Unix: use 'select' instead of 'poll' for waiting for input

So that we can support older macOS versions.

See magiblot/turbo#65.

include/tvision/internal/events.h

@@ -7,29 +7,27 @@
 #include <memory>
 #include <vector>
 
-#ifdef _TV_UNIX
-#include <poll.h>
-#else
+#ifdef _WIN32
 #include <tvision/compat/windows/windows.h>
 #endif
 
 namespace tvision
 {
 
-#ifdef _TV_UNIX
-using SysHandle = int;
-#else
+#ifdef _WIN32
 using SysHandle = HANDLE;
+#else
+using SysHandle = int;
 #endif
 
 struct SysManualEvent
 {
-#ifdef _TV_UNIX
- using Handle = int[2];
- Handle fds;
-#else
+#ifdef _WIN32
  using Handle = HANDLE;
  Handle hEvent;
+#else
+ using Handle = int[2];
+ Handle fds;
 #endif
 
  static bool createHandle(Handle &handle) noexcept;
@@ -42,20 +40,20 @@ struct SysManualEvent
 };
 
 inline SysManualEvent::SysManualEvent(Handle aHandle) noexcept :
-#ifdef _TV_UNIX
- fds {aHandle[0], aHandle[1]}
-#else
+#ifdef _WIN32
  hEvent {aHandle}
+#else
+ fds {aHandle[0], aHandle[1]}
 #endif
 {
 }
 
 inline SysHandle SysManualEvent::getWaitableHandle(Handle handle) noexcept
 {
-#ifdef _TV_UNIX
- return handle[0];
-#else
+#ifdef _WIN32
  return handle;
+#else
+ return handle[0];
 #endif
 }
 
@@ -109,14 +107,6 @@ inline WakeUpEventSource::WakeUpEventSource( SysManualEvent::Handle aHandle,
 {
 }
 
-#ifdef _TV_UNIX
-using PollItem = struct pollfd;
-static inline PollItem pollItem(SysHandle fd) noexcept { return {fd, POLLIN}; }
-#else
-using PollItem = HANDLE;
-static inline PollItem pollItem(SysHandle h) noexcept { return h; }
-#endif
-
 enum PollState : uint8_t
 {
  psNothing,
@@ -126,24 +116,24 @@ enum PollState : uint8_t
 
 struct PollData
 {
- std::vector<PollItem> items;
+ std::vector<SysHandle> handles;
  std::vector<PollState> states;
 
  void push_back(SysHandle h)
  {
- items.push_back(pollItem(h));
+ handles.push_back(h);
  states.push_back(psNothing);
  }
 
  void erase(size_t i)
  {
- items.erase(items.begin() + i);
+ handles.erase(handles.begin() + i);
  states.erase(states.begin() + i);
  }
 
  size_t size()
  {
- return items.size();
+ return handles.size();
  }
 };
 

include/tvision/internal/stdioctl.h

@@ -22,10 +22,9 @@ class StdioCtl final
  } cn[3];
  bool ownsConsole {false};
 #else
- int ttyfd {-1};
  int fds[2] {-1, -1};
- FILE *infile {nullptr};
- FILE *outfile {nullptr};
+ FILE *files[2] {nullptr, nullptr};
+ bool ownsFiles {false};
 #endif // _WIN32
 
  static StdioCtl *instance;
@@ -56,8 +55,8 @@ class StdioCtl final
 #else
  int in() const noexcept { return fds[0]; }
  int out() const noexcept { return fds[1]; }
- FILE *fin() const noexcept { return infile; }
- FILE *fout() const noexcept { return outfile; }
+ FILE *fin() const noexcept { return files[0]; }
+ FILE *fout() const noexcept { return files[1]; }
 #ifdef __linux__
  bool isLinuxConsole() const noexcept;
 #endif

source/platform/events.cpp

@@ -10,6 +10,7 @@ using std::chrono::steady_clock;
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
+#include <sys/select.h>
 #endif
 
 namespace tvision
@@ -133,33 +134,53 @@ static bool fdEmpty(int fd) noexcept
 
 static void pollHandles(PollData &pd, int ms) noexcept
 {
- auto &fds = pd.items;
+ auto &fds = pd.handles;
  auto &states = pd.states;
- if (poll(fds.data(), fds.size(), ms) > 0)
- for (size_t i = 0; i < fds.size(); ++i)
+ // We use 'select' instead of 'poll' because it is more portable, especially
+ // on macOS. However, 'select' only supports file descriptors smaller than
+ // 'FD_SETSIZE'. But this should not be an issue, since we just open a few
+ // of them at program startup and when suspending/resuming the application.
+ fd_set readFds;
+ FD_ZERO(&readFds);
+ int maxFd = -1;
+ for (size_t i = 0; i < fds.size(); ++i)
+ if (fds[i] < FD_SETSIZE)
  {
- if ( (fds[i].revents & POLLHUP) ||
- ((fds[i].revents & POLLIN) && fdEmpty(fds[i].fd)) )
- // Broken pipe or EOF will cause poll to return immediately,
- // so remove it from the list.
- states[i] = psDisconnect;
- else if (fds[i].revents & POLLIN)
- states[i] = psReady;
+ FD_SET(fds[i], &readFds);
+ if (fds[i] > maxFd)
+ maxFd = fds[i];
  }
+
+ if (maxFd >= 0)
+ {
+ struct timeval timeout;
+ timeout.tv_sec = 0;
+ timeout.tv_usec = ms*1000;
+ if ( select( maxFd + 1, &readFds, nullptr, nullptr,
+ (ms < 0 ? nullptr : &timeout) ) >= 0 )
+ for (size_t i = 0; i < fds.size(); ++i)
+ if (fds[i] < FD_SETSIZE && FD_ISSET(fds[i], &readFds))
+ {
+ if (fdEmpty(fds[i]))
+ states[i] = psDisconnect;
+ else
+ states[i] = psReady;
+ }
+ }
 }
 
 #else
 
 static void pollHandles(PollData &pd, int ms) noexcept
 {
- auto &handles = pd.items;
+ auto &handles = pd.handles;
  auto &states = pd.states;
  if (handles.size() == 0)
  Sleep(ms);
  else
  {
  DWORD res = WaitForMultipleObjects(
- handles.size(), handles.data(), FALSE, ms < 0 ? INFINITE : ms);
+ handles.size(), &handles[0], FALSE, (ms < 0 ? INFINITE : ms));
  size_t i = 0;
  while (WAIT_OBJECT_0 <= res && res <= WAIT_OBJECT_0 + handles.size() - i - 1)
  {

source/platform/stdioctl.cpp

@@ -3,7 +3,6 @@
 
 #include <internal/stdioctl.h>
 #include <internal/getenv.h>
-#include <initializer_list>
 
 namespace tvision
 {
@@ -39,46 +38,34 @@ namespace tvision
 
 StdioCtl::StdioCtl() noexcept
 {
- if (getEnv<TStringView>("TVISION_USE_STDIO").empty())
+ if ( getEnv<TStringView>("TVISION_USE_STDIO").empty()
+ && (files[0] = fopen("/dev/tty", "r")) != nullptr
+ && (files[1] = fopen("/dev/tty", "w")) != nullptr )
  {
- for (int fd : {0, 1, 2})
- if (auto *name = ::ttyname(fd))
- if ((ttyfd = ::open(name, O_RDWR)) != -1)
- break;
- // Last resort, although this may lead to 100% CPU usage because
- // /dev/tty is not supported by macOS's poll(),
- if (ttyfd == -1)
- ttyfd = ::open("/dev/tty", O_RDWR);
- }
-
- if (ttyfd != -1)
- {
- for (auto &fd : fds)
- fd = ttyfd;
- int ttyfd2 = dup(ttyfd);
- if (ttyfd2 == -1)
- ttyfd2 = ttyfd; // This is wrong, but aborting is worse.
- infile = ::fdopen(ttyfd, "r");
- outfile = ::fdopen(ttyfd2, "w");
- fcntl(ttyfd, F_SETFD, FD_CLOEXEC);
- fcntl(ttyfd2, F_SETFD, FD_CLOEXEC);
+ ownsFiles = true;
+ fds[0] = fileno(files[0]);
+ fds[1] = fileno(files[1]);
+ // Subprocesses must not inherit these file descriptors.
+ for (int fd : fds)
+ fcntl(fd, F_SETFD, FD_CLOEXEC);
  }
  else
  {
- for (int i = 0; i < 2; ++i)
- fds[i] = i;
- infile = stdin;
- outfile = stdout;
+ for (FILE *file : files)
+ if (file != nullptr)
+ fclose(file);
+ fds[0] = STDIN_FILENO;
+ fds[1] = STDOUT_FILENO;
+ files[0] = stdin;
+ files[1] = stdout;
  }
 }
 
 StdioCtl::~StdioCtl()
 {
- if (ttyfd != -1)
- {
- ::fclose(infile);
- ::fclose(outfile);
- }
+ if (ownsFiles)
+ for (FILE *file : files)
+ fclose(file);
 }
 
 void StdioCtl::write(const char *data, size_t bytes) const noexcept
@@ -94,7 +81,7 @@ void StdioCtl::write(const char *data, size_t bytes) const noexcept
 TPoint StdioCtl::getSize() const noexcept
 {
  struct winsize w;
- for (int fd : {in(), out()})
+ for (int fd : fds)
  {
  if (ioctl(fd, TIOCGWINSZ, &w) != -1)
  {
@@ -115,15 +102,15 @@ TPoint StdioCtl::getFontSize() const noexcept
  struct console_font_op cfo {};
  cfo.op = KD_FONT_OP_GET;
  cfo.width = cfo.height = 32;
- for (int fd : {in(), out()})
+ for (int fd : fds)
  if (ioctl(fd, KDFONTOP, &cfo) != -1)
  return {
  max(cfo.width, 0),
  max(cfo.height, 0),
  };
 #endif
  struct winsize w;
- for (int fd : {in(), out()})
+ for (int fd : fds)
  if (ioctl(fd, TIOCGWINSZ, &w) != -1)
  return {
  w.ws_xpixel / max(w.ws_col, 1),
@@ -138,7 +125,7 @@ bool StdioCtl::isLinuxConsole() const noexcept
 {
  // This is the same function used to get the Shift/Ctrl/Alt modifiers
  // on the console. It only succeeds if a console file descriptor is used.
- for (int fd : {in(), out()})
+ for (int fd : fds)
  {
  char subcode = 6;
  if (ioctl(fd, TIOCLINUX, &subcode) != -1)