0001-datetime-in-JsonbValue-2.patch

commit 0845588d81414ba96f2e6ed6003164794800366b
Author: Alexander Korotkov <akorotkov@postgresql.org>
Date:   Thu May 16 21:48:26 2019 +0300

    Allow datetime values in JsonbValue
    
    SQL/JSON standard allows manipulation with datetime values.  So, it appears to
    be convinient to allow datetime values to be represented in JsonbValue struct.
    These datetime values are allowed for temporary representation only.  During
    serialization datetime values are converted into strings.
    
    SQL/JSON requires writing timestamps with timezone in the same timezone offset
    as they were parsed.  This is why we allow storage of timezone offset in
    JsonbValue struct.  For the same reason timezone offset argument is added to
    JsonEncodeDateTime() function.

diff --git a/src/backend/utils/adt/json.c b/src/backend/utils/adt/json.c
index 26d293709aa..7440f77cbe5 100644
--- a/src/backend/utils/adt/json.c
+++ b/src/backend/utils/adt/json.c
@@ -1506,7 +1506,7 @@ datum_to_json(Datum val, bool is_null, StringInfo result,
 			{
 				char		buf[MAXDATELEN + 1];
 
-				JsonEncodeDateTime(buf, val, DATEOID);
+				JsonEncodeDateTime(buf, val, DATEOID, NULL);
 				appendStringInfo(result, "\"%s\"", buf);
 			}
 			break;
@@ -1514,7 +1514,7 @@ datum_to_json(Datum val, bool is_null, StringInfo result,
 			{
 				char		buf[MAXDATELEN + 1];
 
-				JsonEncodeDateTime(buf, val, TIMESTAMPOID);
+				JsonEncodeDateTime(buf, val, TIMESTAMPOID, NULL);
 				appendStringInfo(result, "\"%s\"", buf);
 			}
 			break;
@@ -1522,7 +1522,7 @@ datum_to_json(Datum val, bool is_null, StringInfo result,
 			{
 				char		buf[MAXDATELEN + 1];
 
-				JsonEncodeDateTime(buf, val, TIMESTAMPTZOID);
+				JsonEncodeDateTime(buf, val, TIMESTAMPTZOID, NULL);
 				appendStringInfo(result, "\"%s\"", buf);
 			}
 			break;
@@ -1550,10 +1550,11 @@ datum_to_json(Datum val, bool is_null, StringInfo result,
 
 /*
  * Encode 'value' of datetime type 'typid' into JSON string in ISO format using
- * optionally preallocated buffer 'buf'.
+ * optionally preallocated buffer 'buf'.  Optional 'tzp' determines time-zone
+ * offset (in seconds) in which we want to show timestamptz.
  */
 char *
-JsonEncodeDateTime(char *buf, Datum value, Oid typid)
+JsonEncodeDateTime(char *buf, Datum value, Oid typid, const int *tzp)
 {
 	if (!buf)
 		buf = palloc(MAXDATELEN + 1);
@@ -1630,11 +1631,30 @@ JsonEncodeDateTime(char *buf, Datum value, Oid typid)
 				const char *tzn = NULL;
 
 				timestamp = DatumGetTimestampTz(value);
+
+				/*
+				 * If time-zone is specified, we apply a time-zone shift,
+				 * convert timestamptz to pg_tm as if it was without
+				 * time-zone, and then use specified time-zone for encoding
+				 * timestamp into a string.
+				 */
+				if (tzp)
+				{
+					tz = *tzp;
+					timestamp -= (TimestampTz) tz * USECS_PER_SEC;
+				}
+
 				/* Same as timestamptz_out(), but forcing DateStyle */
 				if (TIMESTAMP_NOT_FINITE(timestamp))
 					EncodeSpecialTimestamp(timestamp, buf);
-				else if (timestamp2tm(timestamp, &tz, &tm, &fsec, &tzn, NULL) == 0)
+				else if (timestamp2tm(timestamp, tzp ? NULL : &tz, &tm, &fsec,
+									  tzp ? NULL : &tzn, NULL) == 0)
+				{
+					if (tzp)
+						tm.tm_isdst = 1;	/* set time-zone presence flag */
+
 					EncodeDateTime(&tm, fsec, true, tz, tzn, USE_XSD_DATES, buf);
+				}
 				else
 					ereport(ERROR,
 							(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
diff --git a/src/backend/utils/adt/jsonb.c b/src/backend/utils/adt/jsonb.c
index 69f41ab4556..74b4bbe44c6 100644
--- a/src/backend/utils/adt/jsonb.c
+++ b/src/backend/utils/adt/jsonb.c
@@ -206,6 +206,24 @@ JsonbTypeName(JsonbValue *jbv)
 			return "boolean";
 		case jbvNull:
 			return "null";
+		case jbvDatetime:
+			switch (jbv->val.datetime.typid)
+			{
+				case DATEOID:
+					return "date";
+				case TIMEOID:
+					return "time without time zone";
+				case TIMETZOID:
+					return "time with time zone";
+				case TIMESTAMPOID:
+					return "timestamp without time zone";
+				case TIMESTAMPTZOID:
+					return "timestamp with time zone";
+				default:
+					elog(ERROR, "unrecognized jsonb value datetime type: %d",
+						 jbv->val.datetime.typid);
+			}
+			return "unknown";
 		default:
 			elog(ERROR, "unrecognized jsonb value type: %d", jbv->type);
 			return "unknown";
@@ -805,17 +823,20 @@ datum_to_jsonb(Datum val, bool is_null, JsonbInState *result,
 				break;
 			case JSONBTYPE_DATE:
 				jb.type = jbvString;
-				jb.val.string.val = JsonEncodeDateTime(NULL, val, DATEOID);
+				jb.val.string.val = JsonEncodeDateTime(NULL, val,
+													   DATEOID, NULL);
 				jb.val.string.len = strlen(jb.val.string.val);
 				break;
 			case JSONBTYPE_TIMESTAMP:
 				jb.type = jbvString;
-				jb.val.string.val = JsonEncodeDateTime(NULL, val, TIMESTAMPOID);
+				jb.val.string.val = JsonEncodeDateTime(NULL, val,
+													   TIMESTAMPOID, NULL);
 				jb.val.string.len = strlen(jb.val.string.val);
 				break;
 			case JSONBTYPE_TIMESTAMPTZ:
 				jb.type = jbvString;
-				jb.val.string.val = JsonEncodeDateTime(NULL, val, TIMESTAMPTZOID);
+				jb.val.string.val = JsonEncodeDateTime(NULL, val,
+													   TIMESTAMPTZOID, NULL);
 				jb.val.string.len = strlen(jb.val.string.val);
 				break;
 			case JSONBTYPE_JSONCAST:
diff --git a/src/backend/utils/adt/jsonb_util.c b/src/backend/utils/adt/jsonb_util.c
index 7969f6f5843..cb2bd872cf5 100644
--- a/src/backend/utils/adt/jsonb_util.c
+++ b/src/backend/utils/adt/jsonb_util.c
@@ -14,9 +14,12 @@
 #include "postgres.h"
 
 #include "catalog/pg_collation.h"
+#include "catalog/pg_type.h"
 #include "miscadmin.h"
 #include "utils/builtins.h"
+#include "utils/datetime.h"
 #include "utils/hashutils.h"
+#include "utils/jsonapi.h"
 #include "utils/jsonb.h"
 #include "utils/memutils.h"
 #include "utils/varlena.h"
@@ -241,6 +244,7 @@ compareJsonbContainers(JsonbContainer *a, JsonbContainer *b)
 							res = (va.val.object.nPairs > vb.val.object.nPairs) ? 1 : -1;
 						break;
 					case jbvBinary:
+					case jbvDatetime:
 						elog(ERROR, "unexpected jbvBinary value");
 				}
 			}
@@ -1749,6 +1753,22 @@ convertJsonbScalar(StringInfo buffer, JEntry *jentry, JsonbValue *scalarVal)
 				JENTRY_ISBOOL_TRUE : JENTRY_ISBOOL_FALSE;
 			break;
 
+		case jbvDatetime:
+			{
+				char		buf[MAXDATELEN + 1];
+				size_t		len;
+
+				JsonEncodeDateTime(buf,
+								   scalarVal->val.datetime.value,
+								   scalarVal->val.datetime.typid,
+								   &scalarVal->val.datetime.tz);
+				len = strlen(buf);
+				appendToBuffer(buffer, buf, len);
+
+				*jentry = JENTRY_ISSTRING | len;
+			}
+			break;
+
 		default:
 			elog(ERROR, "invalid jsonb scalar type");
 	}
diff --git a/src/include/utils/jsonapi.h b/src/include/utils/jsonapi.h
index 5f4d479a7b2..b707b09ce31 100644
--- a/src/include/utils/jsonapi.h
+++ b/src/include/utils/jsonapi.h
@@ -161,6 +161,7 @@ extern Jsonb *transform_jsonb_string_values(Jsonb *jsonb, void *action_state,
 extern text *transform_json_string_values(text *json, void *action_state,
 										  JsonTransformStringValuesAction transform_action);
 
-extern char *JsonEncodeDateTime(char *buf, Datum value, Oid typid);
+extern char *JsonEncodeDateTime(char *buf, Datum value, Oid typid,
+								const int *tzp);
 
 #endif							/* JSONAPI_H */
diff --git a/src/include/utils/jsonb.h b/src/include/utils/jsonb.h
index 2fe7d32fec2..ec66d150263 100644
--- a/src/include/utils/jsonb.h
+++ b/src/include/utils/jsonb.h
@@ -241,7 +241,15 @@ enum jbvType
 	jbvArray = 0x10,
 	jbvObject,
 	/* Binary (i.e. struct Jsonb) jbvArray/jbvObject */
-	jbvBinary
+	jbvBinary,
+
+	/*
+	 * Virtual types.
+	 *
+	 * These types are used only for in-memory JSON processing and serialized
+	 * into JSON strings when outputted to json/jsonb.
+	 */
+	jbvDatetime = 0x20,
 };
 
 /*
@@ -282,11 +290,21 @@ struct JsonbValue
 			int			len;
 			JsonbContainer *data;
 		}			binary;		/* Array or object, in on-disk format */
+
+		struct
+		{
+			Datum		value;
+			Oid			typid;
+			int32		typmod;
+			int			tz;		/* Numeric time zone, in seconds for
+								 * TimestampTz data type */
+		}			datetime;
 	}			val;
 };
 
-#define IsAJsonbScalar(jsonbval)	((jsonbval)->type >= jbvNull && \
-									 (jsonbval)->type <= jbvBool)
+#define IsAJsonbScalar(jsonbval)	(((jsonbval)->type >= jbvNull && \
+									  (jsonbval)->type <= jbvBool) || \
+									  (jsonbval)->type == jbvDatetime)
 
 /*
  * Key/value pair within an Object.