ipc, srv, gtk: the client's text goes over and a take-back comes back

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>

fn.h

@@ -1,6 +1,7 @@
 void	die(char*, ...);
 
 int	sinit(Str*, char*, int);
+void	stail(Str*, char*, int);
 void	sclear(Str*);
 void	sputr(Str*, Rune);
 void	spopr(Str*);

gtk/main.c

@@ -24,6 +24,9 @@ struct Im
 	int cursorvalid;
 	int caretsent;
 	unsigned char sent[Ipccaretsz];
+	char surround[Ipcfieldmax];
+	int nsurround;
+	int surroundsent;
 };
 
 typedef struct ImClass ImClass;
@@ -65,6 +68,7 @@ srvdrop(Im *im, int notify)
 	im->fd = -1;
 	im->ext = 0;
 	im->caretsent = 0;
+	im->surroundsent = 0;
 	if(notify)
 		setpreedit(im, "", 0);
 	else{
@@ -157,6 +161,58 @@ sendcaret(Im *im)
 	return 0;
 }
 
+/*
+ * The text just before the cursor, as much of it as a reading can use,
+ * cut on a rune boundary.  A widget that keeps none leaves it empty, and
+ * then the daemon never asks for any of it back.
+ */
+static void
+readsurround(Im *im, GtkIMContext *ctx)
+{
+	char *text, *p;
+	gint cursor;
+	int start;
+
+	im->nsurround = 0;
+	if(!gtk_im_context_get_surrounding(ctx, &text, &cursor))
+		return;
+	if(cursor < 0 || cursor > (gint)strlen(text)){
+		g_free(text);
+		return;
+	}
+	start = cursor > Ipcfieldmax ? cursor - Ipcfieldmax : 0;
+	for(p = text + start; p < text + cursor && (*p & 0xc0) == 0x80; p++)
+		;
+	im->nsurround = text + cursor - p;
+	memcpy(im->surround, p, im->nsurround);
+	g_free(text);
+}
+
+/* Sent only when it changes, as the caret is. */
+static int
+sendsurround(Im *im, GtkIMContext *ctx)
+{
+	unsigned char hdr[Ipcreqsz];
+	char was[Ipcfieldmax];
+	int nwas;
+
+	if(im->fd < 0 || !im->ext)
+		return 0;
+	nwas = im->nsurround;
+	memcpy(was, im->surround, nwas);
+	readsurround(im, ctx);
+	if(im->surroundsent && nwas == im->nsurround &&
+	   memcmp(was, im->surround, nwas) == 0)
+		return 0;
+	ipcpacksurround(hdr, im->nsurround);
+	if(ipcsend(im->fd, hdr, sizeof hdr) < 0 ||
+	   (im->nsurround > 0 &&
+	   ipcsend(im->fd, im->surround, im->nsurround) < 0))
+		return -1;
+	im->surroundsent = 1;
+	return 0;
+}
+
 static int
 srvconnect(Im *im)
 {
@@ -286,7 +342,7 @@ kpress(GtkIMContext *ctx, GdkEventKey *ev)
 	if(srvconnect(im) < 0)
 		return simplefilter(ctx, ev, 0);
 	/* A retained GDK window may have moved since the last cursor report. */
-	if(sendcaret(im) < 0){
+	if(sendcaret(im) < 0 || sendsurround(im, ctx) < 0){
 		srvclose(im);
 		return simplefilter(ctx, ev, 0);
 	}
@@ -298,6 +354,11 @@ kpress(GtkIMContext *ctx, GdkEventKey *ev)
 	}
 	if(im->usepreedit && commit[0] != '\0' && im->prelen > 0)
 		setpreedit(im, "", 0);
+	/* The reading reached into the widget's own text: give it back. */
+	if(resp.del > 0){
+		gtk_im_context_delete_surrounding(ctx, -resp.del, resp.del);
+		im->surroundsent = 0;
+	}
 	if(commit[0] != '\0')
 		g_signal_emit_by_name(ctx, "commit", commit);
 	if(im->usepreedit)

ipc.c

@@ -252,6 +252,22 @@ ipcpackcaret(unsigned char req[Ipccaretsz], int valid, int32_t x,
 	}
 }
 
+void
+ipcpacksurround(unsigned char req[Ipcreqsz], size_t n)
+{
+	memset(req, 0, Ipcreqsz);
+	req[0] = Ipcext;
+	req[1] = Ipcversion;
+	req[2] = Ipcopsurround;
+	putlen(req + 4, n);
+}
+
+size_t
+ipcsurroundlen(const unsigned char req[Ipcreqsz])
+{
+	return getlen(req + 4);
+}
+
 void
 ipcunpackreq(const unsigned char req[Ipcreqsz], int *want, uint32_t *mod,
 	uint32_t *key)
@@ -281,6 +297,11 @@ ipcreqtype(const unsigned char req[Ipcreqsz])
 		if(req[0] != Ipcext || req[3] > 1)
 			return Ipcunknown;
 		return Ipccaret;
+	case Ipcopsurround:
+		if(req[0] != Ipcext || req[3] != 0 ||
+		   getlen(req + 4) > Ipcfieldmax)
+			return Ipcunknown;
+		return Ipcsurround;
 	}
 	return Ipcunknown;
 }
@@ -305,19 +326,21 @@ ipcreqreset(const unsigned char req[Ipcreqsz])
 }
 
 int
-ipcpackresp(unsigned char *dst, size_t cap, int eaten,
+ipcpackresp(unsigned char *dst, size_t cap, int eaten, int del,
 	const char *commit, size_t ncommit, const char *preedit, size_t npreedit,
 	int want)
 {
 	size_t n;
 
-	if(ncommit > Ipcfieldmax || npreedit > Ipcfieldmax)
+	if(ncommit > Ipcfieldmax || npreedit > Ipcfieldmax ||
+	   del < 0 || del > 0xff)
 		return -1;
 	n = Ipcresphdrsz + ncommit + (want ? Ipclensz + npreedit : 0);
 	if(cap < n)
 		return -1;
 	dst[0] = eaten != 0;
-	putlen(dst + 1, ncommit);
+	dst[1] = del;
+	putlen(dst + 2, ncommit);
 	memcpy(dst + Ipcresphdrsz, commit, ncommit);
 	if(want){
 		putlen(dst + Ipcresphdrsz + ncommit, npreedit);
@@ -398,7 +421,7 @@ readfield(int fd, char *dst, int64_t until)
 int
 ipcreadresp(int fd, int want, char *commit, char *preedit, Ipcresp *resp)
 {
-	unsigned char eaten;
+	unsigned char head[2];
 	int64_t until;
 	int n;
 
@@ -406,13 +429,14 @@ ipcreadresp(int fd, int want, char *commit, char *preedit, Ipcresp *resp)
 	preedit[0] = '\0';
 	memset(resp, 0, sizeof *resp);
 	until = deadline();
-	if(readwait(fd, &eaten, 1, until) < 0)
+	if(readwait(fd, head, sizeof head, until) < 0)
 		return -1;
-	if(eaten > 1){
+	if(head[0] > 1){
 		errno = EPROTO;
 		return -1;
 	}
-	resp->eaten = eaten;
+	resp->eaten = head[0];
+	resp->del = head[1];
 	n = readfield(fd, commit, until);
 	if(n < 0)
 		return -1;

ipc.h

@@ -8,9 +8,11 @@
  * The server identifies the connection as the engine owner; that identity is
  * not sent on the wire.
  * Only Mmask modifier bits are retained.
- * Response: [eaten, commit-length-low, commit-length-high, commit...],
- * followed, when requested, by
+ * Response: [eaten, take-back, commit-length-low, commit-length-high,
+ * commit...], followed, when requested, by
  * [preedit-length-low, preedit-length-high, preedit...].
+ * Take-back is the count of runes of the client's own text, just before the
+ * cursor, to remove before inserting the commit.
  * Lengths are little-endian byte counts; fields are at most Ipcfieldmax bytes,
  * so callers read them into char[Ipcfieldmax+1].
  *
@@ -19,6 +21,10 @@
  * frames are understood.
  * Caret control is sixteen bytes: [0x80, version, 1, valid, x, y, h],
  * with the signed coordinates and height encoded as little-endian 32-bit words.
+ * Surrounding-text control is six bytes, [0x80, version, 2, 0, length-low,
+ * length-high], and then that many bytes of the text just before the cursor.
+ * It changes what rides along with the requests that follow and is not
+ * answered.
  */
 
 enum
@@ -26,9 +32,10 @@ enum
 	Ipcreqwant = 1<<0,
 	Ipcreqreset = 1<<1,
 	Ipcext = 1<<7,
-	Ipcversion = 1,
+	Ipcversion = 2,
 	Ipcopcap = 0,
 	Ipcopcaret = 1,
+	Ipcopsurround = 2,
 
 	Kspec = 0x110000,
 	Kback = Kspec|0x08,
@@ -57,7 +64,7 @@ enum
 	Ipcreqsz = 6,
 	Ipccaretsz = 16,
 	Ipclensz = 2,
-	Ipcresphdrsz = 1 + Ipclensz,
+	Ipcresphdrsz = 2 + Ipclensz,
 	Ipcfieldmax = 256,
 	Ipcmaxresp = Ipcresphdrsz + Ipcfieldmax + Ipclensz + Ipcfieldmax,
 	Ipcwaitms = 250,
@@ -69,12 +76,14 @@ enum
 	Ipckey,
 	Ipccap,
 	Ipccaret,
+	Ipcsurround,
 };
 
 typedef struct Ipcresp Ipcresp;
 struct Ipcresp
 {
 	int	eaten;
+	int	del;	/* runes of the client's own text to take back first */
 	/* Bytes copied to each caller buffer, excluding its trailing NUL. */
 	size_t	commitlen;
 	size_t	preeditlen;
@@ -86,11 +95,13 @@ void	ipcpackreq(unsigned char[Ipcreqsz], int, uint32_t, uint32_t);
 void	ipcpackreset(unsigned char[Ipcreqsz], int);
 void	ipcpackcap(unsigned char[Ipcreqsz], int);
 void	ipcpackcaret(unsigned char[Ipccaretsz], int, int32_t, int32_t, int32_t);
+void	ipcpacksurround(unsigned char[Ipcreqsz], size_t);
+size_t	ipcsurroundlen(const unsigned char[Ipcreqsz]);
 void	ipcunpackreq(const unsigned char[Ipcreqsz], int*, uint32_t*, uint32_t*);
 int	ipcunpackcaret(const unsigned char[Ipccaretsz], int*, int32_t*, int32_t*, int32_t*);
 int	ipcreqtype(const unsigned char[Ipcreqsz]);
 int	ipcreqreset(const unsigned char[Ipcreqsz]);
-int	ipcpackresp(unsigned char*, size_t, int, const char*, size_t, const char*, size_t, int);
+int	ipcpackresp(unsigned char*, size_t, int, int, const char*, size_t, const char*, size_t, int);
 int	ipcreadn(int, void*, size_t);
 int	ipcsend(int, const void*, size_t);
 int	ipcreadresp(int, int, char*, char*, Ipcresp*);

srv.c

@@ -31,11 +31,17 @@ srvnote(void *v, char *note)
 	return 0;
 }
 
+/*
+ * 0 for a request to make, 1 for a frame that only changes what rides
+ * along with the requests after it, -1 for anything else.
+ */
 static int
 srvreadreq(int fd, Keyreq *kr, int *want)
 {
 	uchar req[Ipccaretsz];
+	char text[Ipcfieldmax];
 	int valid;
+	size_t n;
 	int32_t x, y, h;
 
 	if(ipcreadn(fd, req, Ipcreqsz) < 0)
@@ -62,6 +68,12 @@ srvreadreq(int fd, Keyreq *kr, int *want)
 		kr->caret.y = y;
 		kr->caret.h = h;
 		return 0;
+	case Ipcsurround:
+		n = ipcsurroundlen(req);
+		if(n > 0 && ipcreadn(fd, text, n) < 0)
+			return -1;
+		stail(&kr->surround, text, n);
+		return 1;
 	}
 	return -1;
 }
@@ -78,7 +90,7 @@ clientthread(void *arg)
 	Keyres res;
 	uchar out[Ipcmaxresp], token;
 	char commit[Maxutf], preedit[Maxutf];
-	int fd, n, ncommit, npreedit, want;
+	int fd, n, ncommit, npreedit, rv, want;
 
 	fd = (int)(uintptr)arg;
 	threadsetname("client %d", fd);
@@ -86,7 +98,9 @@ clientthread(void *arg)
 	kr.reply = chancreate(sizeof(Keyres), 0);
 	kr.owner = &fd;
 	kr.clientpre = 1;
-	while(srvreadreq(fd, &kr, &want) >= 0){
+	while((rv = srvreadreq(fd, &kr, &want)) >= 0){
+		if(rv != 0)
+			continue;
 		if(kr.op != Keycaret)
 			kr.clientpre = want;
 		chansend(keyc, &kr);
@@ -97,7 +111,7 @@ clientthread(void *arg)
 		npreedit = stoutf(&res.preedit, preedit, sizeof preedit);
 		/* A capability reply is always eaten: it marks the extension. */
 		n = ipcpackresp(out, sizeof out, kr.op == Keycap || res.eaten,
-			commit, ncommit, preedit, npreedit, want);
+			res.del, commit, ncommit, preedit, npreedit, want);
 		if(n < 0 || ipcsend(fd, out, n) < 0)
 			break;
 	}

str.c

@@ -24,6 +24,21 @@ sinit(Str *s, char *src, int n)
 	return 1;
 }
 
+/* The last runes of n bytes of UTF-8, as many as a Str holds. */
+void
+stail(Str *s, char *src, int n)
+{
+	Rune r;
+	char *p;
+	int nr;
+
+	nr = utfnlen(src, n);
+	for(p = src; nr > Maxrunes; nr--)
+		p += chartorune(&r, p);
+	if(!sinit(s, p, n - (p - src)))
+		sclear(s);
+}
+
 void
 sclear(Str *s)
 {

tests/daemon_restart_test.c

@@ -297,8 +297,8 @@ rejectold(Test *t, char *where)
 static int
 openreplacement(Test *t)
 {
-	unsigned char selectjp[] = {1, 0, 0, 0, 0};
-	unsigned char keyk[] = {1, 0, 0, 1, 0, 'k'};
+	unsigned char selectjp[] = {1, 0, 0, 0, 0, 0};
+	unsigned char keyk[] = {1, 0, 0, 0, 1, 0, 'k'};
 	char path[96];
 
 	t->ipcnew = connectsocket(t->l.socket, nowms() + Calltimeout);

tests/gtk_live_test.c

@@ -32,6 +32,7 @@ enum
 	Ecaret,
 	Ekey,
 	Ereset,
+	Esurround,
 };
 
 enum
@@ -55,6 +56,7 @@ struct Event
 	int32_t x;
 	int32_t y;
 	int32_t h;
+	char text[Ipcfieldmax+1];
 };
 
 struct Server
@@ -69,6 +71,7 @@ struct Server
 	int eaten;
 	int stall;
 	int response;
+	int del;
 	int nclose;
 	char pre[Ipcfieldmax+1];
 	Event ev[Maxevent];
@@ -83,6 +86,10 @@ struct Siglog
 	char shown[Ipcfieldmax+1];
 	char commit[Ipcfieldmax+1];
 	int prechanged;
+	char around[64];	/* what the widget answers retrieve-surrounding */
+	int aroundcursor;
+	int deloffset;
+	int deln;
 };
 
 static void
@@ -110,13 +117,14 @@ sendresponse(Server *s, int fd, int eaten, int want, int key)
 	unsigned char buf[Ipcmaxresp];
 	const char *commit;
 	char pre[Ipcfieldmax+1];
-	int n, response, stall;
+	int del, n, response, stall;
 	size_t ncommit, npreedit;
 
 	pthread_mutex_lock(&s->lock);
 	memcpy(pre, s->pre, sizeof pre);
 	response = s->response;
 	stall = s->stall;
+	del = key ? s->del : 0;
 	pthread_mutex_unlock(&s->lock);
 	if(stall)
 		return 1;
@@ -135,7 +143,7 @@ sendresponse(Server *s, int fd, int eaten, int want, int key)
 		pre[2] = 'y';
 		npreedit = 3;
 	}
-	n = ipcpackresp(buf, sizeof buf, eaten, commit, ncommit,
+	n = ipcpackresp(buf, sizeof buf, eaten, del, commit, ncommit,
 		pre, npreedit, want);
 	return n >= 0 && ipcsend(fd, buf, n) == 0;
 }
@@ -146,6 +154,7 @@ request(Server *s, int fd)
 	unsigned char buf[Ipccaretsz];
 	uint32_t mod, key;
 	Event e;
+	size_t n;
 	int old, type, want;
 
 	if(ipcreadn(fd, buf, Ipcreqsz) < 0)
@@ -168,6 +177,14 @@ request(Server *s, int fd)
 		e.type = Ecaret;
 		record(s, &e);
 		return 1;
+	case Ipcsurround:
+		n = ipcsurroundlen(buf);
+		if(n > 0 && ipcreadn(fd, e.text, n) < 0)
+			return 0;
+		e.text[n] = '\0';
+		e.type = Esurround;
+		record(s, &e);
+		return 1;
 	case Ipckey:
 		ipcunpackreq(buf, &want, &mod, &key);
 		e.want = want;
@@ -513,6 +530,25 @@ clearlog(Siglog *l)
 	memset(l, 0, sizeof *l);
 }
 
+/* The widget's half of the surrounding-text contract. */
+static gboolean
+retrievearound(GtkIMContext *ctx, Siglog *l)
+{
+	if(l->around[0] == '\0')
+		return FALSE;
+	gtk_im_context_set_surrounding(ctx, l->around, -1, l->aroundcursor);
+	return TRUE;
+}
+
+static gboolean
+deletearound(GtkIMContext *ctx, gint offset, gint n, Siglog *l)
+{
+	(void)ctx;
+	l->deloffset = offset;
+	l->deln = n;
+	return TRUE;
+}
+
 static GtkIMContext*
 newcontext(Siglog *l)
 {
@@ -520,6 +556,8 @@ newcontext(Siglog *l)
 
 	ctx = gtk_im_multicontext_new();
 	gtk_im_multicontext_set_context_id(GTK_IM_MULTICONTEXT(ctx), "strans");
+	g_signal_connect(ctx, "retrieve-surrounding", G_CALLBACK(retrievearound), l);
+	g_signal_connect(ctx, "delete-surrounding", G_CALLBACK(deletearound), l);
 	g_signal_connect(ctx, "preedit-start", G_CALLBACK(prestart), l);
 	g_signal_connect(ctx, "preedit-changed", G_CALLBACK(prechange), l);
 	g_signal_connect(ctx, "preedit-end", G_CALLBACK(preend), l);
@@ -667,7 +705,7 @@ main(int argc, char **argv)
 	Check(eventcount(&srv) == 0, "cursor reporting opened the socket");
 	setpre(&srv, "");
 	Check(key(ctx, win, GDK_KEY_a), "initial key was not eaten");
-	Check(waitcount(&srv, 3), "initial protocol frames timed out");
+	Check(waitcount(&srv, 4), "initial protocol frames timed out");
 	e = getevent(&srv, 0);
 	Check(e.type == Ecap && e.want == 1, "default preedit capability missing");
 	e = getevent(&srv, 1);
@@ -682,6 +720,9 @@ main(int argc, char **argv)
 		e.x, e.y, e.h, (ox + rect.x) * scale,
 		(oy + rect.y) * scale, rect.height * scale);
 	e = getevent(&srv, 2);
+	Check(e.type == Esurround && e.text[0] == '\0',
+		"a widget that keeps no text sent some");
+	e = getevent(&srv, 3);
 	Check(e.type == Ekey && e.want == 1, "initial key framing changed");
 	Check(log.n == 0, "initial empty preedit emitted %s", log.event);
 	setpre(&srv, "ㅋ");
@@ -804,6 +845,38 @@ main(int argc, char **argv)
 		"visible-entry key did not reach the daemon");
 	gtk_im_context_set_client_window(ctx, win);
 
+	/* The widget's own text goes over, and a take-back comes back. */
+	setpre(&srv, "");
+	clearlog(&log);
+	snprintf(log.around, sizeof log.around, "%s", "가나한");
+	log.aroundcursor = 9;
+	first = eventcount(&srv);
+	Check(key(ctx, win, GDK_KEY_j), "surrounding-text key was not eaten");
+	Check(waitcount(&srv, first + 2), "surrounding text did not reach the daemon");
+	e = getevent(&srv, first);
+	Check(e.type == Esurround && strcmp(e.text, "가나한") == 0,
+		"the daemon was sent %s, not the text before the cursor", e.text);
+	Check(getevent(&srv, first + 1).type == Ekey,
+		"the text did not ride ahead of the key");
+	/* Sent again only when it changes. */
+	first = eventcount(&srv);
+	Check(key(ctx, win, GDK_KEY_j), "second surrounding-text key was not eaten");
+	Check(waitcount(&srv, first + 1) && getevent(&srv, first).type == Ekey,
+		"unchanged surrounding text was sent again");
+	setreply(&srv, 1, Rnormal, 0);
+	pthread_mutex_lock(&srv.lock);
+	srv.del = 2;
+	pthread_mutex_unlock(&srv.lock);
+	log.deln = 0;
+	Check(key(ctx, win, GDK_KEY_j), "take-back key was not eaten");
+	Check(log.deloffset == -2 && log.deln == 2,
+		"the widget was told to take back %d runes at %d", log.deln,
+		log.deloffset);
+	pthread_mutex_lock(&srv.lock);
+	srv.del = 0;
+	pthread_mutex_unlock(&srv.lock);
+	log.around[0] = '\0';
+
 	setpre(&srv, "reset");
 	clearlog(&log);
 	Check(key(ctx, win, GDK_KEY_e), "reset setup key was not eaten");

tests/ipc_live_test.c

@@ -23,6 +23,7 @@ typedef struct Response Response;
 struct Response
 {
 	int eaten;
+	int del;
 	char commit[Ipcfieldmax+1];
 	char preedit[Ipcfieldmax+1];
 };
@@ -50,7 +51,8 @@ readresponseuntil(int fd, int want, Response *res, int64_t deadline,
 		return rv;
 	}
 	res->eaten = hdr[0] != 0;
-	n = getlen(hdr + 1);
+	res->del = hdr[1];
+	n = getlen(hdr + 2);
 	if(n > Ipcfieldmax){
 		fail("invalid commit length %zu", n);
 		return -1;
@@ -119,6 +121,18 @@ sendcap(int fd, int cap)
 	return ipcsend(fd, req, sizeof req) == 0;
 }
 
+static int
+sendsurround(int fd, char *text)
+{
+	unsigned char req[Ipcreqsz];
+	size_t n;
+
+	n = strlen(text);
+	ipcpacksurround(req, n);
+	return ipcsend(fd, req, sizeof req) == 0 &&
+		(n == 0 || ipcsend(fd, text, n) == 0);
+}
+
 static int
 expectresponse(int fd, int want, int eaten, char *commit, char *preedit,
 	char *where)
@@ -152,6 +166,33 @@ requestkey(int fd, int want, uint32_t mod, uint32_t key, int eaten,
 	return expectresponse(fd, want, eaten, commit, preedit, where);
 }
 
+/*
+ * The Korean habit: 한자 typed, then the Hanja key.  The 한 is the
+ * client's by then, so the daemon must ask for it back and answer with
+ * the whole word.
+ */
+static int
+requesthanja(int fd)
+{
+	Response res;
+
+	if(!sendsurround(fd, "저는 한"))
+		return fail("send surrounding text: %s", strerror(errno));
+	if(!requestkey(fd, 1, Mctrl, 's', 1, "", "", "select Korean") ||
+	   !requestkey(fd, 1, 0, 'w', 1, "", "ㅈ", "jamo") ||
+	   !requestkey(fd, 1, 0, 'k', 1, "", "자", "syllable") ||
+	   !requestkey(fd, 1, Mctrl, 'h', 1, "", "자", "Hanja search"))
+		return 0;
+	if(!sendkey(fd, 1, 0, Kret))
+		return fail("send Hanja pick: %s", strerror(errno));
+	if(readresponseuntil(fd, 1, &res, nowms() + Calltimeout, 0) != 1)
+		return 0;
+	if(strcmp(res.commit, "漢字") != 0 || res.del != 1)
+		return fail("Hanja pick committed %s and took back %d",
+			res.commit, res.del);
+	return 1;
+}
+
 static int
 tryclient(char *path, int64_t deadline, int *client)
 {
@@ -258,7 +299,8 @@ runsmoke(char *path)
 		requestkey(client, 1, Mctrl, 'n', 1, "", "",
 		"select Japanese") &&
 		requestkey(client, 1, 0, 'k', 1, "", "k", "preedit") &&
-		requestreset(client, 1, 1, "k", "", "reset");
+		requestreset(client, 1, 1, "k", "", "reset") &&
+		requesthanja(client);
 	close(client);
 	return ok;
 }

tests/ipc_test.c

@@ -177,34 +177,37 @@ ipc_runtime_path(struct ct *t)
 void
 ipc_response_pack_boundaries(struct ct *t)
 {
-	static const uchar withpre[] = { 1, 1, 0, 'A', 2, 0, 'x', 'y' };
-	static const uchar withoutpre[] = { 1, 1, 0, 'A' };
+	static const uchar withpre[] = { 1, 3, 1, 0, 'A', 2, 0, 'x', 'y' };
+	static const uchar withoutpre[] = { 1, 0, 1, 0, 'A' };
 	uchar out[Ipcmaxresp+1], field[Ipcfieldmax];
 	int n;
 
-	n = ipcpackresp(out, sizeof out, 7, "A", 1, "xy", 2, 1);
+	n = ipcpackresp(out, sizeof out, 7, 3, "A", 1, "xy", 2, 1);
 	CT_EQ_INT(t, sizeof withpre, n);
 	CT_EQ_MEM(t, withpre, out, sizeof withpre);
-	n = ipcpackresp(out, sizeof out, 1, "A", 1, "xy", 2, 0);
+	n = ipcpackresp(out, sizeof out, 1, 0, "A", 1, "xy", 2, 0);
 	CT_EQ_INT(t, sizeof withoutpre, n);
 	CT_EQ_MEM(t, withoutpre, out, sizeof withoutpre);
-	n = ipcpackresp(out, sizeof out, 0, nil, 0, nil, 0, 1);
+	n = ipcpackresp(out, sizeof out, 0, 0, nil, 0, nil, 0, 1);
 	CT_EQ_INT(t, Ipcresphdrsz + Ipclensz, n);
 
 	memset(field, 'x', sizeof field);
 	memset(out, 0xa5, sizeof out);
-	n = ipcpackresp(out, Ipcmaxresp, 1,
+	n = ipcpackresp(out, Ipcmaxresp, 1, 0,
 		(char*)field, sizeof field, (char*)field, sizeof field, 1);
 	CT_EQ_INT(t, Ipcmaxresp, n);
-	CT_EQ_INT(t, 0, out[1]);
-	CT_EQ_INT(t, 1, out[2]);
-	CT_EQ_INT(t, 0, out[3+Ipcfieldmax]);
-	CT_EQ_INT(t, 1, out[4+Ipcfieldmax]);
+	CT_EQ_INT(t, 0, out[2]);
+	CT_EQ_INT(t, 1, out[3]);
+	CT_EQ_INT(t, 0, out[4+Ipcfieldmax]);
+	CT_EQ_INT(t, 1, out[5+Ipcfieldmax]);
 	CT_EQ_INT(t, 0xa5, out[Ipcmaxresp]);
-	CT_EQ_INT(t, -1, ipcpackresp(out, Ipcmaxresp-1, 1,
+	CT_EQ_INT(t, -1, ipcpackresp(out, Ipcmaxresp-1, 1, 0,
 		(char*)field, sizeof field, (char*)field, sizeof field, 1));
-	CT_EQ_INT(t, -1, ipcpackresp(out, sizeof out, 0,
+	CT_EQ_INT(t, -1, ipcpackresp(out, sizeof out, 0, 0,
 		(char*)field, Ipcfieldmax+1, "", 0, 0));
+	/* A take-back is a rune count and never leaves its byte. */
+	CT_EQ_INT(t, -1, ipcpackresp(out, sizeof out, 0, -1, "", 0, "", 0, 0));
+	CT_EQ_INT(t, -1, ipcpackresp(out, sizeof out, 0, 256, "", 0, "", 0, 0));
 }
 
 void
@@ -215,8 +218,8 @@ ipc_response_empty_and_preedit(struct ct *t)
 	Ipcresp resp;
 	int fd[2], nfirst, nsecond;
 
-	nfirst = ipcpackresp(first, sizeof first, 0, "", 0, "", 0, 0);
-	nsecond = ipcpackresp(second, sizeof second, 1,
+	nfirst = ipcpackresp(first, sizeof first, 0, 0, "", 0, "", 0, 0);
+	nsecond = ipcpackresp(second, sizeof second, 1, 0,
 		"go", 2, "kana", 4, 1);
 	if(!CT_CHECK(t, nfirst > 0 && nsecond > 0))
 		return;
@@ -252,9 +255,9 @@ ipc_response_max_and_drain(struct ct *t)
 	int fd[2], nfirst, nsecond;
 
 	memset(field, 'x', sizeof field);
-	nfirst = ipcpackresp(first, sizeof first, 1,
+	nfirst = ipcpackresp(first, sizeof first, 1, 0,
 		(char*)field, sizeof field, (char*)field, sizeof field, 1);
-	nsecond = ipcpackresp(second, sizeof second, 0, "ok", 2, "", 0, 0);
+	nsecond = ipcpackresp(second, sizeof second, 0, 0, "ok", 2, "", 0, 0);
 	if(!CT_CHECK(t, nfirst == Ipcmaxresp && nsecond > 0))
 		return;
 	if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0){
@@ -285,7 +288,7 @@ ipc_response_fragmented_and_truncated(struct ct *t)
 	Ipcresp resp;
 	int fd[2], i, n;
 
-	n = ipcpackresp(frame, sizeof frame, 1, "abc", 3, "xy", 2, 1);
+	n = ipcpackresp(frame, sizeof frame, 1, 2, "abc", 3, "xy", 2, 1);
 	if(!CT_CHECK(t, n > 0))
 		return;
 	if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0){

tests/live.c

@@ -767,7 +767,8 @@ ipcrequest(int fd, uint32_t mod, uint32_t key, unsigned char *want,
 int
 ipcprobe(int fd, char *where)
 {
-	unsigned char empty[] = {0, 0, 0, 0, 0};
+	/* eaten, take-back, no commit, no preedit */
+	unsigned char empty[] = {0, 0, 0, 0, 0, 0};
 
 	return ipcrequest(fd, 0, 0, empty, sizeof empty, where);
 }