Use a select based event handling and fix deadlock

src/buffer_utils.cc

@@ -95,7 +95,7 @@ Buffer* create_fifo_buffer(String name, int fd, bool scroll)
 
     auto watcher_deleter = [buffer](FDWatcher* watcher) {
         kak_assert(buffer->flags() & Buffer::Flags::Fifo);
-        close(watcher->fd());
+        watcher->close_fd();
         buffer->run_hook_in_own_context("BufCloseFifo", "");
         buffer->flags() &= ~Buffer::Flags::Fifo;
         watcher->~FDWatcher();

src/event_manager.cc

@@ -1,6 +1,6 @@
 #include "event_manager.hh"
 
-#include <poll.h>
+#include <unistd.h>
 
 namespace Kakoune
 {
@@ -21,6 +21,12 @@ void FDWatcher::run(EventMode mode)
     m_callback(*this, mode);
 }
 
+void FDWatcher::close_fd()
+{
+    close(m_fd);
+    m_fd = -1;
+}
+
 Timer::Timer(TimePoint date, Callback callback, EventMode mode)
     : m_date{date}, m_callback{std::move(callback)}, m_mode(mode)
 {
@@ -47,7 +53,7 @@ void Timer::run(EventMode mode)
 
 EventManager::EventManager()
 {
-    m_forced_fd.reserve(4);
+    FD_ZERO(&m_forced_fd);
 }
 
 EventManager::~EventManager()
@@ -58,10 +64,18 @@ EventManager::~EventManager()
 
 void EventManager::handle_next_events(EventMode mode)
 {
-    std::vector<pollfd> events;
-    events.reserve(m_fd_watchers.size());
+    int max_fd = 0;
+    fd_set rfds;
+    FD_ZERO(&rfds);
     for (auto& watcher : m_fd_watchers)
-        events.emplace_back(pollfd{ watcher->fd(), POLLIN | POLLPRI, 0 });
+    {
+        const int fd = watcher->fd();
+        if (fd != -1)
+        {
+            max_fd = std::max(fd, max_fd);
+            FD_SET(fd, &rfds);
+        }
+    }
 
     TimePoint next_timer = TimePoint::max();
     for (auto& timer : m_timers)
@@ -70,21 +84,23 @@ void EventManager::handle_next_events(EventMode mode)
             next_timer = timer->next_date();
     }
     using namespace std::chrono;
-    auto timeout = duration_cast<milliseconds>(next_timer - Clock::now()).count();
-    poll(events.data(), events.size(), timeout < INT_MAX ? (int)timeout : INT_MAX);
+    auto timeout = duration_cast<microseconds>(next_timer - Clock::now()).count();
 
-    // gather forced fds *after* poll, so that signal handlers can write to
+    constexpr auto us = 1000000000ll;
+    timeval tv{ (long)(timeout / us), (long)(timeout % us) };
+    int res = select(max_fd + 1, &rfds, nullptr, nullptr, &tv);
+
+    // copy forced fds *after* poll, so that signal handlers can write to
     // m_forced_fd, interupt poll, and directly be serviced.
-    std::vector<int> forced;
-    std::swap(forced, m_forced_fd);
+    fd_set forced = m_forced_fd;
+    FD_ZERO(&m_forced_fd);
 
-    for (auto& event : events)
+    for (int fd = 0; fd < max_fd + 1; ++fd)
     {
-        const int fd = event.fd;
-        if (event.revents or contains(forced, fd))
+        if ((res > 0 and FD_ISSET(fd, &rfds)) or FD_ISSET(fd, &forced))
         {
             auto it = find_if(m_fd_watchers,
-                              [fd](FDWatcher* w) { return w->fd() == fd; });
+                              [fd](const FDWatcher* w){return w->fd() == fd; });
             if (it != m_fd_watchers.end())
                 (*it)->run(mode);
         }
@@ -100,7 +116,7 @@ void EventManager::handle_next_events(EventMode mode)
 
 void EventManager::force_signal(int fd)
 {
-    m_forced_fd.push_back(fd);
+    FD_SET(fd, &m_forced_fd);
 }
 
 }

src/event_manager.hh

@@ -7,6 +7,8 @@
 #include <chrono>
 #include <unordered_set>
 
+#include <sys/select.h>
+
 namespace Kakoune
 {
 
@@ -28,6 +30,9 @@ public:
 
     int fd() const { return m_fd; }
     void run(EventMode mode);
+
+    void close_fd();
+    bool closed() const { return m_fd == -1; }
 private:
 
     int       m_fd;
@@ -80,7 +85,7 @@ private:
     friend class Timer;
     std::unordered_set<FDWatcher*>  m_fd_watchers;
     std::unordered_set<Timer*>      m_timers;
-    std::vector<int> m_forced_fd;
+    fd_set m_forced_fd;
 
     TimePoint        m_last;
 };

src/remote.cc

@@ -295,7 +295,7 @@ RemoteUI::~RemoteUI()
 {
     write_debug("remote client disconnected: " +
                 to_string(m_socket_watcher.fd()));
-    close(m_socket_watcher.fd());
+    m_socket_watcher.close_fd();
 }
 
 void RemoteUI::menu_show(memoryview<String> choices,
@@ -646,7 +646,7 @@ Server::Server(String session_name)
 void Server::close_session()
 {
     unlink(("/tmp/kak-" + m_session).c_str());
-    close(m_listener->fd());
+    m_listener->close_fd();
     m_listener.reset();
 }
 

src/shell_manager.cc

@@ -66,27 +66,20 @@ String ShellManager::pipe(StringView input,
 
         String error;
         {
-            auto pipe_reader = [](String& output, bool& closed) {
-                return [&output, &closed](FDWatcher& watcher, EventMode) {
-                    if (closed)
-                        return;
-                    const int fd = watcher.fd();
+            auto pipe_reader = [](String& output) {
+                return [&output](FDWatcher& watcher, EventMode) {
                     char buffer[1024];
-                    size_t size = read(fd, buffer, 1024);
+                    size_t size = read(watcher.fd(), buffer, 1024);
                     if (size <= 0)
-                    {
-                        close(fd);
-                        closed = true;
-                    }
+                        watcher.close_fd();
                     output += String(buffer, buffer+size);
                 };
             };
 
-            bool stdout_closed = false, stderr_closed = false;
-            FDWatcher stdout_watcher{read_pipe[0], pipe_reader(output, stdout_closed)};
-            FDWatcher stderr_watcher{error_pipe[0], pipe_reader(error, stderr_closed)};
+            FDWatcher stdout_watcher{read_pipe[0], pipe_reader(output)};
+            FDWatcher stderr_watcher{error_pipe[0], pipe_reader(error)};
 
-            while (not stdout_closed or not stderr_closed)
+            while (not stdout_watcher.closed() and not stderr_watcher.closed())
                 EventManager::instance().handle_next_events(EventMode::Urgent);
         }