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/*
* Author: Thomas E. Dickey 1998
*
* $Id: filter.c,v 1.32 2017/09/28 23:40:39 tom Exp $
*
* An example of the 'filter()' function in ncurses, this program prompts
* for commands and executes them (like a command shell). It illustrates
* how ncurses can be used to implement programs that are not full-screen.
*
* Ncurses differs slightly from SVr4 curses. The latter does not flush its
* state when exiting program mode, so the attributes on the command lines of
* this program 'bleed' onto the executed commands. Rather than use the
* reset_shell_mode() and reset_prog_mode() functions, we could invoke endwin()
* and refresh(), but that does not work any better.
*/
#include <test.priv.h>
#if HAVE_FILTER
#include <time.h>
static int
show_prompt(int underline, bool clocked)
{
int limit = COLS;
move(0, 0);
attrset(A_NORMAL);
clrtoeol();
attrset(A_BOLD);
addstr("Command: ");
limit -= getcurx(stdscr);
if (clocked) {
if (limit >= 3) {
time_t now = time((time_t *) 0);
struct tm *my = localtime(&now);
char buffer[80];
int skip, y, x;
int margin;
_nc_SPRINTF(buffer, _nc_SLIMIT(sizeof(buffer)) "%02d:%02d:%02d",
my->tm_hour,
my->tm_min,
my->tm_sec);
if (limit > 9) {
skip = 0;
} else if (limit > 6) {
skip = 3;
} else {
skip = 6;
}
/*
* Write the clock message on the right-margin so we can show the
* results of resizing the screen.
*/
getyx(stdscr, y, x);
margin = (int) strlen(buffer) - skip;
limit -= margin;
move(0, COLS - margin);
addstr(buffer);
move(y, x);
}
}
attron(underline);
return limit;
}
static int
new_command(char *buffer, int length, int underline, bool clocked, bool polled)
{
int code = OK;
int limit;
if (polled) {
bool done = FALSE;
bool first = TRUE;
int y = 0, x = 0;
int n;
int mark = 0;
int used = 0;
const int gap = 2;
timeout(20); /* no one types 50CPS... */
while (!done) {
int ch = getch();
buffer[used] = '\0';
limit = show_prompt(underline, clocked);
if (first) {
getyx(stdscr, y, x);
first = FALSE;
} else {
int left = 0;
/*
* if the screen is too narrow to show the whole buffer,
* shift the editing point left/right as needed.
*/
move(y, x);
if ((used + gap) > limit) {
while ((mark - left + gap) > limit) {
left += limit / 2;
}
}
printw("%.*s", limit, buffer + left);
move(y, x + mark - left);
}
switch (ch) {
case ERR:
continue;
case '\004':
code = ERR;
done = TRUE;
break;
case KEY_ENTER:
case '\n':
done = TRUE;
break;
case KEY_BACKSPACE:
case '\b':
if (used) {
if (mark < used) {
/* getnstr does not do this */
if (mark > 0) {
--mark;
for (n = mark; n < used; ++n) {
buffer[n] = buffer[n + 1];
}
} else {
flash();
}
} else {
/* getnstr does this */
mark = --used;
buffer[used] = '\0';
}
} else {
flash();
}
break;
/*
* Unlike getnstr, this function can move the cursor into the
* middle of the buffer and insert/delete at that point.
*/
case KEY_HOME:
mark = 0;
break;
case KEY_END:
mark = used;
break;
case KEY_LEFT:
if (mark > 0) {
mark--;
} else {
flash();
}
break;
case KEY_RIGHT:
if (mark < used) {
mark++;
} else {
flash();
}
break;
#ifdef KEY_EVENT
case KEY_EVENT:
continue;
#endif
#ifdef KEY_RESIZE
case KEY_RESIZE:
/*
* Unlike getnstr, this function "knows" what the whole screen
* is supposed to look like, and can handle resize events.
*/
continue;
#endif
case '\t':
ch = ' ';
/* FALLTHRU */
default:
if (ch >= KEY_MIN) {
flash();
continue;
}
if (mark < used) {
/* getnstr does not do this... */
for (n = used + 1; n > mark; --n) {
buffer[n] = buffer[n - 1];
}
buffer[mark] = (char) ch;
used++;
mark++;
} else {
/* getnstr does this part */
buffer[used] = (char) ch;
mark = ++used;
}
break;
}
}
} else {
show_prompt(underline, clocked);
code = getnstr(buffer, length);
/*
* If this returns anything except ERR/OK, it would be one of ncurses's
* extensions. Fill the buffer with something harmless that the shell
* will execute as a comment.
*/
#ifdef KEY_EVENT
if (code == KEY_EVENT)
_nc_STRCPY(buffer, "# event!", length);
#endif
#ifdef KEY_RESIZE
if (code == KEY_RESIZE) {
_nc_STRCPY(buffer, "# resize!", length);
getch();
}
#endif
}
attroff(underline);
attroff(A_BOLD);
refresh();
return code;
}
#ifdef NCURSES_VERSION
/*
* Cancel xterm's alternate-screen mode (from dialog -TD)
*/
#define isprivate(s) ((s) != 0 && strstr(s, "\033[?") != 0)
static void
cancel_altscreen(void)
{
if (isatty(fileno(stdout))
&& key_mouse != 0 /* xterm and kindred */
&& isprivate(enter_ca_mode)
&& isprivate(exit_ca_mode)) {
/*
* initscr() or newterm() already wrote enter_ca_mode as a side effect
* of initializing the screen. It would be nice to not even do that,
* but we do not really have access to the correct copy of the
* terminfo description until those functions have been invoked.
*/
(void) refresh();
(void) putp(exit_ca_mode);
(void) fflush(stdout);
/*
* Prevent ncurses from switching "back" to the normal screen when
* exiting from this program. That would move the cursor to the
* original location saved in xterm. Normally curses sets the cursor
* position to the first line after the display, but the alternate
* screen switching is done after that point.
*
* Cancelling the strings altogether also works around the buggy
* implementation of alternate-screen in rxvt, etc., which clear more
* of the display than they should.
*/
enter_ca_mode = 0;
exit_ca_mode = 0;
}
}
#endif
static void
usage(void)
{
static const char *msg[] =
{
"Usage: filter [options]"
,""
,"Options:"
#ifdef NCURSES_VERSION
," -a suppress xterm alternate-screen by amending smcup/rmcup"
#endif
," -c show current time on prompt line with \"Command\""
#if HAVE_USE_DEFAULT_COLORS
," -d invoke use_default_colors"
#endif
," -i use initscr() rather than newterm()"
," -p poll for individual characters rather than using getnstr"
};
unsigned n;
for (n = 0; n < SIZEOF(msg); n++)
fprintf(stderr, "%s\n", msg[n]);
ExitProgram(EXIT_FAILURE);
}
int
main(int argc, char *argv[])
{
int ch;
char buffer[80];
int underline;
#ifdef NCURSES_VERSION
bool a_option = FALSE;
#endif
bool c_option = FALSE;
#if HAVE_USE_DEFAULT_COLORS
bool d_option = FALSE;
#endif
bool i_option = FALSE;
bool p_option = FALSE;
setlocale(LC_ALL, "");
while ((ch = getopt(argc, argv, "adcip")) != -1) {
switch (ch) {
#ifdef NCURSES_VERSION
case 'a':
a_option = TRUE;
break;
#endif
case 'c':
c_option = TRUE;
break;
#if HAVE_USE_DEFAULT_COLORS
case 'd':
d_option = TRUE;
break;
#endif
case 'i':
i_option = TRUE;
break;
case 'p':
p_option = TRUE;
break;
default:
usage();
}
}
printf("starting filter program using %s...\n",
i_option ? "initscr" : "newterm");
filter();
if (i_option) {
initscr();
} else {
if (newterm((char *) 0, stdout, stdin) == 0) {
fprintf(stderr, "cannot initialize terminal\n");
ExitProgram(EXIT_FAILURE);
}
}
#ifdef NCURSES_VERSION
if (a_option) {
cancel_altscreen();
}
#endif
cbreak();
keypad(stdscr, TRUE);
if (has_colors()) {
int background = COLOR_BLACK;
start_color();
#if HAVE_USE_DEFAULT_COLORS
if (d_option && (use_default_colors() != ERR))
background = -1;
#endif
init_pair(1, COLOR_CYAN, (short) background);
underline = COLOR_PAIR(1);
} else {
underline = A_UNDERLINE;
}
for (;;) {
int code = new_command(buffer, sizeof(buffer) - 1,
underline, c_option, p_option);
if (code == ERR || *buffer == '\0')
break;
reset_shell_mode();
printf("\n");
fflush(stdout);
IGNORE_RC(system(buffer));
reset_prog_mode();
touchwin(stdscr);
erase();
refresh();
}
clear();
refresh();
endwin();
ExitProgram(EXIT_SUCCESS);
}
#else
int
main(void)
{
printf("This program requires the filter function\n");
ExitProgram(EXIT_FAILURE);
}
#endif /* HAVE_FILTER */