circuitpython/lib/mp-readline/readline.c
Damien George 0d3cb6726d py: Change vstr so that it doesn't null terminate buffer by default.
This cleans up vstr so that it's a pure "variable buffer", and the user
can decide whether they need to add a terminating null byte.  In most
places where vstr is used, the vstr did not need to be null terminated
and so this patch saves code size, a tiny bit of RAM, and makes vstr
usage more efficient.  When null termination is needed it must be
done explicitly using vstr_null_terminate.
2015-01-28 23:43:01 +00:00

287 lines
10 KiB
C

/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include "py/mpstate.h"
#include "readline.h"
#include "pybstdio.h"
#if 0 // print debugging info
#define DEBUG_PRINT (1)
#define DEBUG_printf printf
#else // don't print debugging info
#define DEBUG_printf(...) (void)0
#endif
#define READLINE_HIST_SIZE (MP_ARRAY_SIZE(MP_STATE_PORT(readline_hist)))
enum { ESEQ_NONE, ESEQ_ESC, ESEQ_ESC_BRACKET, ESEQ_ESC_BRACKET_DIGIT, ESEQ_ESC_O };
void readline_init0(void) {
memset(MP_STATE_PORT(readline_hist), 0, READLINE_HIST_SIZE * sizeof(const char*));
}
STATIC char *str_dup_maybe(const char *str) {
uint32_t len = strlen(str);
char *s2 = m_new_maybe(char, len + 1);
if (s2 == NULL) {
return NULL;
}
memcpy(s2, str, len + 1);
return s2;
}
STATIC void move_cursor_back(uint pos) {
if (pos <= 4) {
// fast path for most common case of 1 step back
stdout_tx_strn("\b\b\b\b", pos);
} else {
char vt100_command[6];
// snprintf needs space for the terminating null character
int n = snprintf(&vt100_command[0], sizeof(vt100_command), "\x1b[%u", pos);
if (n > 0) {
vt100_command[n] = 'D'; // replace null char
stdout_tx_strn(vt100_command, n + 1);
}
}
}
STATIC void erase_line_from_cursor(void) {
stdout_tx_strn("\x1b[K", 3);
}
typedef struct _readline_t {
vstr_t *line;
int orig_line_len;
int escape_seq;
int hist_cur;
int cursor_pos;
char escape_seq_buf[1];
} readline_t;
STATIC readline_t rl;
int readline_process_char(int c) {
int last_line_len = rl.line->len;
int redraw_step_back = 0;
bool redraw_from_cursor = false;
int redraw_step_forward = 0;
if (rl.escape_seq == ESEQ_NONE) {
if (CHAR_CTRL_A <= c && c <= CHAR_CTRL_D && vstr_len(rl.line) == rl.orig_line_len) {
// control character with empty line
return c;
} else if (c == CHAR_CTRL_A) {
// CTRL-A with non-empty line is go-to-start-of-line
goto home_key;
} else if (c == CHAR_CTRL_C) {
// CTRL-C with non-empty line is cancel
return c;
} else if (c == CHAR_CTRL_E) {
// CTRL-E is go-to-end-of-line
goto end_key;
} else if (c == '\r') {
// newline
stdout_tx_str("\r\n");
if (rl.line->len > rl.orig_line_len && (MP_STATE_PORT(readline_hist)[0] == NULL || strcmp(MP_STATE_PORT(readline_hist)[0], rl.line->buf + rl.orig_line_len) != 0)) {
// a line which is not empty and different from the last one
// so update the history
vstr_null_terminate(rl.line);
char *most_recent_hist = str_dup_maybe(rl.line->buf + rl.orig_line_len);
if (most_recent_hist != NULL) {
for (int i = READLINE_HIST_SIZE - 1; i > 0; i--) {
MP_STATE_PORT(readline_hist)[i] = MP_STATE_PORT(readline_hist)[i - 1];
}
MP_STATE_PORT(readline_hist)[0] = most_recent_hist;
}
}
return 0;
} else if (c == 27) {
// escape sequence
rl.escape_seq = ESEQ_ESC;
} else if (c == 8 || c == 127) {
// backspace/delete
if (rl.cursor_pos > rl.orig_line_len) {
vstr_cut_out_bytes(rl.line, rl.cursor_pos - 1, 1);
// set redraw parameters
redraw_step_back = 1;
redraw_from_cursor = true;
}
} else if (32 <= c && c <= 126) {
// printable character
vstr_ins_char(rl.line, rl.cursor_pos, c);
// set redraw parameters
redraw_from_cursor = true;
redraw_step_forward = 1;
}
} else if (rl.escape_seq == ESEQ_ESC) {
switch (c) {
case '[':
rl.escape_seq = ESEQ_ESC_BRACKET;
break;
case 'O':
rl.escape_seq = ESEQ_ESC_O;
break;
default:
DEBUG_printf("(ESC %d)", c);
rl.escape_seq = ESEQ_NONE;
}
} else if (rl.escape_seq == ESEQ_ESC_BRACKET) {
if ('0' <= c && c <= '9') {
rl.escape_seq = ESEQ_ESC_BRACKET_DIGIT;
rl.escape_seq_buf[0] = c;
} else {
rl.escape_seq = ESEQ_NONE;
if (c == 'A') {
// up arrow
if (rl.hist_cur + 1 < READLINE_HIST_SIZE && MP_STATE_PORT(readline_hist)[rl.hist_cur + 1] != NULL) {
// increase hist num
rl.hist_cur += 1;
// set line to history
rl.line->len = rl.orig_line_len;
vstr_add_str(rl.line, MP_STATE_PORT(readline_hist)[rl.hist_cur]);
// set redraw parameters
redraw_step_back = rl.cursor_pos - rl.orig_line_len;
redraw_from_cursor = true;
redraw_step_forward = rl.line->len - rl.orig_line_len;
}
} else if (c == 'B') {
// down arrow
if (rl.hist_cur >= 0) {
// decrease hist num
rl.hist_cur -= 1;
// set line to history
vstr_cut_tail_bytes(rl.line, rl.line->len - rl.orig_line_len);
if (rl.hist_cur >= 0) {
vstr_add_str(rl.line, MP_STATE_PORT(readline_hist)[rl.hist_cur]);
}
// set redraw parameters
redraw_step_back = rl.cursor_pos - rl.orig_line_len;
redraw_from_cursor = true;
redraw_step_forward = rl.line->len - rl.orig_line_len;
}
} else if (c == 'C') {
// right arrow
if (rl.cursor_pos < rl.line->len) {
redraw_step_forward = 1;
}
} else if (c == 'D') {
// left arrow
if (rl.cursor_pos > rl.orig_line_len) {
redraw_step_back = 1;
}
} else if (c == 'H') {
// home
goto home_key;
} else if (c == 'F') {
// end
goto end_key;
} else {
DEBUG_printf("(ESC [ %d)", c);
}
}
} else if (rl.escape_seq == ESEQ_ESC_BRACKET_DIGIT) {
if (c == '~') {
if (rl.escape_seq_buf[0] == '1' || rl.escape_seq_buf[0] == '7') {
home_key:
redraw_step_back = rl.cursor_pos - rl.orig_line_len;
} else if (rl.escape_seq_buf[0] == '4' || rl.escape_seq_buf[0] == '8') {
end_key:
redraw_step_forward = rl.line->len - rl.cursor_pos;
} else {
DEBUG_printf("(ESC [ %c %d)", rl.escape_seq_buf[0], c);
}
} else {
DEBUG_printf("(ESC [ %c %d)", rl.escape_seq_buf[0], c);
}
rl.escape_seq = ESEQ_NONE;
} else if (rl.escape_seq == ESEQ_ESC_O) {
switch (c) {
case 'H':
goto home_key;
case 'F':
goto end_key;
default:
DEBUG_printf("(ESC O %d)", c);
rl.escape_seq = ESEQ_NONE;
}
} else {
rl.escape_seq = ESEQ_NONE;
}
// redraw command prompt, efficiently
if (redraw_step_back > 0) {
move_cursor_back(redraw_step_back);
rl.cursor_pos -= redraw_step_back;
}
if (redraw_from_cursor) {
if (rl.line->len < last_line_len) {
// erase old chars
// (number of chars to erase: last_line_len - rl.cursor_pos)
erase_line_from_cursor();
}
// draw new chars
stdout_tx_strn(rl.line->buf + rl.cursor_pos, rl.line->len - rl.cursor_pos);
// move cursor forward if needed (already moved forward by length of line, so move it back)
move_cursor_back(rl.line->len - (rl.cursor_pos + redraw_step_forward));
rl.cursor_pos += redraw_step_forward;
} else if (redraw_step_forward > 0) {
// draw over old chars to move cursor forwards
stdout_tx_strn(rl.line->buf + rl.cursor_pos, redraw_step_forward);
rl.cursor_pos += redraw_step_forward;
}
return -1;
}
void readline_note_newline(void) {
rl.orig_line_len = rl.line->len;
rl.cursor_pos = rl.orig_line_len;
}
void readline_init(vstr_t *line) {
rl.line = line;
rl.orig_line_len = line->len;
rl.escape_seq = ESEQ_NONE;
rl.escape_seq_buf[0] = 0;
rl.hist_cur = -1;
rl.cursor_pos = rl.orig_line_len;
}
int readline(vstr_t *line, const char *prompt) {
stdout_tx_str(prompt);
readline_init(line);
for (;;) {
int c = stdin_rx_chr();
int r = readline_process_char(c);
if (r >= 0) {
return r;
}
}
}