Bug 1658072 - Cleanup: remove the signal handling glue in the IPC event loop. r=nika

Now that we're no longer using libevent's signal handling, we don't need
an OO wrapper for it.

Differential Revision: https://phabricator.services.mozilla.com/D141311

ipc/chromium/src/base/message_loop.cc

@@ -728,9 +728,4 @@ bool MessageLoopForIO::WatchFileDescriptor(int fd, bool persistent, Mode mode,
       controller, delegate);
 }
 
-bool MessageLoopForIO::CatchSignal(int sig, SignalEvent* sigevent,
-                                   SignalWatcher* delegate) {
-  return pump_libevent()->CatchSignal(sig, sigevent, delegate);
-}
-
 #endif

ipc/chromium/src/base/message_loop.h

@@ -543,10 +543,6 @@ class MessageLoopForIO : public MessageLoop {
                            FileDescriptorWatcher* controller,
                            Watcher* delegate);
 
-  typedef base::MessagePumpLibevent::SignalEvent SignalEvent;
-  typedef base::MessagePumpLibevent::SignalWatcher SignalWatcher;
-  bool CatchSignal(int sig, SignalEvent* sigevent, SignalWatcher* delegate);
-
 #endif  // defined(OS_POSIX)
 };
 

ipc/chromium/src/base/message_pump_libevent.cc

@@ -262,76 +262,6 @@ void MessagePumpLibevent::OnLibeventNotification(int fd, short flags,
   }
 }
 
-MessagePumpLibevent::SignalEvent::SignalEvent() : event_(NULL) {}
-
-MessagePumpLibevent::SignalEvent::~SignalEvent() {
-  if (event_) {
-    StopCatching();
-  }
-}
-
-void MessagePumpLibevent::SignalEvent::Init(event* e) {
-  DCHECK(e);
-  DCHECK(event_ == NULL);
-  event_ = e;
-}
-
-bool MessagePumpLibevent::SignalEvent::StopCatching() {
-  // XXX/cjones: this code could be shared with
-  // FileDescriptorWatcher. ironic that libevent is "more"
-  // object-oriented than this C++
-  event* e = ReleaseEvent();
-  if (e == NULL) return true;
-
-  // event_del() is a no-op if the event isn't active.
-  int rv = event_del(e);
-  delete e;
-  return (rv == 0);
-}
-
-event* MessagePumpLibevent::SignalEvent::ReleaseEvent() {
-  event* e = event_;
-  event_ = NULL;
-  return e;
-}
-
-bool MessagePumpLibevent::CatchSignal(int sig, SignalEvent* sigevent,
-                                      SignalWatcher* delegate) {
-  DCHECK(sig > 0);
-  DCHECK(sigevent);
-  DCHECK(delegate);
-  // TODO if we want to support re-using SignalEvents, this code needs
-  // to jump through the same hoops as WatchFileDescriptor().  Not
-  // needed at present
-  DCHECK(NULL == sigevent->event_);
-
-  mozilla::UniquePtr<event> evt = mozilla::MakeUnique<event>();
-  signal_set(evt.get(), sig, OnLibeventSignalNotification, delegate);
-
-  if (event_base_set(event_base_, evt.get())) return false;
-
-  if (signal_add(evt.get(), NULL)) return false;
-
-  // Transfer ownership of evt to controller.
-  sigevent->Init(evt.release());
-  return true;
-}
-
-void MessagePumpLibevent::OnLibeventSignalNotification(int sig, short flags,
-                                                       void* context) {
-  if (!awake_) {
-    profiler_thread_wake();
-    awake_ = true;
-  }
-  AUTO_PROFILER_LABEL("MessagePumpLibevent::OnLibeventSignalNotification",
-                      OTHER);
-
-  DCHECK(sig > 0);
-  DCHECK(EV_SIGNAL == flags);
-  DCHECK(context);
-  reinterpret_cast<SignalWatcher*>(context)->OnSignal(sig);
-}
-
 // Reentrant!
 void MessagePumpLibevent::Run(Delegate* delegate) {
   DCHECK(keep_running_) << "Quit must have been called outside of Run!";

ipc/chromium/src/base/message_pump_libevent.h

@@ -82,48 +82,6 @@ class MessagePumpLibevent : public MessagePump {
                            FileDescriptorWatcher* controller,
                            Watcher* delegate);
 
-  // This is analagous to FileDescriptorWatcher above, which really is
-  // just a wrapper around libevent's |struct event|.  This class acts
-  // as a sort of "scoped event watcher" in that it guarantees that
-  // when this class is out of scope, the signal-event it wraps is
-  // removed from libevent's guts.
-  //
-  // XXX/cjones: this isn't my favorite API, but preserving it in
-  // order to match code above
-  class SignalEvent {
-    friend class MessagePumpLibevent;
-
-   public:
-    SignalEvent();
-    ~SignalEvent();  // implicitly calls StopCatching()
-
-    // Have libevent forget this event.
-    bool StopCatching();
-
-   private:
-    void Init(event* e);
-    event* ReleaseEvent();
-
-    event* event_;
-
-    DISALLOW_COPY_AND_ASSIGN(SignalEvent);
-  };
-
-  class SignalWatcher {
-   public:
-    virtual ~SignalWatcher() {}
-    // Called from MessageLoop::Run when |sig| has been delivered to
-    // this process
-    virtual void OnSignal(int sig) = 0;
-  };
-
-  // Have the current thread's message loop catch the signal |sig|.
-  // Multiple watchers can catch the same signal; they're all notified
-  // upon its delivery.  Callers must provide a preallocated
-  // SignalEvent object which can be used to manage the lifetime of
-  // this event.  Returns true on success.
-  bool CatchSignal(int sig, SignalEvent* sigevent, SignalWatcher* delegate);
-
   // MessagePump methods:
   virtual void Run(Delegate* delegate) override;
   virtual void Quit() override;
@@ -153,9 +111,6 @@ class MessagePumpLibevent : public MessagePump {
   // Called by libevent to tell us a registered FD can be read/written to.
   static void OnLibeventNotification(int fd, short flags, void* context);
 
-  // Called by libevent upon receiving a signal
-  static void OnLibeventSignalNotification(int sig, short flags, void* context);
-
   // Unix pipe used to implement ScheduleWork()
   // ... callback; called by libevent inside Run() when pipe is ready to read
   static void OnWakeup(int socket, short flags, void* context);

xpcom/base/nsDumpUtils.cpp

@@ -39,10 +39,6 @@ using namespace mozilla;
  * This scheme is similar to using signalfd(), except it's portable and it
  * doesn't require the use of sigprocmask, which is problematic because it
  * masks signals received by child processes.
- *
- * In theory, we could use Chromium's MessageLoopForIO::CatchSignal() for this.
- * But that uses libevent, which does not handle the realtime signals (bug
- * 794074).
  */
 
 // This is the write-end of a pipe that we use to notice when a

xpcom/base/nsMemoryInfoDumper.cpp

@@ -142,10 +142,6 @@ namespace {
  * This scheme is similar to using signalfd(), except it's portable and it
  * doesn't require the use of sigprocmask, which is problematic because it
  * masks signals received by child processes.
- *
- * In theory, we could use Chromium's MessageLoopForIO::CatchSignal() for this.
- * But that uses libevent, which does not handle the realtime signals (bug
- * 794074).
  */
 
 // It turns out that at least on some systems, SIGRTMIN is not a compile-time