src/linenoise.c

   1 /* linenoise.c -- guerrilla line editing library against the idea that a
   2  * line editing lib needs to be 20,000 lines of C code.
   3  *
   4  * You can find the latest source code at:
   5  *
   6  *   http://github.com/antirez/linenoise
   7  *
   8  * Does a number of crazy assumptions that happen to be true in 99.9999% of
   9  * the 2010 UNIX computers around.
  10  *
  11  * Copyright (c) 2010, Salvatore Sanfilippo <antirez at gmail dot com>
  12  * All rights reserved.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are met:
  16  *
  17  *   * Redistributions of source code must retain the above copyright notice,
  18  *     this list of conditions and the following disclaimer.
  19  *   * Redistributions in binary form must reproduce the above copyright
  20  *     notice, this list of conditions and the following disclaimer in the
  21  *     documentation and/or other materials provided with the distribution.
  22  *   * Neither the name of Redis nor the names of its contributors may be used
  23  *     to endorse or promote products derived from this software without
  24  *     specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  27  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  30  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  36  * POSSIBILITY OF SUCH DAMAGE.
  37  *
  38  * References:
  39  * - http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
  40  * - http://www.3waylabs.com/nw/WWW/products/wizcon/vt220.html
  41  *
  42  * Todo list:
  43  * - Switch to gets() if $TERM is something we can't support.
  44  * - Filter bogus Ctrl+<char> combinations.
  45  * - Win32 support
  46  *
  47  * Bloat:
  48  * - Completion?
  49  * - History search like Ctrl+r in readline?
  50  *
  51  * List of escape sequences used by this program, we do everything just
  52  * with three sequences. In order to be so cheap we may have some
  53  * flickering effect with some slow terminal, but the lesser sequences
  54  * the more compatible.
  55  *
  56  * CHA (Cursor Horizontal Absolute)
  57  *    Sequence: ESC [ n G
  58  *    Effect: moves cursor to column n
  59  *
  60  * EL (Erase Line)
  61  *    Sequence: ESC [ n K
  62  *    Effect: if n is 0 or missing, clear from cursor to end of line
  63  *    Effect: if n is 1, clear from beginning of line to cursor
  64  *    Effect: if n is 2, clear entire line
  65  *
  66  * CUF (CUrsor Forward)
  67  *    Sequence: ESC [ n C
  68  *    Effect: moves cursor forward of n chars
  69  *
  70  */
  71
  72 #include "fmacros.h"
  73
  74 #include <termios.h>
  75 #include <unistd.h>
  76 #include <stdlib.h>
  77 #include <stdio.h>
  78 #include <errno.h>
  79 #include <string.h>
  80 #include <stdlib.h>
  81 #include <sys/types.h>
  82 #include <sys/ioctl.h>
  83 #include <unistd.h>
  84
  85 #define LINENOISE_DEFAULT_HISTORY_MAX_LEN 100
  86 #define LINENOISE_MAX_LINE 4096
  87 static char *unsupported_term[] = {"dumb","cons25",NULL};
  88
  89 static struct termios orig_termios; /* in order to restore at exit */
  90 static int rawmode = 0; /* for atexit() function to check if restore is needed*/
  91 static int atexit_registered = 0; /* register atexit just 1 time */
  92 static int history_max_len = LINENOISE_DEFAULT_HISTORY_MAX_LEN;
  93 static int history_len = 0;
  94 char **history = NULL;
  95
  96 static void linenoiseAtExit(void);
  97 int linenoiseHistoryAdd(const char *line);
  98
  99 static int isUnsupportedTerm(void) {
 100     char *term = getenv("TERM");
 101     int j;
 102
 103     if (term == NULL) return 0;
 104     for (j = 0; unsupported_term[j]; j++)
 105         if (!strcasecmp(term,unsupported_term[j])) return 1;
 106     return 0;
 107 }
 108
 109 static void freeHistory(void) {
 110     if (history) {
 111         int j;
 112
 113         for (j = 0; j < history_len; j++)
 114             free(history[j]);
 115         free(history);
 116     }
 117 }
 118
 119 static int enableRawMode(int fd) {
 120     struct termios raw;
 121
 122     if (!isatty(STDIN_FILENO)) goto fatal;
 123     if (!atexit_registered) {
 124         atexit(linenoiseAtExit);
 125         atexit_registered = 1;
 126     }
 127     if (tcgetattr(fd,&orig_termios) == -1) goto fatal;
 128
 129     raw = orig_termios;  /* modify the original mode */
 130     /* input modes: no break, no CR to NL, no parity check, no strip char,
 131      * no start/stop output control. */
 132     raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
 133     /* output modes - disable post processing */
 134     raw.c_oflag &= ~(OPOST);
 135     /* control modes - set 8 bit chars */
 136     raw.c_cflag |= (CS8);
 137     /* local modes - choing off, canonical off, no extended functions,
 138      * no signal chars (^Z,^C) */
 139     raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
 140     /* control chars - set return condition: min number of bytes and timer.
 141      * We want read to return every single byte, without timeout. */
 142     raw.c_cc[VMIN] = 1; raw.c_cc[VTIME] = 0; /* 1 byte, no timer */
 143
 144     /* put terminal in raw mode after flushing */
 145     if (tcsetattr(fd,TCSAFLUSH,&raw) < 0) goto fatal;
 146     rawmode = 1;
 147     return 0;
 148
 149 fatal:
 150     errno = ENOTTY;
 151     return -1;
 152 }
 153
 154 static void disableRawMode(int fd) {
 155     /* Don't even check the return value as it's too late. */
 156     if (rawmode && tcsetattr(fd,TCSAFLUSH,&orig_termios) != -1)
 157         rawmode = 0;
 158 }
 159
 160 /* At exit we'll try to fix the terminal to the initial conditions. */
 161 static void linenoiseAtExit(void) {
 162     disableRawMode(STDIN_FILENO);
 163     freeHistory();
 164 }
 165
 166 static int getColumns(void) {
 167     struct winsize ws;
 168
 169     if (ioctl(1, TIOCGWINSZ, &ws) == -1) return 80;
 170     return ws.ws_col;
 171 }
 172
 173 static void refreshLine(int fd, const char *prompt, char *buf, size_t len, size_t pos, size_t cols) {
 174     char seq[64];
 175     size_t plen = strlen(prompt);
 176
 177     while((plen+pos) >= cols) {
 178         buf++;
 179         len--;
 180         pos--;
 181     }
 182     while (plen+len > cols) {
 183         len--;
 184     }
 185
 186     /* Cursor to left edge */
 187     snprintf(seq,64,"\x1b[0G");
 188     if (write(fd,seq,strlen(seq)) == -1) return;
 189     /* Write the prompt and the current buffer content */
 190     if (write(fd,prompt,strlen(prompt)) == -1) return;
 191     if (write(fd,buf,len) == -1) return;
 192     /* Erase to right */
 193     snprintf(seq,64,"\x1b[0K");
 194     if (write(fd,seq,strlen(seq)) == -1) return;
 195     /* Move cursor to original position. */
 196     snprintf(seq,64,"\x1b[0G\x1b[%dC", (int)(pos+plen));
 197     if (write(fd,seq,strlen(seq)) == -1) return;
 198 }
 199
 200 static int linenoisePrompt(int fd, char *buf, size_t buflen, const char *prompt) {
 201     size_t plen = strlen(prompt);
 202     size_t pos = 0;
 203     size_t len = 0;
 204     size_t cols = getColumns();
 205     int history_index = 0;
 206
 207     buf[0] = '\0';
 208     buflen--; /* Make sure there is always space for the nulterm */
 209
 210     /* The latest history entry is always our current buffer, that
 211      * initially is just an empty string. */
 212     linenoiseHistoryAdd("");
 213
 214     if (write(fd,prompt,plen) == -1) return -1;
 215     while(1) {
 216         char c;
 217         int nread;
 218         char seq[2];
 219
 220         nread = read(fd,&c,1);
 221         if (nread <= 0) return len;
 222         switch(c) {
 223         case 13:    /* enter */
 224         case 4:     /* ctrl-d */
 225             history_len--;
 226             free(history[history_len]);
 227             return (len == 0 && c == 4) ? -1 : (int)len;
 228         case 3:     /* ctrl-c */
 229             errno = EAGAIN;
 230             return -1;
 231         case 127:   /* backspace */
 232         case 8:     /* ctrl-h */
 233             if (pos > 0 && len > 0) {
 234                 memmove(buf+pos-1,buf+pos,len-pos);
 235                 pos--;
 236                 len--;
 237                 buf[len] = '\0';
 238                 refreshLine(fd,prompt,buf,len,pos,cols);
 239             }
 240             break;
 241         case 20:    /* ctrl-t */
 242             if (pos > 0 && pos < len) {
 243                 int aux = buf[pos-1];
 244                 buf[pos-1] = buf[pos];
 245                 buf[pos] = aux;
 246                 if (pos != len-1) pos++;
 247                 refreshLine(fd,prompt,buf,len,pos,cols);
 248             }
 249             break;
 250         case 2:     /* ctrl-b */
 251             goto left_arrow;
 252         case 6:     /* ctrl-f */
 253             goto right_arrow;
 254         case 16:    /* ctrl-p */
 255             seq[1] = 65;
 256             goto up_down_arrow;
 257         case 14:    /* ctrl-n */
 258             seq[1] = 66;
 259             goto up_down_arrow;
 260             break;
 261         case 27:    /* escape sequence */
 262             if (read(fd,seq,2) == -1) break;
 263             if (seq[0] == 91 && seq[1] == 68) {
 264 left_arrow:
 265                 /* left arrow */
 266                 if (pos > 0) {
 267                     pos--;
 268                     refreshLine(fd,prompt,buf,len,pos,cols);
 269                 }
 270             } else if (seq[0] == 91 && seq[1] == 67) {
 271 right_arrow:
 272                 /* right arrow */
 273                 if (pos != len) {
 274                     pos++;
 275                     refreshLine(fd,prompt,buf,len,pos,cols);
 276                 }
 277             } else if (seq[0] == 91 && (seq[1] == 65 || seq[1] == 66)) {
 278 up_down_arrow:
 279                 /* up and down arrow: history */
 280                 if (history_len > 1) {
 281                     /* Update the current history entry before to
 282                      * overwrite it with tne next one. */
 283                     free(history[history_len-1-history_index]);
 284                     history[history_len-1-history_index] = strdup(buf);
 285                     /* Show the new entry */
 286                     history_index += (seq[1] == 65) ? 1 : -1;
 287                     if (history_index < 0) {
 288                         history_index = 0;
 289                         break;
 290                     } else if (history_index >= history_len) {
 291                         history_index = history_len-1;
 292                         break;
 293                     }
 294                     strncpy(buf,history[history_len-1-history_index],buflen);
 295                     buf[buflen] = '\0';
 296                     len = pos = strlen(buf);
 297                     refreshLine(fd,prompt,buf,len,pos,cols);
 298                 }
 299             }
 300             break;
 301         default:
 302             if (len < buflen) {
 303                 if (len == pos) {
 304                     buf[pos] = c;
 305                     pos++;
 306                     len++;
 307                     buf[len] = '\0';
 308                     if (plen+len < cols) {
 309                         /* Avoid a full update of the line in the
 310                          * trivial case. */
 311                         if (write(fd,&c,1) == -1) return -1;
 312                     } else {
 313                         refreshLine(fd,prompt,buf,len,pos,cols);
 314                     }
 315                 } else {
 316                     memmove(buf+pos+1,buf+pos,len-pos);
 317                     buf[pos] = c;
 318                     len++;
 319                     pos++;
 320                     buf[len] = '\0';
 321                     refreshLine(fd,prompt,buf,len,pos,cols);
 322                 }
 323             }
 324             break;
 325         case 21: /* Ctrl+u, delete the whole line. */
 326             buf[0] = '\0';
 327             pos = len = 0;
 328             refreshLine(fd,prompt,buf,len,pos,cols);
 329             break;
 330         case 11: /* Ctrl+k, delete from current to end of line. */
 331             buf[pos] = '\0';
 332             len = pos;
 333             refreshLine(fd,prompt,buf,len,pos,cols);
 334             break;
 335         case 1: /* Ctrl+a, go to the start of the line */
 336             pos = 0;
 337             refreshLine(fd,prompt,buf,len,pos,cols);
 338             break;
 339         case 5: /* ctrl+e, go to the end of the line */
 340             pos = len;
 341             refreshLine(fd,prompt,buf,len,pos,cols);
 342             break;
 343         }
 344     }
 345     return len;
 346 }
 347
 348 static int linenoiseRaw(char *buf, size_t buflen, const char *prompt) {
 349     int fd = STDIN_FILENO;
 350     int count;
 351
 352     if (buflen == 0) {
 353         errno = EINVAL;
 354         return -1;
 355     }
 356     if (!isatty(STDIN_FILENO)) {
 357         if (fgets(buf, buflen, stdin) == NULL) return -1;
 358         count = strlen(buf);
 359         if (count && buf[count-1] == '\n') {
 360             count--;
 361             buf[count] = '\0';
 362         }
 363     } else {
 364         if (enableRawMode(fd) == -1) return -1;
 365         count = linenoisePrompt(fd, buf, buflen, prompt);
 366         disableRawMode(fd);
 367         printf("\n");
 368     }
 369     return count;
 370 }
 371
 372 char *linenoise(const char *prompt) {
 373     char buf[LINENOISE_MAX_LINE];
 374     int count;
 375
 376     if (isUnsupportedTerm()) {
 377         size_t len;
 378
 379         printf("%s",prompt);
 380         fflush(stdout);
 381         if (fgets(buf,LINENOISE_MAX_LINE,stdin) == NULL) return NULL;
 382         len = strlen(buf);
 383         while(len && (buf[len-1] == '\n' || buf[len-1] == '\r')) {
 384             len--;
 385             buf[len] = '\0';
 386         }
 387         return strdup(buf);
 388     } else {
 389         count = linenoiseRaw(buf,LINENOISE_MAX_LINE,prompt);
 390         if (count == -1) return NULL;
 391         return strdup(buf);
 392     }
 393 }
 394
 395 /* Using a circular buffer is smarter, but a bit more complex to handle. */
 396 int linenoiseHistoryAdd(const char *line) {
 397     char *linecopy;
 398
 399     if (history_max_len == 0) return 0;
 400     if (history == NULL) {
 401         history = malloc(sizeof(char*)*history_max_len);
 402         if (history == NULL) return 0;
 403         memset(history,0,(sizeof(char*)*history_max_len));
 404     }
 405     linecopy = strdup(line);
 406     if (!linecopy) return 0;
 407     if (history_len == history_max_len) {
 408         free(history[0]);
 409         memmove(history,history+1,sizeof(char*)*(history_max_len-1));
 410         history_len--;
 411     }
 412     history[history_len] = linecopy;
 413     history_len++;
 414     return 1;
 415 }
 416
 417 int linenoiseHistorySetMaxLen(int len) {
 418     char **new;
 419
 420     if (len < 1) return 0;
 421     if (history) {
 422         int tocopy = history_len;
 423
 424         new = malloc(sizeof(char*)*len);
 425         if (new == NULL) return 0;
 426         if (len < tocopy) tocopy = len;
 427         memcpy(new,history+(history_max_len-tocopy), sizeof(char*)*tocopy);
 428         free(history);
 429         history = new;
 430     }
 431     history_max_len = len;
 432     if (history_len > history_max_len)
 433         history_len = history_max_len;
 434     return 1;
 435 }
 436
 437 /* Save the history in the specified file. On success 0 is returned
 438  * otherwise -1 is returned. */
 439 int linenoiseHistorySave(char *filename) {
 440     FILE *fp = fopen(filename,"w");
 441     int j;
 442
 443     if (fp == NULL) return -1;
 444     for (j = 0; j < history_len; j++)
 445         fprintf(fp,"%s\n",history[j]);
 446     fclose(fp);
 447     return 0;
 448 }
 449
 450 /* Load the history from the specified file. If the file does not exist
 451  * zero is returned and no operation is performed.
 452  *
 453  * If the file exists and the operation succeeded 0 is returned, otherwise
 454  * on error -1 is returned. */
 455 int linenoiseHistoryLoad(char *filename) {
 456     FILE *fp = fopen(filename,"r");
 457     char buf[LINENOISE_MAX_LINE];
 458
 459     if (fp == NULL) return -1;
 460
 461     while (fgets(buf,LINENOISE_MAX_LINE,fp) != NULL) {
 462         char *p;
 463
 464         p = strchr(buf,'\r');
 465         if (!p) p = strchr(buf,'\n');
 466         if (p) *p = '\0';
 467         linenoiseHistoryAdd(buf);
 468     }
 469     fclose(fp);
 470     return 0;
 471 }