interactive: Implement single key mode.
[paraslash.git] / interactive.c
1 /*
2 * Copyright (C) 2011-2012 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file interactive.c Readline abstraction for interactive sessions. */
8
9 #include <regex.h>
10 #include <stdbool.h>
11 #include <curses.h>
12 #include <readline/readline.h>
13 #include <readline/history.h>
14 #include <sys/ioctl.h>
15 #include <assert.h>
16 #include <signal.h>
17
18 #include "para.h"
19 #include "fd.h"
20 #include "buffer_tree.h"
21 #include "list.h"
22 #include "sched.h"
23 #include "interactive.h"
24 #include "string.h"
25 #include "error.h"
26
27 struct i9e_private {
28 struct i9e_client_info *ici;
29 FILE *stderr_stream;
30 int num_columns;
31 char empty_line[1000];
32 struct task task;
33 struct btr_node *stdout_btrn;
34 bool line_handler_running;
35 bool input_eof;
36 bool caught_sigint;
37 bool caught_sigterm;
38 Keymap standard_km;
39 Keymap bare_km;
40 };
41 static struct i9e_private i9e_private, *i9ep = &i9e_private;
42
43 /**
44 * Return the error state of the i9e task.
45 *
46 * This is mainly useful for other tasks to tell whether the i9e task is still
47 * running.
48 *
49 * \return A negative return value of zero means the i9e task terminated. Only
50 * in this case it is safe to call ie9_close().
51 */
52 int i9e_get_error(void)
53 {
54 return i9ep->task.error;
55 }
56
57 static bool is_prefix(const char *partial, const char *full, size_t len)
58 {
59 if (len == 0)
60 len = strlen(partial);
61 return !strncmp(partial, full, len);
62 }
63
64 /*
65 * Generator function for command completion. STATE lets us know whether
66 * to start from scratch; without any state (i.e. STATE == 0), then we
67 * start at the top of the list.
68 */
69 static char *command_generator(const char *text, int state)
70 {
71 static int list_index, len;
72 const char *name;
73 struct i9e_client_info *ici = i9ep->ici;
74
75 rl_attempted_completion_over = 1; /* disable filename completion */
76 /*
77 * If this is a new word to complete, initialize now. This includes
78 * saving the length of TEXT for efficiency, and initializing the index
79 * variable to 0.
80 */
81 if (state == 0) {
82 list_index = 0;
83 len = strlen(text);
84 }
85 /* Return the next name which partially matches from the command list. */
86 while ((name = ici->completers[list_index].name)) {
87 list_index++;
88 if (is_prefix(text, name, len))
89 return para_strdup(name);
90 }
91 return NULL; /* no names matched */
92 }
93
94 static void reset_completion_result(struct i9e_completion_result *cr)
95 {
96 cr->dont_append_space = false;
97 cr->filename_completion_desired = false;
98 cr->matches = NULL;
99 }
100
101 static void create_matches(struct i9e_completion_info *ci,
102 struct i9e_completer *completers,
103 struct i9e_completion_result *cr)
104 {
105 int i, ret;
106
107 reset_completion_result(cr);
108
109 ret = create_argv(ci->buffer, " ", &ci->argv);
110 if (ret < 0 || !ci->argv[0])
111 return;
112
113 ci->argc = ret;
114 ci->word_num = compute_word_num(ci->buffer, " ", ci->point);
115 for (i = 0; completers[i].name; i++) {
116 if (strcmp(completers[i].name, ci->argv[0]) != 0)
117 continue;
118 completers[i].completer(ci, cr);
119 break;
120 }
121 PARA_DEBUG_LOG("current word: %d (%s)\n", ci->word_num,
122 ci->argv[ci->word_num]);
123 if (cr->matches)
124 for (i = 0; cr->matches[i]; i++)
125 PARA_DEBUG_LOG("match %d: %s\n", i, cr->matches[i]);
126 }
127
128 static char *completion_generator(const char *word, int state)
129 {
130 static int list_index;
131 static char **argv, **matches;
132 struct i9e_completer *completers = i9ep->ici->completers;
133 struct i9e_completion_info ci = {
134 .word = (char *)word,
135 .point = rl_point,
136 .buffer = rl_line_buffer,
137 };
138 struct i9e_completion_result cr = {.matches = NULL};
139
140 if (state != 0)
141 goto out;
142 /* clean up previous matches and set defaults */
143 free(matches);
144 matches = NULL;
145 free_argv(argv);
146 argv = NULL;
147 list_index = 0;
148 rl_completion_append_character = ' ';
149 rl_completion_suppress_append = false;
150 rl_attempted_completion_over = true;
151
152 create_matches(&ci, completers, &cr);
153
154 matches = cr.matches;
155 argv = ci.argv;
156 rl_completion_suppress_append = cr.dont_append_space;
157 rl_attempted_completion_over = !cr.filename_completion_desired;
158 out:
159 if (!matches)
160 return NULL;
161 return matches[list_index++];
162 }
163
164 /*
165 * Attempt to complete on the contents of TEXT. START and END bound the
166 * region of rl_line_buffer that contains the word to complete. TEXT is
167 * the word to complete. We can use the entire contents of rl_line_buffer
168 * in case we want to do some simple parsing. Return the array of matches,
169 * or NULL if there aren't any.
170 */
171 static char **i9e_completer(const char *text, int start, __a_unused int end)
172 {
173 struct i9e_client_info *ici = i9ep->ici;
174
175 if (!ici->completers)
176 return NULL;
177 /* Complete on command names if this is the first word in the line. */
178 if (start == 0)
179 return rl_completion_matches(text, command_generator);
180 return rl_completion_matches(text, completion_generator);
181 }
182
183 /**
184 * Prepare writing to stdout.
185 *
186 * \param producer The buffer tree node which produces output.
187 *
188 * The i9e subsystem maintains a buffer tree node which may be attached to
189 * another node which generates output (a "producer"). When attached, the i9e
190 * buffer tree node copies the buffers generated by the producer to stdout.
191 *
192 * This function attaches the i9e input queue to an output queue of \a
193 * producer.
194 *
195 * \return Standard.
196 */
197 void i9e_attach_to_stdout(struct btr_node *producer)
198 {
199 btr_remove_node(&i9ep->stdout_btrn);
200 i9ep->stdout_btrn = btr_new_node(&(struct btr_node_description)
201 EMBRACE(.name = "interactive_stdout", .parent = producer));
202 rl_set_keymap(i9ep->bare_km);
203 }
204
205 static void wipe_bottom_line(void)
206 {
207 char x[] = " ";
208 int n = i9ep->num_columns;
209
210 /*
211 * For reasons beyond my understanding, writing more than 68 characters
212 * here causes MacOS to mess up the terminal. Writing a line of spaces
213 * in smaller chunks works fine though. Weird.
214 */
215 fprintf(i9ep->stderr_stream, "\r");
216 while (n > 0) {
217 if (n >= sizeof(x)) {
218 fprintf(i9ep->stderr_stream, "%s", x);
219 n -= sizeof(x);
220 continue;
221 }
222 x[n] = '\0';
223 fprintf(i9ep->stderr_stream, "%s", x);
224 break;
225 }
226 fprintf(i9ep->stderr_stream, "\r");
227 }
228
229 /**
230 * Free all storage associated with a keymap.
231 *
232 * This function is not declared in the readline headers although the symbol is
233 * exported and the function is documented in the readline info file. So we
234 * have to declare it here.
235 *
236 * \param keymap The keymap to deallocate.
237 */
238 void rl_free_keymap(Keymap keymap);
239
240 /**
241 * Reset the terminal and save the in-memory command line history.
242 *
243 * This should be called before the caller exits.
244 */
245 void i9e_close(void)
246 {
247 char *hf = i9ep->ici->history_file;
248
249 rl_free_keymap(i9ep->bare_km);
250 rl_callback_handler_remove();
251 if (hf)
252 write_history(hf);
253 wipe_bottom_line();
254 }
255
256 static void clear_bottom_line(void)
257 {
258 int point;
259 char *text;
260
261 if (rl_point == 0 && rl_end == 0)
262 return wipe_bottom_line();
263 /*
264 * We might have a multi-line input that needs to be wiped here, so the
265 * simple printf("\r<space>\r") is insufficient. To workaround this, we
266 * remove the whole line, redisplay and restore the killed text.
267 */
268 point = rl_point;
269 text = rl_copy_text(0, rl_end);
270 rl_kill_full_line(0, 0);
271 rl_redisplay();
272 wipe_bottom_line(); /* wipe out the prompt */
273 rl_insert_text(text);
274 rl_point = point;
275 }
276
277 static bool input_available(void)
278 {
279 fd_set rfds;
280 struct timeval tv = {0, 0};
281 int ret;
282
283 FD_ZERO(&rfds);
284 FD_SET(i9ep->ici->fds[0], &rfds);
285 ret = para_select(1, &rfds, NULL, &tv);
286 return ret > 0;
287 }
288
289 static void i9e_line_handler(char *line)
290 {
291 int ret;
292
293 ret = i9ep->ici->line_handler(line);
294 if (ret < 0)
295 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
296 rl_set_prompt("");
297 if (line) {
298 if (!*line)
299 rl_set_prompt(i9ep->ici->prompt);
300 else
301 add_history(line);
302 free(line);
303 } else {
304 rl_set_prompt("");
305 i9ep->input_eof = true;
306 }
307 }
308
309 static void i9e_post_select(__a_unused struct sched *s, struct task *t)
310 {
311 int ret;
312 struct i9e_client_info *ici = i9ep->ici;
313 char *buf;
314 size_t sz;
315
316 ret = -E_I9E_EOF;
317 if (i9ep->input_eof)
318 goto rm_btrn;
319 ret = -E_I9E_TERM_RQ;
320 if (i9ep->caught_sigterm)
321 goto rm_btrn;
322 ret = 0;
323 if (i9ep->caught_sigint)
324 goto rm_btrn;
325 while (input_available())
326 rl_callback_read_char();
327 if (!i9ep->stdout_btrn)
328 goto out;
329 ret = btr_node_status(i9ep->stdout_btrn, 0, BTR_NT_LEAF);
330 if (ret < 0) {
331 ret = 0;
332 goto rm_btrn;
333 }
334 if (ret == 0)
335 goto out;
336 sz = btr_next_buffer(i9ep->stdout_btrn, &buf);
337 if (sz == 0)
338 goto out;
339 ret = xwrite(ici->fds[1], buf, sz);
340 if (ret < 0)
341 goto rm_btrn;
342 btr_consume(i9ep->stdout_btrn, ret);
343 goto out;
344 rm_btrn:
345 if (i9ep->stdout_btrn) {
346 btr_remove_node(&i9ep->stdout_btrn);
347 rl_set_keymap(i9ep->standard_km);
348 rl_set_prompt(i9ep->ici->prompt);
349 rl_redisplay();
350 }
351 if (ret < 0)
352 wipe_bottom_line();
353 out:
354 i9ep->caught_sigint = false;
355 t->error = ret;
356 }
357
358 static void i9e_pre_select(struct sched *s, __a_unused struct task *t)
359 {
360 int ret;
361
362 if (i9ep->input_eof || i9ep->caught_sigint || i9ep->caught_sigterm) {
363 sched_min_delay(s);
364 return;
365 }
366 if (i9ep->stdout_btrn) {
367 ret = btr_node_status(i9ep->stdout_btrn, 0, BTR_NT_LEAF);
368 if (ret < 0) {
369 sched_min_delay(s);
370 return;
371 }
372 if (ret > 0)
373 para_fd_set(i9ep->ici->fds[1], &s->wfds, &s->max_fileno);
374 }
375 /*
376 * fd[0] might have been reset to blocking mode if our job was moved to
377 * the background due to CTRL-Z or SIGSTOP, so set the fd back to
378 * nonblocking mode.
379 */
380 ret = mark_fd_nonblocking(i9ep->ici->fds[0]);
381 if (ret < 0)
382 PARA_WARNING_LOG("set to nonblock failed: (fd0 %d, %s)\n",
383 i9ep->ici->fds[0], para_strerror(-ret));
384 para_fd_set(i9ep->ici->fds[0], &s->rfds, &s->max_fileno);
385 }
386
387 static void update_winsize(void)
388 {
389 struct winsize w;
390 int ret = ioctl(i9ep->ici->fds[2], TIOCGWINSZ, (char *)&w);
391
392 if (ret >= 0) {
393 assert(w.ws_col < sizeof(i9ep->empty_line));
394 i9ep->num_columns = w.ws_col;
395 } else
396 i9ep->num_columns = 80;
397
398 memset(i9ep->empty_line, ' ', i9ep->num_columns);
399 i9ep->empty_line[i9ep->num_columns] = '\0';
400 }
401
402 /**
403 * Defined key sequences are mapped to keys starting with this offset. I.e.
404 * pressing the first defined key sequence yields the key number \p KEY_OFFSET.
405 */
406 #define KEY_OFFSET 64
407
408 static int dispatch_key(__a_unused int count, int key)
409 {
410 int ret;
411
412 assert(key >= KEY_OFFSET);
413 ret = i9ep->ici->key_handler(key - KEY_OFFSET);
414 return ret < 0? ret : 0;
415 }
416
417 /**
418 * Register the i9e task and initialize readline.
419 *
420 * \param ici The i9e configuration parameters set by the caller.
421 * \param s The scheduler instance to add the i9e task to.
422 *
423 * The caller must allocate and initialize the structure \a ici points to.
424 *
425 * \return Standard.
426 * \sa \ref register_task().
427 */
428 int i9e_open(struct i9e_client_info *ici, struct sched *s)
429 {
430 int ret;
431
432 if (!isatty(ici->fds[0]))
433 return -E_I9E_SETUPTERM;
434 ret = mark_fd_nonblocking(ici->fds[0]);
435 if (ret < 0)
436 return ret;
437 ret = mark_fd_nonblocking(ici->fds[1]);
438 if (ret < 0)
439 return ret;
440 i9ep->task.pre_select = i9e_pre_select;
441 i9ep->task.post_select = i9e_post_select;
442 sprintf(i9ep->task.status, "i9e");
443 register_task(s, &i9ep->task);
444 rl_readline_name = "para_i9e";
445 rl_basic_word_break_characters = " ";
446 rl_attempted_completion_function = i9e_completer;
447 i9ep->ici = ici;
448 i9ep->stderr_stream = fdopen(ici->fds[2], "w");
449 setvbuf(i9ep->stderr_stream, NULL, _IONBF, 0);
450
451 i9ep->standard_km = rl_get_keymap();
452 i9ep->bare_km = rl_make_bare_keymap();
453 if (ici->bound_keyseqs) {
454 char *seq;
455 int i;
456 /* FIXME: This is an arbitrary constant. */
457 for (i = 0; i < 32 && (seq = ici->bound_keyseqs[i]); i++) {
458 char buf[2] = {KEY_OFFSET + i, '\0'};
459 /* readline needs an allocated buffer for the macro */
460 rl_generic_bind(ISMACR, seq, para_strdup(buf), i9ep->bare_km);
461 rl_bind_key_in_map(KEY_OFFSET + i, dispatch_key, i9ep->bare_km);
462 }
463 }
464 if (ici->history_file)
465 read_history(ici->history_file);
466 update_winsize();
467 if (ici->producer) {
468 rl_callback_handler_install("", i9e_line_handler);
469 i9e_attach_to_stdout(ici->producer);
470 rl_set_keymap(i9ep->bare_km);
471 } else
472 rl_callback_handler_install(i9ep->ici->prompt, i9e_line_handler);
473 return 1;
474 }
475
476 static void reset_line_state(void)
477 {
478 if (i9ep->stdout_btrn)
479 return;
480 rl_on_new_line();
481 rl_reset_line_state();
482 rl_forced_update_display();
483 }
484
485 /**
486 * The log function of the i9e subsystem.
487 *
488 * \param ll Severity log level.
489 * \param fmt Printf-like format string.
490 *
491 * This clears the bottom line of the terminal if necessary and writes the
492 * string given by \a fmt to fd[2], where fd[] is the array provided earlier in
493 * \ref i9e_open().
494 */
495 __printf_2_3 void i9e_log(int ll, const char* fmt,...)
496 {
497 va_list argp;
498
499 if (ll < i9ep->ici->loglevel)
500 return;
501 clear_bottom_line();
502 va_start(argp, fmt);
503 vfprintf(i9ep->stderr_stream, fmt, argp);
504 va_end(argp);
505 reset_line_state();
506 }
507
508 /**
509 * Tell i9e that the caller received a signal.
510 *
511 * \param sig_num The number of the signal received.
512 *
513 * Currently the function only cares about \p SIGINT, but this may change.
514 */
515 void i9e_signal_dispatch(int sig_num)
516 {
517 if (sig_num == SIGWINCH)
518 return update_winsize();
519 if (sig_num == SIGINT) {
520 fprintf(i9ep->stderr_stream, "\n");
521 rl_replace_line ("", false /* clear_undo */);
522 reset_line_state();
523 i9ep->caught_sigint = true;
524 }
525 if (sig_num == SIGTERM)
526 i9ep->caught_sigterm = true;
527 }
528
529 /**
530 * Wrapper for select(2) which does not restart on interrupts.
531 *
532 * \param n \sa \ref para_select().
533 * \param readfds \sa \ref para_select().
534 * \param writefds \sa \ref para_select().
535 * \param timeout_tv \sa \ref para_select().
536 *
537 * \return \sa \ref para_select().
538 *
539 * The only difference between this function and \ref para_select() is that
540 * \ref i9e_select() returns zero if the select call returned \p EINTR.
541 */
542 int i9e_select(int n, fd_set *readfds, fd_set *writefds,
543 struct timeval *timeout_tv)
544 {
545 int ret = select(n, readfds, writefds, NULL, timeout_tv);
546
547 if (ret < 0) {
548 if (errno == EINTR)
549 ret = 0;
550 else
551 ret = -ERRNO_TO_PARA_ERROR(errno);
552 }
553 return ret;
554 }
555
556 /**
557 * Return the possible completions for a given word.
558 *
559 * \param word The word to complete.
560 * \param string_list All possible words in this context.
561 * \param result String list is returned here.
562 *
563 * This function never fails. If no completion was found, a string list of
564 * length zero is returned. In any case, the result must be freed by the caller
565 * using \ref free_argv().
566 *
567 * This function is independent of readline and may be called before
568 * i9e_open().
569 *
570 * \return The number of possible completions.
571 */
572 int i9e_extract_completions(const char *word, char **string_list,
573 char ***result)
574 {
575 char **matches = para_malloc(sizeof(char *));
576 int match_count = 0, matches_len = 1;
577 char **p;
578 int len = strlen(word);
579
580 for (p = string_list; *p; p++) {
581 if (!is_prefix(word, *p, len))
582 continue;
583 match_count++;
584 if (match_count >= matches_len) {
585 matches_len *= 2;
586 matches = para_realloc(matches,
587 matches_len * sizeof(char *));
588 }
589 matches[match_count - 1] = para_strdup(*p);
590 }
591 matches[match_count] = NULL;
592 *result = matches;
593 return match_count;
594 }
595
596 /**
597 * Return the list of partially matching words.
598 *
599 * \param word The command to complete.
600 * \param completers The array containing all command names.
601 *
602 * This is similar to \ref i9e_extract_completions(), but completes on the
603 * command names in \a completers.
604 *
605 * \return See \ref i9e_extract_completions().
606 */
607 char **i9e_complete_commands(const char *word, struct i9e_completer *completers)
608 {
609 char **matches;
610 const char *cmd;
611 int i, match_count, len = strlen(word);
612
613 /*
614 * In contrast to completing against an arbitrary string list, here we
615 * know all possible completions and expect that there will not be many
616 * of them. So it should be OK to iterate twice over all commands which
617 * simplifies the code a bit.
618 */
619 for (i = 0, match_count = 0; (cmd = completers[i].name); i++) {
620 if (is_prefix(word, cmd, len))
621 match_count++;
622 }
623 matches = para_malloc((match_count + 1) * sizeof(*matches));
624 for (i = 0, match_count = 0; (cmd = completers[i].name); i++)
625 if (is_prefix(word, cmd, len))
626 matches[match_count++] = para_strdup(cmd);
627 matches[match_count] = NULL;
628 return matches;
629 }
630
631 /**
632 * Complete according to the given options.
633 *
634 * \param opts All available options.
635 * \param ci Information which was passed to the completer.
636 * \param cr Result pointer.
637 *
638 * This convenience helper can be used to complete an option. The array of all
639 * possible options is passed as the first argument. Flags, i.e. options
640 * without an argument, are expected to be listed as strings of type "-X" in \a
641 * opts while options which require an argument should be passed with a
642 * trailing "=" character like "-X=".
643 *
644 * If the word can be uniquely completed to a flag option, an additional space
645 * character is appended to the output. For non-flag options no space character
646 * is appended.
647 */
648 void i9e_complete_option(char **opts, struct i9e_completion_info *ci,
649 struct i9e_completion_result *cr)
650 {
651 int num_matches;
652
653 num_matches = i9e_extract_completions(ci->word, opts, &cr->matches);
654 if (num_matches == 1) {
655 char *opt = cr->matches[0];
656 char c = opt[strlen(opt) - 1];
657 if (c == '=')
658 cr->dont_append_space = true;
659 }
660 }
661
662 /**
663 * Print possible completions to stdout.
664 *
665 * \param completers The array of completion functions.
666 *
667 * At the end of the output a line starting with "-o=", followed by the
668 * (possibly empty) list of completion options is printed. Currently, the only
669 * two completion options are "nospace" and "filenames". The former indicates
670 * that no space should be appended even for a unique match while the latter
671 * indicates that usual filename completion should be performed in addition to
672 * the previously printed options.
673 *
674 * \return Standard.
675 */
676 int i9e_print_completions(struct i9e_completer *completers)
677 {
678 struct i9e_completion_result cr;
679 struct i9e_completion_info ci;
680 char *buf;
681 const char *end, *p;
682 int i, n, ret;
683
684 reset_completion_result(&cr);
685 buf = getenv("COMP_POINT");
686 ci.point = buf? atoi(buf) : 0;
687 ci.buffer = para_strdup(getenv("COMP_LINE"));
688
689 ci.argc = create_argv(ci.buffer, " ", &ci.argv);
690 ci.word_num = compute_word_num(ci.buffer, " ", ci.point);
691
692 end = ci.buffer + ci.point;
693 for (p = end; p > ci.buffer && *p != ' '; p--)
694 ; /* nothing */
695 if (*p == ' ')
696 p++;
697
698 n = end - p + 1;
699 ci.word = para_malloc(n + 1);
700 strncpy(ci.word, p, n);
701 ci.word[n] = '\0';
702
703 PARA_DEBUG_LOG("line: %s, point: %d (%c), wordnum: %d, word: %s\n",
704 ci.buffer, ci.point, ci.buffer[ci.point], ci.word_num, ci.word);
705 if (ci.word_num == 0)
706 cr.matches = i9e_complete_commands(ci.word, completers);
707 else
708 create_matches(&ci, completers, &cr);
709 ret = 0;
710 if (cr.matches && cr.matches[0]) {
711 for (i = 0; cr.matches[i]; i++)
712 printf("%s\n", cr.matches[i]);
713 ret = 1;
714 }
715 printf("-o=");
716 if (cr.dont_append_space)
717 printf("nospace");
718 if (cr.filename_completion_desired)
719 printf(",filenames");
720 printf("\n");
721 free_argv(cr.matches);
722 free_argv(ci.argv);
723 free(ci.buffer);
724 free(ci.word);
725 return ret;
726 }