When embedded, st fails with BadMatch error if the embedder's window has
non-default colormap/depth/visual.  This commit fixes that by creating
st's window inside root and then reparent it into embedder.

The reference window for dc.gc is also changed to match root's visuals.

A similar commit had been made for dmenu[1].
See this issue[2] on github for context.

[1]: https://git.suckless.org/dmenu/commit/0fe460dbd469a1d5b6a7140d0e1801935e4a923b.html
[2]: https://github.com/phillbush/xfiles/issues/47

Patch by Mikhail Kot <to@myrrc.dev>
With some modifications to behave more like xterm (see note below).

Example:

	printf '\033[48;2;255:0:0mtest\n'

https://invisible-island.net/xterm/ctlseqs/ctlseqs.html

Some notes:

"CSI Pm m  Character Attributes (SGR).
[...]
o   xterm allows either colons (standard) or semicolons
(legacy) to separate the subparameters (but after the
first colon, colons must be used).

With this patch, st will reset its window title when an empty string is
given as the terminal title. For example:
	printf "\033]0;\007"

Some applications, like termdown, expect this functionality. xterm
implements it, but it seems that most other terminal emulators don't.
In any case, I don't see why there should ever be a case where the st
window doesn't have a title property.

This reverts commit 7473a8d1a5.

This patch needs some more work. It caused regressions with programs that use
GNU readline, etc.

Original test-case example from Tim Culverhouse <tim@timculverhouse.com>:

	printf " 😀" && sleep 2 && printf "\e[D" && sleep 2 && printf "\e[D" && sleep 2

After the patch it caused regressions, example test-case:

	printf "A字\bB\n"

Previously, printf 'L\033[2147483647b' would call tputc('L') 2^31 times,
making st unresponsive. This commit allows repeating the last character
at most 65535 times in order to prevent freezing and DoS attacks.

st would always move back 1 column,
even with wide glyhps (using more than a single column).

The glyph rune is set on its first column,
and the other ones are to 0,
so loop until we detect the start of the previous glyph.

The handler for 'S' final character does not check for a private
marker. This can cause a conflict with a sequence called 'XTSMGRAPHICS'
which also has an 'S' final character, but uses the private marker '?'.
Without checking for a private marker, st will perform a scroll up
operation when XTSMGRAPHICS is seen, which can cause unexpected display
artifacts.

Helps Vim (and hopefully others) to discover that this feature exists
without further user configuration.

It is unclear if it's "required" to do this on RIS, but it's useful when
calling reset(1) after interactive programs have crashed and garbled up
the screen.

FWIW, other terminals do it as well (tested with XTerm, VTE, Kitty,
Alacritty, Linux VT).

Consider the following example:

    printf '\e[?7l';\
    for i in $(seq $(($(tput cols) - 1))); do printf a; done;\
    printf '🙈\n';\
    printf '\e[?7h'

Even though MODE_WRAP has been disabled, the emoji appeared on the next
line. This patch keeps wide glyphs on the same line and moves them to
the right-most possible position.

Fixes garbage selections when switching to/from the alternate screen.

How to reproduce:

-   Be in primary screen.
-   Select something.
-   Run this (switches to alternate screen, positions the cursor at the
    bottom, triggers selscroll(), and then goes back to primary screen):

        tput smcup; tput cup $(tput lines) 0; echo foo; tput rmcup

-   Notice how the (visual) selection now covers a different line.

The reason is that selscroll() calls selnormalize() and that cannot find
the original range anymore. It's all empty lines now, so it snaps to
"select the whole line".

dc.collen is the length of dc.col, not the maximum index, hence if x is
equal to dc.collen, then it's an error.

With config.def.h, the last valid index is 259, so this correctly
reports "black":

    $ printf '\033]4;259;?\e\\'

260 is an invalid index and this reports garbage instead of printing an
error:

    $ printf '\033]4;260;?\e\\'

The Makefile used to suppress output (by using @), so this target made sense at
the time.

But the Makefile should be simple and make debugging with less abstractions or
fancy printing.  The Makefile was made verbose and doesn't hide the build
output, so remove this target.

Prompted by a question on the mailing list about the options target.

Under insert mode, when inserting a normal character in front of
a wide character, the affected region is shifted to the right by
one cell. However, the empty cell is reset as if being a part of a
wide character, causing the following cell being mishandled as a
dummy cell.
To reproduce the bug:
	printf '\033[4h' # set MODE_INSERT
	printf 妳好
	printf '\033[4D'
	printf 'x'
	printf '\033[4l\n'

Ignore processing and printing C1 control characters in UTF-8 mode.
These are in the range: 0x80 - 0x9f.

By default in st the mode is set to UTF-8.

This matches more the behaviour of xterm with the options -u8 or +u8 also.
Also see the xterm resource "allowC1Printable".

Let me know if this breaks something, in most cases I don't think so.

As usual a very good reference is:
https://invisible-island.net/xterm/ctlseqs/ctlseqs.html

"VT100 defines an escape sequence [1] called Device Status Report (DSR). When
the DSR sequence received is `csi 5n`, an "OK" response `csi 0n` is returned.
This patch adds that "OK" response.

I encountered this missing sequence when I noticed that fzf [2] would clobber
my prompt whenever completing a find.

To test that ST doesn't currently respond to `csi 5n`, use fzf's shell
extension in ST's repo to complete the path for a file.

    my-fancy-prompt $ vim **<tab>
    <select a file>
    st.c

Select a file with <enter>, and notice that fzf clobbers some or all of your
prompt.

After applying this patch, do the same test as above and notice that fzf has no
longer clobbered your prompt by placing the file name in the correct position
in your command.

    my-fancy-prompt $ vim **<tab>
    <select a file>
    my-fancy prompt $ vim st.c

Thank you for considering my first patch submission.

[1] https://www.xfree86.org/current/ctlseqs.html#VT100%20Mode
[2] https://github.com/junegunn/fzf
"

Patch slightly adapted with input from the mailinglist,

Adapted from (garbled) patch by wim <wim@thinkerwim.org>

Additional notes: it should reset all the colors using xloadcols().
To reproduce: set a different (theme) color using some escape code, then reset
it:

	printf '\x1b]104\x07'

To reproduce the issue:

"
If you already have the multi-key enabled on your system, then add this line
to your ~/.XCompose file:

[...]
<question> <T> <E> <S> <T> <question> :
"1234567890123456789012345678901234567890123456789012345678901234567890"
"

Reported by and an initial patch by Andy Gozas <andy@gozas.me>, thanks!

Adapted the patch, for now st (like dmenu) handles a fixed amount of composed
characters, or otherwise ignores it. This is done for simplicity sake.

It is fixed in libXft 2.3.6:

https://gitlab.freedesktop.org/xorg/lib/libxft/-/blob/libXft-2.3.5/NEWS

* adds missing function prototype
* move xgetcolor() prototype to win.h (that's where all the other x.c
  func prototype seems to be declared at)
* check for snprintf error/truncation
* reduces code duplication for osc 10/11/12
* unify osc_color_response() and osc4_color_response() into a single function

the latter two was suggested by Quentin Rameau in his patch review on
the hackers list.

the array is not accessed outside of base64dec() so it makes sense to
limit it's scope to the related function. the static-storage duration of
the array is kept intact.

this also removes unnecessary explicit zeroing from the start and end of
the array. anything that wasn't explicitly zero-ed will now be
implicitly zero-ed instead.

the validity of the new array can be easily confirmed via running this
trivial loop:

	for (int i = 0; i < 255; ++i)
		assert(base64_digits[i] == base64_digits_old[i]);

lastly, as pointed out by Roberto, the array needs to have 256 elements
in order to able access it as any unsigned char as an index; the
previous array had 255.

however, this array will only be accessed at indexes which are
isprint() || '=' (see `base64dec_getc()`), so reducing the size of the
array to the highest printable ascii char (127 AFAIK) + 1 might also be
a valid strategy.

all the ctype.h functions' argument must be representable as an unsigned
char or as EOF, otherwise the behavior is undefined.

Build on auto-sync and only mark window dirty on palette changes and let
the event handler do the actual draw.

This patch replaces the previous one I sent.

The following changes are made in this patch:
 - Fix tracking of pressed buttons. Previously, pressing two buttons and
   then releasing one would make st think no buttons are pressed, which
   in particular broke MODE_MOUSEMOTION.
 - Always send the lowest-numbered pressed button on motion events; when
   no button is pressed for a motion event in MODE_MOUSEMANY, then send
   a release. This matches the behaviour of xterm. (Previously, st sent
   the most recently pressed button in the motion report.)
 - Remove UB (?) access to potentially inactive struct member
   e->xbutton.button of XEvent union.
 - Fix (unlikely) possibility of overflow for large button numbers.

The one discrepancy I found between st and xterm is that xterm sometimes
encodes buttons with large numbers (>5) strangely. E.g., xterm reports
presses of buttons 8 and 9 as releases, whereas st properly (?) encodes
them as presses.

Overtyping the first half of a wide character with the
second half of a wide character results in display garbage.
This is because the trailing dummy is not cleaned up.

i.e.  ATTR_WIDE, ATTR_WDUMMY, ATTR_WDUMMY

Here is a short script for demonstrating the behavior:

	#!/bin/sh
	alias printf=/usr/bin/printf
	printf こんにちは！; sleep 2
	printf '\x1b[5D'; sleep 2
	printf へ; sleep 2
	printf ' '; sleep 2
	echo

According to the spec the argument is optional for 104, so p can be
NULL as can be tested with printf '\x1b]104\x07'. This is a regression
of 8e31030.

Otherwise the message "erresc: unknown str" is printed.

from the XmbTextListToTextProperty(3) man page:

"If insufficient memory is available for the new value string, the functions
return XNoMemory.  If the current locale is not supported, the functions return
XLocaleNotSupported.  In both of these error cases, the functions do not set
text_prop_return."

Reported by Steffen Nurpmeso <steffen@sdaoden.eu>, thanks!

In the current implementation, the slave PTY (assigned to the variable
`s') is always closed after duplicating it to file descriptors of
standard streams (0, 1, and 2).  However, when the allocated slave PTY
`s' is already one of 0, 1, or 2, this causes unexpected closing of a
standard stream.  The same problem occurs when the file descriptor of
the master PTY (the variable `m') is one of 0, 1, or 2.

In this patch, the original master PTY (m) is closed before it would
be overwritten by duplicated slave PTYs.  The original slave PTY (s)
is closed only when it is not one of the stanrad streams.

The bits of uint signal in an XKeyEvent which concern the key group (keyboard
layout) are bits 13 and 14, as documented here:
https://www.x.org/releases/X11R7.7/doc/libX11/XKB/xkblib.html#Groups_and_Shift_Levels
In the older version, only bit 13 was marked as part of XK_SWITCH_MOD, this
causes issues for users who have more than two keymaps. the 14th bit is not
in ignoremod, key sequences are not caught by match(), if they switch to a third
or fourth keyboard.

Only touch a few things, the main focus is to
improve code readability.

These are typically mapped in X11 to the side-buttons (backward/forwards) on
the mouse. A comparison of the button numbers in SGR mode (first field):

st old:
0 1 2 64 65 66 67 68 69 70

st new (it is the same as xterm now):
0 1 2 64 65 66 67 128 129 130

A script to test and reproduce it, first argument is "h" (on) or "l" (off):

	#!/bin/sh
	printf '\x1b[?1000%s\x1b[?1006%s' "$1" "$1"

	for n in 1 2 3 4 5 6 7 8 9 10; do
		printf 'button %d\n' "$n"
		xdotool click "$n"
		printf '\n\n'
	done

Also added _NET_WM_ICON_NAME.