If the window is invalid and recovery is done, string ids will leak if
acquired before validation.
Afterwards, make the rest of the builtin wrappers consistent: extract
parameters, validate, [acquire resources], generate command.
Now that the initial prototype seems to be working well, it's time to
implement more commands. I might have to do some wrappers for actual
command writing (and result reading) as it looks like there will be a
lot of nearly identical code.
So far, no threading has been set up, and only window creation and
printing have been updated, but the basics of the design seem to be
sound.
The builtin functions now no longer call ncurses directly: the build
commands and write them to a command buffer.
Commands that have return values (eg, window creation) write their
results to a results buffer that the originating builtin function
reads. Builtin functions that expect a result "poll" the results buffer
for the correct result (marked by the same command). In a single
UI-thread environment, the results should always be in the same order as
the commands, and in a multi-UI-thread environment, things should
(fingers crossed) sort themselves out as ONE of the threads will be the
originator of the next available result.
Strings in commands (eg, for printing) are handled by acquiring a string
id (index into an array of dstring_t) and including the string id in the
written command. The string id is released upon completion of the
command.
Builtin functions write commands, acquire string ids, and read results.
The command processor reads commands, releases string ids, and writes
results.
Since commands, string ids, and results are all in ring buffers, and
assuming there is only one thread running the builtin functions and only
one thread processing commands (there can be only one because ncurses is
not thread-safe), then there should never be any contention on the
buffers. Of course, if there are multiple threads running the builtin
functions, then locking will be required on the builtin function side.
I expect I will need several messaging buffers, and ring buffers tend to
be quite robust. Replacing the event buffer code with the macros made
testing easy.
id and z seem to always be 0.
Ironically, it turns out that the work needed for "int id" and "large"
struct nil init wasn't strictly necessary to get to this point, but
without having done that work, I wouldn't know :)
