Error suppression support for upcoming jsonpath .datetime() method

Add support of error suppression in some date and time manipulation functions
as it's required for jsonpath .datetime() method support.  This commit doesn't
use PG_TRY()/PG_CATCH() in order to implement that.  Instead, it provides
internal versions of date and time functions used, which support error
suppression.

Discussion: https://postgr.es/m/CAPpHfdsZgYEra_PeCLGNoXOWYx6iU-S3wF8aX0ObQUcZU%2B4XTw%40mail.gmail.com
Author: Alexander Korotkov, Nikita Glukhov
Reviewed-by: Anastasia Lubennikova, Peter Eisentraut

src/backend/utils/adt/date.c

@@ -550,13 +550,15 @@ date_mii(PG_FUNCTION_ARGS)
 	PG_RETURN_DATEADT(result);
 }
 
-/*
- * Internal routines for promoting date to timestamp and timestamp with
- * time zone
- */
 
-static Timestamp
-date2timestamp(DateADT dateVal)
+/*
+ * Promote date to timestamp.
+ *
+ * If 'have_error' is NULL, then errors are thrown, else '*have_error' is set
+ * and zero is returned.
+ */
+Timestamp
+date2timestamp_opt_error(DateADT dateVal, bool *have_error)
 {
 	Timestamp	result;
 
@@ -572,9 +574,19 @@ date2timestamp(DateADT dateVal)
 		 * boundary need be checked for overflow.
 		 */
 		if (dateVal >= (TIMESTAMP_END_JULIAN - POSTGRES_EPOCH_JDATE))
-			ereport(ERROR,
-					(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
-					 errmsg("date out of range for timestamp")));
+		{
+			if (have_error)
+			{
+				*have_error = true;
+				return (Timestamp) 0;
+			}
+			else
+			{
+				ereport(ERROR,
+						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+						 errmsg("date out of range for timestamp")));
+			}
+		}
 
 		/* date is days since 2000, timestamp is microseconds since same... */
 		result = dateVal * USECS_PER_DAY;
@@ -583,8 +595,23 @@ date2timestamp(DateADT dateVal)
 	return result;
 }
 
+/*
+ * Single-argument version of date2timestamp_opt_error().
+ */
 static TimestampTz
-date2timestamptz(DateADT dateVal)
+date2timestamp(DateADT dateVal)
+{
+	return date2timestamp_opt_error(dateVal, NULL);
+}
+
+/*
+ * Promote date to timestamp with time zone.
+ *
+ * If 'have_error' is NULL, then errors are thrown, else '*have_error' is set
+ * and zero is returned.
+ */
+TimestampTz
+date2timestamptz_opt_error(DateADT dateVal, bool *have_error)
 {
 	TimestampTz result;
 	struct pg_tm tt,
@@ -603,9 +630,19 @@ date2timestamptz(DateADT dateVal)
 		 * boundary need be checked for overflow.
 		 */
 		if (dateVal >= (TIMESTAMP_END_JULIAN - POSTGRES_EPOCH_JDATE))
-			ereport(ERROR,
-					(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
-					 errmsg("date out of range for timestamp")));
+		{
+			if (have_error)
+			{
+				*have_error = true;
+				return (TimestampTz) 0;
+			}
+			else
+			{
+				ereport(ERROR,
+						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+						 errmsg("date out of range for timestamp")));
+			}
+		}
 
 		j2date(dateVal + POSTGRES_EPOCH_JDATE,
 			   &(tm->tm_year), &(tm->tm_mon), &(tm->tm_mday));
@@ -621,14 +658,33 @@ date2timestamptz(DateADT dateVal)
 		 * of time zone, check for allowed timestamp range after adding tz.
 		 */
 		if (!IS_VALID_TIMESTAMP(result))
-			ereport(ERROR,
-					(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
-					 errmsg("date out of range for timestamp")));
+		{
+			if (have_error)
+			{
+				*have_error = true;
+				return (TimestampTz) 0;
+			}
+			else
+			{
+				ereport(ERROR,
+						(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+						 errmsg("date out of range for timestamp")));
+			}
+		}
 	}
 
 	return result;
 }
 
+/*
+ * Single-argument version of date2timestamptz_opt_error().
+ */
+static TimestampTz
+date2timestamptz(DateADT dateVal)
+{
+	return date2timestamptz_opt_error(dateVal, NULL);
+}
+
 /*
  * date2timestamp_no_overflow
  *

src/backend/utils/adt/timestamp.c

@@ -329,11 +329,11 @@ timestamp_scale(PG_FUNCTION_ARGS)
 }
 
 /*
- * AdjustTimestampForTypmod --- round off a timestamp to suit given typmod
+ * AdjustTimestampForTypmodError --- round off a timestamp to suit given typmod
  * Works for either timestamp or timestamptz.
  */
-void
-AdjustTimestampForTypmod(Timestamp *time, int32 typmod)
+bool
+AdjustTimestampForTypmodError(Timestamp *time, int32 typmod, bool *error)
 {
 	static const int64 TimestampScales[MAX_TIMESTAMP_PRECISION + 1] = {
 		INT64CONST(1000000),
@@ -359,10 +359,18 @@ AdjustTimestampForTypmod(Timestamp *time, int32 typmod)
 		&& (typmod != -1) && (typmod != MAX_TIMESTAMP_PRECISION))
 	{
 		if (typmod < 0 || typmod > MAX_TIMESTAMP_PRECISION)
+		{
+			if (error)
+			{
+				*error = true;
+				return false;
+			}
+
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 					 errmsg("timestamp(%d) precision must be between %d and %d",
 							typmod, 0, MAX_TIMESTAMP_PRECISION)));
+		}
 
 		if (*time >= INT64CONST(0))
 		{
@@ -375,8 +383,15 @@ AdjustTimestampForTypmod(Timestamp *time, int32 typmod)
 					  * TimestampScales[typmod]);
 		}
 	}
+
+	return true;
 }
 
+void
+AdjustTimestampForTypmod(Timestamp *time, int32 typmod)
+{
+	(void) AdjustTimestampForTypmodError(time, typmod, NULL);
+}
 
 /* timestamptz_in()
  * Convert a string to internal form.
@@ -5172,8 +5187,15 @@ timestamp_timestamptz(PG_FUNCTION_ARGS)
 	PG_RETURN_TIMESTAMPTZ(timestamp2timestamptz(timestamp));
 }
 
-static TimestampTz
-timestamp2timestamptz(Timestamp timestamp)
+/*
+ * Convert timestamp to timestamp with time zone.
+ *
+ * If 'have_error' is NULL, then errors are thrown, else '*have_error' is set
+ * and zero is returned.
+ */
+
+TimestampTz
+timestamp2timestamptz_opt_error(Timestamp timestamp, bool *have_error)
 {
 	TimestampTz result;
 	struct pg_tm tt,
@@ -5182,23 +5204,33 @@ timestamp2timestamptz(Timestamp timestamp)
 	int			tz;
 
 	if (TIMESTAMP_NOT_FINITE(timestamp))
-		result = timestamp;
-	else
-	{
-		if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL, NULL) != 0)
-			ereport(ERROR,
-					(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
-					 errmsg("timestamp out of range")));
+		return timestamp;
 
+	if (!timestamp2tm(timestamp, NULL, tm, &fsec, NULL, NULL))
+	{
 		tz = DetermineTimeZoneOffset(tm, session_timezone);
 
-		if (tm2timestamp(tm, fsec, &tz, &result) != 0)
-			ereport(ERROR,
-					(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
-					 errmsg("timestamp out of range")));
+		if (!tm2timestamp(tm, fsec, &tz, &result))
+			return result;
 	}
 
-	return result;
+	if (have_error)
+		*have_error = true;
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+				 errmsg("timestamp out of range")));
+
+	return 0;
+}
+
+/*
+ * Single-argument version of timestamp2timestamptz_opt_error().
+ */
+static TimestampTz
+timestamp2timestamptz(Timestamp timestamp)
+{
+	return timestamp2timestamptz_opt_error(timestamp, NULL);
 }
 
 /* timestamptz_timestamp()

src/include/utils/date.h

@@ -70,6 +70,8 @@ typedef struct
 /* date.c */
 extern int32 anytime_typmod_check(bool istz, int32 typmod);
 extern double date2timestamp_no_overflow(DateADT dateVal);
+extern Timestamp date2timestamp_opt_error(DateADT dateVal, bool *have_error);
+extern TimestampTz date2timestamptz_opt_error(DateADT dateVal, bool *have_error);
 extern void EncodeSpecialDate(DateADT dt, char *str);
 extern DateADT GetSQLCurrentDate(void);
 extern TimeTzADT *GetSQLCurrentTime(int32 typmod);

src/include/utils/datetime.h

@@ -337,5 +337,7 @@ extern TimeZoneAbbrevTable *ConvertTimeZoneAbbrevs(struct tzEntry *abbrevs,
 extern void InstallTimeZoneAbbrevs(TimeZoneAbbrevTable *tbl);
 
 extern void AdjustTimestampForTypmod(Timestamp *time, int32 typmod);
+extern bool AdjustTimestampForTypmodError(Timestamp *time, int32 typmod,
+										  bool *error);
 
 #endif							/* DATETIME_H */

src/include/utils/formatting.h

@@ -27,6 +27,7 @@ extern char *asc_toupper(const char *buff, size_t nbytes);
 extern char *asc_initcap(const char *buff, size_t nbytes);
 
 extern Datum parse_datetime(text *date_txt, text *fmt, bool std,
-							Oid *typid, int32 *typmod, int *tz);
+							Oid *typid, int32 *typmod, int *tz,
+							bool *have_error);
 
 #endif

src/include/utils/timestamp.h

@@ -97,6 +97,9 @@ extern int	timestamp_cmp_internal(Timestamp dt1, Timestamp dt2);
 /* timestamp comparison works for timestamptz also */
 #define timestamptz_cmp_internal(dt1,dt2)	timestamp_cmp_internal(dt1, dt2)
 
+extern TimestampTz timestamp2timestamptz_opt_error(Timestamp timestamp,
+												   bool *have_error);
+
 extern int	isoweek2j(int year, int week);
 extern void isoweek2date(int woy, int *year, int *mon, int *mday);
 extern void isoweekdate2date(int isoweek, int wday, int *year, int *mon, int *mday);