fish-shell/src/fish_key_reader.cpp
2016-06-26 17:38:19 -07:00

287 lines
10 KiB
C++

// A small utility to print information related to pressing keys. This is similar to using tools
// like `xxd` and `od -tx1z` but provides more information such as the time delay between each
// character. It also allows pressing and interpreting keys that are normally special such as
// [ctrl-C] (interrupt the program) or [ctrl-D] (EOF to signal the program should exit).
// And unlike those other tools this one disables ICRNL mode so it can distinguish between
// carriage-return (\cM) and newline (\cJ).
//
// Type "exit" or "quit" to terminate the program.
#include "config.h" // IWYU pragma: keep
#include <getopt.h>
#include <locale.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wctype.h>
#include <cmath>
#include <iosfwd>
#include <limits>
#include "common.h"
#include "env.h"
#include "fallback.h" // IWYU pragma: keep
#include "input.h"
#include "input_common.h"
#include "proc.h"
#include "reader.h"
#include "wutil.h"
struct config_paths_t determine_config_directory_paths(const char *argv0);
static const char *ctrl_symbolic_names[] = {NULL, NULL, NULL, NULL, NULL, NULL, NULL, "\\a",
"\\b", "\\t", "\\n", "\\v", "\\f", "\\r", NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, "\\e", NULL, NULL, NULL, NULL};
static bool keep_running = true;
/// Return true if the recent sequence of characters indicates the user wants to exit the program.
static bool should_exit(unsigned char c) {
static unsigned char recent_chars[4] = {0};
recent_chars[0] = recent_chars[1];
recent_chars[1] = recent_chars[2];
recent_chars[2] = recent_chars[3];
recent_chars[3] = c;
return (memcmp(recent_chars, "exit", 4) == 0 || memcmp(recent_chars, "quit", 4) == 0 ||
memcmp(recent_chars + 2, "\x3\x3", 2) == 0 || // ctrl-C, ctrl-C
memcmp(recent_chars + 2, "\x4\x4", 2) == 0); // ctrl-D, ctrl-D
}
/// Return the key name if the recent sequence of characters matches a known terminfo sequence.
static char *const key_name(unsigned char c) {
static char recent_chars[8] = {0};
recent_chars[0] = recent_chars[1];
recent_chars[1] = recent_chars[2];
recent_chars[2] = recent_chars[3];
recent_chars[3] = recent_chars[4];
recent_chars[4] = recent_chars[5];
recent_chars[5] = recent_chars[6];
recent_chars[6] = recent_chars[7];
recent_chars[7] = c;
for (int idx = 7; idx >= 0; idx--) {
wcstring out_name;
wcstring seq = str2wcstring(recent_chars + idx, 8 - idx);
bool found = input_terminfo_get_name(seq, &out_name);
if (found) {
return strdup(wcs2string(out_name).c_str());
}
}
return NULL;
}
static void output_info_about_char(unsigned char c) {
printf("dec: %3u oct: %03o hex: %02X char: ", c, c, c);
if (c < 32) {
// Control characters.
printf("\\c%c", c + 64);
if (ctrl_symbolic_names[c]) printf(" (or %s)", ctrl_symbolic_names[c]);
} else if (c == 32) {
// The "space" character.
printf("\\%03o (aka \"space\")", c);
} else if (c == 0x7F) {
// The "del" character.
printf("\\%03o (aka \"del\")", c);
} else if (c >= 128) {
// Non-ASCII characters (i.e., those with bit 7 set).
printf("\\%03o (aka non-ASCII)", c);
} else {
// ASCII characters that are not control characters.
printf("%c", c);
}
putchar('\n');
}
static void output_matching_key_name(unsigned char c) {
char *name = key_name(c);
if (name) {
printf("Sequence matches bind key name \"%s\"\n", name);
free(name);
}
}
static double output_elapsed_time(double prev_tstamp, bool first_char_seen) {
// How much time has passed since the previous char was received in microseconds.
double now = timef();
long long int delta_tstamp_us = 1000000 * (now - prev_tstamp);
if (delta_tstamp_us >= 200000 && first_char_seen) putchar('\n');
if (delta_tstamp_us >= 1000000) {
printf(" ");
} else {
printf("(%3lld.%03lld ms) ", delta_tstamp_us / 1000, delta_tstamp_us % 1000);
}
return now;
}
/// Process the characters we receive as the user presses keys.
static void process_input(bool continuous_mode) {
bool first_char_seen = false;
double prev_tstamp = 0.0;
printf("Press a key\n\n");
while (keep_running) {
wchar_t wc = input_common_readch(first_char_seen && !continuous_mode);
if (wc == WEOF) {
return;
} else if (wc > 255) {
printf("\nUnexpected wide character from input_common_readch(): %lld / 0x%llx\n",
(long long)wc, (long long)wc);
return;
}
unsigned char c = wc;
prev_tstamp = output_elapsed_time(prev_tstamp, first_char_seen);
output_info_about_char(c);
output_matching_key_name(c);
if (should_exit(c)) {
printf("\nExiting at your request.\n");
break;
}
first_char_seen = true;
}
}
/// Make sure we cleanup before exiting if we receive a signal that should cause us to exit.
/// Otherwise just report receipt of the signal.
static struct sigaction old_sigactions[32];
static void signal_handler(int signo, siginfo_t *siginfo, void *siginfo_arg) {
debug(2, L"signal #%d (%ls) received", signo, sig2wcs(signo));
// SIGINT isn't included in the following conditional because it is handled specially by fish;
// i.e., it causes \cC to be reinserted into the tty input stream.
if (signo == SIGHUP || signo == SIGTERM || signo == SIGABRT || signo == SIGSEGV) {
keep_running = false;
}
if (old_sigactions[signo].sa_handler != SIG_IGN &&
old_sigactions[signo].sa_handler != SIG_DFL) {
int needs_siginfo = old_sigactions[signo].sa_flags & SA_SIGINFO;
if (needs_siginfo) {
old_sigactions[signo].sa_sigaction(signo, siginfo, siginfo_arg);
} else {
old_sigactions[signo].sa_handler(signo);
}
}
}
/// Install a handler for every signal. This allows us to restore the tty modes so the terminal is
/// still usable when we die. If the signal already has a handler arrange to invoke it from within
/// our handler.
static void install_our_signal_handlers() {
struct sigaction new_sa, old_sa;
sigemptyset(&new_sa.sa_mask);
new_sa.sa_flags = SA_SIGINFO;
new_sa.sa_sigaction = signal_handler;
for (int signo = 1; signo < 32; signo++) {
if (sigaction(signo, &new_sa, &old_sa) != -1) {
memcpy(&old_sigactions[signo], &old_sa, sizeof(old_sa));
if (old_sa.sa_handler == SIG_IGN) {
debug(2, "signal #%d (%ls) was being ignored", signo, sig2wcs(signo));
}
if (old_sa.sa_flags && ~SA_SIGINFO != 0) {
debug(2, L"signal #%d (%ls) handler had flags 0x%X", signo, sig2wcs(signo),
old_sa.sa_flags);
}
}
}
}
/// Setup our environment (e.g., tty modes), process key strokes, then reset the environment.
static void setup_and_process_keys(bool continuous_mode) {
is_interactive_session = 1; // by definition this program is interactive
setenv("LC_ALL", "POSIX", 1); // ensure we're in a single-byte locale
set_main_thread();
setup_fork_guards();
env_init();
reader_init();
input_init();
proc_push_interactive(1);
signal_set_handlers();
install_our_signal_handlers();
if (continuous_mode) {
printf("\n");
printf("To terminate this program type \"exit\" or \"quit\" in this window,\n");
printf("or press [ctrl-C] or [ctrl-D] twice in a row.\n");
printf("\n");
}
process_input(continuous_mode);
restore_term_mode();
restore_term_foreground_process_group();
input_destroy();
reader_destroy();
}
int main(int argc, char **argv) {
program_name = L"fish_key_reader";
bool continuous_mode = false;
const char *short_opts = "+cd:D:";
const struct option long_opts[] = {{"continuous", no_argument, NULL, 'c'},
{"debug-level", required_argument, NULL, 'd'},
{"debug-stack-frames", required_argument, NULL, 'D'},
{NULL, 0, NULL, 0}};
int opt;
while ((opt = getopt_long(argc, argv, short_opts, long_opts, NULL)) != -1) {
switch (opt) {
case 0: {
fprintf(stderr, "getopt_long() unexpectedly returned zero\n");
exit(1);
}
case 'c': {
continuous_mode = true;
break;
}
case 'd': {
char *end;
long tmp;
errno = 0;
tmp = strtol(optarg, &end, 10);
if (tmp >= 0 && tmp <= 10 && !*end && !errno) {
debug_level = (int)tmp;
} else {
fwprintf(stderr, _(L"Invalid value '%s' for debug-level flag"), optarg);
exit(1);
}
break;
}
case 'D': {
char *end;
long tmp;
errno = 0;
tmp = strtol(optarg, &end, 10);
if (tmp > 0 && tmp <= 128 && !*end && !errno) {
debug_stack_frames = (int)tmp;
} else {
fwprintf(stderr, _(L"Invalid value '%s' for debug-stack-frames flag"), optarg);
exit(1);
}
break;
}
default: {
// We assume getopt_long() has already emitted a diagnostic msg.
exit(1);
}
}
}
argc -= optind;
if (argc != 0) {
fprintf(stderr, "Expected no arguments, got %d\n", argc);
return 1;
}
setup_and_process_keys(continuous_mode);
return 0;
}