate plans to actually do that, but it's nice to
know it wouldn't be ruled out if we ever did need it.
But that's not the main reason I did it. The main reason is that I
recently looked at the output of a Windows build using clang -Wall,
and was horrified by the number of casual shadowings of
generically-named global variables like 'term' and 'conf' with local
variables of the same name. That seemed like a recipe for confusion,
and I decided the best way to disambiguate them all was to do this
refactoring that I'd wanted anyway for years.
A few uses of the global variables occurred in functions that didn't
have convenient access to the right WinGuiSeat via a callback
parameter of some kind. Those had to be treated specially. Most were
cleaned up in advance by the previous few commits; the remaining fixes
in this commit itself were in functions like modalfatalbox(),
nonfatal() and cleanup_exit(). The error reporting functions want the
terminal HWND to use as a MessageBox parameter; they also have the
side effect of un-hiding the mouse pointer in the terminal window, in
case it's hidden; and cleanup_exit wanted to free some resources
dangling off the WinGuiSeat.
For most of those cases, I've made a linked list of all currently live
WinGuiSeat structures, so that they can loop over _all_ live instances
(whether there's one as usual, none, or maybe more than one in
future). The parent window for non-connection-specific error messages
is found by simply picking one arbitrarily off the linked list (if
any); the cleanups are done by iterating over the _whole_ list.
The mouse-pointer unhiding is dealt with by simply allowing
show_mouseptr to take a _null_ WinGuiSeat pointer. The only thing it
needs the context for at all is to check whether pointer-hiding is
enabled in the session's Conf; so if we're _un_-hiding the pointer we
don't need to check, and can unhide it unconditionally.
The remaining global variables in window.c are the new linked list of
all WinGuiSeat structures; 'wm_mousewheel' and 'trust_icon' which
really should be global across all WinGuiSeats even if we were to have
more than one; and there's a static variable 'cursor_visible' in
show_mouseptr() which is likewise legitimately Seat-independent (since
it records the last value we passed to the Win32 API ShowCursor
function, and _that's_ global across the whole process state).
All of this should cause no functional change whatsoever.
Correcting a source file name in the docs just now reminded me that
I've seen a lot of outdated source file names elsewhere in the code,
due to all the reorganisation since we moved to cmake. Here's a giant
pass of trying to make them all accurate again.
This gets rid of all those annoying 'win', 'ux' and 'gtk' prefixes
which made filenames annoying to type and to tab-complete. Also, as
with my other recent renaming sprees, I've taken the opportunity to
expand and clarify some of the names so that they're not such cryptic
abbreviations.
