[cloud] Allow aws-import script to run on Python 3.6
[ipxe.git] / src / hci / readline.c
1 /*
2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 #include <stdio.h>
27 #include <string.h>
28 #include <stdlib.h>
29 #include <errno.h>
30 #include <ipxe/console.h>
31 #include <ipxe/keys.h>
32 #include <ipxe/editstring.h>
33 #include <readline/readline.h>
34
35 /** @file
36 *
37 * Minimal readline
38 *
39 */
40
41 #define READLINE_MAX 1024
42
43 /**
44 * Synchronise console with edited string
45 *
46 * @v string Editable string
47 */
48 static void sync_console ( struct edit_string *string ) {
49 unsigned int mod_start = string->mod_start;
50 unsigned int mod_end = string->mod_end;
51 unsigned int cursor = string->last_cursor;
52 size_t len = strlen ( string->buf );
53
54 /* Expand region back to old cursor position if applicable */
55 if ( mod_start > string->last_cursor )
56 mod_start = string->last_cursor;
57
58 /* Expand region forward to new cursor position if applicable */
59 if ( mod_end < string->cursor )
60 mod_end = string->cursor;
61
62 /* Backspace to start of region */
63 while ( cursor > mod_start ) {
64 putchar ( '\b' );
65 cursor--;
66 }
67
68 /* Print modified region */
69 while ( cursor < mod_end ) {
70 putchar ( ( cursor >= len ) ? ' ' : string->buf[cursor] );
71 cursor++;
72 }
73
74 /* Backspace to new cursor position */
75 while ( cursor > string->cursor ) {
76 putchar ( '\b' );
77 cursor--;
78 }
79 }
80
81 /**
82 * Locate history entry
83 *
84 * @v history History buffer
85 * @v depth Depth within history buffer
86 * @ret entry History entry
87 */
88 static struct readline_history_entry *
89 history_entry ( struct readline_history *history, unsigned int depth ) {
90 unsigned int offset;
91
92 offset = ( ( history->next - depth ) %
93 ( sizeof ( history->entries ) /
94 sizeof ( history->entries[0] ) ) );
95 return &history->entries[offset];
96 }
97
98 /**
99 * Read string from history buffer
100 *
101 * @v history History buffer
102 * @v depth Depth within history buffer
103 * @ret string String
104 */
105 static const char * history_fetch ( struct readline_history *history,
106 unsigned int depth ) {
107 struct readline_history_entry *entry;
108
109 /* Return the temporary copy if it exists, otherwise return
110 * the persistent copy.
111 */
112 entry = history_entry ( history, depth );
113 return ( entry->temp ? entry->temp : entry->string );
114 }
115
116 /**
117 * Write temporary string copy to history buffer
118 *
119 * @v history History buffer
120 * @v depth Depth within history buffer
121 * @v string String
122 */
123 static void history_store ( struct readline_history *history,
124 unsigned int depth, const char *string ) {
125 struct readline_history_entry *entry;
126 char *temp;
127
128 /* Create temporary copy of string */
129 temp = strdup ( string );
130 if ( ! temp ) {
131 /* Just discard the string; there's nothing we can do */
132 DBGC ( history, "READLINE %p could not store string\n",
133 history );
134 return;
135 }
136
137 /* Store temporary copy */
138 entry = history_entry ( history, depth );
139 free ( entry->temp );
140 entry->temp = temp;
141 }
142
143 /**
144 * Move to new history depth
145 *
146 * @v history History buffer
147 * @v offset Offset by which to change depth
148 * @v old_string String (possibly modified) at current depth
149 * @ret new_string String at new depth, or NULL for no movement
150 */
151 static const char * history_move ( struct readline_history *history,
152 int offset, const char *old_string ) {
153 unsigned int new_depth = ( history->depth + offset );
154 const char * new_string = history_fetch ( history, new_depth );
155
156 /* Depth checks */
157 if ( new_depth > READLINE_HISTORY_MAX_DEPTH )
158 return NULL;
159 if ( ! new_string )
160 return NULL;
161
162 /* Store temporary copy of old string at current depth */
163 history_store ( history, history->depth, old_string );
164
165 /* Update depth */
166 history->depth = new_depth;
167
168 /* Return new string */
169 return new_string;
170 }
171
172 /**
173 * Append new history entry
174 *
175 * @v history History buffer
176 * @v string String
177 */
178 static void history_append ( struct readline_history *history,
179 const char *string ) {
180 struct readline_history_entry *entry;
181
182 /* Store new entry */
183 entry = history_entry ( history, 0 );
184 assert ( entry->string == NULL );
185 entry->string = strdup ( string );
186 if ( ! entry->string ) {
187 /* Just discard the string; there's nothing we can do */
188 DBGC ( history, "READLINE %p could not append string\n",
189 history );
190 return;
191 }
192
193 /* Increment history position */
194 history->next++;
195
196 /* Prepare empty "next" slot */
197 entry = history_entry ( history, 0 );
198 free ( entry->string );
199 entry->string = NULL;
200 }
201
202 /**
203 * Clean up history after editing
204 *
205 * @v history History buffer
206 */
207 static void history_cleanup ( struct readline_history *history ) {
208 struct readline_history_entry *entry;
209 unsigned int i;
210
211 /* Discard any temporary strings */
212 for ( i = 0 ; i < ( sizeof ( history->entries ) /
213 sizeof ( history->entries[0] ) ) ; i++ ) {
214 entry = &history->entries[i];
215 free ( entry->temp );
216 entry->temp = NULL;
217 }
218
219 /* Reset depth */
220 history->depth = 0;
221
222 /* Sanity check */
223 entry = history_entry ( history, 0 );
224 assert ( entry->string == NULL );
225 }
226
227 /**
228 * Free history buffer
229 *
230 * @v history History buffer
231 */
232 void history_free ( struct readline_history *history ) {
233 struct readline_history_entry *entry;
234 unsigned int i;
235
236 /* Discard any temporary strings */
237 for ( i = 0 ; i < ( sizeof ( history->entries ) /
238 sizeof ( history->entries[0] ) ) ; i++ ) {
239 entry = &history->entries[i];
240 assert ( entry->temp == NULL );
241 free ( entry->string );
242 }
243 }
244
245 /**
246 * Read line from console (with history)
247 *
248 * @v prompt Prompt string
249 * @v prefill Prefill string, or NULL for no prefill
250 * @v history History buffer, or NULL for no history
251 * @v timeout Timeout period, in ticks (0=indefinite)
252 * @ret line Line read from console (excluding terminating newline)
253 * @ret rc Return status code
254 *
255 * The returned line is allocated with malloc(); the caller must
256 * eventually call free() to release the storage.
257 */
258 int readline_history ( const char *prompt, const char *prefill,
259 struct readline_history *history, unsigned long timeout,
260 char **line ) {
261 struct edit_string string;
262 char *buf;
263 int key;
264 int move_by;
265 const char *new_string;
266 int rc;
267
268 /* Avoid returning uninitialised data on error */
269 *line = NULL;
270
271 /* Display prompt, if applicable */
272 if ( prompt )
273 printf ( "%s", prompt );
274
275 /* Ensure cursor is visible */
276 printf ( "\033[?25h" );
277
278 /* Allocate buffer and initialise editable string */
279 buf = zalloc ( READLINE_MAX );
280 if ( ! buf ) {
281 rc = -ENOMEM;
282 goto done;
283 }
284 memset ( &string, 0, sizeof ( string ) );
285 init_editstring ( &string, buf, READLINE_MAX );
286
287 /* Prefill string, if applicable */
288 if ( prefill ) {
289 replace_string ( &string, prefill );
290 sync_console ( &string );
291 }
292
293 while ( 1 ) {
294
295 /* Get keypress */
296 key = getkey ( timeout );
297 if ( key < 0 ) {
298 rc = -ETIMEDOUT;
299 goto done;
300 }
301 timeout = 0;
302
303 /* Handle keypress */
304 key = edit_string ( &string, key );
305 sync_console ( &string );
306 move_by = 0;
307 switch ( key ) {
308 case CR:
309 case LF:
310 /* Shrink string (ignoring failures) */
311 *line = realloc ( buf,
312 ( strlen ( buf ) + 1 /* NUL */ ) );
313 if ( ! *line )
314 *line = buf;
315 buf = NULL;
316 rc = 0;
317 goto done;
318 case CTRL_C:
319 rc = -ECANCELED;
320 goto done;
321 case KEY_UP:
322 move_by = 1;
323 break;
324 case KEY_DOWN:
325 move_by = -1;
326 break;
327 default:
328 /* Do nothing */
329 break;
330 }
331
332 /* Handle history movement, if applicable */
333 if ( move_by && history ) {
334 new_string = history_move ( history, move_by, buf );
335 if ( new_string ) {
336 replace_string ( &string, new_string );
337 sync_console ( &string );
338 }
339 }
340 }
341
342 done:
343 putchar ( '\n' );
344 free ( buf );
345 if ( history ) {
346 if ( *line && (*line)[0] )
347 history_append ( history, *line );
348 history_cleanup ( history );
349 }
350 assert ( ( rc == 0 ) ^ ( *line == NULL ) );
351 return rc;
352 }
353
354 /**
355 * Read line from console
356 *
357 * @v prompt Prompt string
358 * @ret line Line read from console (excluding terminating newline)
359 *
360 * The returned line is allocated with malloc(); the caller must
361 * eventually call free() to release the storage.
362 */
363 char * readline ( const char *prompt ) {
364 char *line;
365
366 readline_history ( prompt, NULL, NULL, 0, &line );
367 return line;
368 }