The engine can reach a Hanja reading back into the text the client
already holds, but only if the frontend hands that text over and can
take some of it away again. GTK 3 has both: retrieve-surrounding
brings the text around the cursor and delete-surrounding removes runes
before it, and a widget that answers neither leaves the text empty, so
nothing is ever reached into or taken from it.
The wire grows a control frame for the text, sent like the caret only
when it changes, and one byte in every response for the runes to take
back. That byte moves the length fields along, so the version goes to
2: an old daemon and a new module, either way round, fail the handshake
and the module falls through to GtkIMContextSimple rather than misread
a frame.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Shift, Control, and their kin were mapped to special keys that the
engine then had a range and a check to ignore, and the GTK module made a
round trip to the daemon for each press. ipckeysym maps them to key 0,
which was already the "no key" every frontend and the engine skip;
Kmodfirst, Kmodlast, and ismodkey go.
半角/全角, ひらがな/カタカナ, 変換, and 無変換 committed the reading and did
nothing, like any function key. They now stand for what a Japanese
keyboard means by them: toggling Japanese and English, switching kana
modes, converting (or turning Japanese on), and turning it off; the
Korean keys became a switch of the same shape. The keypad's arrows
and page keys, with NumLock off, fold onto the plain ones as its Enter
and Tab already did.
Shift+Tab arrives from every frontend as ISO_Left_Tab (0xfe20), which
has no Unicode value and lies outside the function keysym range, so
ipckeysym gave key 0 and the documented Shift-Tab wrap through search
results never reached the engine; GTK moved focus instead. KP_Enter and
KP_Tab likewise became unknown special keys, so the keypad Enter
committed the reading and passed a newline instead of taking the
highlighted candidate.
ipc.c: an AF_UNIX nonblocking connect completes at once or fails with
EAGAIN, so the EINPROGRESS/poll/SO_ERROR path and the fcntl juggling
were dead; the deadline plumbing checked a clock that cannot fail and
re-tested the deadline before every transfer although only waitfd
blocks; readfield's truncation and discard loop served the unit test,
since every caller owns char[Ipcfieldmax+1]; NULL-argument checks on
in-tree encoders are gone (peer validation stays). The primary key frame
is Ipckey, not 'legacy'; ipckeysym names the keysym mapping.
srv.c: the per-connection capability and caret already lived in the
persistent Keyreq; the mirror locals and 'negotiated' flag guarded a
protocol rule no client relied on. proccreate never fails in libthread.
gtk: focus-out no longer round-trips a reset before closing the socket
that releases the engine; the caret dedup compares the packed frame;
srvconnect's preedit no-ops and the insimple flag are gone.
The keysym-to-engine-key rule lived in ibus.c, xim/xim.c and gtk/main.c,
and the copies disagreed: GTK sent keypad digits as special keys while
IBus and XIM sent '1'..'9'. Modifiers were rebuilt bit by bit in two
places although Mmask already is the X core layout; only the virtual
Super bit (26) that GDK and IBus set needs folding. ipckey/ipcmod in
ipc.c serve the daemon, the module and the tests.
