2 * Copyright (C) 1984-2007 Mark Nudelman
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
7 * For more information about less, or for information on how to
8 * contact the author, see the README file.
13 * Routines to decode user commands.
15 * This is all table driven.
16 * A command table is a sequence of command descriptors.
17 * Each command descriptor is a sequence of bytes with the following format:
18 * <c1><c2>...<cN><0><action>
19 * The characters c1,c2,...,cN are the command string; that is,
20 * the characters which the user must type.
21 * It is terminated by a null <0> byte.
22 * The byte after the null byte is the action code associated
23 * with the command string.
24 * If an action byte is OR-ed with A_EXTRA, this indicates
25 * that the option byte is followed by an extra string.
27 * There may be many command tables.
28 * The first (default) table is built-in.
29 * Other tables are read in from "lesskey" files.
30 * All the tables are linked together and are searched in order.
37 extern int erase_char, erase2_char, kill_char;
41 SK_SPECIAL_KEY, (k), 6, 1, 1, 1
43 * Command table is ordered roughly according to expected
44 * frequency of use, so the common commands are near the beginning.
47 static unsigned char cmdtable[] =
53 SK(SK_DOWN_ARROW),0, A_F_LINE,
54 CONTROL('E'),0, A_F_LINE,
55 CONTROL('N'),0, A_F_LINE,
58 CONTROL('Y'),0, A_B_LINE,
59 SK(SK_CONTROL_K),0, A_B_LINE,
60 CONTROL('P'),0, A_B_LINE,
61 SK(SK_UP_ARROW),0, A_B_LINE,
66 CONTROL('D'),0, A_F_SCROLL,
68 CONTROL('U'),0, A_B_SCROLL,
71 CONTROL('F'),0, A_F_SCREEN,
72 CONTROL('V'),0, A_F_SCREEN,
73 SK(SK_PAGE_DOWN),0, A_F_SCREEN,
75 CONTROL('B'),0, A_B_SCREEN,
76 ESC,'v',0, A_B_SCREEN,
77 SK(SK_PAGE_UP),0, A_B_SCREEN,
80 ESC,' ',0, A_FF_SCREEN,
84 CONTROL('R'),0, A_REPAINT,
85 CONTROL('L'),0, A_REPAINT,
86 ESC,'u',0, A_UNDO_SEARCH,
88 SK(SK_HOME),0, A_GOLINE,
97 SK(SK_RIGHT_ARROW),0, A_RSHIFT,
98 SK(SK_LEFT_ARROW),0, A_LSHIFT,
99 '{',0, A_F_BRACKET|A_EXTRA, '{','}',0,
100 '}',0, A_B_BRACKET|A_EXTRA, '{','}',0,
101 '(',0, A_F_BRACKET|A_EXTRA, '(',')',0,
102 ')',0, A_B_BRACKET|A_EXTRA, '(',')',0,
103 '[',0, A_F_BRACKET|A_EXTRA, '[',']',0,
104 ']',0, A_B_BRACKET|A_EXTRA, '[',']',0,
105 ESC,CONTROL('F'),0, A_F_BRACKET,
106 ESC,CONTROL('B'),0, A_B_BRACKET,
110 SK(SK_END),0, A_GOEND,
126 CONTROL('G'),0, A_STAT,
130 ESC,'/',0, A_F_SEARCH|A_EXTRA, '*',0,
131 ESC,'?',0, A_B_SEARCH|A_EXTRA, '*',0,
132 'n',0, A_AGAIN_SEARCH,
133 ESC,'n',0, A_T_AGAIN_SEARCH,
134 'N',0, A_REVERSE_SEARCH,
135 ESC,'N',0, A_T_REVERSE_SEARCH,
138 CONTROL('X'),CONTROL('X'),0, A_GOMARK,
140 ':','e',0, A_EXAMINE,
141 CONTROL('X'),CONTROL('V'),0, A_EXAMINE,
142 ':','n',0, A_NEXT_FILE,
143 ':','p',0, A_PREV_FILE,
146 ':','x',0, A_INDEX_FILE,
147 ':','d',0, A_REMOVE_FILE,
149 ':','t',0, A_OPT_TOGGLE|A_EXTRA, 't',0,
150 's',0, A_OPT_TOGGLE|A_EXTRA, 'o',0,
151 '_',0, A_DISP_OPTION,
168 static unsigned char edittable[] =
170 '\t',0, EC_F_COMPLETE, /* TAB */
171 '\17',0, EC_B_COMPLETE, /* BACKTAB */
172 SK(SK_BACKTAB),0, EC_B_COMPLETE, /* BACKTAB */
173 ESC,'\t',0, EC_B_COMPLETE, /* ESC TAB */
174 CONTROL('L'),0, EC_EXPAND, /* CTRL-L */
175 CONTROL('V'),0, EC_LITERAL, /* BACKSLASH */
176 CONTROL('A'),0, EC_LITERAL, /* BACKSLASH */
177 ESC,'l',0, EC_RIGHT, /* ESC l */
178 SK(SK_RIGHT_ARROW),0, EC_RIGHT, /* RIGHTARROW */
179 ESC,'h',0, EC_LEFT, /* ESC h */
180 SK(SK_LEFT_ARROW),0, EC_LEFT, /* LEFTARROW */
181 ESC,'b',0, EC_W_LEFT, /* ESC b */
182 ESC,SK(SK_LEFT_ARROW),0, EC_W_LEFT, /* ESC LEFTARROW */
183 SK(SK_CTL_LEFT_ARROW),0, EC_W_LEFT, /* CTRL-LEFTARROW */
184 ESC,'w',0, EC_W_RIGHT, /* ESC w */
185 ESC,SK(SK_RIGHT_ARROW),0, EC_W_RIGHT, /* ESC RIGHTARROW */
186 SK(SK_CTL_RIGHT_ARROW),0, EC_W_RIGHT, /* CTRL-RIGHTARROW */
187 ESC,'i',0, EC_INSERT, /* ESC i */
188 SK(SK_INSERT),0, EC_INSERT, /* INSERT */
189 ESC,'x',0, EC_DELETE, /* ESC x */
190 SK(SK_DELETE),0, EC_DELETE, /* DELETE */
191 ESC,'X',0, EC_W_DELETE, /* ESC X */
192 ESC,SK(SK_DELETE),0, EC_W_DELETE, /* ESC DELETE */
193 SK(SK_CTL_DELETE),0, EC_W_DELETE, /* CTRL-DELETE */
194 SK(SK_CTL_BACKSPACE),0, EC_W_BACKSPACE, /* CTRL-BACKSPACE */
195 ESC,'\b',0, EC_W_BACKSPACE, /* ESC BACKSPACE */
196 ESC,'0',0, EC_HOME, /* ESC 0 */
197 SK(SK_HOME),0, EC_HOME, /* HOME */
198 ESC,'$',0, EC_END, /* ESC $ */
199 SK(SK_END),0, EC_END, /* END */
200 ESC,'k',0, EC_UP, /* ESC k */
201 SK(SK_UP_ARROW),0, EC_UP, /* UPARROW */
202 ESC,'j',0, EC_DOWN, /* ESC j */
203 SK(SK_DOWN_ARROW),0, EC_DOWN, /* DOWNARROW */
207 * Structure to support a list of command tables.
211 struct tablelist *t_next;
217 * List of command tables and list of line-edit tables.
219 static struct tablelist *list_fcmd_tables = NULL;
220 static struct tablelist *list_ecmd_tables = NULL;
221 static struct tablelist *list_var_tables = NULL;
222 static struct tablelist *list_sysvar_tables = NULL;
226 * Expand special key abbreviations in a command table.
229 expand_special_keys(table, len)
239 for (fm = table; fm < table + len; )
242 * Rewrite each command in the table with any
243 * special key abbreviations expanded.
245 for (to = fm; *fm != '\0'; )
247 if (*fm != SK_SPECIAL_KEY)
253 * After SK_SPECIAL_KEY, next byte is the type
254 * of special key (one of the SK_* contants),
255 * and the byte after that is the number of bytes,
256 * N, reserved by the abbreviation (including the
257 * SK_SPECIAL_KEY and key type bytes).
258 * Replace all N bytes with the actual bytes
259 * output by the special key on this terminal.
261 repl = special_key_str(fm[1]);
264 if (repl == NULL || (int) strlen(repl) > klen)
266 while (*repl != '\0')
271 * Fill any unused bytes between end of command and
272 * the action byte with A_SKIP.
280 while (*fm++ != '\0')
287 * Initialize the command lists.
293 * Add the default command tables.
295 add_fcmd_table((char*)cmdtable, sizeof(cmdtable));
296 add_ecmd_table((char*)edittable, sizeof(edittable));
299 * For backwards compatibility,
300 * try to add tables in the OLD system lesskey file.
303 add_hometable(NULL, BINDIR "/.sysless", 1);
306 * Try to add the tables in the system lesskey file.
308 add_hometable("LESSKEY_SYSTEM", LESSKEYFILE_SYS, 1);
310 * Try to add the tables in the standard lesskey file "$HOME/.less".
312 add_hometable("LESSKEY", LESSKEYFILE, 0);
317 * Add a command table.
320 add_cmd_table(tlist, buf, len)
321 struct tablelist **tlist;
325 register struct tablelist *t;
330 * Allocate a tablelist structure, initialize it,
331 * and link it into the list of tables.
333 if ((t = (struct tablelist *)
334 calloc(1, sizeof(struct tablelist))) == NULL)
338 expand_special_keys(buf, len);
340 t->t_end = buf + len;
347 * Add a command table.
350 add_fcmd_table(buf, len)
354 if (add_cmd_table(&list_fcmd_tables, buf, len) < 0)
355 error("Warning: some commands disabled", NULL_PARG);
359 * Add an editing command table.
362 add_ecmd_table(buf, len)
366 if (add_cmd_table(&list_ecmd_tables, buf, len) < 0)
367 error("Warning: some edit commands disabled", NULL_PARG);
371 * Add an environment variable table.
374 add_var_table(tlist, buf, len)
375 struct tablelist **tlist;
379 if (add_cmd_table(tlist, buf, len) < 0)
380 error("Warning: environment variables from lesskey file unavailable", NULL_PARG);
384 * Search a single command table for the command string in cmd.
387 cmd_search(cmd, table, endtable, sp)
398 for (p = table, q = cmd; p < endtable; p++, q++)
403 * Current characters match.
404 * If we're at the end of the string, we've found it.
405 * Return the action code, which is the character
406 * after the null at the end of the string
407 * in the command table.
417 * We get here only if the original
418 * cmd string passed in was empty ("").
419 * I don't think that can happen,
420 * but just in case ...
425 * Check for an "extra" string.
434 } else if (*q == '\0')
437 * Hit the end of the user's command,
438 * but not the end of the string in the command table.
439 * The user's command is incomplete.
446 * Skip ahead to the next command in the
447 * command table, and reset the pointer
448 * to the beginning of the user's command.
450 if (*p == '\0' && p[1] == A_END_LIST)
453 * A_END_LIST is a special marker that tells
454 * us to abort the cmd search.
469 * No match found in the entire command table.
475 * Decode a command character and return the associated action.
476 * The "extra" string, if any, is returned in sp.
479 cmd_decode(tlist, cmd, sp)
480 struct tablelist *tlist;
484 register struct tablelist *t;
485 register int action = A_INVALID;
488 * Search thru all the command tables.
489 * Stop when we find an action which is not A_INVALID.
491 for (t = tlist; t != NULL; t = t->t_next)
493 action = cmd_search(cmd, t->t_start, t->t_end, sp);
494 if (action != A_INVALID)
497 if (action == A_UINVALID)
503 * Decode a command from the cmdtables list.
510 return (cmd_decode(list_fcmd_tables, cmd, sp));
514 * Decode a command from the edittables list.
521 return (cmd_decode(list_ecmd_tables, cmd, sp));
525 * Get the value of an environment variable.
526 * Looks first in the lesskey file, then in the real environment.
535 a = cmd_decode(list_var_tables, var, &s);
539 if (s != NULL && *s != '\0')
541 a = cmd_decode(list_sysvar_tables, var, &s);
549 * Get an "integer" from a lesskey file.
550 * Integers are stored in a funny format:
551 * two bytes, low order first, in radix KRADIX.
560 n += *(*sp)++ * KRADIX;
565 * Process an old (pre-v241) lesskey file.
568 old_lesskey(buf, len)
573 * Old-style lesskey file.
574 * The file must end with either
576 * or ...,cmd,0,action|A_EXTRA,string,0
577 * So the last byte or the second to last byte must be zero.
579 if (buf[len-1] != '\0' && buf[len-2] != '\0')
581 add_fcmd_table(buf, len);
586 * Process a new (post-v241) lesskey file.
589 new_lesskey(buf, len, sysvar)
599 * New-style lesskey file.
600 * Extract the pieces.
602 if (buf[len-3] != C0_END_LESSKEY_MAGIC ||
603 buf[len-2] != C1_END_LESSKEY_MAGIC ||
604 buf[len-1] != C2_END_LESSKEY_MAGIC)
614 add_fcmd_table(p, n);
619 add_ecmd_table(p, n);
624 add_var_table((sysvar) ?
625 &list_sysvar_tables : &list_var_tables, p, n);
632 * Unrecognized section type.
640 * Set up a user command table, based on a "lesskey" file.
643 lesskey(filename, sysvar)
648 register POSITION len;
655 * Try to open the lesskey file.
657 filename = shell_unquote(filename);
658 f = open(filename, OPEN_READ);
664 * Read the file into a buffer.
665 * We first figure out the size of the file and allocate space for it.
666 * {{ Minimal error checking is done here.
667 * A garbage .less file will produce strange results.
668 * To avoid a large amount of error checking code here, we
669 * rely on the lesskey program to generate a good .less file. }}
672 if (len == NULL_POSITION || len < 3)
675 * Bad file (valid file must have at least 3 chars).
680 if ((buf = (char *) calloc((int)len, sizeof(char))) == NULL)
685 if (lseek(f, (off_t)0, SEEK_SET) == BAD_LSEEK)
691 n = read(f, buf, (unsigned int) len);
700 * Figure out if this is an old-style (before version 241)
701 * or new-style lesskey file format.
703 if (buf[0] != C0_LESSKEY_MAGIC || buf[1] != C1_LESSKEY_MAGIC ||
704 buf[2] != C2_LESSKEY_MAGIC || buf[3] != C3_LESSKEY_MAGIC)
705 return (old_lesskey(buf, (int)len));
706 return (new_lesskey(buf, (int)len, sysvar));
710 * Add the standard lesskey file "$HOME/.less"
713 add_hometable(envname, def_filename, sysvar)
721 if (envname != NULL && (filename = lgetenv(envname)) != NULL)
722 filename = save(filename);
724 filename = save(def_filename);
726 filename = homefile(def_filename);
727 if (filename == NULL)
729 if (lesskey(filename, sysvar) < 0)
731 parg.p_string = filename;
732 error("Cannot use lesskey file \"%s\"", &parg);
739 * See if a char is a special line-editing command.
749 char usercmd[MAX_CMDLEN+1];
752 * An editing character could actually be a sequence of characters;
753 * for example, an escape sequence sent by pressing the uparrow key.
754 * To match the editing string, we use the command decoder
755 * but give it the edit-commands command table
756 * This table is constructed to match the user's keyboard.
758 if (c == erase_char || c == erase2_char)
759 return (EC_BACKSPACE);
761 return (EC_LINEKILL);
764 * Collect characters in a buffer.
765 * Start with the one we have, and get more if we need them.
772 usercmd[nch+1] = '\0';
774 action = ecmd_decode(usercmd, &s);
775 } while (action == A_PREFIX);
777 if (flags & EC_NORIGHTLEFT)
788 if (flags & EC_NOHISTORY)
791 * The caller says there is no history list.
792 * Reject any history-manipulation action.
803 #if TAB_COMPLETE_FILENAME
804 if (flags & EC_NOCOMPLETE)
807 * The caller says we don't want any filename completion cmds.
820 if ((flags & EC_PEEK) || action == A_INVALID)
823 * We're just peeking, or we didn't understand the command.
824 * Unget all the characters we read in the loop above.
825 * This does NOT include the original character that was
826 * passed in as a parameter.
830 ungetcc(usercmd[--nch]);