Make FDWatcher support Read, Write and Except events, instead of just Read

7 files changed, 57 insertions, 26 deletions

diff --git a/src/buffer_utils.cc b/src/buffer_utils.cc
index 735657e0..4ff1c1cf 100644
--- a/src/buffer_utils.cc
+++ b/src/buffer_utils.cc
@@ -114,7 +114,8 @@ Buffer* create_fifo_buffer(String name, int fd, bool scroll)
     ValueId fifo_watcher_id = s_fifo_watcher_id;
 
     std::unique_ptr<FDWatcher, decltype(watcher_deleter)> watcher(
-        new FDWatcher(fd, [buffer, scroll, fifo_watcher_id](FDWatcher& watcher, EventMode mode) {
+        new FDWatcher(fd, FdEvents::Read,
+                      [buffer, scroll, fifo_watcher_id](FDWatcher& watcher, FdEvents, EventMode mode) {
         if (mode != EventMode::Normal)
             return;
 
diff --git a/src/event_manager.cc b/src/event_manager.cc
index d42f53c8..221a6d0d 100644
--- a/src/event_manager.cc
+++ b/src/event_manager.cc
@@ -7,8 +7,8 @@
 namespace Kakoune
 {
 
-FDWatcher::FDWatcher(int fd, Callback callback)
-    : m_fd{fd}, m_callback{std::move(callback)}
+FDWatcher::FDWatcher(int fd, FdEvents events, Callback callback)
+    : m_fd{fd}, m_events{events}, m_callback{std::move(callback)}
 {
     EventManager::instance().m_fd_watchers.push_back(this);
 }
@@ -18,9 +18,9 @@ FDWatcher::~FDWatcher()
     unordered_erase(EventManager::instance().m_fd_watchers, this);
 }
 
-void FDWatcher::run(EventMode mode)
+void FDWatcher::run(FdEvents events, EventMode mode)
 {
-    m_callback(*this, mode);
+    m_callback(*this, events, mode);
 }
 
 void FDWatcher::close_fd()
@@ -71,15 +71,21 @@ EventManager::~EventManager()
 void EventManager::handle_next_events(EventMode mode, sigset_t* sigmask)
 {
     int max_fd = 0;
-    fd_set rfds;
-    FD_ZERO(&rfds);
+    fd_set rfds, wfds, efds;
+    FD_ZERO(&rfds); FD_ZERO(&wfds); FD_ZERO(&efds);
     for (auto& watcher : m_fd_watchers)
     {
         const int fd = watcher->fd();
         if (fd != -1)
         {
             max_fd = std::max(fd, max_fd);
-            FD_SET(fd, &rfds);
+            auto events = watcher->events();
+            if (events & FdEvents::Read)
+                FD_SET(fd, &rfds);
+            if (events & FdEvents::Write)
+                FD_SET(fd, &wfds);
+            if (events & FdEvents::Except)
+                FD_SET(fd, &efds);
         }
     }
 
@@ -101,7 +107,7 @@ void EventManager::handle_next_events(EventMode mode, sigset_t* sigmask)
             ts = timespec{ (time_t)secs.count(), (long)(nsecs - secs).count() };
         }
     }
-    int res = pselect(max_fd + 1, &rfds, nullptr, nullptr,
+    int res = pselect(max_fd + 1, &rfds, &wfds, &efds,
                       with_timeout ? &ts : nullptr, sigmask);
 
     // copy forced fds *after* select, so that signal handlers can write to
@@ -111,12 +117,18 @@ void EventManager::handle_next_events(EventMode mode, sigset_t* sigmask)
 
     for (int fd = 0; fd < max_fd + 1; ++fd)
     {
-        if ((res > 0 and FD_ISSET(fd, &rfds)) or FD_ISSET(fd, &forced))
+        auto events =  FD_ISSET(fd, &forced) ? FdEvents::Read : FdEvents::None;
+        if (res > 0)
+            events |= (FD_ISSET(fd, &rfds) ? FdEvents::Read : FdEvents::None) |
+                      (FD_ISSET(fd, &wfds) ? FdEvents::Write : FdEvents::None) |
+                      (FD_ISSET(fd, &efds) ? FdEvents::Except : FdEvents::None);
+
+        if (events != FdEvents::None)
         {
             auto it = find_if(m_fd_watchers,
                               [fd](const FDWatcher* w){return w->fd() == fd; });
             if (it != m_fd_watchers.end())
-                (*it)->run(mode);
+                (*it)->run(events, mode);
         }
     }
 
diff --git a/src/event_manager.hh b/src/event_manager.hh
index 5121b324..3d222f48 100644
--- a/src/event_manager.hh
+++ b/src/event_manager.hh
@@ -20,24 +20,38 @@ enum class EventMode
     Urgent,
 };
 
+enum class FdEvents
+{
+    None = 0,
+    Read = 1 << 0,
+    Write = 1 << 1,
+    Except = 1 << 2,
+};
+
+template<> struct WithBitOps<FdEvents> : std::true_type {};
+
 class FDWatcher
 {
 public:
-    using Callback = std::function<void (FDWatcher& watcher, EventMode mode)>;
-    FDWatcher(int fd, Callback callback);
+    using Callback = std::function<void (FDWatcher& watcher, FdEvents events, EventMode mode)>;
+    FDWatcher(int fd, FdEvents events, Callback callback);
     FDWatcher(const FDWatcher&) = delete;
     FDWatcher& operator=(const FDWatcher&) = delete;
     ~FDWatcher();
 
     int fd() const { return m_fd; }
-    void run(EventMode mode);
+    FdEvents events() const { return m_events; }
+    FdEvents& events() { return m_events; }
+
+    void run(FdEvents events, EventMode mode);
 
     void close_fd();
     void disable() { m_fd = -1; }
 private:
 
-    int       m_fd;
-    Callback  m_callback;
+    int      m_fd;
+    FdEvents m_events;
+    Callback m_callback;
 };
 
 class Timer
diff --git a/src/json_ui.cc b/src/json_ui.cc
index 0a82e07e..95697d73 100644
--- a/src/json_ui.cc
+++ b/src/json_ui.cc
@@ -164,7 +164,8 @@ void rpc_call(StringView method, Args&&... args)
 }
 
 JsonUI::JsonUI()
-    : m_stdin_watcher{0, [this](FDWatcher&, EventMode mode) {
+    : m_stdin_watcher{0, FdEvents::Read,
+                      [this](FDWatcher&, FdEvents, EventMode mode) {
         parse_requests(mode);
       }}, m_dimensions{24, 80}
 {
diff --git a/src/ncurses_ui.cc b/src/ncurses_ui.cc
index 89aefcc0..64f9a82a 100644
--- a/src/ncurses_ui.cc
+++ b/src/ncurses_ui.cc
@@ -219,7 +219,8 @@ void on_term_resize(int)
 }
 
 NCursesUI::NCursesUI()
-    : m_stdin_watcher{0, [this](FDWatcher&, EventMode mode) {
+    : m_stdin_watcher{0, FdEvents::Read,
+                      [this](FDWatcher&, FdEvents, EventMode mode) {
         if (not m_on_key)
             return;
 
diff --git a/src/remote.cc b/src/remote.cc
index 682971ef..7d44c2e5 100644
--- a/src/remote.cc
+++ b/src/remote.cc
@@ -345,7 +345,8 @@ private:
 
 
 RemoteUI::RemoteUI(int socket, DisplayCoord dimensions)
-    : m_socket_watcher(socket, [this](FDWatcher& watcher, EventMode mode) {
+    : m_socket_watcher(socket,  FdEvents::Read,
+                       [this](FDWatcher& watcher, FdEvents, EventMode mode) {
           const int sock = watcher.fd();
           try
           {
@@ -506,7 +507,8 @@ RemoteClient::RemoteClient(StringView session, std::unique_ptr<UserInterface>&&
      });
 
     MsgReader reader;
-    m_socket_watcher.reset(new FDWatcher{sock, [this, reader](FDWatcher& watcher, EventMode) mutable {
+    m_socket_watcher.reset(new FDWatcher{sock, FdEvents::Read,
+                           [this, reader](FDWatcher& watcher, FdEvents, EventMode) mutable {
         const int sock = watcher.fd();
         while (fd_readable(sock) and not reader.ready())
             reader.read_available(sock);
@@ -593,8 +595,8 @@ class Server::Accepter
 {
 public:
     Accepter(int socket)
-        : m_socket_watcher(socket,
-                           [this](FDWatcher&, EventMode mode) {
+        : m_socket_watcher(socket, FdEvents::Read,
+                           [this](FDWatcher&, FdEvents, EventMode mode) {
                                if (mode == EventMode::Normal)
                                    handle_available_input();
                            })
@@ -681,7 +683,7 @@ Server::Server(String session_name)
     if (listen(listen_sock, 4) == -1)
        throw runtime_error(format("unable to listen on socket '{}'", addr.sun_path));
 
-    auto accepter = [this](FDWatcher& watcher, EventMode mode) {
+    auto accepter = [this](FDWatcher& watcher, FdEvents, EventMode mode) {
         sockaddr_un client_addr;
         socklen_t   client_addr_len = sizeof(sockaddr_un);
         int sock = accept(watcher.fd(), (sockaddr*) &client_addr,
@@ -692,7 +694,7 @@ Server::Server(String session_name)
 
         m_accepters.emplace_back(new Accepter{sock});
     };
-    m_listener.reset(new FDWatcher{listen_sock, accepter});
+    m_listener.reset(new FDWatcher{listen_sock, FdEvents::Read, accepter});
 }
 
 bool Server::rename_session(StringView name)
diff --git a/src/shell_manager.cc b/src/shell_manager.cc
index 81df87ee..25cc2be6 100644
--- a/src/shell_manager.cc
+++ b/src/shell_manager.cc
@@ -158,8 +158,8 @@ std::pair<String, int> ShellManager::eval(
     struct PipeReader : FDWatcher
     {
         PipeReader(Pipe& pipe, String& contents)
-            : FDWatcher(pipe.read_fd(),
-                        [&contents, &pipe](FDWatcher& watcher, EventMode) {
+            : FDWatcher(pipe.read_fd(), FdEvents::Read,
+                        [&contents, &pipe](FDWatcher& watcher, FdEvents, EventMode) {
                             char buffer[1024];
                             size_t size = ::read(pipe.read_fd(), buffer, 1024);
                             if (size <= 0)