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Date:: Sat May 19 21:46:50 2018 UTC
Message:: read a variable length list of completion
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1 /* mymenu -- simple dmenu alternative */
2 
3 /* Copyright (C) 2018  Omar Polo <omar.polo@europecom.net>
4  *
5  * This program is free software: you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation, either version 3 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
17  */
18 
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>    // strdup, strnlen, ...
22 #include <ctype.h>     // isalnum
23 #include <locale.h>    // setlocale
24 #include <unistd.h>
25 #include <sysexits.h>
26 #include <stdbool.h>
27 #include <limits.h>
28 #include <errno.h>
29 
30 #include <X11/Xlib.h>
31 #include <X11/Xutil.h> // XLookupString
32 #include <X11/Xresource.h>
33 #include <X11/Xcms.h>  // colors
34 #include <X11/keysym.h>
35 
36 #ifdef USE_XINERAMA
37 # include <X11/extensions/Xinerama.h>
38 #endif
39 
40 #define nil NULL
41 #define resname "MyMenu"
42 #define resclass "mymenu"
43 
44 #define MIN(X, Y) (((X) < (Y)) ? (X) : (Y))
45 #define MAX(a, b) ((a) > (b) ? (a) : (b))
46 #define OVERLAP(a,b,c,d) (((a)==(c) && (b)==(d)) || MIN((a)+(b), (c)+(d)) - MAX((a), (c)) > 0)
47 #define INTERSECT(x,y,w,h,x1,y1,w1,h1) (OVERLAP((x),(w),(x1),(w1)) && OVERLAP((y),(h),(y1),(h1)))
48 
49 #define update_completions(cs, text, lines) {   \
50     compl_delete(cs);                           \
51     cs = filter(text, lines);                   \
52   }
53 
54 // TODO: dynamic?
55 #define INITIAL_ITEMS 64
56 
57 #define TODO(s) {                               \
58     fprintf(stderr, "TODO! " s "\n");           \
59   }
60 
61 #define cannot_allocate_memory {                        \
62     fprintf(stderr, "Could not allocate memory\n");     \
63     exit(EX_UNAVAILABLE);                               \
64   }
65 
66 #define check_allocation(a) {     \
67     if (a == nil)                 \
68       cannot_allocate_memory;     \
69   }
70 
71 enum state {LOOPING, OK, ERR};
72 
73 struct rendering {
74   Display *d;
75   Window w;
76   GC prompt;
77   GC prompt_bg;
78   GC completion;
79   GC completion_bg;
80   GC completion_highlighted;
81   GC completion_highlighted_bg;
82   int width;
83   int height;
84   XFontSet *font;
85   bool horizontal_layout;
86 };
87 
88 struct completions {
89   char *completion;
90   bool selected;
91   struct completions *next;
92 };
93 
94 struct completions *compl_new() {
95   struct completions *c = malloc(sizeof(struct completions));
96 
97   if (c == nil)
98     return c;
99 
100   c->completion = nil;
101   c->selected = false;
102   c->next = nil;
103   return c;
104 }
105 
106 void compl_delete(struct completions *c) {
107   free(c);
108 }
109 
110 struct completions *compl_select_next(struct completions *c, bool n) {
111   if (c == nil)
112     return nil;
113   if (n) {
114     c->selected = true;
115     return c;
116   }
117 
118   struct completions *orig = c;
119   while (c != nil) {
120     if (c->selected) {
121       c->selected = false;
122       if (c->next != nil) {
123         // the current one is selected and the next one exists
124         c->next->selected = true;
125         return c->next;
126       } else {
127         // the current one is selected and the next one is nill,
128         // select the first one
129         orig->selected = true;
130         return orig;
131       }
132     }
133     c = c->next;
134   }
135   return nil;
136 }
137 
138 struct completions *compl_select_prev(struct completions *c, bool n) {
139   if (c == nil)
140     return nil;
141 
142   struct completions *cc = c;
143 
144   if (n) // select the last one
145     while (cc != nil) {
146       if (cc->next == nil) {
147         cc->selected = true;
148         return cc;
149       }
150       cc = cc->next;
151     }
152   else // select the previous one
153     while (cc != nil) {
154       if (cc->next != nil && cc->next->selected) {
155         cc->next->selected = false;
156         cc->selected = true;
157         return cc;
158       }
159       cc = cc->next;
160     }
161   
162   return nil;
163 }
164 
165 struct completions *filter(char *text, char **lines) {
166   int i = 0;
167   struct completions *root = compl_new();
168   struct completions *c = root;
169 
170   for (;;) {
171     char *l = lines[i];
172     if (l == nil)
173       break;
174 
175     if (strstr(l, text) != nil) {
176       c->next = compl_new();
177       c = c->next;
178       c->completion = l;
179     }
180 
181     ++i;
182   }
183 
184   struct completions *r = root->next;
185   compl_delete(root);
186   return r;
187 }
188 
189 // push the character c at the end of the string pointed by p
190 int pushc(char **p, int maxlen, char c) {
191   int len = strnlen(*p, maxlen);
192 
193   if (!(len < maxlen -2)) {
194     maxlen += maxlen >> 1;
195     char *newptr = realloc(*p, maxlen);
196     if (newptr == nil) { // bad!
197       return -1;
198     }
199     *p = newptr;
200   }
201 
202   (*p)[len] = c;
203   (*p)[len+1] = '\0';
204   return maxlen;
205 }
206 
207 int utf8strnlen(char *s, int maxlen) {
208   int len = 0;
209   while (*s && maxlen > 0) {
210     len += (*s++ & 0xc0) != 0x80;
211     maxlen--;
212   }
213   return len;
214 }
215 
216 // remove the last *glyph* from the *utf8* string!
217 // this is different from just setting the last byte to 0 (in some
218 // cases ofc). The actual implementation is quite inefficient because
219 // it remove the last char until the number of glyphs doesn't change
220 void popc(char *p, int maxlen) {
221   int len = strnlen(p, maxlen);
222 
223   if (len == 0)
224     return;
225 
226   int ulen = utf8strnlen(p, maxlen);
227   while (len > 0 && utf8strnlen(p, maxlen) == ulen) {
228     len--;
229     p[len] = 0;
230   }
231 }
232 
233 // read an arbitrary long line from stdin and return a pointer to it
234 // TODO: resize the allocated memory to exactly fit the string once
235 // read?
236 char *readline(bool *eof) {
237   int maxlen = 8;
238   char *str = calloc(maxlen, sizeof(char));
239   if (str == nil) {
240     fprintf(stderr, "Cannot allocate memory!\n");
241     exit(EX_UNAVAILABLE);
242   }
243 
244   int c;
245   while((c = getchar()) != EOF) {
246     if (c == '\n')
247       return str;
248     else
249       maxlen = pushc(&str, maxlen, c);
250 
251     if (maxlen == -1) {
252       fprintf(stderr, "Cannot allocate memory!\n");
253       exit(EX_UNAVAILABLE);
254     }
255   }
256   *eof = true;
257   return str;
258 }
259 
260 int readlines (char ***lns, int items) {
261   bool finished = false;
262   int n = 0;
263   char **lines = *lns;
264   while (true) {
265     lines[n] = readline(&finished);
266 
267     if (strlen(lines[n]) == 0 || lines[n][0] == '\n')
268       --n; // forget about this line
269 
270     if (finished)
271       break;
272 
273     ++n;
274 
275     if (n == items - 1) {
276       items += items >>1;
277       char **l = realloc(lines, sizeof(char*) * items);
278       check_allocation(l);
279       *lns = l;
280       lines = l;
281     }
282   }
283 
284   n++;
285   lines[n] = nil;
286   return items;
287 }
288 
289 // |------------------|----------------------------------------------|
290 // | 20 char text     | completion | completion | completion | compl |
291 // |------------------|----------------------------------------------|
292 void draw_horizontally(struct rendering *r, char *text, struct completions *cs) {
293   // TODO: make these dynamic?
294   int prompt_width = 20; // char
295   int padding = 10;
296   /* int start_at = XTextWidth(r->font, " ", 1) * prompt_width + padding; */
297 
298   XRectangle rect;
299   int start_at = XmbTextExtents(*r->font, " ", 1, nil, &rect);
300   start_at = start_at * prompt_width + padding;
301 
302   int texty = (rect.height + r->height) >>1;
303 
304   XFillRectangle(r->d, r->w, r->prompt_bg, 0, 0, start_at, r->height);
305 
306   int text_len = strlen(text);
307   if (text_len > prompt_width)
308     text = text + (text_len - prompt_width);
309   /* XDrawString(r->d, r->w, r->prompt, padding, texty, text, MIN(text_len, prompt_width)); */
310   Xutf8DrawString(r->d, r->w, *r->font, r->prompt, padding, texty, text, MIN(text_len, prompt_width));
311 
312   XFillRectangle(r->d, r->w, r->completion_bg, start_at, 0, r->width, r->height);
313 
314   while (cs != nil) {
315     GC g = cs->selected ? r->completion_highlighted    : r->completion;
316     GC h = cs->selected ? r->completion_highlighted_bg : r->completion_bg;
317 
318     int len = strlen(cs->completion);
319     /* int text_width = XTextWidth(r->font, cs->completion, len); */
320     int text_width = XmbTextExtents(*r->font, cs->completion, len, nil, nil);
321 
322     XFillRectangle(r->d, r->w, h, start_at, 0, text_width + padding*2, r->height);
323 
324     /*  XDrawString(r->d, r->w,           g, start_at + padding, texty, cs->completion, len); */
325     Xutf8DrawString(r->d, r->w, *r->font, g, start_at + padding, texty, cs->completion, len);
326 
327     start_at += text_width + padding * 2;
328 
329     cs = cs->next;
330   }
331 
332   XFlush(r->d);
333 }
334 
335 // |-----------------------------------------------------------------|
336 // |  prompt                                                         |
337 // |-----------------------------------------------------------------|
338 // |  completion                                                     |
339 // |-----------------------------------------------------------------|
340 // |  completion                                                     |
341 // |-----------------------------------------------------------------|
342 // TODO: dunno why but in the call to Xutf8DrawString, by logic,
343 // should be padding and not padding*2, but the text doesn't seem to
344 // be vertically centered otherwise....
345 void draw_vertically(struct rendering *r, char *text, struct completions *cs) {
346   int padding = 10; // TODO make this dynamic
347 
348   XRectangle rect;
349   XmbTextExtents(*r->font, "fjpgl", 5, &rect, nil);
350   int start_at = rect.height + padding*2;
351 
352   XFillRectangle(r->d, r->w, r->completion_bg, 0, 0, r->width, r->height);
353   XFillRectangle(r->d, r->w, r->prompt_bg, 0, 0, r->width, start_at);
354   Xutf8DrawString(r->d, r->w, *r->font, r->prompt, padding, padding*2, text, strlen(text));
355 
356   while (cs != nil) {
357     GC g = cs->selected ? r->completion_highlighted    : r->completion;
358     GC h = cs->selected ? r->completion_highlighted_bg : r->completion_bg;
359 
360     int len = strlen(cs->completion);
361     XmbTextExtents(*r->font, cs->completion, len, &rect, nil);
362     XFillRectangle(r->d, r->w, h, 0, start_at, r->width, rect.height + padding*2);
363     Xutf8DrawString(r->d, r->w, *r->font, g, padding, start_at + padding*2, cs->completion, len);
364 
365     start_at += rect.height + padding *2;
366     cs = cs->next;
367   }
368 
369   XFlush(r->d);
370 }
371 
372 void draw(struct rendering *r, char *text, struct completions *cs) {
373   if (r->horizontal_layout)
374     draw_horizontally(r, text, cs);
375   else
376     draw_vertically(r, text, cs);
377 }
378 
379 /* Set some WM stuff */
380 void set_win_atoms_hints(Display *d, Window w, int width, int height) {
381   Atom type;
382   type = XInternAtom(d, "_NET_WM_WINDOW_TYPE_DOCK", false);
383   XChangeProperty(
384                   d,
385                   w,
386                   XInternAtom(d, "_NET_WM_WINDOW_TYPE", false),
387                   XInternAtom(d, "ATOM", false),
388                   32,
389                   PropModeReplace,
390                   (unsigned char *)&type,
391                   1
392                   );
393 
394   /* some window managers honor this properties */
395   type = XInternAtom(d, "_NET_WM_STATE_ABOVE", false);
396   XChangeProperty(d,
397                   w,
398                   XInternAtom(d, "_NET_WM_STATE", false),
399                   XInternAtom(d, "ATOM", false),
400                   32,
401                   PropModeReplace,
402                   (unsigned char *)&type,
403                   1
404                   );
405 
406   type = XInternAtom(d, "_NET_WM_STATE_FOCUSED", false);
407   XChangeProperty(d,
408                   w,
409                   XInternAtom(d, "_NET_WM_STATE", false),
410                   XInternAtom(d, "ATOM", false),
411                   32,
412                   PropModeAppend,
413                   (unsigned char *)&type,
414                   1
415                   );
416 
417   // setting window hints
418   XClassHint *class_hint = XAllocClassHint();
419   if (class_hint == nil) {
420     fprintf(stderr, "Could not allocate memory for class hint\n");
421     exit(EX_UNAVAILABLE);
422   }
423   class_hint->res_name = "mymenu";
424   class_hint->res_class = "mymenu";
425   XSetClassHint(d, w, class_hint);
426   XFree(class_hint);
427 
428   XSizeHints *size_hint = XAllocSizeHints();
429   if (size_hint == nil) {
430     fprintf(stderr, "Could not allocate memory for size hint\n");
431     exit(EX_UNAVAILABLE);
432   }
433   size_hint->min_width = width;
434   size_hint->base_width = width;
435   size_hint->min_height = height;
436   size_hint->base_height = height;
437 
438   XFlush(d);
439 }
440 
441 void get_wh(Display *d, Window *w, int *width, int *height) {
442   XWindowAttributes win_attr;
443   XGetWindowAttributes(d, *w, &win_attr);
444   *height = win_attr.height;
445   *width = win_attr.width;
446 }
447 
448 // I know this may seem a little hackish BUT is the only way I managed
449 // to actually grab that goddam keyboard. Only one call to
450 // XGrabKeyboard does not always end up with the keyboard grabbed!
451 int take_keyboard(Display *d, Window w) {
452   int i;
453   for (i = 0; i < 100; i++) {
454     if (XGrabKeyboard(d, w, True, GrabModeAsync, GrabModeAsync, CurrentTime) == GrabSuccess)
455       return 1;
456     usleep(1000);
457   }
458   return 0;
459 }
460 
461 void release_keyboard(Display *d) {
462   XUngrabKeyboard(d, CurrentTime);
463 }
464 
465 int parse_integer(const char *str, int default_value, int max) {
466   int len = strlen(str);
467   if (len > 0 && str[len-1] == '%') {
468     char *cpy = strdup(str);
469     check_allocation(cpy);
470     cpy[len-1] = '\0';
471     int val = parse_integer(cpy, default_value, max);
472     free(cpy);
473     return val * max / 100;
474   }
475 
476   errno = 0;
477   char *ep;
478   long lval = strtol(str, &ep, 10);
479   if (str[0] == '\0' || *ep != '\0') { // NaN
480     fprintf(stderr, "'%s' is not a valid number! Using %d as default.\n", str, default_value);
481     return default_value;
482   }
483   if ((errno == ERANGE && (lval == LONG_MAX || lval == LONG_MIN)) ||
484       (lval > INT_MAX || lval < INT_MIN)) {
485     fprintf(stderr, "%s out of range! Using %d as default.\n", str, default_value);
486     return default_value;
487   }
488   return lval;
489 }
490 
491 int parse_int_with_middle(const char *str, int default_value, int max, int self) {
492   if (!strcmp(str, "middle")) {
493     return (max - self)/2;
494   }
495   return parse_integer(str, default_value, max);
496 }
497 
498 int main() {
499   /* char *lines[INITIAL_ITEMS] = {0}; */
500   char **lines = calloc(INITIAL_ITEMS, sizeof(char*));
501   readlines(&lines, INITIAL_ITEMS);
502 
503   setlocale(LC_ALL, getenv("LANG"));
504 
505   enum state status = LOOPING;
506 
507   // where the monitor start (used only with xinerama)
508   int offset_x = 0;
509   int offset_y = 0;
510 
511   // width and height of the window
512   int width = 400;
513   int height = 20;
514 
515   // position on the screen
516   int x = 0;
517   int y = 0;
518 
519   char *fontname = strdup("fixed");
520   check_allocation(fontname);
521 
522   int textlen = 10;
523   char *text = malloc(textlen * sizeof(char));
524   check_allocation(text);
525 
526   struct completions *cs = filter(text, lines);
527   bool nothing_selected = true;
528 
529   // start talking to xorg
530   Display *d = XOpenDisplay(nil);
531   if (d == nil) {
532     fprintf(stderr, "Could not open display!\n");
533     return EX_UNAVAILABLE;
534   }
535 
536   // get display size
537   // XXX: is getting the default root window dimension correct?
538   XWindowAttributes xwa;
539   XGetWindowAttributes(d, DefaultRootWindow(d), &xwa);
540   int d_width = xwa.width;
541   int d_height = xwa.height;
542 
543 #ifdef USE_XINERAMA
544   // TODO: this bit still needs to be improved
545   if (XineramaIsActive(d)) {
546     int monitors;
547     XineramaScreenInfo *info = XineramaQueryScreens(d, &monitors);
548     if (info)
549       for (int i = 0; i < monitors; ++i) {
550         if (INTERSECT(x, y, 1, 1, info[i].x_org, info[i].y_org, info[i].width, info[i].height)) {
551           offset_x = info[x].x_org;
552           offset_y = info[y].y_org;
553           d_width = info[i].width;
554           d_height = info[i].height;
555         }
556       }
557     XFree(info);
558   }
559 #endif
560 
561   /* fprintf(stderr, "offset_x:\t%d\n" */
562   /*                 "offset_y:\t%d\n" */
563   /*                 "d_width:\t%d\n" */
564   /*                 "d_height:\t%d\n" */
565   /*         , offset_x, offset_y, d_width, d_height); */
566 
567   Colormap cmap = DefaultColormap(d, DefaultScreen(d));
568   XColor p_fg, p_bg,
569     compl_fg, compl_bg,
570     compl_highlighted_fg, compl_highlighted_bg;
571 
572   bool horizontal_layout = true;
573 
574   // read resource
575   XrmInitialize();
576   char *xrm = XResourceManagerString(d);
577   XrmDatabase xdb = nil;
578   if (xrm != nil) {
579     xdb = XrmGetStringDatabase(xrm);
580     XrmValue value;
581     char *datatype[20];
582 
583     if (XrmGetResource(xdb, "MyMenu.font", "*", datatype, &value) == true) {
584       fontname = strdup(value.addr);
585       check_allocation(fontname);
586     }
587     else
588       fprintf(stderr, "no font defined, using %s\n", fontname);
589 
590     if (XrmGetResource(xdb, "MyMenu.layout", "*", datatype, &value) == true) {
591       char *v = strdup(value.addr);
592       check_allocation(v);
593       horizontal_layout = !strcmp(v, "horizontal");
594       free(v);
595     }
596     else
597       fprintf(stderr, "no layout defined, using horizontal\n");
598 
599     if (XrmGetResource(xdb, "MyMenu.width", "*", datatype, &value) == true)
600       width = parse_integer(value.addr, width, d_width);
601     else
602       fprintf(stderr, "no width defined, using %d\n", width);
603 
604     if (XrmGetResource(xdb, "MyMenu.height", "*", datatype, &value) == true)
605       height = parse_integer(value.addr, height, d_height);
606     else
607       fprintf(stderr, "no height defined, using %d\n", height);
608 
609     if (XrmGetResource(xdb, "MyMenu.x", "*", datatype, &value) == true)
610       x = parse_int_with_middle(value.addr, x, d_width, width);
611     else
612       fprintf(stderr, "no x defined, using %d\n", width);
613 
614     if (XrmGetResource(xdb, "MyMenu.y", "*", datatype, &value) == true)
615       y = parse_int_with_middle(value.addr, y, d_height, height);
616     else
617       fprintf(stderr, "no y defined, using %d\n", height);
618 
619     XColor tmp;
620     // TODO: tmp needs to be free'd after every allocation?
621 
622     // prompt
623     if (XrmGetResource(xdb, "MyMenu.prompt.foreground", "*", datatype, &value) == true)
624       XAllocNamedColor(d, cmap, value.addr, &p_fg, &tmp);
625     else
626       XAllocNamedColor(d, cmap, "white", &p_fg, &tmp);
627 
628     if (XrmGetResource(xdb, "MyMenu.prompt.background", "*", datatype, &value) == true)
629       XAllocNamedColor(d, cmap, value.addr, &p_bg, &tmp);
630     else
631       XAllocNamedColor(d, cmap, "black", &p_bg, &tmp);
632 
633     // completion
634     if (XrmGetResource(xdb, "MyMenu.completion.foreground", "*", datatype, &value) == true)
635       XAllocNamedColor(d, cmap, value.addr, &compl_fg, &tmp);
636     else
637       XAllocNamedColor(d, cmap, "white", &compl_fg, &tmp);
638 
639     if (XrmGetResource(xdb, "MyMenu.completion.background", "*", datatype, &value) == true)
640       XAllocNamedColor(d, cmap, value.addr, &compl_bg, &tmp);
641     else
642       XAllocNamedColor(d, cmap, "black", &compl_bg, &tmp);
643 
644     // completion highlighted
645     if (XrmGetResource(xdb, "MyMenu.completion_highlighted.foreground", "*", datatype, &value) == true)
646       XAllocNamedColor(d, cmap, value.addr, &compl_highlighted_fg, &tmp);
647     else
648       XAllocNamedColor(d, cmap, "black", &compl_highlighted_fg, &tmp);
649 
650     if (XrmGetResource(xdb, "MyMenu.completion_highlighted.background", "*", datatype, &value) == true)
651       XAllocNamedColor(d, cmap, value.addr, &compl_highlighted_bg, &tmp);
652     else
653       XAllocNamedColor(d, cmap, "white", &compl_highlighted_bg, &tmp);
654   } else {
655     XColor tmp;
656     XAllocNamedColor(d, cmap, "white", &p_fg, &tmp);
657     XAllocNamedColor(d, cmap, "black", &p_bg, &tmp);
658     XAllocNamedColor(d, cmap, "white", &compl_fg, &tmp);
659     XAllocNamedColor(d, cmap, "black", &compl_bg, &tmp);
660     XAllocNamedColor(d, cmap, "black", &compl_highlighted_fg, &tmp);
661     XAllocNamedColor(d, cmap, "white", &compl_highlighted_bg, &tmp);
662   }
663 
664   // load the font
665   /* XFontStruct *font = XLoadQueryFont(d, fontname); */
666   /* if (font == nil) { */
667   /*   fprintf(stderr, "Unable to load %s font\n", fontname); */
668   /*   font = XLoadQueryFont(d, "fixed"); */
669   /* } */
670   // load the font
671   char **missing_charset_list;
672   int missing_charset_count;
673   XFontSet font = XCreateFontSet(d, fontname, &missing_charset_list, &missing_charset_count, nil);
674   if (font == nil) {
675     fprintf(stderr, "Unable to load the font(s) %s\n", fontname);
676     return EX_UNAVAILABLE;
677   }
678 
679   // create the window
680   XSetWindowAttributes attr;
681 
682   Window w = XCreateWindow(d,                                   // display
683                            DefaultRootWindow(d),                // parent
684                            x + offset_x, y + offset_y,          // x y
685                            width, height,                       // w h
686                            0,                                   // border width
687                            DefaultDepth(d, DefaultScreen(d)),   // depth
688                            InputOutput,                         // class
689                            DefaultVisual(d, DefaultScreen(d)),  // visual
690                            0,                                   // value mask
691                            &attr);
692 
693   set_win_atoms_hints(d, w, width, height);
694 
695   // we want some events
696   XSelectInput(d, w, StructureNotifyMask | KeyPressMask | KeyReleaseMask | KeymapStateMask);
697 
698   // make the window appear on the screen
699   XMapWindow(d, w);
700 
701   // wait for the MapNotify event (i.e. the event "window rendered")
702   for (;;) {
703     XEvent e;
704     XNextEvent(d, &e);
705     if (e.type == MapNotify)
706       break;
707   }
708 
709   // get the *real* width & height after the window was rendered
710   get_wh(d, &w, &width, &height);
711 
712   // grab keyboard
713   take_keyboard(d, w);
714 
715   // Create some graphics contexts
716   XGCValues values;
717   /* values.font = font->fid; */
718 
719   struct rendering r = {
720     .d                          = d,
721     .w                          = w,
722     .prompt                     = XCreateGC(d, w, 0, &values),
723     .prompt_bg                  = XCreateGC(d, w, 0, &values),
724     .completion                 = XCreateGC(d, w, 0, &values),
725     .completion_bg              = XCreateGC(d, w, 0, &values),
726     .completion_highlighted     = XCreateGC(d, w, 0, &values),
727     .completion_highlighted_bg  = XCreateGC(d, w, 0, &values),
728     /* .prompt                     = XCreateGC(d, w, GCFont, &values), */
729     /* .prompt_bg                  = XCreateGC(d, w, GCFont, &values), */
730     /* .completion                 = XCreateGC(d, w, GCFont, &values), */
731     /* .completion_bg              = XCreateGC(d, w, GCFont, &values), */
732     /* .completion_highlighted     = XCreateGC(d, w, GCFont, &values), */
733     /* .completion_highlighted_bg  = XCreateGC(d, w, GCFont, &values), */
734     .width                      = width,
735     .height                     = height,
736     .font                       = &font,
737     .horizontal_layout          = horizontal_layout
738   };
739 
740   // load the colors in our GCs
741   XSetForeground(d, r.prompt, p_fg.pixel);
742   XSetForeground(d, r.prompt_bg, p_bg.pixel);
743   XSetForeground(d, r.completion, compl_fg.pixel);
744   XSetForeground(d, r.completion_bg, compl_bg.pixel);
745   XSetForeground(d, r.completion_highlighted, compl_highlighted_fg.pixel);
746   XSetForeground(d, r.completion_highlighted_bg, compl_highlighted_bg.pixel);
747 
748   // open the X input method
749   XIM xim = XOpenIM(d, xdb, resname, resclass);
750   check_allocation(xim);
751 
752   XIMStyles *xis = nil;
753   if (XGetIMValues(xim, XNQueryInputStyle, &xis, NULL) || !xis) {
754     fprintf(stderr, "Input Styles could not be retrieved\n");
755     return EX_UNAVAILABLE;
756   }
757 
758   XIMStyle bestMatchStyle = 0;
759   for (int i = 0; i < xis->count_styles; ++i) {
760     XIMStyle ts = xis->supported_styles[i];
761     if (ts == (XIMPreeditNothing | XIMStatusNothing)) {
762       bestMatchStyle = ts;
763       break;
764     }
765   }
766   XFree(xis);
767 
768   if (!bestMatchStyle) {
769     fprintf(stderr, "No matching input style could be determined\n");
770   }
771 
772   XIC xic = XCreateIC(xim, XNInputStyle, bestMatchStyle, XNClientWindow, w, XNFocusWindow, w, NULL);
773   check_allocation(xic);
774 
775   // draw the window for the first time
776   draw(&r, text, cs);
777 
778   // main loop
779   while (status == LOOPING) {
780     XEvent e;
781     XNextEvent(d, &e);
782 
783     if (XFilterEvent(&e, w))
784       continue;
785 
786     switch (e.type) {
787     case KeymapNotify:
788       XRefreshKeyboardMapping(&e.xmapping);
789       break;
790 
791     case KeyRelease: break; // ignore this
792 
793     case KeyPress: {
794       XKeyPressedEvent *ev = (XKeyPressedEvent*)&e;
795 
796       if (ev->keycode == XKeysymToKeycode(d, XK_Tab)) {
797         bool shift = (ev->state & ShiftMask);
798         struct completions *n = shift ? compl_select_prev(cs, nothing_selected)
799                                       : compl_select_next(cs, nothing_selected);
800         if (n != nil) {
801           nothing_selected = false;
802           free(text);
803           text = strdup(n->completion);
804           if (text == nil) {
805             fprintf(stderr, "Memory allocation error!\n");
806             status = ERR;
807             break;
808           }
809           textlen = strlen(text);
810         }
811         draw(&r, text, cs);
812         break;
813       }
814 
815       if (ev->keycode == XKeysymToKeycode(d, XK_BackSpace)) {
816         nothing_selected = true;
817         popc(text, textlen);
818         update_completions(cs, text, lines);
819         draw(&r, text, cs);
820         break;
821       }
822 
823       if (ev->keycode == XKeysymToKeycode(d, XK_Return)) {
824         status = OK;
825         break;
826       }
827 
828       if (ev->keycode == XKeysymToKeycode(d, XK_Escape)) {
829         status = ERR;
830         break;
831       }
832 
833       // try to read what the user pressed
834       int symbol = 0;
835       Status s = 0;
836       Xutf8LookupString(xic, ev, (char*)&symbol, 4, 0, &s);
837 
838       if (s == XBufferOverflow) {
839         // should not happen since there are no utf-8 characters
840         // larger than 24bits, but is something to be aware of when
841         // used to directly write to a string buffer
842         fprintf(stderr, "Buffer overflow when trying to create keyboard symbol map.\n");
843         break;
844       }
845       char *str = (char*)&symbol;
846 
847       if (ev->state & ControlMask) {
848         // check for some key bindings
849         if (!strcmp(str, "")) { // C-u
850           nothing_selected = true;
851           for (int i = 0; i < textlen; ++i)
852             text[i] = 0;
853           update_completions(cs, text, lines);
854         }
855         if (!strcmp(str, "")) { // C-h
856           nothing_selected = true;
857           popc(text, textlen);
858           update_completions(cs, text, lines);
859         }
860         if (!strcmp(str, "")) { // C-w
861           nothing_selected = true;
862 
863           // `textlen` is the length of the allocated string, not the
864           // length of the ACTUAL string
865           int p = strlen(text) - 1;
866           if (p >= 0) { // delete the current char
867             text[p] = 0;
868             p--;
869           }
870           while (p >= 0 && isalnum(text[p])) {
871             text[p] = 0;
872             p--;
873           }
874           // erase also trailing white space
875           while (p >= 0 && isspace(text[p])) {
876             text[p] = 0;
877             p--;
878           }
879           update_completions(cs, text, lines);
880         }
881         if (!strcmp(str, "\r")) { // C-m
882           status = OK;
883         }
884         draw(&r, text, cs);
885         break;
886       }
887 
888       int str_len = strlen(str);
889       for (int i = 0; i < str_len; ++i) {
890         textlen = pushc(&text, textlen, str[i]);
891         if (textlen == -1) {
892           fprintf(stderr, "Memory allocation error\n");
893           status = ERR;
894           break;
895         }
896         nothing_selected = true;
897         update_completions(cs, text, lines);
898       }
899 
900     }
901       draw(&r, text, cs);
902       break;
903 
904     default:
905       fprintf(stderr, "Unknown event %d\n", e.type);
906     }
907   }
908 
909   release_keyboard(d);
910 
911   if (status == OK)
912     printf("%s\n", text);
913 
914   free(fontname);
915   free(text);
916   free(lines);
917   compl_delete(cs);
918 
919   /* XDestroyWindow(d, w); */
920   XCloseDisplay(d);
921 
922   return status == OK ? 0 : 1;
923 }