#include "git-compat-util.h"

#include "sigchain.h"

#define SIGCHAIN_MAX_SIGNALS 32

struct sigchain_signal {

  sigchain_fun *old;

  int n;

  int alloc;

};

static struct sigchain_signal signals[SIGCHAIN_MAX_SIGNALS];

static void check_signum(int sig)

{

  if (sig < 1 || sig >= SIGCHAIN_MAX_SIGNALS)

    BUG("signal out of range: %d", sig);

}

int sigchain_push(int sig, sigchain_fun f)

{

  struct sigchain_signal *s = signals + sig;

  check_signum(sig);

  ALLOC_GROW(s->old, s->n + 1, s->alloc);

  s->old[s->n] = signal(sig, f);

  if (s->old[s->n] == SIG_ERR)

    return -1;

  s->n++;

  return 0;

}

int sigchain_pop(int sig)

{

  struct sigchain_signal *s = signals + sig;

  check_signum(sig);

  if (s->n < 1)

    return 0;

  if (signal(sig, s->old[s->n - 1]) == SIG_ERR)

    return -1;

  s->n--;

  return 0;

}

void sigchain_push_common(sigchain_fun f)

{

  sigchain_push(SIGINT, f);

  sigchain_push(SIGHUP, f);

  sigchain_push(SIGTERM, f);

  sigchain_push(SIGQUIT, f);

  sigchain_push(SIGPIPE, f);

}

void sigchain_pop_common(void)

{

  sigchain_pop(SIGPIPE);

  sigchain_pop(SIGQUIT);

  sigchain_pop(SIGTERM);

  sigchain_pop(SIGHUP);

  sigchain_pop(SIGINT);

}