MDEV-3802: Millisecond timeout support in non-blocking client library + fix incorrect blocking.

After the merge of VIO stuff from MySQL 5.6, there were some bugs left
in the non-blocking client library:

 - vio_io_wait() was introduced without any support for non-blocking operation,
   so async queries could turn into sync.

 - Timeouts were changed to milliseconds, but this was not reflected in the
   non-blocking API, also semantics was changed so signed -1 was used for
   "no timeout" rather than unsigned 0.

Fix by implementing and using my_io_wait_async() in the non-blocking case. And
by introducing a new mysql_get_timeout_value_ms() API function that provides
the timeout with millisecond granularity. The old mysql_get_timeout_value()
is kept and fixed to work correctly, converting the timeout to whole seconds.

1 files changed, 30 insertions, 0 deletions

diff --git a/vio/viosocket.c b/vio/viosocket.c
index f7ab95d3e6c..b13fc2d3a83 100644
--- a/vio/viosocket.c
+++ b/vio/viosocket.c
@@ -897,6 +897,21 @@ int vio_io_wait(Vio *vio, enum enum_vio_io_event event, int timeout)
   MYSQL_SOCKET_WAIT_VARIABLES(locker, state) /* no ';' */
   DBUG_ENTER("vio_io_wait");
 
+  /*
+    Note that if zero timeout, then we will not block, so we do not need to
+    yield to calling application in the async case.
+  */
+  if (timeout != 0 && vio->async_context && vio->async_context->active)
+  {
+    MYSQL_START_SOCKET_WAIT(locker, &state, vio->mysql_socket,
+                            PSI_SOCKET_SELECT, 0);
+    ret= my_io_wait_async(vio->async_context, event, timeout);
+    if (ret == 0)
+      errno= SOCKET_ETIMEDOUT;
+    MYSQL_END_SOCKET_WAIT(locker, 0);
+    DBUG_RETURN(ret);
+  }
+
   memset(&pfd, 0, sizeof(pfd));
 
   pfd.fd= sd;
@@ -957,6 +972,21 @@ int vio_io_wait(Vio *vio, enum enum_vio_io_event event, int timeout)
   MYSQL_SOCKET_WAIT_VARIABLES(locker, state) /* no ';' */
   DBUG_ENTER("vio_io_wait");
 
+  /*
+    Note that if zero timeout, then we will not block, so we do not need to
+    yield to calling application in the async case.
+  */
+  if (timeout != 0 && vio->async_context && vio->async_context->active)
+  {
+    MYSQL_START_SOCKET_WAIT(locker, &state, vio->mysql_socket,
+                            PSI_SOCKET_SELECT, 0);
+    ret= my_io_wait_async(vio->async_context, event, timeout);
+    if (ret == 0)
+      WSASetLastError(SOCKET_ETIMEDOUT);
+    MYSQL_END_SOCKET_WAIT(locker, 0);
+    DBUG_RETURN(ret);
+  }
+
   /* Convert the timeout, in milliseconds, to seconds and microseconds. */
   if (timeout >= 0)
   {