MDEV-3802. Millisecond timeout support in non-blocking client library.

In 10.0, VIO timeouts can be in milliseconds, so we add a new function
mysql_get_timeout_value_ms() which can return millisecond-precision
timeout values.

In 5.5, we do not have millisecond precision for timeouts. But we still
provide the mysql_get_timeout_value_ms() function; this makes it easier
for applications as they can use the millisecond function in 10.0 and
still work with the 5.5 version of the client library.

include/mysql.h

@@ -848,6 +848,7 @@ int STDCALL mysql_close_start(MYSQL *sock);
 int STDCALL mysql_close_cont(MYSQL *sock, int status);
 my_socket STDCALL mysql_get_socket(const MYSQL *mysql);
 unsigned int STDCALL mysql_get_timeout_value(const MYSQL *mysql);
+unsigned int STDCALL mysql_get_timeout_value_ms(const MYSQL *mysql);
 
 /* status return codes */
 #define MYSQL_NO_DATA        100

include/mysql.h.pp

@@ -729,3 +729,4 @@ int mysql_close_start(MYSQL *sock);
 int mysql_close_cont(MYSQL *sock, int status);
 my_socket mysql_get_socket(const MYSQL *mysql);
 unsigned int mysql_get_timeout_value(const MYSQL *mysql);
+unsigned int mysql_get_timeout_value_ms(const MYSQL *mysql);

sql-common/mysql_async.c

@@ -246,6 +246,28 @@ mysql_get_timeout_value(const MYSQL *mysql)
 }
 
 
+/*
+  In 10.0, VIO timeouts are in milliseconds, so we support getting the
+  millisecond timeout value from async applications.
+
+  In 5.5, timeouts are always in seconds, but we support the 10.0 version
+  that provides milliseconds, so applications can work with either version
+  of the library easily.
+
+  When merging this to 10.0, this function must be removed and the 10.0
+  version used.
+*/
+unsigned int STDCALL
+mysql_get_timeout_value_ms(const MYSQL *mysql)
+{
+  unsigned int timeout= mysql->options.extension->async_context->timeout_value;
+  if (timeout <= UINT_MAX / 1000)
+    return timeout*1000;
+  else
+    return UINT_MAX;
+}
+
+
 /*
   Now create non-blocking definitions for all the calls that may block.