/* linenoise.c -- guerrilla line editing library against the idea that a
* line editing lib needs to be 20,000 lines of C code.
*
* You can find the latest source code at:
*
* http://github.com/antirez/linenoise
*
* Does a number of crazy assumptions that happen to be true in 99.9999% of
* the 2010 UNIX computers around.
*
* Copyright (c) 2010, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* References:
* - http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
* - http://www.3waylabs.com/nw/WWW/products/wizcon/vt220.html
*
* Todo list:
* - Switch to gets() if $TERM is something we can't support.
* - Filter bogus Ctrl+<char> combinations.
* - Win32 support
*
* Bloat:
* - Completion?
* - History search like Ctrl+r in readline?
*
* List of escape sequences used by this program, we do everything just
* with three sequences. In order to be so cheap we may have some
* flickering effect with some slow terminal, but the lesser sequences
* the more compatible.
*
* CHA (Cursor Horizontal Absolute)
* Sequence: ESC [ n G
* Effect: moves cursor to column n
*
* EL (Erase Line)
* Sequence: ESC [ n K
* Effect: if n is 0 or missing, clear from cursor to end of line
* Effect: if n is 1, clear from beginning of line to cursor
* Effect: if n is 2, clear entire line
*
* CUF (CUrsor Forward)
* Sequence: ESC [ n C
* Effect: moves cursor forward of n chars
*
*/
#include <termios.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <unistd.h>
#define LINENOISE_MAX_LINE 4096
static char *unsupported_term[] = {"dumb","cons25",NULL};
static struct termios orig_termios; /* in order to restore at exit */
static int rawmode = 0; /* for atexit() function to check if restore is needed*/
static int atexit_registered = 0; /* register atexit just 1 time */
static int history_max_len = 100;
static int history_len = 0;
char **history = NULL;
static void linenoiseAtExit(void);
int linenoiseHistoryAdd(const char *line);
static int isUnsupportedTerm(void) {
char *term = getenv("TERM");
int j;
if (term == NULL) return 0;
for (j = 0; unsupported_term[j]; j++)
if (!strcasecmp(term,unsupported_term[j])) return 1;
return 0;
}
static void freeHistory(void) {
if (history) {
int j;
for (j = 0; j < history_len; j++)
free(history[j]);
free(history);
}
}
static int enableRawMode(int fd) {
struct termios raw;
if (!isatty(STDIN_FILENO)) goto fatal;
if (!atexit_registered) {
atexit(linenoiseAtExit);
atexit_registered = 1;
}
if (tcgetattr(fd,&orig_termios) == -1) goto fatal;
raw = orig_termios; /* modify the original mode */
/* input modes: no break, no CR to NL, no parity check, no strip char,
* no start/stop output control. */
raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
/* output modes - disable post processing */
raw.c_oflag &= ~(OPOST);
/* control modes - set 8 bit chars */
raw.c_cflag |= (CS8);
/* local modes - choing off, canonical off, no extended functions,
* no signal chars (^Z,^C) */
raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
/* control chars - set return condition: min number of bytes and timer.
* We want read to return every single byte, without timeout. */
raw.c_cc[VMIN] = 1; raw.c_cc[VTIME] = 0; /* 1 byte, no timer */
/* put terminal in raw mode */
if (tcsetattr(fd,TCSADRAIN,&raw) < 0) goto fatal;
rawmode = 1;
return 0;
fatal:
errno = ENOTTY;
return -1;
}
static void disableRawMode(int fd) {
/* Don't even check the return value as it's too late. */
if (rawmode && tcsetattr(fd,TCSADRAIN,&orig_termios) != -1)
rawmode = 0;
}
/* At exit we'll try to fix the terminal to the initial conditions. */
static void linenoiseAtExit(void) {
disableRawMode(STDIN_FILENO);
freeHistory();
}
static int getColumns(void) {
struct winsize ws;
if (ioctl(1, TIOCGWINSZ, &ws) == -1) return 4096;
if (ws.ws_col == 0) {
return 4096;
}
return ws.ws_col;
}
static int effectiveLen(const char* prompt) {
int col = 0;
char c;
// TODO: Handle escape sequences.
while ( (c = *prompt++) != 0 ) {
if (c == '\n') {
col = 0;
} else {
col++;
}
}
return col;
}
static void refreshLine(int fd, const char *prompt, char *buf, size_t len, size_t pos, size_t cols) {
char seq[64];
size_t plen = effectiveLen(prompt);
while((plen+pos) >= cols) {
buf++;
len--;
pos--;
}
while (plen+len > cols) {
len--;
}
/* Cursor to left edge */
snprintf(seq,64,"\x1b[0G");
if (write(fd,seq,strlen(seq)) == -1) return;
/* Write the prompt and the current buffer content */
if (write(fd,prompt,strlen(prompt)) == -1) return;
if (write(fd,buf,len) == -1) return;
/* Erase to right */
snprintf(seq,64,"\x1b[0K");
if (write(fd,seq,strlen(seq)) == -1) return;
/* Move cursor to original position. */
snprintf(seq,64,"\x1b[0G\x1b[%dC", (int)(pos+plen));
if (write(fd,seq,strlen(seq)) == -1) return;
}
static int linenoisePrompt(int fd, char *buf, size_t buflen, const char *prompt) {
size_t plen = strlen(prompt);
size_t pos = 0;
size_t len = 0;
size_t cols = getColumns();
int history_index = 0;
buf[0] = '\0';
buflen--; /* Make sure there is always space for the nulterm */
/* The latest history entry is always our current buffer, that
* initially is just an empty string. */
linenoiseHistoryAdd("");
if (write(fd,prompt,plen) == -1) return -1;
while(1) {
char c;
int nread;
char seq[2];
nread = read(fd,&c,1);
if (nread <= 0) return len;
switch(c) {
case 10: /* line feed. */
case 13: /* enter */
history_len--;
return len;
case 4: /* ctrl-d */
history_len--;
return (len == 0) ? -1 : (int)len;
case 3: /* ctrl-c */
errno = EAGAIN;
return -1;
case 127: /* backspace */
case 8: /* ctrl-h */
if (pos > 0 && len > 0) {
memmove(buf+pos-1,buf+pos,len-pos);
pos--;
len--;
buf[len] = '\0';
refreshLine(fd,prompt,buf,len,pos,cols);
}
break;
case 20: /* ctrl-t */
if (pos > 0 && pos < len) {
int aux = buf[pos-1];
buf[pos-1] = buf[pos];
buf[pos] = aux;
if (pos != len-1) pos++;
refreshLine(fd,prompt,buf,len,pos,cols);
}
break;
case 2: /* ctrl-b */
goto left_arrow;
case 6: /* ctrl-f */
goto right_arrow;
case 16: /* ctrl-p */
seq[1] = 65;
goto up_down_arrow;
case 14: /* ctrl-n */
seq[1] = 66;
goto up_down_arrow;
break;
case 27: /* escape sequence */
if (read(fd,seq,2) == -1) break;
if (seq[0] == 91 && seq[1] == 68) {
left_arrow:
/* left arrow */
if (pos > 0) {
pos--;
refreshLine(fd,prompt,buf,len,pos,cols);
}
} else if (seq[0] == 91 && seq[1] == 67) {
right_arrow:
/* right arrow */
if (pos != len) {
pos++;
refreshLine(fd,prompt,buf,len,pos,cols);
}
} else if (seq[0] == 91 && (seq[1] == 65 || seq[1] == 66)) {
up_down_arrow:
/* up and down arrow: history */
if (history_len > 1) {
/* Update the current history entry before to
* overwrite it with tne next one. */
free(history[history_len-1-history_index]);
history[history_len-1-history_index] = strdup(buf);
/* Show the new entry */
history_index += (seq[1] == 65) ? 1 : -1;
if (history_index < 0) {
history_index = 0;
break;
} else if (history_index >= history_len) {
history_index = history_len-1;
break;
}
strncpy(buf,history[history_len-1-history_index],buflen);
buf[buflen] = '\0';
len = pos = strlen(buf);
refreshLine(fd,prompt,buf,len,pos,cols);
}
}
break;
default:
if (len < buflen) {
if (len == pos) {
buf[pos] = c;
pos++;
len++;
buf[len] = '\0';
if (plen+len < cols) {
/* Avoid a full update of the line in the
* trivial case. */
if (write(fd,&c,1) == -1) return -1;
} else {
refreshLine(fd,prompt,buf,len,pos,cols);
}
} else {
memmove(buf+pos+1,buf+pos,len-pos);
buf[pos] = c;
len++;
pos++;
buf[len] = '\0';
refreshLine(fd,prompt,buf,len,pos,cols);
}
}
break;
case 21: /* Ctrl+u, delete the whole line. */
buf[0] = '\0';
pos = len = 0;
refreshLine(fd,prompt,buf,len,pos,cols);
break;
case 11: /* Ctrl+k, delete from current to end of line. */
buf[pos] = '\0';
len = pos;
refreshLine(fd,prompt,buf,len,pos,cols);
break;
case 1: /* Ctrl+a, go to the start of the line */
pos = 0;
refreshLine(fd,prompt,buf,len,pos,cols);
break;
case 5: /* ctrl+e, go to the end of the line */
pos = len;
refreshLine(fd,prompt,buf,len,pos,cols);
break;
}
}
return len;
}
static int linenoiseRaw(char *buf, size_t buflen, const char *prompt) {
int fd = STDIN_FILENO;
int count;
if (buflen == 0) {
errno = EINVAL;
return -1;
}
if (!isatty(STDIN_FILENO)) {
if (fgets(buf, buflen, stdin) == NULL) return -1;
count = strlen(buf);
if (count && buf[count-1] == '\n') {
count--;
buf[count] = '\0';
}
} else {
if (enableRawMode(fd) == -1) return -1;
count = linenoisePrompt(fd, buf, buflen, prompt);
disableRawMode(fd);
}
return count;
}
char *linenoise(const char *prompt) {
char buf[LINENOISE_MAX_LINE];
int count;
if (isUnsupportedTerm()) {
size_t len;
printf("%s",prompt);
fflush(stdout);
if (fgets(buf,LINENOISE_MAX_LINE,stdin) == NULL) return NULL;
len = strlen(buf);
while(len && (buf[len-1] == '\n' || buf[len-1] == '\r')) {
len--;
buf[len] = '\0';
}
return strdup(buf);
} else {
count = linenoiseRaw(buf,LINENOISE_MAX_LINE,prompt);
if (count == -1) return NULL;
return strdup(buf);
}
}
/* Using a circular buffer is smarter, but a bit more complex to handle. */
int linenoiseHistoryAdd(const char *line) {
char *linecopy;
if (history_max_len == 0) return 0;
if (history == 0) {
history = malloc(sizeof(char*)*history_max_len);
if (history == NULL) return 0;
memset(history,0,(sizeof(char*)*history_max_len));
}
linecopy = strdup(line);
if (!linecopy) return 0;
if (history_len == history_max_len) {
memmove(history,history+1,sizeof(char*)*(history_max_len-1));
history_len--;
}
history[history_len] = linecopy;
history_len++;
return 1;
}
int linenoiseHistorySetMaxLen(int len) {
char **new;
if (len < 1) return 0;
if (history) {
int tocopy = history_len;
new = malloc(sizeof(char*)*len);
if (new == NULL) return 0;
if (len < tocopy) tocopy = len;
memcpy(new,history+(history_max_len-tocopy), sizeof(char*)*tocopy);
free(history);
history = new;
}
history_max_len = len;
if (history_len > history_max_len)
history_len = history_max_len;
return 1;
}