Implemented UTC_TIME, UTC_DATE and UTC_TIMESTAMP functions (WL#345)

configure.in:
  ./configure now tests if gmtime_r is present
include/config-os2.h:
  Supposing that OS/2 have gmtime_r
include/my_pthread.h:
  Use our imeplementation of gmtime_r if system lacks one
mysql-test/r/func_time.result:
  Added UTC_* functions to test
mysql-test/t/func_time.test:
  Added UTC_* functions to test
mysys/my_pthread.c:
  Our implementation of gmtime_r
mysys/my_thr_init.c:
  Now we also need LOCK_locktime_r if gmtime_r is absent
sql/item_timefunc.cc:
  Generalized classes for CURDATE, CURTIME and NOW, abstracted them from
  timezone. Added new children classes for implementing these and UTC_*
  functions.
sql/item_timefunc.h:
  Generalized classes for CURDATE, CURTIME and NOW, abstracted them from
  timezone. Added new children classes for implementing these and UTC_*
  functions.
sql/lex.h:
  Added tokens for UTC_TIME, UTC_DATE and UTC_TIMESTAMP
sql/sql_yacc.yy:
  Added UTC_* functions to grammar. Current functions are using 
  classes now.

1 files changed, 20 insertions, 1 deletions

diff --git a/mysys/my_pthread.c b/mysys/my_pthread.c
index 4f472f61593..32528707480 100644
--- a/mysys/my_pthread.c
+++ b/mysys/my_pthread.c
@@ -133,10 +133,13 @@ int my_sigwait(const sigset_t *set,int *sig)
 
 /* localtime_r for SCO 3.2V4.2 */
 
-#ifndef HAVE_LOCALTIME_R
+#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
 
 extern pthread_mutex_t LOCK_localtime_r;
 
+#endif
+
+#if !defined(HAVE_LOCALTIME_R)
 struct tm *localtime_r(const time_t *clock, struct tm *res)
 {
   struct tm *tmp;
@@ -148,6 +151,22 @@ struct tm *localtime_r(const time_t *clock, struct tm *res)
 }
 #endif
 
+#if !defined(HAVE_GMTIME_R)
+/* 
+  Reentrant version of standard gmtime() function. 
+  Needed on some systems which don't implement it.
+*/
+
+struct tm *gmtime_r(const time_t *clock, struct tm *res)
+{
+  struct tm *tmp;
+  pthread_mutex_lock(&LOCK_localtime_r);
+  tmp= gmtime(clock);
+  *res= *tmp;
+  pthread_mutex_unlock(&LOCK_localtime_r);
+  return res;
+}
+#endif
 
 /****************************************************************************
 ** Replacement of sigwait if the system doesn't have one (like BSDI 3.0)