Add new function gst_poll_fd_ignored() for improved Windows compatibility.

Original commit message from CVS:
Patch by: Ole André Vadla Ravnås
<ole dot andre dot ravnas at tandberg dot com>
* docs/gst/gstreamer-sections.txt:
* gst/gstpoll.c: (gst_poll_winsock_error_to_errno),
(gst_poll_update_winsock_event_mask),
(gst_poll_prepare_winsock_active_sets),
(gst_poll_collect_winsock_events), (gst_poll_new), (gst_poll_free),
(gst_poll_add_fd_unlocked), (gst_poll_fd_ctl_write),
(gst_poll_fd_ctl_read_unlocked), (gst_poll_fd_ignored),
(gst_poll_fd_has_error), (gst_poll_fd_can_read_unlocked),
(gst_poll_check_ctrl_commands), (gst_poll_wait):
* gst/gstpoll.h:
* win32/common/libgstreamer.def:
Add new function gst_poll_fd_ignored() for improved Windows
compatibility.
Various minor fixes and cleanups. See #520808.

ChangeLog

@@ -1,3 +1,23 @@
+2008-03-18  Wim Taymans  <wim.taymans@collabora.co.uk>
+
+	Patch by: Ole André Vadla Ravnås
+	    <ole dot andre dot ravnas at tandberg dot com>
+
+	* docs/gst/gstreamer-sections.txt:
+	* gst/gstpoll.c: (gst_poll_winsock_error_to_errno),
+	(gst_poll_update_winsock_event_mask),
+	(gst_poll_prepare_winsock_active_sets),
+	(gst_poll_collect_winsock_events), (gst_poll_new), (gst_poll_free),
+	(gst_poll_add_fd_unlocked), (gst_poll_fd_ctl_write),
+	(gst_poll_fd_ctl_read_unlocked), (gst_poll_fd_ignored),
+	(gst_poll_fd_has_error), (gst_poll_fd_can_read_unlocked),
+	(gst_poll_check_ctrl_commands), (gst_poll_wait):
+	* gst/gstpoll.h:
+	* win32/common/libgstreamer.def:
+	Add new function gst_poll_fd_ignored() for improved Windows
+	compatibility.
+	Various minor fixes and cleanups. See #520808.
+
 2008-03-17  Tim-Philipp Müller  <tim at centricular dot net>
 
 	* gst/gstindex.c: (gst_index_entry_free):

docs/gst/gstreamer-sections.txt

@@ -1617,6 +1617,7 @@ gst_poll_fd_ctl_read
 gst_poll_fd_ctl_write
 gst_poll_fd_has_closed
 gst_poll_fd_has_error
+gst_poll_fd_ignored
 gst_poll_fd_init
 gst_poll_free
 gst_poll_new

gst/gstpoll.c

@@ -112,6 +112,7 @@ struct _WinsockFd
   gint fd;
   glong event_mask;
   WSANETWORKEVENTS events;
+  glong ignored_event_mask;
 };
 #endif
 
@@ -137,6 +138,8 @@ struct _GstPoll
   GstPollFD control_read_fd;
   GstPollFD control_write_fd;
 #else
+  GArray *active_fds_ignored;
+
   GArray *events;
   GArray *active_events;
 
@@ -304,6 +307,32 @@ fd_set_to_pollfd (GstPoll * set, fd_set * readfds, fd_set * writefds)
   g_mutex_unlock (set->lock);
 }
 #else /* G_OS_WIN32 */
+/*
+ * Translate errors thrown by the Winsock API used by GstPoll:
+ *   WSAEventSelect, WSAWaitForMultipleEvents and WSAEnumNetworkEvents
+ */
+static gint
+gst_poll_winsock_error_to_errno (DWORD last_error)
+{
+  switch (last_error) {
+    case WSA_INVALID_HANDLE:
+    case WSAEINVAL:
+    case WSAENOTSOCK:
+      return EBADF;
+
+    case WSA_NOT_ENOUGH_MEMORY:
+      return ENOMEM;
+
+      /*
+       * Anything else, including:
+       *   WSA_INVALID_PARAMETER, WSAEFAULT, WSAEINPROGRESS, WSAENETDOWN,
+       *   WSANOTINITIALISED
+       */
+    default:
+      return EINVAL;
+  }
+}
+
 static void
 gst_poll_free_winsock_event (GstPoll * set, gint idx)
 {
@@ -314,30 +343,104 @@ gst_poll_free_winsock_event (GstPoll * set, gint idx)
   CloseHandle (event);
 }
 
-static gboolean
+static void
 gst_poll_update_winsock_event_mask (GstPoll * set, gint idx, glong flags,
     gboolean active)
 {
   WinsockFd *wfd;
-  HANDLE event;
-  glong new_mask;
-  gint ret;
 
   wfd = &g_array_index (set->fds, WinsockFd, idx);
-  event = g_array_index (set->events, HANDLE, idx);
 
   if (active)
-    new_mask = wfd->event_mask | flags;
+    wfd->event_mask |= flags;
   else
-    new_mask = wfd->event_mask & ~flags;
+    wfd->event_mask &= ~flags;
 
-  ret = WSAEventSelect (wfd->fd, event, new_mask);
+  /* reset ignored state if the new mask doesn't overlap at all */
-  if (G_LIKELY (ret == 0))
+  if ((wfd->ignored_event_mask & wfd->event_mask) == 0)
-    wfd->event_mask = new_mask;
+    wfd->ignored_event_mask = 0;
-  else
+}
-    GST_ERROR ("WSAEventSelect failed: 0x%08x", GetLastError ());
 
-  return ret == 0;
+static gboolean
+gst_poll_prepare_winsock_active_sets (GstPoll * set)
+{
+  guint i;
+
+  g_array_set_size (set->active_fds, 0);
+  g_array_set_size (set->active_fds_ignored, 0);
+  g_array_set_size (set->active_events, 0);
+  g_array_append_val (set->active_events, set->wakeup_event);
+
+  for (i = 0; i < set->fds->len; i++) {
+    WinsockFd *wfd = &g_array_index (set->fds, WinsockFd, i);
+    HANDLE event = g_array_index (set->events, HANDLE, i);
+
+    if (wfd->ignored_event_mask == 0) {
+      gint ret;
+
+      g_array_append_val (set->active_fds, *wfd);
+      g_array_append_val (set->active_events, event);
+
+      ret = WSAEventSelect (wfd->fd, event, wfd->event_mask);
+      if (G_UNLIKELY (ret != 0)) {
+        errno = gst_poll_winsock_error_to_errno (WSAGetLastError ());
+        return FALSE;
+      }
+    } else {
+      g_array_append_val (set->active_fds_ignored, wfd);
+    }
+  }
+
+  return TRUE;
+}
+
+static gint
+gst_poll_collect_winsock_events (GstPoll * set)
+{
+  gint res, i;
+
+  /*
+   * We need to check which events are signaled, and call
+   * WSAEnumNetworkEvents for those that are, which resets
+   * the event and clears the internal network event records.
+   */
+  res = 0;
+  for (i = 0; i < set->active_fds->len; i++) {
+    WinsockFd *wfd = &g_array_index (set->active_fds, WinsockFd, i);
+    HANDLE event = g_array_index (set->active_events, HANDLE, i + 1);
+    DWORD wait_ret;
+
+    wait_ret = WaitForSingleObject (event, 0);
+    if (wait_ret == WAIT_OBJECT_0) {
+      gint enum_ret = WSAEnumNetworkEvents (wfd->fd, event, &wfd->events);
+
+      if (G_UNLIKELY (enum_ret != 0)) {
+        res = -1;
+        errno = gst_poll_winsock_error_to_errno (WSAGetLastError ());
+        break;
+      }
+
+      res++;
+    } else {
+      /* clear any previously stored result */
+      memset (&wfd->events, 0, sizeof (wfd->events));
+    }
+  }
+
+  /* If all went well we also need to reset the ignored fds. */
+  if (res >= 0) {
+    res += set->active_fds_ignored->len;
+
+    for (i = 0; i < set->active_fds_ignored->len; i++) {
+      WinsockFd *wfd = g_array_index (set->active_fds_ignored, WinsockFd *, i);
+
+      wfd->ignored_event_mask = 0;
+    }
+
+    g_array_set_size (set->active_fds_ignored, 0);
+  }
+
+  return res;
 }
 #endif
 
@@ -371,6 +474,7 @@ gst_poll_new (gboolean controllable)
   nset->mode = GST_POLL_MODE_WINDOWS;
   nset->fds = g_array_new (FALSE, FALSE, sizeof (WinsockFd));
   nset->active_fds = g_array_new (FALSE, FALSE, sizeof (WinsockFd));
+  nset->active_fds_ignored = g_array_new (FALSE, FALSE, sizeof (WinsockFd *));
   nset->events = g_array_new (FALSE, FALSE, sizeof (HANDLE));
   nset->active_events = g_array_new (FALSE, FALSE, sizeof (HANDLE));
 
@@ -420,6 +524,7 @@ gst_poll_free (GstPoll * set)
 
   g_array_free (set->active_events, TRUE);
   g_array_free (set->events, TRUE);
+  g_array_free (set->active_fds_ignored, TRUE);
 #endif
 
   g_array_free (set->active_fds, TRUE);
@@ -468,16 +573,15 @@ gst_poll_add_fd_unlocked (GstPoll * set, GstPollFD * fd)
     HANDLE event;
 
     wfd.fd = fd->fd;
-    wfd.event_mask = 0;
+    wfd.event_mask = FD_CLOSE;
     memset (&wfd.events, 0, sizeof (wfd.events));
+    wfd.ignored_event_mask = 0;
     event = WSACreateEvent ();
 
     g_array_append_val (set->fds, wfd);
     g_array_append_val (set->events, event);
 
     fd->idx = set->fds->len - 1;
-
-    gst_poll_update_winsock_event_mask (set, fd->idx, FD_CLOSE, TRUE);
 #endif
   }
 
@@ -590,8 +694,7 @@ gst_poll_fd_ctl_write (GstPoll * set, GstPollFD * fd, gboolean active)
     else
       pfd->events &= ~POLLOUT;
 #else
-    if (!gst_poll_update_winsock_event_mask (set, idx, FD_WRITE, active))
+    gst_poll_update_winsock_event_mask (set, idx, FD_WRITE, active);
-      idx = -1;
 #endif
   }
 
@@ -616,8 +719,7 @@ gst_poll_fd_ctl_read_unlocked (GstPoll * set, GstPollFD * fd, gboolean active)
     else
       pfd->events &= ~(POLLIN | POLLPRI);
 #else
-    if (!gst_poll_update_winsock_event_mask (set, idx, FD_READ, active))
+    gst_poll_update_winsock_event_mask (set, idx, FD_READ | FD_ACCEPT, active);
-      idx = -1;
 #endif
   }
 
@@ -655,6 +757,45 @@ gst_poll_fd_ctl_read (GstPoll * set, GstPollFD * fd, gboolean active)
   return ret;
 }
 
+/**
+ * gst_poll_fd_ignored:
+ * @set: a file descriptor set.
+ * @fd: a file descriptor.
+ *
+ * Mark @fd as ignored so that the next call to gst_poll_wait() will yield
+ * the same result for @fd as last time. This function must be called if no
+ * operation (read/write/recv/send/etc.) will be performed on @fd before
+ * the next call to gst_poll_wait().
+ *
+ * The reason why this is needed is because the underlying implementation
+ * might not allow querying the fd more than once between calls to one of
+ * the re-enabling operations.
+ *
+ * Since: 0.10.18
+ */
+void
+gst_poll_fd_ignored (GstPoll * set, GstPollFD * fd)
+{
+#ifdef G_OS_WIN32
+  gint idx;
+
+  g_return_if_fail (set != NULL);
+  g_return_if_fail (fd != NULL);
+  g_return_if_fail (fd->fd >= 0);
+
+  g_mutex_lock (set->lock);
+
+  idx = find_index (set->fds, fd);
+  if (idx >= 0) {
+    WinsockFd *wfd = &g_array_index (set->fds, WinsockFd, idx);
+
+    wfd->ignored_event_mask = wfd->event_mask & (FD_READ | FD_WRITE);
+  }
+
+  g_mutex_unlock (set->lock);
+#endif
+}
+
 /**
  * gst_poll_fd_has_closed:
  * @set: a file descriptor set.
@@ -730,7 +871,8 @@ gst_poll_fd_has_error (const GstPoll * set, GstPollFD * fd)
 
     res = (wfd->events.iErrorCode[FD_CLOSE_BIT] != 0) ||
         (wfd->events.iErrorCode[FD_READ_BIT] != 0) ||
-        (wfd->events.iErrorCode[FD_WRITE_BIT] != 0);
+        (wfd->events.iErrorCode[FD_WRITE_BIT] != 0) ||
+        (wfd->events.iErrorCode[FD_ACCEPT_BIT] != 0);
 #endif
   }
 
@@ -754,7 +896,7 @@ gst_poll_fd_can_read_unlocked (const GstPoll * set, GstPollFD * fd)
 #else
     WinsockFd *wfd = &g_array_index (set->active_fds, WinsockFd, idx);
 
-    res = (wfd->events.lNetworkEvents & FD_READ) != 0;
+    res = (wfd->events.lNetworkEvents & (FD_READ | FD_ACCEPT)) != 0;
 #endif
   }
 
@@ -831,6 +973,42 @@ gst_poll_fd_can_write (const GstPoll * set, GstPollFD * fd)
   return res;
 }
 
+static void
+gst_poll_check_ctrl_commands (GstPoll * set, gint res, gboolean * restarting)
+{
+  /* check if the poll/select was aborted due to a command */
+  if (set->controllable) {
+#ifndef G_OS_WIN32
+    while (TRUE) {
+      guchar cmd;
+      gint result;
+
+      /* we do not check the read status of the control socket here because
+       * there may have been a write to the socket between the time the
+       * poll/select finished and before we got the mutex back, and we need
+       * to clear out the control socket before leaving */
+      READ_COMMAND (set, cmd, result);
+      if (result <= 0) {
+        /* no more commands, quit the loop */
+        break;
+      }
+
+      /* if the control socket is the only socket with activity when we get
+       * here, we restart the _wait operation, else we allow the caller to
+       * process the other file descriptors */
+      if (res == 1 &&
+          gst_poll_fd_can_read_unlocked (set, &set->control_read_fd))
+        *restarting = TRUE;
+    }
+#else
+    if (WaitForSingleObject (set->wakeup_event, 0) == WAIT_OBJECT_0) {
+      ResetEvent (set->wakeup_event);
+      *restarting = TRUE;
+    }
+#endif
+  }
+}
+
 /**
  * gst_poll_wait:
  * @set: a #GstPoll.
@@ -876,19 +1054,15 @@ gst_poll_wait (GstPoll * set, GstClockTime timeout)
 
     mode = choose_mode (set, timeout);
 
-    g_array_set_size (set->active_fds, set->fds->len);
 #ifndef G_OS_WIN32
+    g_array_set_size (set->active_fds, set->fds->len);
     memcpy (set->active_fds->data, set->fds->data,
         set->fds->len * sizeof (struct pollfd));
 #else
-    memcpy (set->active_fds->data, set->fds->data,
+    if (!gst_poll_prepare_winsock_active_sets (set))
-        set->fds->len * sizeof (WinsockFd));
+      goto winsock_error;
-
-    g_array_set_size (set->active_events, set->events->len + 1);
-    *((HANDLE *) set->active_events->data) = set->wakeup_event;
-    memcpy (set->active_events->data + sizeof (HANDLE), set->events->data,
-        set->events->len * sizeof (HANDLE));
 #endif
+
     g_mutex_unlock (set->lock);
 
     switch (mode) {
@@ -994,52 +1168,31 @@ gst_poll_wait (GstPoll * set, GstClockTime timeout)
       case GST_POLL_MODE_WINDOWS:
       {
 #ifdef G_OS_WIN32
+        gint ignore_count = set->active_fds_ignored->len;
         DWORD t, wait_ret;
 
+        if (G_LIKELY (ignore_count == 0)) {
           if (timeout != GST_CLOCK_TIME_NONE)
             t = GST_TIME_AS_MSECONDS (timeout);
           else
             t = INFINITE;
+        } else {
+          /* already one or more ignored fds, so we quickly sweep the others */
+          t = 0;
+        }
 
         wait_ret = WSAWaitForMultipleEvents (set->active_events->len,
             (HANDLE *) set->active_events->data, FALSE, t, FALSE);
 
-        if (wait_ret == WSA_WAIT_TIMEOUT)
+        if (ignore_count == 0 && wait_ret == WSA_WAIT_TIMEOUT) {
           res = 0;
-        else if (wait_ret == WSA_WAIT_FAILED)
+        } else if (wait_ret == WSA_WAIT_FAILED) {
           res = -1;
-        else {
+          errno = gst_poll_winsock_error_to_errno (WSAGetLastError ());
+        } else {
           /* the first entry is the wakeup event */
           if (wait_ret - WSA_WAIT_EVENT_0 >= 1) {
-            gint i, enum_ret;
+            res = gst_poll_collect_winsock_events (set);
-
-            /*
-             * We need to check which events are signaled, and call
-             * WSAEnumNetworkEvents for those that are, which resets
-             * the event and clears the internal network event records.
-             */
-            res = 0;
-            for (i = 0; i < set->active_fds->len; i++) {
-              WinsockFd *wfd = &g_array_index (set->active_fds, WinsockFd, i);
-              HANDLE event = g_array_index (set->active_events, HANDLE, i + 1);
-
-              wait_ret = WaitForSingleObject (event, 0);
-              if (wait_ret == WAIT_OBJECT_0) {
-                enum_ret = WSAEnumNetworkEvents (wfd->fd, event, &wfd->events);
-
-                if (G_UNLIKELY (enum_ret != 0)) {
-                  res = -1;
-                  break;
-                }
-
-                res++;
-              } else {
-                /* clear any previously stored result */
-                memset (&wfd->events, 0, sizeof (wfd->events));
-              }
-            }
-
-            g_assert (res > 0);
           } else {
             res = 1;            /* wakeup event */
           }
@@ -1054,38 +1207,7 @@ gst_poll_wait (GstPoll * set, GstClockTime timeout)
 
     g_mutex_lock (set->lock);
 
-    /* check if the poll/select was aborted due to a command, FIXME, If we have an
+    gst_poll_check_ctrl_commands (set, res, &restarting);
-     * ERROR, we might not clear the control socket. */
-    if (res > 0 && set->controllable) {
-#ifndef G_OS_WIN32
-      while (TRUE) {
-        guchar cmd;
-        gint result;
-
-        /* we do not check the read status of the control socket here because
-         * there may have been a write to the socket between the time the
-         * poll/select finished and before we got the mutex back, and we need
-         * to clear out the control socket before leaving */
-        READ_COMMAND (set, cmd, result);
-        if (result <= 0) {
-          /* no more commands, quit the loop */
-          break;
-        }
-
-        /* if the control socket is the only socket with activity when we get
-         * here, we restart the _wait operation, else we allow the caller to
-         * process the other file descriptors */
-        if (res == 1 &&
-            gst_poll_fd_can_read_unlocked (set, &set->control_read_fd))
-          restarting = TRUE;
-      }
-#else
-      if (WaitForSingleObject (set->wakeup_event, 0) == WAIT_OBJECT_0) {
-        ResetEvent (set->wakeup_event);
-        restarting = TRUE;
-      }
-#endif
-    }
 
     /* update the controllable state if needed */
     set->controllable = set->new_controllable;
@@ -1117,6 +1239,13 @@ flushing:
     errno = EBUSY;
     return -1;
   }
+#ifdef G_OS_WIN32
+winsock_error:
+  {
+    g_mutex_unlock (set->lock);
+    return -1;
+  }
+#endif
 }
 
 /**

gst/gstpoll.h

@@ -73,6 +73,7 @@ gboolean        gst_poll_remove_fd        (GstPoll *set, GstPollFD *fd);
 
 gboolean        gst_poll_fd_ctl_write     (GstPoll *set, GstPollFD *fd, gboolean active);
 gboolean        gst_poll_fd_ctl_read      (GstPoll *set, GstPollFD *fd, gboolean active);
+void            gst_poll_fd_ignored       (GstPoll *set, GstPollFD *fd);
 
 gboolean        gst_poll_fd_has_closed    (const GstPoll *set, GstPollFD *fd);
 gboolean        gst_poll_fd_has_error     (const GstPoll *set, GstPollFD *fd);

win32/common/libgstreamer.def

@@ -655,6 +655,7 @@ EXPORTS
 	gst_poll_fd_ctl_write
 	gst_poll_fd_has_closed
 	gst_poll_fd_has_error
+	gst_poll_fd_ignored
 	gst_poll_fd_init
 	gst_poll_free
 	gst_poll_new