#include "git-compat-util.h"

#include "compat/terminal.h"

#include "gettext.h"

#include "sigchain.h"

#include "strbuf.h"

#include "run-command.h"

#include "string-list.h"

#include "hashmap.h"

#if defined(HAVE_DEV_TTY) || defined(GIT_WINDOWS_NATIVE)

static void restore_term_on_signal(int sig)

{

  restore_term();

  /* restore_term calls sigchain_pop_common */

  raise(sig);

}

#ifdef HAVE_DEV_TTY

#define INPUT_PATH "/dev/tty"

#define OUTPUT_PATH "/dev/tty"

static volatile sig_atomic_t term_fd_needs_closing;

static int term_fd = -1;

static struct termios old_term;

static const char *background_resume_msg;

static const char *restore_error_msg;

static volatile sig_atomic_t ttou_received;

/* async safe error function for use by signal handlers. */

static void write_err(const char *msg)

{

  write_in_full(2, "error: ", strlen("error: "));

  write_in_full(2, msg, strlen(msg));

  write_in_full(2, "\n", 1);

}

static void print_background_resume_msg(int signo)

{

  int saved_errno = errno;

  sigset_t mask;

  struct sigaction old_sa;

  struct sigaction sa = { .sa_handler = SIG_DFL };

  ttou_received = 1;

  write_err(background_resume_msg);

  sigaction(signo, &sa, &old_sa);

  raise(signo);

  sigemptyset(&mask);

  sigaddset(&mask, signo);

  sigprocmask(SIG_UNBLOCK, &mask, NULL);

  /* Stopped here */

  sigprocmask(SIG_BLOCK, &mask, NULL);

  sigaction(signo, &old_sa, NULL);

  errno = saved_errno;

}

static void restore_terminal_on_suspend(int signo)

{

  int saved_errno = errno;

  int res;

  struct termios t;

  sigset_t mask;

  struct sigaction old_sa;

  struct sigaction sa = { .sa_handler = SIG_DFL };

  int can_restore = 1;

  if (tcgetattr(term_fd, &t) < 0)

    can_restore = 0;

  if (tcsetattr(term_fd, TCSAFLUSH, &old_term) < 0)

    write_err(restore_error_msg);

  sigaction(signo, &sa, &old_sa);

  raise(signo);

  sigemptyset(&mask);

  sigaddset(&mask, signo);

  sigprocmask(SIG_UNBLOCK, &mask, NULL);

  /* Stopped here */

  sigprocmask(SIG_BLOCK, &mask, NULL);

  sigaction(signo, &old_sa, NULL);

  if (!can_restore) {

    write_err(restore_error_msg);

    goto out;

  }

  /*

   * If we resume in the background then we receive SIGTTOU when calling

   * tcsetattr() below. Set up a handler to print an error message in that

   * case.

   */

  sigemptyset(&mask);

  sigaddset(&mask, SIGTTOU);

  sa.sa_mask = old_sa.sa_mask;

  sa.sa_handler = print_background_resume_msg;

  sa.sa_flags = SA_RESTART;

  sigaction(SIGTTOU, &sa, &old_sa);

 again:

  ttou_received = 0;

  sigprocmask(SIG_UNBLOCK, &mask, NULL);

  res = tcsetattr(term_fd, TCSAFLUSH, &t);

  sigprocmask(SIG_BLOCK, &mask, NULL);

  if (ttou_received)

    goto again;

  else if (res < 0)

    write_err(restore_error_msg);

  sigaction(SIGTTOU, &old_sa, NULL);

 out:

  errno = saved_errno;

}

static void reset_job_signals(void)

{

  if (restore_error_msg) {

    signal(SIGTTIN, SIG_DFL);

    signal(SIGTTOU, SIG_DFL);

    signal(SIGTSTP, SIG_DFL);

    restore_error_msg = NULL;

    background_resume_msg = NULL;

  }

}

static void close_term_fd(void)

{

  if (term_fd_needs_closing)

    close(term_fd);

  term_fd_needs_closing = 0;

  term_fd = -1;

}

void restore_term(void)

{

  if (term_fd < 0)

    return;

  tcsetattr(term_fd, TCSAFLUSH, &old_term);

  close_term_fd();

  sigchain_pop_common();

  reset_job_signals();

}

int save_term(enum save_term_flags flags)

{

  struct sigaction sa;

  if (term_fd < 0)

    term_fd = ((flags & SAVE_TERM_STDIN)

         ? 0

         : open("/dev/tty", O_RDWR));

  if (term_fd < 0)

    return -1;

  term_fd_needs_closing = !(flags & SAVE_TERM_STDIN);

  if (tcgetattr(term_fd, &old_term) < 0) {

    close_term_fd();

    return -1;

  }

  sigchain_push_common(restore_term_on_signal);

  /*

   * If job control is disabled then the shell will have set the

   * disposition of SIGTSTP to SIG_IGN.

   */

  sigaction(SIGTSTP, NULL, &sa);

  if (sa.sa_handler == SIG_IGN)

    return 0;

  /* avoid calling gettext() from signal handler */

  background_resume_msg = _("cannot resume in the background, please use 'fg' to resume");

  restore_error_msg = _("cannot restore terminal settings");

  sa.sa_handler = restore_terminal_on_suspend;

  sa.sa_flags = SA_RESTART;

  sigemptyset(&sa.sa_mask);

  sigaddset(&sa.sa_mask, SIGTSTP);

  sigaddset(&sa.sa_mask, SIGTTIN);

  sigaddset(&sa.sa_mask, SIGTTOU);

  sigaction(SIGTSTP, &sa, NULL);

  sigaction(SIGTTIN, &sa, NULL);

  sigaction(SIGTTOU, &sa, NULL);

  return 0;

}

static int disable_bits(enum save_term_flags flags, tcflag_t bits)

{

  struct termios t;

  if (save_term(flags) < 0)

    return -1;

  t = old_term;

  t.c_lflag &= ~bits;

  if (bits & ICANON) {

    t.c_cc[VMIN] = 1;

    t.c_cc[VTIME] = 0;

  }

  if (!tcsetattr(term_fd, TCSAFLUSH, &t))

    return 0;

  sigchain_pop_common();

  reset_job_signals();

  close_term_fd();

  return -1;

}

static int disable_echo(enum save_term_flags flags)

{

  return disable_bits(flags, ECHO);

}

static int enable_non_canonical(enum save_term_flags flags)

{

  return disable_bits(flags, ICANON | ECHO);

}

/*

 * On macos it is not possible to use poll() with a terminal so use select

 * instead.

 */

static int getchar_with_timeout(int timeout)

{

  struct timeval tv, *tvp = NULL;

  fd_set readfds;

  int res;

 again:

  if (timeout >= 0) {

    tv.tv_sec = timeout / 1000;

    tv.tv_usec = (timeout % 1000) * 1000;

    tvp = &tv;

  }

  FD_ZERO(&readfds);

  FD_SET(0, &readfds);

  res = select(1, &readfds, NULL, NULL, tvp);

  if (!res)

    return EOF;

  if (res < 0) {

    if (errno == EINTR)

      goto again;

    else

      return EOF;

  }

  return getchar();

}

#elif defined(GIT_WINDOWS_NATIVE)

#define INPUT_PATH "CONIN$"

#define OUTPUT_PATH "CONOUT$"

#define FORCE_TEXT "t"

static int use_stty = 1;

static struct string_list stty_restore = STRING_LIST_INIT_DUP;

static HANDLE hconin = INVALID_HANDLE_VALUE;

static HANDLE hconout = INVALID_HANDLE_VALUE;

static DWORD cmode_in, cmode_out;

void restore_term(void)

{

  if (use_stty) {

    int i;

    struct child_process cp = CHILD_PROCESS_INIT;

    if (stty_restore.nr == 0)

      return;

    strvec_push(&cp.args, "stty");

    for (i = 0; i < stty_restore.nr; i++)

      strvec_push(&cp.args, stty_restore.items[i].string);

    run_command(&cp);

    string_list_clear(&stty_restore, 0);

    return;

  }

  sigchain_pop_common();

  if (hconin == INVALID_HANDLE_VALUE)

    return;

  SetConsoleMode(hconin, cmode_in);

  CloseHandle(hconin);

  if (cmode_out) {

    assert(hconout != INVALID_HANDLE_VALUE);

    SetConsoleMode(hconout, cmode_out);

    CloseHandle(hconout);

  }

  hconin = hconout = INVALID_HANDLE_VALUE;

}

int save_term(enum save_term_flags flags)

{

  hconin = CreateFileA("CONIN$", GENERIC_READ | GENERIC_WRITE,

      FILE_SHARE_READ, NULL, OPEN_EXISTING,

      FILE_ATTRIBUTE_NORMAL, NULL);

  if (hconin == INVALID_HANDLE_VALUE)

    return -1;

  if (flags & SAVE_TERM_DUPLEX) {

    hconout = CreateFileA("CONOUT$", GENERIC_READ | GENERIC_WRITE,

      FILE_SHARE_WRITE, NULL, OPEN_EXISTING,

      FILE_ATTRIBUTE_NORMAL, NULL);

    if (hconout == INVALID_HANDLE_VALUE)

      goto error;

    GetConsoleMode(hconout, &cmode_out);

  }

  GetConsoleMode(hconin, &cmode_in);

  use_stty = 0;

  sigchain_push_common(restore_term_on_signal);

  return 0;

error:

  CloseHandle(hconin);

  hconin = INVALID_HANDLE_VALUE;

  return -1;

}

static int disable_bits(enum save_term_flags flags, DWORD bits)

{

  if (use_stty) {

    struct child_process cp = CHILD_PROCESS_INIT;

    strvec_push(&cp.args, "stty");

    if (bits & ENABLE_LINE_INPUT) {

      string_list_append(&stty_restore, "icanon");

      /*

       * POSIX allows VMIN and VTIME to overlap with VEOF and

       * VEOL - let's hope that is not the case on windows.

       */

      strvec_pushl(&cp.args, "-icanon", "min", "1", "time", "0", NULL);

    }

    if (bits & ENABLE_ECHO_INPUT) {

      string_list_append(&stty_restore, "echo");

      strvec_push(&cp.args, "-echo");

    }

    if (bits & ENABLE_PROCESSED_INPUT) {

      string_list_append(&stty_restore, "-ignbrk");

      string_list_append(&stty_restore, "intr");

      string_list_append(&stty_restore, "^c");

      strvec_push(&cp.args, "ignbrk");

      strvec_push(&cp.args, "intr");

      strvec_push(&cp.args, "");

    }

    if (run_command(&cp) == 0)

      return 0;

    /* `stty` could not be executed; access the Console directly */

    use_stty = 0;

  }

  if (save_term(flags) < 0)

    return -1;

  if (!SetConsoleMode(hconin, cmode_in & ~bits)) {

    CloseHandle(hconin);

    hconin = INVALID_HANDLE_VALUE;

    sigchain_pop_common();

    return -1;

  }

  return 0;

}

static int disable_echo(enum save_term_flags flags)

{

  return disable_bits(flags, ENABLE_ECHO_INPUT);

}

static int enable_non_canonical(enum save_term_flags flags)

{

  return disable_bits(flags,

          ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT | ENABLE_PROCESSED_INPUT);

}

/*

 * Override `getchar()`, as the default implementation does not use

 * `ReadFile()`.

 *

 * This poses a problem when we want to see whether the standard

 * input has more characters, as the default of Git for Windows is to start the

 * Bash in a MinTTY, which uses a named pipe to emulate a pty, in which case

 * our `poll()` emulation calls `PeekNamedPipe()`, which seems to require

 * `ReadFile()` to be called first to work properly (it only reports 0

 * available bytes, otherwise).

 *

 * So let's just override `getchar()` with a version backed by `ReadFile()` and

 * go our merry ways from here.

 */

static int mingw_getchar(void)

{

  DWORD read = 0;

  unsigned char ch;

  if (!ReadFile(GetStdHandle(STD_INPUT_HANDLE), &ch, 1, &read, NULL))

    return EOF;

  if (!read) {

    error("Unexpected 0 read");

    return EOF;

  }

  return ch;

}

#define getchar mingw_getchar

static int getchar_with_timeout(int timeout)

{

  struct pollfd pfd = { .fd = 0, .events = POLLIN };

  if (poll(&pfd, 1, timeout) < 1)

    return EOF;

  return getchar();

}

#endif

#ifndef FORCE_TEXT

#define FORCE_TEXT

#endif

char *git_terminal_prompt(const char *prompt, int echo)

{

  static struct strbuf buf = STRBUF_INIT;

  int r;

  FILE *input_fh, *output_fh;

  input_fh = fopen(INPUT_PATH, "r" FORCE_TEXT);

  if (!input_fh)

    return NULL;

  output_fh = fopen(OUTPUT_PATH, "w" FORCE_TEXT);

  if (!output_fh) {

    fclose(input_fh);

    return NULL;

  }

  if (!echo && disable_echo(0)) {

    fclose(input_fh);

    fclose(output_fh);

    return NULL;

  }

  fputs(prompt, output_fh);

  fflush(output_fh);

  r = strbuf_getline_lf(&buf, input_fh);

  if (!echo) {

    putc('\n', output_fh);

    fflush(output_fh);

  }

  restore_term();

  fclose(input_fh);

  fclose(output_fh);

  if (r == EOF)

    return NULL;

  return buf.buf;

}

/*

 * The `is_known_escape_sequence()` function returns 1 if the passed string

 * corresponds to an Escape sequence that the terminal capabilities contains.

 *

 * To avoid depending on ncurses or other platform-specific libraries, we rely

 * on the presence of the `infocmp` executable to do the job for us (failing

 * silently if the program is not available or refused to run).

 */

struct escape_sequence_entry {

  struct hashmap_entry entry;

  char sequence[FLEX_ARRAY];

};

static int sequence_entry_cmp(const void *hashmap_cmp_fn_data UNUSED,

            const struct hashmap_entry *he1,

            const struct hashmap_entry *he2,

            const void *keydata)

{

  const struct escape_sequence_entry

    *e1 = container_of(he1, const struct escape_sequence_entry, entry),

    *e2 = container_of(he2, const struct escape_sequence_entry, entry);

  return strcmp(e1->sequence, keydata ? keydata : e2->sequence);

}

static int is_known_escape_sequence(const char *sequence)

{

  static struct hashmap sequences;

  static int initialized;

  if (!initialized) {

    struct child_process cp = CHILD_PROCESS_INIT;

    struct strbuf buf = STRBUF_INIT;

    char *p, *eol;

    hashmap_init(&sequences, sequence_entry_cmp, NULL, 0);

    strvec_pushl(&cp.args, "infocmp", "-L", "-1", NULL);

    if (pipe_command(&cp, NULL, 0, &buf, 0, NULL, 0))

      strbuf_setlen(&buf, 0);

    for (eol = p = buf.buf; *p; p = eol + 1) {

      p = strchr(p, '=');

      if (!p)

        break;

      p++;

      eol = strchrnul(p, '\n');

      if (starts_with(p, "\\E")) {

        char *comma = memchr(p, ',', eol - p);

        struct escape_sequence_entry *e;

        p[0] = '^';

        p[1] = '[';

        FLEX_ALLOC_MEM(e, sequence, p, comma - p);

        hashmap_entry_init(&e->entry,

               strhash(e->sequence));

        hashmap_add(&sequences, &e->entry);

      }

      if (!*eol)

        break;

    }

    initialized = 1;

  }

  return !!hashmap_get_from_hash(&sequences, strhash(sequence), sequence);

}

int read_key_without_echo(struct strbuf *buf)

{

  static int warning_displayed;

  int ch;

  if (warning_displayed || enable_non_canonical(SAVE_TERM_STDIN) < 0) {

    if (!warning_displayed) {

      warning("reading single keystrokes not supported on "

        "this platform; reading line instead");

      warning_displayed = 1;

    }

    return strbuf_getline(buf, stdin);

  }

  strbuf_reset(buf);

  ch = getchar();

  if (ch == EOF) {

    restore_term();

    return EOF;

  }

  strbuf_addch(buf, ch);

  if (ch == '\033' /* ESC */) {

    /*

     * We are most likely looking at an Escape sequence. Let's try

     * to read more bytes, waiting at most half a second, assuming

     * that the sequence is complete if we did not receive any byte

     * within that time.

     *

     * Start by replacing the Escape byte with ^[ */

    strbuf_splice(buf, buf->len - 1, 1, "^[", 2);

    /*

     * Query the terminal capabilities once about all the Escape

     * sequences it knows about, so that we can avoid waiting for

     * half a second when we know that the sequence is complete.

     */

    while (!is_known_escape_sequence(buf->buf)) {

      ch = getchar_with_timeout(500);

      if (ch == EOF)

        break;

      strbuf_addch(buf, ch);

    }

  }

  restore_term();

  return 0;

}

#else

int save_term(enum save_term_flags flags)

{

  /* no duplex support available */

  return -!!(flags & SAVE_TERM_DUPLEX);

}

void restore_term(void)

{

}

char *git_terminal_prompt(const char *prompt, int echo)

{

  return getpass(prompt);

}

int read_key_without_echo(struct strbuf *buf)

{

  static int warning_displayed;

  const char *res;

  if (!warning_displayed) {

    warning("reading single keystrokes not supported on this "

      "platform; reading line instead");

    warning_displayed = 1;

  }

  res = getpass("");

  strbuf_reset(buf);

  if (!res)

    return EOF;

  strbuf_addstr(buf, res);

  return 0;

}

#endif