Merge sigint_checker_t generalizations from #7060

This makes it possible to expand the signals checked by the type. I can't merge
the sigttin fixes for #7060 yet because they introduce new breakage, but this
will make merging any future fix easier.

src/builtin_wait.cpp

@@ -64,7 +64,7 @@ static bool any_jobs_finished(size_t jobs_len, const parser_t &parser) {
 }
 
 static int wait_for_backgrounds(parser_t &parser, bool any_flag) {
-    sigint_checker_t sigint;
+    sigchecker_t sigint(topic_t::sighupint);
     size_t jobs_len = parser.jobs().size();
     while ((!any_flag && !all_jobs_finished(parser)) ||
            (any_flag && !any_jobs_finished(jobs_len, parser))) {
@@ -106,7 +106,7 @@ static bool any_specified_jobs_finished(const parser_t &parser, const std::vecto
 
 static int wait_for_backgrounds_specified(parser_t &parser, const std::vector<job_id_t> &ids,
                                           bool any_flag) {
-    sigint_checker_t sigint;
+    sigchecker_t sigint(topic_t::sighupint);
     while ((!any_flag && !all_specified_jobs_finished(parser, ids)) ||
            (any_flag && !any_specified_jobs_finished(parser, ids))) {
         if (sigint.check()) {

src/common.cpp

@@ -1953,7 +1953,7 @@ extern "C" {
 [[gnu::noinline]] void debug_thread_error(void) {
     // Wait for a SIGINT. We can't use sigsuspend() because the signal may be delivered on another
     // thread.
-    sigint_checker_t sigint;
+    sigchecker_t sigint(topic_t::sighupint);
     sigint.wait();
 }
 }

src/signal.cpp

@@ -395,22 +395,23 @@ void signal_unblock_all() {
     sigprocmask(SIG_SETMASK, &iset, nullptr);
 }
 
-sigint_checker_t::sigint_checker_t() {
+sigchecker_t::sigchecker_t(topic_t signal) {
+    topic_ = signal;
     // Call check() to update our generation.
     check();
 }
 
-bool sigint_checker_t::check() {
+bool sigchecker_t::check() {
     auto &tm = topic_monitor_t::principal();
-    generation_t gen = tm.generation_for_topic(topic_t::sighupint);
+    generation_t gen = tm.generation_for_topic(topic_);
     bool changed = this->gen_ != gen;
     this->gen_ = gen;
     return changed;
 }
 
-void sigint_checker_t::wait() const {
+void sigchecker_t::wait() const {
     auto &tm = topic_monitor_t::principal();
     generation_list_t gens{};
-    gens[topic_t::sighupint] = this->gen_;
-    tm.check(&gens, {topic_t::sighupint}, true /* wait */);
+    gens[topic_] = this->gen_;
+    tm.check(&gens, {topic_}, true /* wait */);
 }

src/signal.h

@@ -33,12 +33,14 @@ void signal_unblock_all();
 /// Returns signals with non-default handlers.
 void get_signals_with_handlers(sigset_t *set);
 
+enum class topic_t : uint8_t;
 /// A sigint_detector_t can be used to check if a SIGINT (or SIGHUP) has been delivered.
-class sigint_checker_t {
+class sigchecker_t {
+    topic_t topic_;
     uint64_t gen_{0};
 
    public:
-    sigint_checker_t();
+    sigchecker_t(topic_t signal);
 
     /// Check if a sigint has been delivered since the last call to check(), or since the detector
     /// was created.