revert a suggested "optimization" that introduced a bug

compilation error in mysys/my_getsystime.c fixed
some redundant code removed
sec_to_time, time_to_sec, from_unixtime, unix_timestamp, @@timestamp now
  use decimal, not double for numbers with a fractional part.
purge_master_logs_before_date() fixed
many bugs in corner cases fixed

mysys/my_getsystime.c:
  compilation failure fixed
sql/sql_parse.cc:
  don't cut corners. it backfires.

1 files changed, 45 insertions, 38 deletions

diff --git a/sql/tztime.cc b/sql/tztime.cc
index 7ebb8eb392a..9921f9db0d4 100644
--- a/sql/tztime.cc
+++ b/sql/tztime.cc
@@ -815,9 +815,11 @@ sec_since_epoch(int year, int mon, int mday, int hour, int min ,int sec)
     TIME_to_gmt_sec()
       t               - pointer to structure for broken down represenatation
       sp              - pointer to struct with time zone description
-      in_dst_time_gap - pointer to bool which is set to true if datetime
-                        value passed doesn't really exist (i.e. falls into
-                        spring time-gap) and is not touched otherwise.
+      error_code      - 0, if the conversion was successful;
+                        ER_WARN_DATA_OUT_OF_RANGE, if t contains datetime value
+                           which is out of TIMESTAMP range;
+                        ER_WARN_INVALID_TIMESTAMP, if t represents value which
+                           doesn't exists (falls into the spring time-gap).
 
   DESCRIPTION
     This is mktime analog for MySQL. It is essentially different
@@ -880,8 +882,7 @@ sec_since_epoch(int year, int mon, int mday, int hour, int min ,int sec)
     0 in case of error.
 */
 static my_time_t
-TIME_to_gmt_sec(const MYSQL_TIME *t, const TIME_ZONE_INFO *sp,
-                my_bool *in_dst_time_gap)
+TIME_to_gmt_sec(const MYSQL_TIME *t, const TIME_ZONE_INFO *sp, uint *error_code)
 {
   my_time_t local_t;
   uint saved_seconds;
@@ -891,8 +892,12 @@ TIME_to_gmt_sec(const MYSQL_TIME *t, const TIME_ZONE_INFO *sp,
   DBUG_ENTER("TIME_to_gmt_sec");
 
   if (!validate_timestamp_range(t))
+  {
+    *error_code= ER_WARN_DATA_OUT_OF_RANGE;
     DBUG_RETURN(0);
+  }
 
+  *error_code= 0;
 
   /* We need this for correct leap seconds handling */
   if (t->second < SECS_PER_MIN)
@@ -936,6 +941,7 @@ TIME_to_gmt_sec(const MYSQL_TIME *t, const TIME_ZONE_INFO *sp,
       This means that source time can't be represented as my_time_t due to
       limited my_time_t range.
     */
+    *error_code= ER_WARN_DATA_OUT_OF_RANGE;
     DBUG_RETURN(0);
   }
 
@@ -952,6 +958,7 @@ TIME_to_gmt_sec(const MYSQL_TIME *t, const TIME_ZONE_INFO *sp,
     if (local_t > (my_time_t) (TIMESTAMP_MAX_VALUE - shift * SECS_PER_DAY +
                                sp->revtis[i].rt_offset - saved_seconds))
     {
+      *error_code= ER_WARN_DATA_OUT_OF_RANGE;
       DBUG_RETURN(0);                           /* my_time_t overflow */
     }
     local_t+= shift * SECS_PER_DAY;
@@ -965,7 +972,7 @@ TIME_to_gmt_sec(const MYSQL_TIME *t, const TIME_ZONE_INFO *sp,
       Now we are returning my_time_t value corresponding to the
       beginning of the gap.
     */
-    *in_dst_time_gap= 1;
+    *error_code= ER_WARN_INVALID_TIMESTAMP;
     local_t= sp->revts[i] - sp->revtis[i].rt_offset + saved_seconds;
   }
   else
@@ -1007,8 +1014,7 @@ class Time_zone_system : public Time_zone
 {
 public:
   Time_zone_system() {}                       /* Remove gcc warning */
-  virtual my_time_t TIME_to_gmt_sec(const MYSQL_TIME *t,
-                                    my_bool *in_dst_time_gap) const;
+  virtual my_time_t TIME_to_gmt_sec(const MYSQL_TIME *t, uint *error_code) const;
   virtual void gmt_sec_to_TIME(MYSQL_TIME *tmp, my_time_t t) const;
   virtual const String * get_name() const;
 };
@@ -1022,9 +1028,11 @@ public:
     TIME_to_gmt_sec()
       t               - pointer to MYSQL_TIME structure with local time in
                         broken-down representation.
-      in_dst_time_gap - pointer to bool which is set to true if datetime
-                        value passed doesn't really exist (i.e. falls into
-                        spring time-gap) and is not touched otherwise.
+      error_code      - 0, if the conversion was successful;
+                        ER_WARN_DATA_OUT_OF_RANGE, if t contains datetime value
+                           which is out of TIMESTAMP range;
+                        ER_WARN_INVALID_TIMESTAMP, if t represents value which
+                           doesn't exists (falls into the spring time-gap).
 
   DESCRIPTION
     This method uses system function (localtime_r()) for conversion
@@ -1040,10 +1048,10 @@ public:
     Corresponding my_time_t value or 0 in case of error
 */
 my_time_t
-Time_zone_system::TIME_to_gmt_sec(const MYSQL_TIME *t, my_bool *in_dst_time_gap) const
+Time_zone_system::TIME_to_gmt_sec(const MYSQL_TIME *t, uint *error_code) const
 {
   long not_used;
-  return my_system_gmt_sec(t, &not_used, in_dst_time_gap);
+  return my_system_gmt_sec(t, &not_used, error_code);
 }
 
 
@@ -1103,7 +1111,7 @@ class Time_zone_utc : public Time_zone
 public:
   Time_zone_utc() {}                          /* Remove gcc warning */
   virtual my_time_t TIME_to_gmt_sec(const MYSQL_TIME *t,
-                                    my_bool *in_dst_time_gap) const;
+                                    uint *error_code) const;
   virtual void gmt_sec_to_TIME(MYSQL_TIME *tmp, my_time_t t) const;
   virtual const String * get_name() const;
 };
@@ -1112,14 +1120,6 @@ public:
 /*
   Convert UTC time from MYSQL_TIME representation to its my_time_t representation.
 
-  SYNOPSIS
-    TIME_to_gmt_sec()
-      t               - pointer to MYSQL_TIME structure with local time
-                        in broken-down representation.
-      in_dst_time_gap - pointer to bool which is set to true if datetime
-                        value passed doesn't really exist (i.e. falls into
-                        spring time-gap) and is not touched otherwise.
-
   DESCRIPTION
     Since Time_zone_utc is used only internally for my_time_t -> TIME
     conversions, this function of Time_zone interface is not implemented for
@@ -1129,10 +1129,11 @@ public:
     0
 */
 my_time_t
-Time_zone_utc::TIME_to_gmt_sec(const MYSQL_TIME *t, my_bool *in_dst_time_gap) const
+Time_zone_utc::TIME_to_gmt_sec(const MYSQL_TIME *t, uint *error_code) const
 {
   /* Should be never called */
   DBUG_ASSERT(0);
+  *error_code= ER_WARN_DATA_OUT_OF_RANGE;
   return 0;
 }
 
@@ -1192,8 +1193,7 @@ class Time_zone_db : public Time_zone
 {
 public:
   Time_zone_db(TIME_ZONE_INFO *tz_info_arg, const String * tz_name_arg);
-  virtual my_time_t TIME_to_gmt_sec(const MYSQL_TIME *t,
-                                    my_bool *in_dst_time_gap) const;
+  virtual my_time_t TIME_to_gmt_sec(const MYSQL_TIME *t, uint *error_code) const;
   virtual void gmt_sec_to_TIME(MYSQL_TIME *tmp, my_time_t t) const;
   virtual const String * get_name() const;
 private:
@@ -1230,9 +1230,11 @@ Time_zone_db::Time_zone_db(TIME_ZONE_INFO *tz_info_arg,
     TIME_to_gmt_sec()
       t               - pointer to MYSQL_TIME structure with local time
                         in broken-down representation.
-      in_dst_time_gap - pointer to bool which is set to true if datetime
-                        value passed doesn't really exist (i.e. falls into
-                        spring time-gap) and is not touched otherwise.
+      error_code      - 0, if the conversion was successful;
+                        ER_WARN_DATA_OUT_OF_RANGE, if t contains datetime value
+                           which is out of TIMESTAMP range;
+                        ER_WARN_INVALID_TIMESTAMP, if t represents value which
+                           doesn't exists (falls into the spring time-gap).
 
   DESCRIPTION
     Please see ::TIME_to_gmt_sec for function description and
@@ -1242,9 +1244,9 @@ Time_zone_db::Time_zone_db(TIME_ZONE_INFO *tz_info_arg,
     Corresponding my_time_t value or 0 in case of error
 */
 my_time_t
-Time_zone_db::TIME_to_gmt_sec(const MYSQL_TIME *t, my_bool *in_dst_time_gap) const
+Time_zone_db::TIME_to_gmt_sec(const MYSQL_TIME *t, uint *error_code) const
 {
-  return ::TIME_to_gmt_sec(t, tz_info, in_dst_time_gap);
+  return ::TIME_to_gmt_sec(t, tz_info, error_code);
 }
 
 
@@ -1290,7 +1292,7 @@ class Time_zone_offset : public Time_zone
 public:
   Time_zone_offset(long tz_offset_arg);
   virtual my_time_t TIME_to_gmt_sec(const MYSQL_TIME *t,
-                                    my_bool *in_dst_time_gap) const;
+                                    uint *error_code) const;
   virtual void   gmt_sec_to_TIME(MYSQL_TIME *tmp, my_time_t t) const;
   virtual const String * get_name() const;
   /*
@@ -1332,17 +1334,17 @@ Time_zone_offset::Time_zone_offset(long tz_offset_arg):
     TIME_to_gmt_sec()
       t               - pointer to MYSQL_TIME structure with local time
                         in broken-down representation.
-      in_dst_time_gap - pointer to bool which should be set to true if
-                        datetime  value passed doesn't really exist
-                        (i.e. falls into spring time-gap) and is not
-                        touched otherwise.
-                        It is not really used in this class.
+      error_code      - 0, if the conversion was successful;
+                        ER_WARN_DATA_OUT_OF_RANGE, if t contains datetime value
+                           which is out of TIMESTAMP range;
+                        ER_WARN_INVALID_TIMESTAMP, if t represents value which
+                           doesn't exists (falls into the spring time-gap).
 
   RETURN VALUE
     Corresponding my_time_t value or 0 in case of error
 */
 my_time_t
-Time_zone_offset::TIME_to_gmt_sec(const MYSQL_TIME *t, my_bool *in_dst_time_gap) const
+Time_zone_offset::TIME_to_gmt_sec(const MYSQL_TIME *t, uint *error_code) const
 {
   my_time_t local_t;
   int shift= 0;
@@ -1352,7 +1354,11 @@ Time_zone_offset::TIME_to_gmt_sec(const MYSQL_TIME *t, my_bool *in_dst_time_gap)
     us to make all validation checks here.
   */
   if (!validate_timestamp_range(t))
+  {
+    *error_code= ER_WARN_DATA_OUT_OF_RANGE;
     return 0;
+  }
+  *error_code= 0;
 
   /*
     Do a temporary shift of the boundary dates to avoid
@@ -1376,6 +1382,7 @@ Time_zone_offset::TIME_to_gmt_sec(const MYSQL_TIME *t, my_bool *in_dst_time_gap)
     return local_t;
 
   /* range error*/
+  *error_code= ER_WARN_DATA_OUT_OF_RANGE;
   return 0;
 }
 
@@ -2733,7 +2740,7 @@ main(int argc, char **argv)
             for (time_tmp.second=0; time_tmp.second<60; time_tmp.second+=25)
             {
               long not_used;
-              my_bool not_used_2;
+              uint not_used_2;
               t= (time_t)my_system_gmt_sec(&time_tmp, &not_used, &not_used_2);
               t1= (time_t)TIME_to_gmt_sec(&time_tmp, &tz_info, &not_used_2);
               if (t != t1)