The number of people has been steadily increasing who read our source
code with an editor that thinks tab stops are 4 spaces apart, as
opposed to the traditional tty-derived 8 that the PuTTY code expects.
So I've been wondering for ages about just fixing it, and switching to
a spaces-only policy throughout the code. And I recently found out
about 'git blame -w', which should make this change not too disruptive
for the purposes of source-control archaeology; so perhaps now is the
time.
While I'm at it, I've also taken the opportunity to remove all the
trailing spaces from source lines (on the basis that git dislikes
them, and is the only thing that seems to have a strong opinion one
way or the other).
Apologies to anyone downstream of this code who has complicated patch
sets to rebase past this change. I don't intend it to be needed again.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
This commit includes <stdbool.h> from defs.h and deletes my
traditional definitions of TRUE and FALSE, but other than that, it's a
100% mechanical search-and-replace transforming all uses of TRUE and
FALSE into the C99-standardised lowercase spellings.
No actual types are changed in this commit; that will come next. This
is just getting the noise out of the way, so that subsequent commits
can have a higher proportion of signal.
Without this, we don't receive EOF notifications on pipes, because gtk
uses poll rather than select, which separates those out into distinct
event types.
This is another major source of unexplained 'void *' parameters
throughout the code.
In particular, the currently unused testback.c actually gave the wrong
pointer type to its internal store of the frontend handle - it cast
the input void * to a Terminal *, from which it got implicitly cast
back again when calling from_backend, and nobody noticed. Now it uses
the right type internally as well as externally.
This existed in order to avoid the various confusions that could
happen if a toplevel callback ran in the context of a subsidiary
instance of gtk_main(). Now there aren't any subsidiary gtk_main
instances any more, this mechanism is no longer needed, and I can
throw it out. It was horrible anyway.
This lays further groundwork for the OS X GTK3 port, which is going to
have to deal with multiple sessions sharing the same process. gtkwin.c
was a bit too monolithic for this, since it included some
process-global runtime state (timers, toplevel callbacks), some
process startup stuff (gtk_init, gtk_main, argv processing) and some
per-session-window stuff.
The per-session stuff remains in gtkwin.c, with the top-level function
now being new_session_window() taking a Conf. The new gtkmain.c
contains the outer skeleton of pt_main(), handling argv processing and
one-off startup stuff like setlocale; and the new gtkcomm.c contains
the pieces of PuTTY infrastructure like timers and uxsel that are
shared between multiple sessions rather than reinstantiated per
session, which have been rewritten to use global variables rather than
fields in 'inst' (since it's now clear to me that they'll have to
apply to all the insts in existence at once).
There are still some lurking assumptions of one-session-per-process,
e.g. the use of gtk_main_quit when a session finishes, and the fact
that the config box insists on running as a separate invocation of
gtk_main so that one session's preliminary config box can't coexist
with another session already active. But this should make it possible
to at least write an OS X app good enough to start testing with, even
if it doesn't get everything quite right yet.
This change is almost entirely rearranging existing code, so it
shouldn't be seriously destabilising. But two noticeable actual
changes have happened, both pleasantly simplifying:
Firstly, the global-variables rewrite of gtkcomm.c has allowed the
post_main edifice to become a great deal simpler. Most of its
complexity was about remembering what 'inst' it had to call back to,
and in fact the right answer is that it shouldn't be calling back to
one at all. So now the post_main() called by gtkdlg.c has become the
same function as the old inst_post_main() that actually did the work,
instead of the two having to be connected by a piece of ugly plumbing.
Secondly, a piece of code that's vanished completely in this
refactoring is the temporary blocking of SIGCHLD around most of the
session setup code. This turns out to have been introduced in 2002,
_before_ I switched to using the intra-process signal pipe strategy
for SIGCHLD handling in 2003. So I now expect that we should be robust
in any case against receiving SIGCHLD at an inconvenient moment, and
hence there's no need to block it.
