first commit

.gitignore

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+*.o
+emxkb

Makefile

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+PKGS      = x11
+
+INCS     := $(shell pkg-config --cflags $(PKGS)) -I./
+CFLAGS   := -std=gnu99 -ggdb -W -Wall -Wextra $(INCS) $(CFLAGS)
+
+LIBS     := $(shell pkg-config --libs $(PKGS))
+LDFLAGS  := $(LIBS) $(LDFLAGS) -Wl,--export-dynamic
+
+SRCS  = $(wildcard *.c)
+HEADS = $(wildcard *.h)
+OBJS  = $(foreach obj,$(SRCS:.c=.o),$(obj))
+
+emxkb: $(OBJS)
+	@echo $(CC) -o $@ $(OBJS)
+	@$(CC) -o $@ $(OBJS) $(LDFLAGS)
+
+$(OBJS): $(HEADS)
+
+.c.o:
+	@echo $(CC) -c $< -o $@
+	@$(CC) -c $(CFLAGS) $(CPPFLAGS) $< -o $@
+
+clean:
+	rm -f emxkb $(OBJS)
+
+all: emxkb
+

README

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+X11 keyboard switcher.
+emxkb switches Emacs input method instead xkb group
+if focused window is Emacs' window.

emxkb.c

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+/* Thanks to Evgeny Chukreev © 2005, GNU GPL */
+/* See http://akshaal.livejournal.com/58473.html */
+/* Modified a little by Bzek .) */
+/* Modified by Roman Leonov */
+
+/* Usage:
+ *      emxkb 0  # For first  group
+ *      emxkb 1  # For second group
+ */
+
+#include <X11/Xlib.h>
+#include <X11/XKBlib.h>
+#include <X11/keysym.h>
+#include <X11/Xutil.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define EMACS_CLASS "Emacs"
+
+int    lock_group(int window_id, int group);
+int    send_key_to_emacs(Display *display, int window_id, int group);
+Window get_client(Display *display, Window w);
+int    fprintf_return_error(int return_code, const char *message);
+
+int fprintf_return_error(int return_code, const char *message)
+{
+    fprintf(stderr, "%s\n", message);
+    return return_code;
+}
+
+int main(int argc, char *argv[])
+{
+    Display    *display;
+    XClassHint  class_hint;
+    Window      focus;
+    Window      focus_parent;
+    int         unused_rtr;
+    int         group;
+
+    if (argc < 2)
+        return fprintf_return_error(1, "Usage: emxkb <group>");
+    group   = strtol(argv[1], NULL, 0);
+    display = XOpenDisplay(NULL);
+    if (!display)
+        return fprintf_return_error(2, "Can't open display");
+
+    XGetInputFocus(display, &focus, &unused_rtr);
+    if (!focus)
+        return fprintf_return_error(3, "Can't get focus");
+
+    focus_parent = get_client(display, focus);
+    if (!focus_parent)
+        return fprintf_return_error(3, "Can't get focus parent");
+
+    XGetClassHint(display, focus_parent, &class_hint);
+    if (class_hint.res_class != NULL
+        && !strncmp(class_hint.res_class, EMACS_CLASS, strlen(EMACS_CLASS)))
+    {
+        /* Yeah, Emacs! Send a key. */
+        if (!send_key_to_emacs(display, focus, group))
+            return fprintf_return_error(4, "Failed during sending a key to Emacs");
+        /* Change group to 0 (it should be "us") for Emacs */
+        group = 0;
+    }
+    if (!lock_group(focus, group))
+        return fprintf_return_error(5, "Failed during locking group");
+    XCloseDisplay(display);
+    return EXIT_SUCCESS;
+}
+
+Window get_client(Display *display, Window w)
+{
+    int    done = False;
+    Atom   atom = XInternAtom(display, "WM_STATE", False);
+    while (!done)
+    {
+        if (w == 0) return 0;
+        long unsigned int  items      = 0;
+        Atom               unused_atr = 0;
+        int                unused_afr = 0;
+        unsigned long      unused_bar = 0;
+        unsigned char     *unused_prop;
+        if (Success != XGetWindowProperty(display, w, atom,
+                                          0, (~0L), False,
+                                          AnyPropertyType, &unused_atr, &unused_afr,
+                                          &items,
+                                          &unused_bar, &unused_prop))
+        {
+            return 0;
+        }
+        if (items == 0)
+        {
+            Window parent;
+            Window *children = NULL;
+            Window unused_root;
+            unsigned int unused_nchildren_return;
+            XQueryTree(display, w, &unused_root, &parent, &children, &unused_nchildren_return);
+            if (children != NULL)
+                XFree(children);
+            w = parent;
+        }
+        else
+        {
+            done = True;
+        }
+    }
+    return w;
+}
+
+int send_key_to_emacs(Display *display, int window_id, int group)
+{
+    XKeyEvent event;
+
+    /* Init event */
+    memset(&event, 0, sizeof(event));
+    event.window  = window_id;
+    event.display = display;
+    event.root    = RootWindow(display, DefaultScreen(display));
+    event.state   = 0;
+    event.keycode = XKeysymToKeycode(display, XStringToKeysym("space"));
+
+    switch (group)
+    {
+    case 0:
+        event.state = Mod4Mask;
+        /* event.keycode = XKeysymToKeycode(display, XStringToKeysym("F31")); */
+        break;
+    case 1:
+        event.state = Mod3Mask;
+        /* event.keycode = XKeysymToKeycode(display, XStringToKeysym("F32")); */
+        break;
+    default:
+        event.state = Mod4Mask;
+        /* event.keycode = XKeysymToKeycode(display, XStringToKeysym("F31")); */
+        break;
+    }
+
+    /* Send KeyPress event */
+    event.type = KeyPress;
+    if (!XSendEvent(display, window_id, False, 0, (XEvent*) &event))
+        return fprintf_return_error(False, "send_key_to_emacs(): Can't send KeyPress event");
+    /* Send KeyRelease event */
+    event.type = KeyRelease;
+    if (!XSendEvent(display, window_id, False, 0, (XEvent*) &event))
+        return fprintf_return_error(False, "send_key_to_emacs(): Can't send KeyRelease event");
+
+    XSync(display, False);
+    return True;
+}
+
+int lock_group(int window_id, int group)
+{
+    Display *xkb_display = XkbOpenDisplay(NULL, NULL, NULL, NULL, NULL, NULL);
+    if (!xkb_display)
+        return fprintf_return_error(False, "lock_group(): Can't open display");
+    /* Init XKB */
+    if (!XkbQueryExtension(xkb_display, NULL, NULL, NULL, NULL, NULL))
+        return fprintf_return_error(False, "lock_group(): Can't init XKB");
+    /* Set Focus */
+    if (window_id > 0)
+    {
+        XSetInputFocus(xkb_display, window_id, RevertToParent, CurrentTime);
+        XSync(xkb_display, False);
+    }
+    if (!XkbLockGroup(xkb_display, XkbUseCoreKbd, abs(group % 4)))
+        return fprintf_return_error(False, "lock_group(): Can't lock group");
+
+    XSync(xkb_display, False);
+    XCloseDisplay(xkb_display);
+    return True;
+}