27763eb3c16a819c39479e9411c7fd6109571396
[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 char empty_line[1000];
31 struct task task;
32 struct btr_node *stdout_btrn;
33 bool line_handler_running;
34 bool input_eof;
35 bool caught_sigint;
36 };
37 static struct i9e_private i9e_private, *i9ep = &i9e_private;
38
39 static bool is_prefix(const char *partial, const char *full, size_t len)
40 {
41 if (len == 0)
42 len = strlen(partial);
43 return !strncmp(partial, full, len);
44 }
45
46 /*
47 * Generator function for command completion. STATE lets us know whether
48 * to start from scratch; without any state (i.e. STATE == 0), then we
49 * start at the top of the list.
50 */
51 static char *command_generator(const char *text, int state)
52 {
53 static int list_index, len;
54 const char *name;
55 struct i9e_client_info *ici = i9ep->ici;
56
57 rl_attempted_completion_over = 1; /* disable filename completion */
58 /*
59 * If this is a new word to complete, initialize now. This includes
60 * saving the length of TEXT for efficiency, and initializing the index
61 * variable to 0.
62 */
63 if (state == 0) {
64 list_index = 0;
65 len = strlen(text);
66 }
67 /* Return the next name which partially matches from the command list. */
68 while ((name = ici->completers[list_index].name)) {
69 list_index++;
70 if (is_prefix(text, name, len))
71 return para_strdup(name);
72 }
73 return NULL; /* no names matched */
74 }
75
76 static void reset_completion_result(struct i9e_completion_result *cr)
77 {
78 cr->dont_append_space = false;
79 cr->filename_completion_desired = false;
80 cr->matches = NULL;
81 }
82
83 static void create_matches(struct i9e_completion_info *ci,
84 struct i9e_completer *completers,
85 struct i9e_completion_result *cr)
86 {
87 int i, ret;
88
89 reset_completion_result(cr);
90
91 ret = create_argv(ci->buffer, " ", &ci->argv);
92 if (ret < 0 || !ci->argv[0])
93 return;
94
95 ci->argc = ret;
96 ci->word_num = compute_word_num(ci->buffer, " ", ci->point);
97 for (i = 0; completers[i].name; i++) {
98 if (strcmp(completers[i].name, ci->argv[0]) != 0)
99 continue;
100 completers[i].completer(ci, cr);
101 break;
102 }
103 PARA_DEBUG_LOG("current word: %d (%s)\n", ci->word_num,
104 ci->argv[ci->word_num]);
105 if (cr->matches)
106 for (i = 0; cr->matches[i]; i++)
107 PARA_DEBUG_LOG("match %d: %s\n", i, cr->matches[i]);
108 }
109
110 static char *completion_generator(const char *word, int state)
111 {
112 static int list_index;
113 static char **argv, **matches;
114 struct i9e_completer *completers = i9ep->ici->completers;
115 struct i9e_completion_info ci = {
116 .word = (char *)word,
117 .point = rl_point,
118 .buffer = rl_line_buffer,
119 };
120 struct i9e_completion_result cr = {.matches = NULL};
121
122 if (state != 0)
123 goto out;
124 /* clean up previous matches and set defaults */
125 free(matches);
126 matches = NULL;
127 free_argv(argv);
128 argv = NULL;
129 list_index = 0;
130 rl_completion_append_character = ' ';
131 rl_completion_suppress_append = false;
132 rl_attempted_completion_over = true;
133
134 create_matches(&ci, completers, &cr);
135
136 matches = cr.matches;
137 argv = ci.argv;
138 rl_completion_suppress_append = cr.dont_append_space;
139 rl_attempted_completion_over = !cr.filename_completion_desired;
140 out:
141 if (!matches)
142 return NULL;
143 return matches[list_index++];
144 }
145
146 /*
147 * Attempt to complete on the contents of TEXT. START and END bound the
148 * region of rl_line_buffer that contains the word to complete. TEXT is
149 * the word to complete. We can use the entire contents of rl_line_buffer
150 * in case we want to do some simple parsing. Return the array of matches,
151 * or NULL if there aren't any.
152 */
153 static char **i9e_completer(const char *text, int start, __a_unused int end)
154 {
155 struct i9e_client_info *ici = i9ep->ici;
156
157 if (!ici->completers)
158 return NULL;
159 /* Complete on command names if this is the first word in the line. */
160 if (start == 0)
161 return rl_completion_matches(text, command_generator);
162 return rl_completion_matches(text, completion_generator);
163 }
164
165 /**
166 * Prepare writing to stdout.
167 *
168 * \param producer The buffer tree node which produces output.
169 *
170 * The i9e subsystem maintains a buffer tree node which may be attached to
171 * another node which generates output (a "producer"). When attached, the i9e
172 * buffer tree node copies the buffers generated by the producer to stdout.
173 *
174 * This function attaches the i9e input queue to an output queue of \a
175 * producer.
176 *
177 * \return Standard.
178 */
179 void i9e_attach_to_stdout(struct btr_node *producer)
180 {
181 assert(!i9ep->stdout_btrn);
182 i9ep->stdout_btrn = btr_new_node(&(struct btr_node_description)
183 EMBRACE(.name = "interactive_stdout", .parent = producer));
184 }
185
186 static void wipe_bottom_line(void)
187 {
188 fprintf(i9ep->stderr_stream, "\r%s\r", i9ep->empty_line);
189 }
190
191 /**
192 * Reset the terminal and save the in-memory command line history.
193 *
194 * This should be called before the caller exits.
195 */
196 void i9e_close(void)
197 {
198 char *hf = i9ep->ici->history_file;
199
200 rl_deprep_terminal();
201 if (hf)
202 write_history(hf);
203 wipe_bottom_line();
204 }
205
206 static void clear_bottom_line(void)
207 {
208 int point;
209 char *text;
210
211 if (rl_point == 0 && rl_end == 0)
212 return wipe_bottom_line();
213 /*
214 * We might have a multi-line input that needs to be wiped here, so the
215 * simple printf("\r<space>\r") is insufficient. To workaround this, we
216 * remove the whole line, redisplay and restore the killed text.
217 */
218 point = rl_point;
219 text = rl_copy_text(0, rl_end);
220 rl_kill_full_line(0, 0);
221 rl_redisplay();
222 wipe_bottom_line(); /* wipe out the prompt */
223 rl_insert_text(text);
224 rl_point = point;
225 }
226
227 static bool input_available(void)
228 {
229 fd_set rfds;
230 struct timeval tv = {0, 0};
231 int ret;
232
233 FD_ZERO(&rfds);
234 FD_SET(i9ep->ici->fds[0], &rfds);
235 ret = para_select(1, &rfds, NULL, &tv);
236 return ret > 0;
237 }
238
239 static void i9e_line_handler(char *line)
240 {
241 int ret;
242
243 ret = i9ep->ici->line_handler(line);
244 if (ret < 0)
245 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
246 rl_set_prompt("");
247 if (line) {
248 if (!*line)
249 rl_set_prompt(i9ep->ici->prompt);
250 else
251 add_history(line);
252 free(line);
253 } else {
254 rl_set_prompt("");
255 i9ep->input_eof = true;
256 }
257 }
258
259 static void i9e_input(void)
260 {
261 do {
262 rl_callback_read_char();
263 } while (input_available());
264 }
265
266 static void i9e_post_select(struct sched *s, struct task *t)
267 {
268 int ret;
269 struct btr_node *btrn = i9ep->stdout_btrn;
270 struct i9e_client_info *ici = i9ep->ici;
271 char *buf;
272 size_t sz;
273
274 if (i9ep->input_eof) {
275 t->error = -E_I9E_EOF;
276 return;
277 }
278 if (!btrn) {
279 i9ep->caught_sigint = false;
280 if (FD_ISSET(ici->fds[0], &s->rfds))
281 i9e_input();
282 return;
283 }
284 if (i9ep->caught_sigint)
285 goto rm_btrn;
286 ret = btr_node_status(i9ep->stdout_btrn, 0, BTR_NT_LEAF);
287 if (ret < 0)
288 goto rm_btrn;
289 sz = btr_next_buffer(btrn, &buf);
290 if (sz == 0)
291 goto out;
292 ret = xwrite(ici->fds[1], buf, sz);
293 if (ret < 0)
294 goto rm_btrn;
295 btr_consume(btrn, ret);
296 goto out;
297 rm_btrn:
298 btr_remove_node(&i9ep->stdout_btrn);
299 rl_set_prompt(i9ep->ici->prompt);
300 rl_redisplay();
301 out:
302 t->error = 0;
303 }
304
305 static void i9e_pre_select(struct sched *s, __a_unused struct task *t)
306 {
307 int ret;
308
309 if (i9ep->input_eof || i9ep->caught_sigint) {
310 sched_min_delay(s);
311 return;
312 }
313 if (i9ep->stdout_btrn) {
314 ret = btr_node_status(i9ep->stdout_btrn, 0, BTR_NT_LEAF);
315 if (ret < 0) {
316 sched_min_delay(s);
317 return;
318 }
319 if (ret > 0)
320 para_fd_set(i9ep->ici->fds[1], &s->wfds, &s->max_fileno);
321 }
322 /*
323 * fd[0] might have been reset to blocking mode if our job was moved to
324 * the background due to CTRL-Z or SIGSTOP, so set the fd back to
325 * nonblocking mode.
326 */
327 ret = mark_fd_nonblocking(i9ep->ici->fds[0]);
328 if (ret < 0)
329 PARA_WARNING_LOG("set to nonblock failed: (fd0 %d, %s)\n",
330 i9ep->ici->fds[0], para_strerror(-ret));
331 para_fd_set(i9ep->ici->fds[0], &s->rfds, &s->max_fileno);
332 }
333
334 static void update_winsize(void)
335 {
336 struct winsize w;
337 int ret = ioctl(i9ep->ici->fds[2], TIOCGWINSZ, (char *)&w);
338 int num_columns = 80;
339
340 if (ret >= 0) {
341 assert(w.ws_col < sizeof(i9ep->empty_line));
342 num_columns = w.ws_col;
343 }
344 memset(i9ep->empty_line, ' ', num_columns);
345 i9ep->empty_line[num_columns] = '\0';
346 }
347
348 /**
349 * Register the i9e task and initialize readline.
350 *
351 * \param ici The i9e configuration parameters set by the caller.
352 * \param s The scheduler instance to add the i9e task to.
353 *
354 * The caller must allocate and initialize the structure \a ici points to.
355 *
356 * \return Standard.
357 * \sa \ref register_task().
358 */
359 int i9e_open(struct i9e_client_info *ici, struct sched *s)
360 {
361 int ret;
362
363 if (!isatty(ici->fds[0]))
364 return -E_I9E_SETUPTERM;
365 ret = mark_fd_nonblocking(ici->fds[0]);
366 if (ret < 0)
367 return ret;
368 ret = mark_fd_nonblocking(ici->fds[1]);
369 if (ret < 0)
370 return ret;
371 i9ep->task.pre_select = i9e_pre_select;
372 i9ep->task.post_select = i9e_post_select;
373 sprintf(i9ep->task.status, "i9e");
374 register_task(s, &i9ep->task);
375 rl_readline_name = "para_i9e";
376 rl_basic_word_break_characters = " ";
377 rl_attempted_completion_function = i9e_completer;
378 i9ep->ici = ici;
379 i9ep->stderr_stream = fdopen(ici->fds[2], "w");
380 setvbuf(i9ep->stderr_stream, NULL, _IONBF, 0);
381
382 if (ici->history_file)
383 read_history(ici->history_file);
384 update_winsize();
385 rl_callback_handler_install(i9ep->ici->prompt, i9e_line_handler);
386 return 1;
387 }
388
389 static void reset_line_state(void)
390 {
391 if (i9ep->stdout_btrn)
392 return;
393 rl_on_new_line();
394 rl_reset_line_state();
395 rl_forced_update_display();
396 }
397
398 /**
399 * The log function of the i9e subsystem.
400 *
401 * \param ll Severity log level.
402 * \param fmt Printf-like format string.
403 *
404 * This clears the bottom line of the terminal if necessary and writes the
405 * string given by \a fmt to fd[2], where fd[] is the array provided earlier in
406 * \ref i9e_open().
407 */
408 __printf_2_3 void i9e_log(int ll, const char* fmt,...)
409 {
410 va_list argp;
411
412 if (ll < i9ep->ici->loglevel)
413 return;
414 clear_bottom_line();
415 va_start(argp, fmt);
416 vfprintf(i9ep->stderr_stream, fmt, argp);
417 va_end(argp);
418 reset_line_state();
419 }
420
421 /**
422 * Tell i9e that the caller received a signal.
423 *
424 * \param sig_num The number of the signal received.
425 *
426 * Currently the function only cares about \p SIGINT, but this may change.
427 */
428 void i9e_signal_dispatch(int sig_num)
429 {
430 if (sig_num == SIGINT) {
431 fprintf(i9ep->stderr_stream, "\n");
432 rl_replace_line ("", false /* clear_undo */);
433 reset_line_state();
434 i9ep->caught_sigint = true;
435 }
436 }
437
438 /**
439 * Wrapper for select(2) which does not restart on interrupts.
440 *
441 * \param n \sa \ref para_select().
442 * \param readfds \sa \ref para_select().
443 * \param writefds \sa \ref para_select().
444 * \param timeout_tv \sa \ref para_select().
445 *
446 * \return \sa \ref para_select().
447 *
448 * The only difference between this function and \ref para_select() is that
449 * \ref i9e_select() returns zero if the select call returned \p EINTR.
450 */
451 int i9e_select(int n, fd_set *readfds, fd_set *writefds,
452 struct timeval *timeout_tv)
453 {
454 int ret = select(n, readfds, writefds, NULL, timeout_tv);
455
456 if (ret < 0) {
457 if (errno == EINTR)
458 ret = 0;
459 else
460 ret = -ERRNO_TO_PARA_ERROR(errno);
461 }
462 return ret;
463 }
464
465 /**
466 * Return the possible completions for a given word.
467 *
468 * \param word The word to complete.
469 * \param string_list All possible words in this context.
470 * \param result String list is returned here.
471 *
472 * This function never fails. If no completion was found, a string list of
473 * length zero is returned. In any case, the result must be freed by the caller
474 * using \ref free_argv().
475 *
476 * This function is independent of readline and may be called before
477 * i9e_open().
478 *
479 * \return The number of possible completions.
480 */
481 int i9e_extract_completions(const char *word, char **string_list,
482 char ***result)
483 {
484 char **matches = para_malloc(sizeof(char *));
485 int match_count = 0, matches_len = 1;
486 char **p;
487 int len = strlen(word);
488
489 for (p = string_list; *p; p++) {
490 if (!is_prefix(word, *p, len))
491 continue;
492 match_count++;
493 if (match_count >= matches_len) {
494 matches_len *= 2;
495 matches = para_realloc(matches,
496 matches_len * sizeof(char *));
497 }
498 matches[match_count - 1] = para_strdup(*p);
499 }
500 matches[match_count] = NULL;
501 *result = matches;
502 return match_count;
503 }
504
505 /**
506 * Return the list of partially matching words.
507 *
508 * \param word The command to complete.
509 * \param completers The array containing all command names.
510 *
511 * This is similar to \ref i9e_extract_completions(), but completes on the
512 * command names in \a completers.
513 *
514 * \return See \ref i9e_extract_completions().
515 */
516 char **i9e_complete_commands(const char *word, struct i9e_completer *completers)
517 {
518 char **matches;
519 const char *cmd;
520 int i, match_count, len = strlen(word);
521
522 /*
523 * In contrast to completing against an arbitrary string list, here we
524 * know all possible completions and expect that there will not be many
525 * of them. So it should be OK to iterate twice over all commands which
526 * simplifies the code a bit.
527 */
528 for (i = 0, match_count = 0; (cmd = completers[i].name); i++) {
529 if (is_prefix(word, cmd, len))
530 match_count++;
531 }
532 matches = para_malloc((match_count + 1) * sizeof(*matches));
533 for (i = 0, match_count = 0; (cmd = completers[i].name); i++)
534 if (is_prefix(word, cmd, len))
535 matches[match_count++] = para_strdup(cmd);
536 matches[match_count] = NULL;
537 return matches;
538 }
539
540 /**
541 * Complete according to the given options.
542 *
543 * \param opts All available options.
544 * \param ci Information which was passed to the completer.
545 * \param cr Result pointer.
546 *
547 * This convenience helper can be used to complete an option. The array of all
548 * possible options is passed as the first argument. Flags, i.e. options
549 * without an argument, are expected to be listed as strings of type "-X" in \a
550 * opts while options which require an argument should be passed with a
551 * trailing "=" character like "-X=".
552 *
553 * If the word can be uniquely completed to a flag option, an additional space
554 * character is appended to the output. For non-flag options no space character
555 * is appended.
556 */
557 void i9e_complete_option(char **opts, struct i9e_completion_info *ci,
558 struct i9e_completion_result *cr)
559 {
560 int num_matches;
561
562 num_matches = i9e_extract_completions(ci->word, opts, &cr->matches);
563 if (num_matches == 1) {
564 char *opt = cr->matches[0];
565 char c = opt[strlen(opt) - 1];
566 if (c == '=')
567 cr->dont_append_space = true;
568 }
569 }
570
571 /**
572 * Print possible completions to stdout.
573 *
574 * \param completers The array of completion functions.
575 *
576 * At the end of the output a line starting with "-o=", followed by the
577 * (possibly empty) list of completion options is printed. Currently, the only
578 * two completion options are "nospace" and "filenames". The former indicates
579 * that no space should be appended even for a unique match while the latter
580 * indicates that usual filename completion should be performed in addition to
581 * the previously printed options.
582 *
583 * \return Standard.
584 */
585 int i9e_print_completions(struct i9e_completer *completers)
586 {
587 struct i9e_completion_result cr;
588 struct i9e_completion_info ci;
589 char *buf;
590 const char *end, *p;
591 int i, n, ret;
592
593 reset_completion_result(&cr);
594 buf = getenv("COMP_POINT");
595 ci.point = buf? atoi(buf) : 0;
596 ci.buffer = para_strdup(getenv("COMP_LINE"));
597
598 ci.argc = create_argv(ci.buffer, " ", &ci.argv);
599 ci.word_num = compute_word_num(ci.buffer, " ", ci.point);
600
601 end = ci.buffer + ci.point;
602 for (p = end; p > ci.buffer && *p != ' '; p--)
603 ; /* nothing */
604 if (*p == ' ')
605 p++;
606
607 n = end - p + 1;
608 ci.word = para_malloc(n + 1);
609 strncpy(ci.word, p, n);
610 ci.word[n] = '\0';
611
612 PARA_DEBUG_LOG("line: %s, point: %d (%c), wordnum: %d, word: %s\n",
613 ci.buffer, ci.point, ci.buffer[ci.point], ci.word_num, ci.word);
614 if (ci.word_num == 0)
615 cr.matches = i9e_complete_commands(ci.word, completers);
616 else
617 create_matches(&ci, completers, &cr);
618 ret = 0;
619 if (cr.matches && cr.matches[0]) {
620 for (i = 0; cr.matches[i]; i++)
621 printf("%s\n", cr.matches[i]);
622 ret = 1;
623 }
624 printf("-o=");
625 if (cr.dont_append_space)
626 printf("nospace");
627 if (cr.filename_completion_desired)
628 printf(",filenames");
629 printf("\n");
630 free_argv(cr.matches);
631 free_argv(ci.argv);
632 free(ci.buffer);
633 free(ci.word);
634 return ret;
635 }