client: Implement interactive mode.
[paraslash.git] / interactive.c
1 /*
2 * Copyright (C) 2011 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 /**
187 * Reset the terminal and save the in-memory command line history.
188 *
189 * This should be called before the caller exits.
190 */
191 void i9e_close(void)
192 {
193 char *hf = i9ep->ici->history_file;
194
195 rl_deprep_terminal();
196 fprintf(i9ep->stderr_stream, "\n");
197 if (hf)
198 write_history(hf);
199 fclose(i9ep->stderr_stream);
200 }
201
202 static void wipe_bottom_line(void)
203 {
204 fprintf(i9ep->stderr_stream, "\r%s\r", i9ep->empty_line);
205 }
206
207 static void clear_bottom_line(void)
208 {
209 int point;
210 char *text;
211
212 if (rl_point == 0 && rl_end == 0)
213 return wipe_bottom_line();
214 /*
215 * We might have a multi-line input that needs to be wiped here, so the
216 * simple printf("\r<space>\r") is insufficient. To workaround this, we
217 * remove the whole line, redisplay and restore the killed text.
218 */
219 point = rl_point;
220 text = rl_copy_text(0, rl_end);
221 rl_kill_full_line(0, 0);
222 rl_redisplay();
223 wipe_bottom_line(); /* wipe out the prompt */
224 rl_insert_text(text);
225 rl_point = point;
226 }
227
228 static bool input_available(void)
229 {
230 fd_set rfds;
231 struct timeval tv = {0, 0};
232 int ret;
233
234 FD_ZERO(&rfds);
235 FD_SET(i9ep->ici->fds[0], &rfds);
236 ret = para_select(1, &rfds, NULL, &tv);
237 return ret > 0;
238 }
239
240 static void i9e_line_handler(char *line)
241 {
242 int ret;
243
244 i9ep->line_handler_running = true;
245 ret = i9ep->ici->line_handler(line);
246 i9ep->line_handler_running = false;
247 if (ret < 0)
248 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
249 rl_set_prompt("");
250 if (line) {
251 if (!*line)
252 rl_set_prompt(i9ep->ici->prompt);
253 else
254 add_history(line);
255 free(line);
256 } else {
257 rl_set_prompt("");
258 i9ep->input_eof = true;
259 }
260 }
261
262 static void i9e_input(void)
263 {
264 do {
265 rl_callback_read_char();
266 } while (input_available());
267 }
268
269 static void i9e_post_select(struct sched *s, struct task *t)
270 {
271 int ret;
272 struct btr_node *btrn = i9ep->stdout_btrn;
273 struct i9e_client_info *ici = i9ep->ici;
274 char *buf;
275 size_t sz;
276
277 if (i9ep->input_eof) {
278 t->error = -E_I9E_EOF;
279 return;
280 }
281 if (!btrn) {
282 i9ep->caught_sigint = false;
283 if (FD_ISSET(ici->fds[0], &s->rfds))
284 i9e_input();
285 return;
286 }
287 if (i9ep->caught_sigint)
288 goto rm_btrn;
289 ret = btr_node_status(i9ep->stdout_btrn, 0, BTR_NT_LEAF);
290 if (ret < 0)
291 goto rm_btrn;
292 sz = btr_next_buffer(btrn, &buf);
293 if (sz == 0)
294 goto out;
295 ret = write_nonblock(ici->fds[1], buf, sz);
296 if (ret < 0)
297 goto rm_btrn;
298 btr_consume(btrn, ret);
299 goto out;
300 rm_btrn:
301 btr_remove_node(btrn);
302 btr_free_node(btrn);
303 i9ep->stdout_btrn = NULL;
304 rl_set_prompt(i9ep->ici->prompt);
305 rl_forced_update_display();
306 out:
307 t->error = 0;
308 }
309
310 static void i9e_pre_select(struct sched *s, __a_unused struct task *t)
311 {
312 int ret;
313
314 if (i9ep->input_eof || i9ep->caught_sigint) {
315 sched_min_delay(s);
316 return;
317 }
318 if (i9ep->stdout_btrn) {
319 ret = btr_node_status(i9ep->stdout_btrn, 0, BTR_NT_LEAF);
320 if (ret < 0) {
321 sched_min_delay(s);
322 return;
323 }
324 if (ret > 0)
325 para_fd_set(i9ep->ici->fds[1], &s->wfds, &s->max_fileno);
326 }
327 /*
328 * fd[0] might have been reset to blocking mode if our job was moved to
329 * the background due to CTRL-Z or SIGSTOP, so set the fd back to
330 * nonblocking mode.
331 */
332 ret = mark_fd_nonblocking(i9ep->ici->fds[0]);
333 if (ret < 0)
334 PARA_WARNING_LOG("set to nonblock failed: (fd0 %d, %s)\n",
335 i9ep->ici->fds[0], para_strerror(-ret));
336 para_fd_set(i9ep->ici->fds[0], &s->rfds, &s->max_fileno);
337 return;
338 }
339
340 static void update_winsize(void)
341 {
342 struct winsize w;
343 int ret = ioctl(i9ep->ici->fds[2], TIOCGWINSZ, (char *)&w);
344 int num_columns = 80;
345
346 if (ret >= 0) {
347 assert(w.ws_col < sizeof(i9ep->empty_line));
348 num_columns = w.ws_col;
349 }
350 memset(i9ep->empty_line, ' ', num_columns);
351 i9ep->empty_line[num_columns] = '\0';
352 }
353
354 /**
355 * Register the i9e task and initialize readline.
356 *
357 * \param ici The i9e configuration parameters set by the caller.
358 * \param s The scheduler instance to add the i9e task to.
359 *
360 * The caller must allocate and initialize the structure \a ici points to.
361 *
362 * \return Standard.
363 * \sa \ref register_task().
364 */
365 int i9e_open(struct i9e_client_info *ici, struct sched *s)
366 {
367 int ret;
368
369 if (!isatty(ici->fds[0]))
370 return -E_I9E_SETUPTERM;
371 ret = mark_fd_nonblocking(ici->fds[0]);
372 if (ret < 0)
373 return ret;
374 ret = mark_fd_nonblocking(ici->fds[1]);
375 if (ret < 0)
376 return ret;
377 i9ep->task.pre_select = i9e_pre_select;
378 i9ep->task.post_select = i9e_post_select;
379 register_task(s, &i9ep->task);
380 rl_readline_name = "para_i9e";
381 rl_basic_word_break_characters = " ";
382 rl_attempted_completion_function = i9e_completer;
383 i9ep->ici = ici;
384 i9ep->stderr_stream = fdopen(ici->fds[2], "w");
385
386 if (ici->history_file)
387 read_history(ici->history_file);
388 update_winsize();
389 rl_callback_handler_install(i9ep->ici->prompt, i9e_line_handler);
390 return 1;
391 }
392
393 static void reset_line_state(void)
394 {
395 if (i9ep->line_handler_running)
396 return;
397 rl_on_new_line();
398 rl_reset_line_state();
399 rl_forced_update_display();
400 }
401
402 /**
403 * The log function of the i9e subsystem.
404 *
405 * \param ll Severity log level.
406 * \param fmt Printf-like format string.
407 *
408 * This clears the bottom line of the terminal if necessary and writes the
409 * string given by \a fmt to fd[2], where fd[] is the array provided earlier in
410 * \ref i9e_open().
411 */
412 __printf_2_3 void i9e_log(int ll, const char* fmt,...)
413 {
414 va_list argp;
415
416 if (ll < i9ep->ici->loglevel)
417 return;
418 if (i9ep->line_handler_running == false)
419 clear_bottom_line();
420 va_start(argp, fmt);
421 vfprintf(i9ep->stderr_stream, fmt, argp);
422 va_end(argp);
423 reset_line_state();
424 }
425
426 /**
427 * Tell i9e that the caller received a signal.
428 *
429 * \param sig_num The number of the signal received.
430 *
431 * Currently the function only cares about \p SIGINT, but this may change.
432 */
433 void i9e_signal_dispatch(int sig_num)
434 {
435 if (sig_num == SIGINT) {
436 fprintf(i9ep->stderr_stream, "\n");
437 rl_replace_line ("", false /* clear_undo */);
438 reset_line_state();
439 i9ep->caught_sigint = true;
440 }
441 }
442
443 /**
444 * Wrapper for select(2) which does not restart on interrupts.
445 *
446 * \param n \sa \ref para_select().
447 * \param readfds \sa \ref para_select().
448 * \param writefds \sa \ref para_select().
449 * \param timeout_tv \sa \ref para_select().
450 *
451 * \return \sa \ref para_select().
452 *
453 * The only difference between this function and \ref para_select() is that
454 * \ref i9e_select() returns zero if the select call returned \p EINTR.
455 */
456 int i9e_select(int n, fd_set *readfds, fd_set *writefds,
457 struct timeval *timeout_tv)
458 {
459 int ret = select(n, readfds, writefds, NULL, timeout_tv);
460
461 if (ret < 0) {
462 if (errno == EINTR)
463 ret = 0;
464 else
465 ret = -ERRNO_TO_PARA_ERROR(errno);
466 }
467 return ret;
468 }
469
470 /**
471 * Return the possible completions for a given word.
472 *
473 * \param word The word to complete.
474 * \param string_list All possible words in this context.
475 * \param result String list is returned here.
476 *
477 * This function never fails. If no completion was found, a string list of
478 * length zero is returned. In any case, the result must be freed by the caller
479 * using \ref free_argv().
480 *
481 * This function is independent of readline and may be called before
482 * i9e_open().
483 *
484 * return The number of possible completions.
485 */
486 int i9e_extract_completions(const char *word, char **string_list,
487 char ***result)
488 {
489 char **matches = para_malloc(sizeof(char *));
490 int match_count = 0, matches_len = 1;
491 char **p;
492 int len = strlen(word);
493
494 for (p = string_list; *p; p++) {
495 if (!is_prefix(word, *p, len))
496 continue;
497 match_count++;
498 if (match_count >= matches_len) {
499 matches_len *= 2;
500 matches = para_realloc(matches,
501 matches_len * sizeof(char *));
502 }
503 matches[match_count - 1] = para_strdup(*p);
504 }
505 matches[match_count] = NULL;
506 *result = matches;
507 return match_count;
508 }
509
510 /**
511 * Return the list of partially matching words.
512 *
513 * \param word The command to complete.
514 * \param completers The array containing all command names.
515 *
516 * This is similar to \ref i9e_extract_completions(), but completes on the
517 * command names in \a completers.
518 *
519 * \return See \ref i9e_extract_completions().
520 */
521 char **i9e_complete_commands(const char *word, struct i9e_completer *completers)
522 {
523 char **matches;
524 const char *cmd;
525 int i, match_count, len = strlen(word);
526
527 /*
528 * In contrast to completing against an arbitrary string list, here we
529 * know all possible completions and expect that there will not be many
530 * of them. So it should be OK to iterate twice over all commands which
531 * simplifies the code a bit.
532 */
533 for (i = 0, match_count = 0; (cmd = completers[i].name); i++) {
534 if (is_prefix(word, cmd, len))
535 match_count++;
536 }
537 matches = para_malloc((match_count + 1) * sizeof(*matches));
538 for (i = 0, match_count = 0; (cmd = completers[i].name); i++)
539 if (is_prefix(word, cmd, len))
540 matches[match_count++] = para_strdup(cmd);
541 matches[match_count] = NULL;
542 return matches;
543 }
544
545 /**
546 * Complete according to the given options.
547 *
548 * \param opts All available options.
549 * \param ci Information which was passed to the completer.
550 * \param cr Result pointer.
551 *
552 * This convenience helper can be used to complete an option. The array of all
553 * possible options is passed as the first argument. Flags, i.e. options
554 * without an argument, are expected to be listed as strings of type "-X" in \a
555 * opts while options which require an argument should be passed with a
556 * trailing "=" character like "-X=".
557 *
558 * If the word can be uniquely completed to a flag option, an additional space
559 * character is appended to the output. For non-flag options no space character
560 * is appended.
561 */
562 void i9e_complete_option(char **opts, struct i9e_completion_info *ci,
563 struct i9e_completion_result *cr)
564 {
565 int num_matches;
566
567 num_matches = i9e_extract_completions(ci->word, opts, &cr->matches);
568 if (num_matches == 1) {
569 char *opt = cr->matches[0];
570 char c = opt[strlen(opt) - 1];
571 if (c == '=')
572 cr->dont_append_space = true;
573 }
574 }
575
576 /**
577 * Print possible completions to stdout.
578 *
579 * \param completers The array of completion functions.
580 *
581 * At the end of the output a line starting with "-o=", followed by the
582 * (possibly empty) list of completion options is printed. Currently, the only
583 * two completion options are "nospace" and "filenames". The former indicates
584 * that no space should be appended even for a unique match while the latter
585 * indicates that usual filename completion should be performed in addition to
586 * the previously printed options.
587 *
588 * \return Standard.
589 */
590 int i9e_print_completions(struct i9e_completer *completers)
591 {
592 struct i9e_completion_result cr;
593 struct i9e_completion_info ci;
594 char *buf;
595 const char *end, *p;
596 int i, n, ret;
597
598 reset_completion_result(&cr);
599 buf = getenv("COMP_POINT");
600 ci.point = buf? atoi(buf) : 0;
601 ci.buffer = para_strdup(getenv("COMP_LINE"));
602
603 ci.argc = create_argv(ci.buffer, " ", &ci.argv);
604 ci.word_num = compute_word_num(ci.buffer, " ", ci.point);
605
606 end = ci.buffer + ci.point;
607 for (p = end; p > ci.buffer && *p != ' '; p--)
608 ; /* nothing */
609 if (*p == ' ')
610 p++;
611
612 n = end - p + 1;
613 ci.word = para_malloc(n + 1);
614 strncpy(ci.word, p, n);
615 ci.word[n] = '\0';
616
617 PARA_DEBUG_LOG("line: %s, point: %d (%c), wordnum: %d, word: %s\n",
618 ci.buffer, ci.point, ci.buffer[ci.point], ci.word_num, ci.word);
619 if (ci.word_num == 0)
620 cr.matches = i9e_complete_commands(ci.word, completers);
621 else
622 create_matches(&ci, completers, &cr);
623 ret = 0;
624 if (cr.matches && cr.matches[0]) {
625 for (i = 0; cr.matches[i]; i++)
626 printf("%s\n", cr.matches[i]);
627 ret = 1;
628 }
629 printf("-o=");
630 if (cr.dont_append_space)
631 printf("nospace");
632 if (cr.filename_completion_desired)
633 printf(",filenames");
634 printf("\n");
635 free_argv(cr.matches);
636 free_argv(ci.argv);
637 free(ci.buffer);
638 free(ci.word);
639 return ret;
640 }