xim: clear callback preedit on owner loss

xim/xim.c

@@ -1,6 +1,10 @@
 #include "dat.h"
 #include "fn.h"
 
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <unistd.h>
 #include <xcb/xcb.h>
 #include <xkbcommon/xkbcommon.h>
 #include <xcb-imdkit/imdkit.h>
@@ -52,6 +56,7 @@ static Ic *ics;
 static Ic *preowner;
 static Clientenc clientenc[Maxclients];
 static Channel *replyc;
+static int wakefd[2] = {-1, -1};
 
 static char *encs[] = {"COMPOUND_TEXT", "UTF8_STRING"};
 static u32int styles[] = {
@@ -75,6 +80,71 @@ stylecap(u32int style, int *cap)
 	return 0;
 }
 
+static int
+wakeinit(void)
+{
+	int fd[2];
+	int flags, i;
+
+	if(wakefd[0] >= 0)
+		return 0;
+	if(pipe(fd) < 0)
+		return -1;
+	for(i = 0; i < nelem(fd); i++){
+		flags = fcntl(fd[i], F_GETFL);
+		if(flags < 0 || fcntl(fd[i], F_SETFL,
+		   flags | O_NONBLOCK) < 0)
+			goto fail;
+		flags = fcntl(fd[i], F_GETFD);
+		if(flags < 0 || fcntl(fd[i], F_SETFD,
+		   flags | FD_CLOEXEC) < 0)
+			goto fail;
+	}
+	wakefd[0] = fd[0];
+	wakefd[1] = fd[1];
+	return 0;
+fail:
+	close(fd[0]);
+	close(fd[1]);
+	return -1;
+}
+
+/* imthread only leaves a wake token; XIM ownership stays on the XIM thread. */
+void
+ximownernotify(void)
+{
+	uchar token;
+	int n;
+
+	if(wakefd[1] < 0)
+		return;
+	token = 0;
+	do
+		n = write(wakefd[1], &token, 1);
+	while(n < 0 && errno == EINTR);
+	/* EAGAIN means a pending byte will already wake the XIM poll loop. */
+}
+
+static int
+wakedrain(void)
+{
+	uchar buf[32];
+	int n, total;
+
+	total = 0;
+	for(;;){
+		n = read(wakefd[0], buf, sizeof buf);
+		if(n > 0){
+			total += n;
+			continue;
+		}
+		if(n < 0 && errno == EINTR)
+			continue;
+		break;
+	}
+	return total;
+}
+
 static int
 getencoding(xcb_im_client_t *client)
 {
@@ -272,11 +342,9 @@ place(Ic *state)
 	nwin = 1;
 	if(state->clientwin != state->focuswin)
 		win[nwin++] = state->clientwin;
-	if(state->hasspot)
-		for(i = 0; i < nwin; i++)
-			if(translate(win[i], state->spot.x, state->spot.y,
-			   &state->caret))
-				return;
+	if(state->hasspot && translate(state->focuswin,
+	   state->spot.x, state->spot.y, &state->caret))
+		return;
 	for(i = 0; i < nwin; i++)
 		if(placebottom(state, win[i]))
 			return;
@@ -395,6 +463,25 @@ sendrequest(Ic *state, int op, u32int key, u32int mod, Keyres *res)
 	chanrecv(replyc, res);
 }
 
+static void
+checkpreowner(void)
+{
+	Keyres res;
+
+	if(preowner == nil)
+		return;
+	sendrequest(preowner, Keycap, 0, 0, &res);
+	if(!res.eaten)
+		clearpreedit(preowner);
+}
+
+static void
+checkownerwake(void)
+{
+	if(wakedrain() > 0)
+		checkpreowner();
+}
+
 static void
 keypress(Ic *state, u32int key, u32int mod, Keyres *res)
 {
@@ -611,6 +698,10 @@ ximinit(void)
 		ximlog("cannot create reply channel");
 		return -1;
 	}
+	if(wakeinit() < 0){
+		ximlog("cannot create owner wake pipe");
+		return -1;
+	}
 	st.nStyles = nelem(styles);
 	st.styles = styles;
 	enc.nEncodings = nelem(encs);
@@ -653,8 +744,10 @@ ximinit(void)
 void
 ximthread(void *arg)
 {
+	struct pollfd pfd[2];
 	xcb_generic_event_t *ev;
 	uint8_t type;
+	int fd, n;
 
 	USED(arg);
 	threadsetname("xim");
@@ -662,17 +755,35 @@ ximthread(void *arg)
 		ximclose();
 		return;
 	}
+	fd = xcb_get_file_descriptor(conn);
+	pfd[0].fd = fd;
+	pfd[0].events = POLLIN;
+	pfd[1].fd = wakefd[0];
+	pfd[1].events = POLLIN;
 	for(;;){
-		ev = xcb_wait_for_event(conn);
-		if(ev == nil)
+		pfd[0].revents = pfd[1].revents = 0;
+		n = poll(pfd, nelem(pfd), -1);
+		if(n < 0){
+			if(errno == EINTR)
+				continue;
+			break;
+		}
+		if(pfd[1].revents & POLLIN)
+			checkownerwake();
+		if(pfd[0].revents)
+			while((ev = xcb_poll_for_event(conn)) != nil){
+				type = ev->response_type & ~0x80;
+				if(type == XCB_MAPPING_NOTIFY){
+					if(kinit() < 0)
+						ximlog("cannot refresh keyboard mapping");
+				}else
+					xcb_im_filter_event(xim, ev);
+				free(ev);
+				/* Ownership changes outrank the next queued X event. */
+				checkownerwake();
+			}
+		if(pfd[0].revents & (POLLERR|POLLHUP|POLLNVAL))
 			break;
-		type = ev->response_type & ~0x80;
-		if(type == XCB_MAPPING_NOTIFY){
-			if(kinit() < 0)
-				ximlog("cannot refresh keyboard mapping");
-		}else
-			xcb_im_filter_event(xim, ev);
-		free(ev);
 	}
 	if(xcb_connection_has_error(conn))
 		ximlog("X server disconnected");