Bug#13699303 - THREAD POOL PLUGIN IGNORES TIMEOUT.

PROBLEM: 
mysql provides a feature where in a session which is 
idle for a period specified by the wait_timeout variable
(whose value is in seconds), the session is closed
This feature is not present when we use thread pool.
FIX:
This patch implements the interface functions which is 
required to implement the wait_timeout functionality
in the thread pool plugin.

include/mysql/thread_pool_priv.h

@@ -35,6 +35,7 @@
 #include <debug_sync.h>
 #include <sql_profile.h>
 #include <table.h>
+#include <sql_list.h>
 
 /* Needed to get access to scheduler variables */
 void* thd_get_scheduler_data(THD *thd);
@@ -56,9 +57,30 @@ void thd_unlock_data(THD *thd);
 bool thd_is_transaction_active(THD *thd);
 int thd_connection_has_data(THD *thd);
 void thd_set_net_read_write(THD *thd, uint val);
+uint thd_get_net_read_write(THD *thd);
 void thd_set_mysys_var(THD *thd, st_my_thread_var *mysys_var);
+ulong  thd_get_net_wait_timeout(THD *thd);
 my_socket thd_get_fd(THD *thd);
 
+/* Interface class for  global thread  list iteration */
+class Thread_iterator
+{
+  public:
+    Thread_iterator() : m_iterator(threads) {}
+    THD* next()
+    {
+      THD* tmp = m_iterator++;
+      return tmp;
+    }
+  private:
+    /*
+      Don't allow copying  of this class.
+    */
+    Thread_iterator(const Thread_iterator&);
+    void operator=(const Thread_iterator&);
+    I_List_iterator<THD> m_iterator;
+};
+
 /* Print to the MySQL error log */
 void sql_print_error(const char *format, ...);
 

sql/sql_class.cc

@@ -254,6 +254,18 @@ PSI_thread *thd_get_psi(THD *thd)
   return thd->scheduler.m_psi;
 }
 
+/**
+  Get net_wait_timeout for THD object
+
+  @param thd            THD object
+
+  @retval               net_wait_timeout value for thread on THD
+*/
+ulong thd_get_net_wait_timeout(THD* thd)
+{
+  return thd->variables.net_wait_timeout;
+}
+
 /**
   Set reference to Performance Schema object for THD object
 
@@ -422,6 +434,17 @@ void thd_set_net_read_write(THD *thd, uint val)
   thd->net.reading_or_writing= val;
 }
 
+/**
+  Get reading/writing on socket from THD object
+  @param thd                       THD object
+
+  @retval               net.reading_or_writing value for thread on THD.
+*/
+uint thd_get_net_read_write(THD *thd)
+{
+  return thd->net.reading_or_writing;
+}
+
 /**
   Set reference to mysys variable in THD object