[wing/wip/nacho/poll] Add wing poll

[Ignacio Casal Quinteiro <icq src gnome org>]

commit 596f8cefeb237d9ed7aa8a0ab137d4f1cecc518a
Author: Ignacio Casal Quinteiro <qignacio amazon com>
Date:   Fri Nov 30 17:02:00 2018 +0100

    Add wing poll

 wing/wing.h     |   1 +
 wing/wingpoll.c | 210 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 wing/wingpoll.h |  46 +++++++++++++
 3 files changed, 257 insertions(+)
---
diff --git a/wing/wing.h b/wing/wing.h
index 5cc2ed3..20e72bf 100644
--- a/wing/wing.h
+++ b/wing/wing.h
@@ -25,6 +25,7 @@
 #include <wing/wingnamedpipeclient.h>
 #include <wing/wingnamedpipelistener.h>
 #include <wing/wingnamedpipeconnection.h>
+#include <wing/wingpoll.h>
 #include <wing/wingservice.h>
 #include <wing/wingservicemanager.h>
 #include <wing/wingsource.h>
diff --git a/wing/wingpoll.c b/wing/wingpoll.c
new file mode 100644
index 0000000..2ab6ec3
--- /dev/null
+++ b/wing/wingpoll.c
@@ -0,0 +1,210 @@
+#include "wingpoll.h"
+
+#ifdef G_OS_WIN32
+#define STRICT
+#include <windows.h>
+#endif /* G_OS_WIN32 */
+
+#ifdef _WIN32
+/* Always enable debugging printout on Windows, as it is more often
+ * needed there...
+ */
+#define G_MAIN_POLL_DEBUG
+#endif
+
+#ifdef G_MAIN_POLL_DEBUG
+extern gboolean _g_main_poll_debug;
+#endif
+
+static int
+poll_rest (GPollFD *msg_fd,
+           HANDLE  *handles,
+           GPollFD *handle_to_fd[],
+           gint     nhandles,
+           gint     timeout)
+{
+  DWORD ready;
+  GPollFD *f;
+  int recursed_result;
+
+  if (msg_fd != NULL)
+    {
+      /* Wait for either messages or handles
+       * -> Use MsgWaitForMultipleObjectsEx
+       */
+      if (_g_main_poll_debug)
+       g_print ("  MsgWaitForMultipleObjectsEx(%d, %d)\n", nhandles, timeout);
+
+      ready = MsgWaitForMultipleObjectsEx (nhandles, handles, timeout,
+                                          QS_ALLINPUT, MWMO_ALERTABLE);
+
+      if (ready == WAIT_FAILED)
+       {
+         gchar *emsg = g_win32_error_message (GetLastError ());
+         g_warning ("MsgWaitForMultipleObjectsEx failed: %s", emsg);
+         g_free (emsg);
+       }
+    }
+  else if (nhandles == 0)
+    {
+      /* No handles to wait for, just the timeout */
+      if (timeout == INFINITE)
+       ready = WAIT_FAILED;
+      else
+        {
+          /* Wait for the current process to die, more efficient than SleepEx(). */
+          WaitForSingleObjectEx (GetCurrentProcess (), timeout, TRUE);
+          ready = WAIT_TIMEOUT;
+        }
+    }
+  else
+    {
+      /* Wait for just handles
+       * -> Use WaitForMultipleObjectsEx
+       */
+      if (_g_main_poll_debug)
+       g_print ("  WaitForMultipleObjectsEx(%d, %d)\n", nhandles, timeout);
+
+      ready = WaitForMultipleObjectsEx (nhandles, handles, FALSE, timeout, TRUE);
+      if (ready == WAIT_FAILED)
+       {
+         gchar *emsg = g_win32_error_message (GetLastError ());
+         g_warning ("WaitForMultipleObjectsEx failed: %s", emsg);
+         g_free (emsg);
+       }
+    }
+
+  if (_g_main_poll_debug)
+    g_print ("  wait returns %ld%s\n",
+            ready,
+            (ready == WAIT_FAILED ? " (WAIT_FAILED)" :
+             (ready == WAIT_TIMEOUT ? " (WAIT_TIMEOUT)" :
+              (msg_fd != NULL && ready == WAIT_OBJECT_0 + nhandles ? " (msg)" : ""))));
+
+  if (ready == WAIT_FAILED)
+    return -1;
+  else if (ready == WAIT_TIMEOUT ||
+          ready == WAIT_IO_COMPLETION)
+    return 0;
+  else if (msg_fd != NULL && ready == WAIT_OBJECT_0 + nhandles)
+    {
+      msg_fd->revents |= G_IO_IN;
+
+      /* If we have a timeout, or no handles to poll, be satisfied
+       * with just noticing we have messages waiting.
+       */
+      if (timeout != 0 || nhandles == 0)
+       return 1;
+
+      /* If no timeout and handles to poll, recurse to poll them,
+       * too.
+       */
+      recursed_result = poll_rest (NULL, handles, handle_to_fd, nhandles, 0);
+      return (recursed_result == -1) ? -1 : 1 + recursed_result;
+    }
+  else if (ready >= WAIT_OBJECT_0 && ready < WAIT_OBJECT_0 + nhandles)
+    {
+      f = handle_to_fd[ready - WAIT_OBJECT_0];
+      f->revents = f->events;
+      if (_g_main_poll_debug)
+        g_print ("  got event %p\n", (HANDLE) f->fd);
+
+      /* If no timeout and polling several handles, recurse to poll
+       * the rest of them.
+       */
+      if (timeout == 0 && nhandles > 1)
+       {
+         /* Poll the handles with index > ready */
+          HANDLE  *shorter_handles;
+          GPollFD **shorter_handle_to_fd;
+          gint     shorter_nhandles;
+
+          shorter_handles = &handles[ready - WAIT_OBJECT_0 + 1];
+          shorter_handle_to_fd = &handle_to_fd[ready - WAIT_OBJECT_0 + 1];
+          shorter_nhandles = nhandles - (ready - WAIT_OBJECT_0 + 1);
+
+         recursed_result = poll_rest (NULL, shorter_handles, shorter_handle_to_fd, shorter_nhandles, 0);
+         return (recursed_result == -1) ? -1 : 1 + recursed_result;
+       }
+      return 1;
+    }
+
+  return 0;
+}
+
+gint
+wing_poll (GPollFD *fds,
+           guint    nfds,
+           gint     timeout)
+{
+  HANDLE handles[MAXIMUM_WAIT_OBJECTS];
+  GPollFD *handle_to_fd[MAXIMUM_WAIT_OBJECTS];
+  GPollFD *msg_fd = NULL;
+  GPollFD *f;
+  gint nhandles = 0;
+  int retval;
+
+  if (_g_main_poll_debug)
+    g_print ("g_poll: waiting for");
+
+  for (f = fds; f < &fds[nfds]; ++f)
+    {
+      if (f->fd == G_WIN32_MSG_HANDLE && (f->events & G_IO_IN))
+        {
+          if (_g_main_poll_debug && msg_fd == NULL)
+            g_print (" MSG");
+          msg_fd = f;
+        }
+      else if (f->fd > 0)
+        {
+          if (nhandles == MAXIMUM_WAIT_OBJECTS)
+            {
+              g_warning ("Too many handles to wait for!\n");
+              break;
+            }
+          else
+            {
+              if (_g_main_poll_debug)
+                g_print (" %p", (HANDLE) f->fd);
+              handle_to_fd[nhandles] = f;
+              handles[nhandles++] = (HANDLE) f->fd;
+            }
+        }
+      f->revents = 0;
+    }
+
+  if (_g_main_poll_debug)
+    g_print ("\n");
+
+  if (timeout == -1)
+    timeout = INFINITE;
+
+  /* Polling for several things? */
+  if (nhandles > 1 || (nhandles > 0 && msg_fd != NULL))
+    {
+      /* First check if one or several of them are immediately
+       * available
+       */
+      retval = poll_rest (msg_fd, handles, handle_to_fd, nhandles, 0);
+
+      /* If not, and we have a significant timeout, poll again with
+       * timeout then. Note that this will return indication for only
+       * one event, or only for messages.
+       */
+      if (retval == 0 && (timeout == INFINITE || timeout > 0))
+       retval = poll_rest (msg_fd, handles, handle_to_fd, nhandles, timeout);
+    }
+  else
+    {
+      /* Just polling for one thing, so no need to check first if
+       * available immediately
+       */
+      retval = poll_rest (msg_fd, handles, handle_to_fd, nhandles, timeout);
+    }
+
+  if (retval == -1)
+    for (f = fds; f < &fds[nfds]; ++f)
+      f->revents = 0;
+
+  return retval;
+}
diff --git a/wing/wingpoll.h b/wing/wingpoll.h
new file mode 100644
index 0000000..111cbb6
--- /dev/null
+++ b/wing/wingpoll.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
+ *
+ * gpoll.c: poll(2) abstraction
+ * Copyright 1998 Owen Taylor
+ * Copyright 2008 Red Hat, Inc.
+ * Copyright (C) 2018 NICE s.r.l.
+ * 
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.         See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
+ * file for a list of people on the GLib Team.  See the ChangeLog
+ * files for a list of changes.  These files are distributed with
+ * GLib at ftp://ftp.gtk.org/pub/gtk/.
+ */
+
+#ifndef WING_POLL_H
+#define WING_POLL_H
+
+#include <glib.h>
+#include <wing/wingversionmacros.h>
+
+G_BEGIN_DECLS
+
+WING_AVAILABLE_IN_ALL
+gint wing_poll (GPollFD *fds,
+                guint    nfds,
+                gint     timeout);
+
+G_END_DECLS
+
+#endif /* WING_UTILS_H */