C-Menu 0.2.9
A User Interface Toolkit
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menu_engine.c
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1/** @file menu_engine.c
2 @brief The working part of C-Menu Menu
3 @author Bill Waller
4 Copyright (c) 2025
5 MIT License
6 billxwaller@gmail.com
7 @date 2026-02-09
8 */
9
10/** @defgroup menu_engine Menu Engine
11 @brief Main loop and command processor for the C-Menu menu system
12 @details This module contains the core functionality for displaying menus,
13 processing user input, and executing commands associated with menu choices.
14 It handles navigation through menu options, responding to special keys,
15 and managing the display of submenus, pick lists, forms, and views.
16 */
17
18#include "common.h"
19#include <stdlib.h>
20#include <string.h>
21#include <termios.h>
22#include <unistd.h>
23
24unsigned int menu_engine(Init *);
25unsigned int menu_cmd_processor(Init *);
26
27/** @brief The main loop of the menu system.
28 @ingroup menu_engine
29 @param init A pointer to an Init structure containing initialization data for
30 the menu system.
31 @returns an integer indicating the action taken by the user, such as
32 returning to the main menu or exiting the menu system.
33 @details displays the menu and processes user input until the user exits the
34 menu or returns to the main menu.
35 */
36unsigned int menu_engine(Init *init) {
37 uint action;
38 uint i;
39 char tmp_str[MAXLEN];
40 Menu *menu = init->menu;
41 if (menu == nullptr) {
42 Perror("menu_engine: menu is nullptr");
43 return (1);
44 }
45 menu->lines = 0;
46 menu->cols = 0;
47 menu->line_idx = 0;
48 menu->item_count = 0;
49 menu->title[0] = '\0';
50 menu->choice_max_len = 0;
51 menu->text_max_len = 0;
52 parse_menu_description(init);
53 surface_box_win_new(menu->lines, menu->cols, menu->begy, menu->begx, menu->title);
54 UiSurface *sfc = ui_surface[sfc_ptr];
55 if (sfc == nullptr) {
56 ssnprintf(tmp_str, MAXLEN - 1, "surface_box_win_new(%d, %d, %d, %d, %s) failed",
57 menu->lines, menu->cols, menu->begy, menu->begx, menu->title);
58 Perror(tmp_str);
59 return 1;
60 }
61 mbstate_t mbstate;
62 memset(&mbstate, 0, sizeof(mbstate));
63 action = MA_DISPLAY_MENU;
64 while (action) {
65 switch (action) {
66 case MA_RETURN:
67 cm_surface_destroy(sfc);
68 if (sfc_ptr < 0) {
69 destroy_menu(init);
70 return 0;
71 }
72 ui_restore_wins();
73 return 0;
74 case MA_DISPLAY_MENU:
75 for (menu->line_idx = 0; menu->line_idx < menu->item_count;
76 menu->line_idx++) {
77 ui_bkgdset(sfc, WIN, &cell_nt);
78 ui_draw_text_fill(sfc, WIN, menu->line_idx, 0,
79 menu->line[menu->line_idx]->choice_text,
80 menu->cols);
81 ui_bkgdset(sfc, WIN, &cell_nt_hl);
82 ui_mvwaddch(sfc, WIN, menu->line_idx,
83 menu->line[menu->line_idx]->letter_pos,
84 menu->line[menu->line_idx]->choice_letter);
85 ui_bkgdset(sfc, WIN, &cell_nt);
86 ui_render();
87 }
88 action = MA_RESET_MENU;
89 break;
90 case MA_RESET_MENU:
91 menu->line_idx = 0;
92 for (i = 0; i < menu->item_count; i++) {
93 if (menu->line[i]->type == MT_CHOICE) {
94 menu->line_idx = i;
95 break;
96 }
97 }
98 action = MA_CONTINUE;
99 break;
100 case MA_CONTINUE:
101 action = menu_cmd_processor(init);
102 break;
103 default:
104 break;
105 }
106 }
107 destroy_menu(init);
108 return 0;
109}
110/** @brief Processes user input for the menu system.
111 @ingroup menu_engine
112 @param init A pointer to an Init structure containing initialization data
113 for the menu system.
114 @returns an integer indicating the action taken by the user, such as
115 returning to the main menu, displaying a submenu, or executing a command
116 associated with a menu choice.
117 @details handles navigation through the menu options, executing commands
118 associated with menu choices, and responding to special keys such as
119 function keys and mouse clicks.
120 */
121unsigned int menu_cmd_processor(Init *init) {
122 uint i;
123 uint c;
124 char *d;
125 int in_key;
126 char tmp_str[MAXLEN];
127 char earg_str[MAXLEN];
128 char *eargv[MAXARGS];
129 int eargc;
130 UiSurface *sfc = ui_surface[sfc_ptr];
131 mbstate_t mbstate;
132 memset(&mbstate, 0, sizeof(mbstate));
133 Menu *menu = init->menu;
134 ui_keypad(sfc, WIN, true);
135 ui_scrollok(sfc, WIN, false);
136#ifdef UAL_UI
137 ui_mousemask(ALL_MOUSE_EVENTS | REPORT_MOUSE_POSITION);
138#else
139 ui_mice_enable(NCMICE_ALL_EVENTS);
140#endif
141 UiEvent event;
142 // Highlight the currently selected menu choice
143
144 while (1) {
145 ui_bkgdset(sfc, WIN, &cell_nt_rev);
146 ui_draw_text_fill(sfc, WIN, menu->line_idx, 0,
147 menu->line[menu->line_idx]->choice_text,
148 menu->cols);
149 ui_bkgdset(sfc, WIN, &cell_nt_hl_rev);
150 ui_draw_ch_yx(sfc, WIN, menu->line_idx,
151 menu->line[menu->line_idx]->letter_pos,
152 menu->line[menu->line_idx]->choice_letter);
153 ui_bkgdset(sfc, WIN, &cell_nt);
154 // Wait for user input and process it
155 event.y = event.x = -1;
156 ui_wmove(sfc, WIN, menu->line_idx, 1);
157 ui_render();
158 in_key = ui_get_event(sfc, WIN, &event, -1);
159 // Remove the highlight from the currently selected menu choice
160 ui_bkgdset(sfc, WIN, &cell_nt);
161 ui_draw_text_fill(sfc, WIN, menu->line_idx, 0,
162 menu->line[menu->line_idx]->choice_text,
163 menu->cols);
164 ui_bkgdset(sfc, WIN, &cell_nt_hl);
165 ui_draw_ch_yx(sfc, WIN, menu->line_idx,
166 menu->line[menu->line_idx]->letter_pos,
167 menu->line[menu->line_idx]->choice_letter);
168 ui_render();
169 // Initialize the mouse event coordinates to -1 to indicate no mouse
170 // event
171 switch (in_key) {
172 /** Move up to the previous menu choice */
173 case KEY_UP:
174 i = menu->line_idx;
175 while (i > 0) {
176 i--;
177 if (menu->line[i]->type == MT_CHOICE) {
178 menu->line_idx = i;
179 break;
180 }
181 }
182 return (MA_CONTINUE);
183 /** Move down to the next menu choice */
184 case KEY_DOWN:
185 i = menu->line_idx;
186 while (i < menu->item_count - 1) {
187 i++;
188 if (menu->line[i]->type == MT_CHOICE) {
189 menu->line_idx = i;
190 break;
191 }
192 }
193 return (MA_CONTINUE);
194 /** Select the current menu choice and execute its associated
195 * command */
196 case '\n':
197 case KEY_ENTER:
198 break;
199 /** @brief Display help information for the menu system */
200 case '?':
201 case KEY_F01:
202 if (menu->f_help_spec && menu->help_spec[0] != '\0')
203 strnz__cpy(tmp_str, menu->help_spec, MAXLEN - 1);
204 else {
205 strnz__cpy(tmp_str, init->mapp_help, MAXLEN - 1);
206 strnz__cat(tmp_str, "/", MAXLEN - 1);
207 strnz__cat(tmp_str, MENU_HELP_FILE, MAXLEN - 1);
208 }
209 eargc = 0;
210 eargv[eargc++] = strdup("view");
211 eargv[eargc++] = strdup("-Nf");
212 eargv[eargc++] = strdup(tmp_str);
213 eargv[eargc] = nullptr;
214 init->lines = 51;
215 init->cols = 86;
216 init->begy = menu->begy + 1;
217 init->begx = menu->begx + 1;
218 strnz__cpy(init->title, "Menu Help", MAXLEN - 1);
219 popup_view(init, eargc, eargv, init->lines, init->cols, init->begy,
220 init->begx);
221 destroy_argv(eargc, eargv);
222 return (MA_DISPLAY_MENU);
223 /** Exit the menu and return to the previous menu or exit if at top
224 */
225 case KEY_F09:
226 case KEY_BREAK:
227 return (MA_RETURN);
228 /** @brief send default printer output file to printer */
229 case KEY_F07:
230 d = getenv("PRTCMD");
231 if (d == nullptr || *d == '\0')
232 strnz__cpy(earg_str, PRINTCMD, MAXLEN - 1);
233 else
234 strnz__cpy(earg_str, d, MAXLEN - 1);
235 strnz__cat(earg_str, " ", MAXLEN - 1);
236 d = getenv("PRTFILE");
237 if (d == nullptr || *d == '\0') {
238 d = getenv("HOME");
239 if (d == nullptr || *d == '\0')
240 strnz__cat(earg_str, VIEW_PRT_FILE, MAXLEN - 1);
241 else {
242 strnz__cat(earg_str, d, MAXLEN - 1);
243 strnz__cat(earg_str, "/", MAXLEN - 1);
244 strnz__cat(earg_str, VIEW_PRT_FILE, MAXLEN - 1);
245 }
246 } else
247 strnz__cat(earg_str, d, MAXLEN - 1);
248 full_screen_shell(earg_str);
249 return (MA_RESET_MENU);
250 /** @brief open the default editor */
251 case KEY_ALTF(10):
252 ui_restore_wins();
253 return (MA_DISPLAY_MENU);
254 /** @brief process mouse event */
255 case KEY_MOUSE:
256 if (event.y >= menu->item_count)
257 return (MA_CONTINUE);
258 menu->line_idx = event.y;
259 break;
260 case 'q':
261 return (MA_RETURN);
262 break;
263 default:
264 /** @brief If the user presses a key that corresponds to a menu
265 * choice's letter, select that menu choice */
266 for (i = 0; i < menu->item_count; i++) {
267 if (menu->line[i]->raw_text[0] == '_') {
268 if (menu->line[i]->choice_letter == (char)in_key) {
269 menu->line_idx = i;
270 break;
271 }
272 } else {
273 if (menu->line[i]->choice_letter == (char)in_key) {
274 menu->line_idx = i;
275 break;
276 }
277 }
278 }
279 if (i >= menu->item_count)
280 return (MA_CONTINUE);
281 break;
282 }
283 char *s;
284 c = (int)menu->line[menu->line_idx]->command_type;
285 switch (c) {
286 /** @brief Execute the command associated with the selected menu
287 * choice
288 */
289 case CT_DEXE:
290 s = strpbrk(menu->line[menu->line_idx]->command_str, " \t\f\v");
291 strnz__cpy(earg_str, s, MAXLEN - 1);
292 trim(earg_str);
293 eargc = str_to_args(eargv, s, MAX_ARGS);
294 fork_detach_execvp(eargv);
295 destroy_argv(eargc, eargv);
296 return (MA_RESET_MENU);
297 case CT_EXEC:
298 s = strpbrk(menu->line[menu->line_idx]->command_str, " \t\f\v");
299 strnz__cpy(earg_str, s, MAXLEN - 1);
300 trim(earg_str);
301 eargc = str_to_args(eargv, s, MAX_ARGS);
302 stdio_names(stdio_names_str, "menu_engine.c:328");
303 full_screen_fork_exec(eargv);
304 destroy_argv(eargc, eargv);
305 return (MA_RESET_MENU);
306 /** @brief Display help information for the menu system */
307 case CT_HELP:
308 if (menu->f_help_spec && menu->help_spec[0] != '\0')
309 strnz__cpy(tmp_str, menu->help_spec, MAXLEN - 1);
310 else {
311 strnz__cpy(tmp_str, init->mapp_help, MAXLEN - 1);
312 strnz__cat(tmp_str, "/", MAXLEN - 1);
313 strnz__cat(tmp_str, MENU_HELP_FILE, MAXLEN - 1);
314 }
315 eargc = 0;
316 eargv[eargc++] = strdup("view");
317 eargv[eargc++] = strdup("-N");
318 eargv[eargc++] = strdup("f");
319 eargv[eargc++] = strdup(tmp_str);
320 eargv[eargc] = nullptr;
321 init->lines = 40;
322 init->cols = 60;
323 init->begy = menu->begy + 1;
324 init->begx = menu->begx + 1;
325 strnz__cpy(init->title, "Menu Help", MAXLEN - 1);
326 popup_view(init, eargc, eargv, init->lines, init->cols, init->begy,
327 init->begx);
328 destroy_argv(eargc, eargv);
329 return (MA_DISPLAY_MENU);
330 /** @brief Display a submenu or perform an action associated with
331 * the selected menu choice */
332 case CT_MENU:
333 strnz__cpy(earg_str, menu->line[menu->line_idx]->command_str,
334 MAXLEN - 1);
335 eargc = str_to_args(eargv, earg_str, MAX_ARGS);
336 if (eargc == 0)
337 return (MA_DISPLAY_MENU);
338 popup_menu(init, eargc, eargv, menu->begy + 1, menu->begx + 1);
339 destroy_argv(eargc, eargv);
340 return (MA_RESET_MENU);
341 /** @brief Display a pick list or form associated with the selected
342 * menu choice */
343 case CT_PICK:
344 strnz__cpy(earg_str, menu->line[menu->line_idx]->command_str,
345 MAXLEN - 1);
346 eargc = str_to_args(eargv, earg_str, MAX_ARGS);
347 popup_pick(init, eargc, eargv, menu->begy + 1, menu->begx + 1);
348 destroy_argv(eargc, eargv);
349 return (MA_DISPLAY_MENU);
350 /** @brief Display a form associated with the selected menu choice
351 */
352 case CT_FORM:
353 strnz__cpy(earg_str, menu->line[menu->line_idx]->command_str,
354 MAXLEN - 1);
355 eargc = str_to_args(eargv, earg_str, MAX_ARGS);
356 popup_form(init, eargc, eargv, menu->begy + 1, menu->begx + 1);
357 destroy_argv(eargc, eargv);
358 return (MA_RESET_MENU);
359 /** @brief Display a view associated with the selected menu choice
360 */
361 case CT_VIEW:
362 strnz__cpy(earg_str, menu->line[menu->line_idx]->command_str,
363 MAXLEN - 1);
364 eargc = str_to_args(eargv, earg_str, MAX_ARGS);
365 init->lines = 66;
366 init->cols = 80;
367 init->begy = menu->begy + 1;
368 init->begx = menu->begx + 1;
369 strnz__cpy(init->title, menu->line[menu->line_idx]->raw_text,
370 MAXLEN - 1);
371 popup_view(init, eargc, eargv, init->lines, init->cols, init->begy,
372 init->begx);
373 destroy_argv(eargc, eargv);
374 return (MA_DISPLAY_MENU);
375 /** @brief open ckeys (test curses keys) */
376 case CT_CKEYS:
377 popup_ckeys();
378 return (MA_DISPLAY_MENU);
379 /** @brief return to calling program */
380 case CT_RETURN:
381 return (MA_RETURN);
382 /** @brief write the current menu configuration to a file */
383 case CT_WRITE_CONFIG:
384 write_config(init);
385 return (MA_CONTINUE);
386 default:
387 return (MA_CONTINUE);
388 }
389 }
390 return 0;
391}
PRINTCMD
#define PRINTCMD
Definition common.h:47
VIEW_PRT_FILE
#define VIEW_PRT_FILE
Definition common.h:36
popup_form
int popup_form(Init *, int, char **, uint, uint)
instantiate a form popup window
Definition popups.c:113
popup_menu
int popup_menu(Init *, int, char **, uint, uint)
instantiate a menu popup window
Definition popups.c:53
MENU_HELP_FILE
#define MENU_HELP_FILE
Definition common.h:32
popup_pick
int popup_pick(Init *, int, char **, uint, uint)
instantiate a pick popup window
Definition popups.c:83
popup_view
int popup_view(Init *, int, char **, uint, uint, uint, uint)
instantiate a view popup window
Definition popups.c:145
MAX_ARGS
#define MAX_ARGS
Definition cm.h:48
stdio_names_str
char stdio_names_str[4096]
Definition futil.c:127
MAXARGS
#define MAXARGS
Definition cm.h:50
stdio_names
char * stdio_names(char *, char *)
Definition futil.c:1057
KEY_ALTF
#define KEY_ALTF(n)
Definition cm.h:503
MT_CHOICE
@ MT_CHOICE
Definition menu.h:24
CT_PICK
@ CT_PICK
Definition menu.h:46
CT_FORM
@ CT_FORM
Definition menu.h:42
CT_DEXE
@ CT_DEXE
Definition menu.h:38
CT_MENU
@ CT_MENU
Definition menu.h:45
CT_RETURN
@ CT_RETURN
Definition menu.h:49
CT_HELP
@ CT_HELP
Definition menu.h:40
CT_WRITE_CONFIG
@ CT_WRITE_CONFIG
Definition menu.h:51
CT_EXEC
@ CT_EXEC
Definition menu.h:39
CT_VIEW
@ CT_VIEW
Definition menu.h:47
CT_CKEYS
@ CT_CKEYS
Definition menu.h:48
MA_RETURN
@ MA_RETURN
Definition menu.h:29
MA_DISPLAY_MENU
@ MA_DISPLAY_MENU
Definition menu.h:30
MA_RESET_MENU
@ MA_RESET_MENU
Definition menu.h:31
MA_CONTINUE
@ MA_CONTINUE
Definition menu.h:32
ui_render
void ui_render()
Definition ui_ncurses.c:800
ui_draw_ch_yx
int ui_draw_ch_yx(UiSurface *s, uint w, uint y, uint x, const char c)
Definition ui_ncurses_draw.c:40
ui_bkgdset
int ui_bkgdset(UiSurface *s, uint w, const UiCell *cell)
Definition ui_ncurses.c:760
ui_mice_enable
int ui_mice_enable(int mask)
Definition ui_ncurses_input.c:234
ui_scrollok
int ui_scrollok(UiSurface *s, uint w, bool enable)
Definition ui_ncurses.c:626
ui_mvwaddch
int ui_mvwaddch(UiSurface *s, uint w, uint y, uint x, const char c)
Definition ui_ncurses_draw.c:125
ui_get_event
int ui_get_event(UiSurface *s, uint w, UiEvent *ev, int timeout_ms)
Wait for an input event on target (or stdscr if NULL).
Definition ui_ncurses_input.c:103
ui_restore_wins
void ui_restore_wins()
Definition ui_ncurses_draw.c:210
ui_wmove
int ui_wmove(UiSurface *s, uint w, uint y, uint x)
Definition ui_ncurses.c:732
ui_surface
UiSurface * ui_surface[UI_SFC_MAX]
Definition ui_ncurses.c:28
ui_draw_text_fill
int ui_draw_text_fill(UiSurface *s, uint w, uint y, uint x, const char *text, int m)
Definition ui_ncurses_draw.c:61
sfc_ptr
int sfc_ptr
Definition nckeys.c:47
ui_keypad
int ui_keypad(UiSurface *s, uint w, bool enable)
Definition ui_ncurses.c:635
KEY_F01
#define KEY_F01
Definition ui_ncurses_internal.h:25
KEY_F07
#define KEY_F07
Definition ui_ncurses_internal.h:31
KEY_F09
#define KEY_F09
Definition ui_ncurses_internal.h:33
KEY_DOWN
#define KEY_DOWN
Definition ui_notcurses_internal.h:24
KEY_BREAK
#define KEY_BREAK
Definition ui_notcurses_internal.h:51
KEY_ENTER
#define KEY_ENTER
Definition ui_notcurses_internal.h:48
KEY_MOUSE
#define KEY_MOUSE
Definition ui_notcurses_internal.h:52
KEY_UP
#define KEY_UP
Definition ui_notcurses_internal.h:25
popup_ckeys
int popup_ckeys()
Definition curskeys.c:31
MAXLEN
#define MAXLEN
Definition curskeys.c:15
surface_box_win_new
int surface_box_win_new(uint wlines, uint wcols, uint wbegy, uint wbegx, char *wtitle)
Definition dwin.c:521
cell_nt
UiCell cell_nt
Definition dwin.c:94
cell_nt_hl_rev
UiCell cell_nt_hl_rev
Definition dwin.c:97
cell_nt_hl
UiCell cell_nt_hl
Definition dwin.c:96
cell_nt_rev
UiCell cell_nt_rev
Definition dwin.c:95
cm_surface_destroy
int cm_surface_destroy(UiSurface *sfc)
Destroy the most recently created surface.
Definition dwin.c:576
Perror
int Perror(char *emsg_str)
Display a simple error message window or print to stderr.
Definition dwin.c:841
full_screen_fork_exec
int full_screen_fork_exec(char **)
Execute a command in full screen mode.
Definition exec.c:45
full_screen_shell
int full_screen_shell(char *)
Execute a shell command in full screen mode.
Definition exec.c:58
fork_detach_execvp
int fork_detach_execvp(char **eargv)
Fork, set new session ID, close files, and execute detached command.
Definition detach.c:29
strnz__cpy
size_t strnz__cpy(char *, const char *, size_t)
safer alternative to strncpy
Definition futil.c:537
trim
size_t trim(char *)
Trims leading and trailing spaces from string s in place.
Definition futil.c:384
ssnprintf
size_t ssnprintf(char *, size_t, const char *,...)
ssnprintf was designed to be a safer alternative to snprintf.
Definition futil.c:413
str_to_args
int str_to_args(char **, char *, uint)
Converts a string into an array of argument strings.
Definition futil.c:433
strnz__cat
size_t strnz__cat(char *, const char *, size_t)
safer alternative to strncat
Definition futil.c:566
destroy_argv
int destroy_argv(uint argc, char **argv)
Deallocates memory allocated for argument strings in argv.
Definition futil.c:487
write_config
int write_config(Init *init)
Write the current configuration to a file specified in init->minitrc.
Definition init.c:1103
destroy_menu
Menu * destroy_menu(Init *init)
Destroy Menu structure.
Definition mem.c:155
menu_engine
unsigned int menu_engine(Init *)
The main loop of the menu system.
Definition menu_engine.c:36
menu_cmd_processor
unsigned int menu_cmd_processor(Init *)
Processes user input for the menu system.
Definition menu_engine.c:121
parse_menu_description
unsigned int parse_menu_description(Init *)
Parse menu description file and create Menu.
Definition parse_menu_desc.c:29
Init::title
char title[MAXLEN]
Definition common.h:129
Init::mapp_help
char mapp_help[MAXLEN]
Definition common.h:149
Init::begx
int begx
Definition common.h:118
Init::cols
int cols
Definition common.h:116
Init::begy
int begy
Definition common.h:117
Init::menu
Menu * menu
Definition common.h:183
Init::lines
int lines
Definition common.h:115
Line::choice_text
char * choice_text
Definition menu.h:79
Line::raw_text
char * raw_text
Definition menu.h:76
Line::command_str
char * command_str
Definition menu.h:94
Line::type
unsigned int type
Definition menu.h:74
Line::letter_pos
uint letter_pos
Definition menu.h:85
Line::choice_letter
char choice_letter
Definition menu.h:82
Line::command_type
uint command_type
Definition menu.h:88
Menu::line
Line * line[MAX_MENU_LINES]
Definition menu.h:223
Menu::f_help_spec
bool f_help_spec
Definition menu.h:182
Menu::text_max_len
uint text_max_len
Definition menu.h:210
Menu::begy
uint begy
Definition menu.h:118
Menu::cols
uint cols
Definition menu.h:116
Menu::choice_max_len
uint choice_max_len
Definition menu.h:204
Menu::help_spec
char help_spec[MAXLEN]
Definition menu.h:150
Menu::begx
uint begx
Definition menu.h:121
Menu::line_idx
uint line_idx
Definition menu.h:219
Menu::lines
uint lines
Definition menu.h:114
Menu::item_count
uint item_count
Definition menu.h:216
Menu::title
char title[MAXLEN]
Definition menu.h:135