1 files changed, 132 insertions, 0 deletions
diff --git a/src/backend/access/common/printsimple.c b/src/backend/access/common/printsimple.c
new file mode 100644
index 0000000..e99aa27
--- /dev/null
+++ b/src/backend/access/common/printsimple.c
@@ -0,0 +1,132 @@
+/*-------------------------------------------------------------------------
+ *
+ * printsimple.c
+ *	  Routines to print out tuples containing only a limited range of
+ *	  builtin types without catalog access.  This is intended for
+ *	  backends that don't have catalog access because they are not bound
+ *	  to a specific database, such as some walsender processes.  It
+ *	  doesn't handle standalone backends or protocol versions other than
+ *	  3.0, because we don't need such handling for current applications.
+ *
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/access/common/printsimple.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/printsimple.h"
+#include "catalog/pg_type.h"
+#include "libpq/pqformat.h"
+#include "utils/builtins.h"
+
+/*
+ * At startup time, send a RowDescription message.
+ */
+void
+printsimple_startup(DestReceiver *self, int operation, TupleDesc tupdesc)
+{
+	StringInfoData buf;
+	int			i;
+
+	pq_beginmessage(&buf, 'T'); /* RowDescription */
+	pq_sendint16(&buf, tupdesc->natts);
+
+	for (i = 0; i < tupdesc->natts; ++i)
+	{
+		Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+		pq_sendstring(&buf, NameStr(attr->attname));
+		pq_sendint32(&buf, 0);	/* table oid */
+		pq_sendint16(&buf, 0);	/* attnum */
+		pq_sendint32(&buf, (int) attr->atttypid);
+		pq_sendint16(&buf, attr->attlen);
+		pq_sendint32(&buf, attr->atttypmod);
+		pq_sendint16(&buf, 0);	/* format code */
+	}
+
+	pq_endmessage(&buf);
+}
+
+/*
+ * For each tuple, send a DataRow message.
+ */
+bool
+printsimple(TupleTableSlot *slot, DestReceiver *self)
+{
+	TupleDesc	tupdesc = slot->tts_tupleDescriptor;
+	StringInfoData buf;
+	int			i;
+
+	/* Make sure the tuple is fully deconstructed */
+	slot_getallattrs(slot);
+
+	/* Prepare and send message */
+	pq_beginmessage(&buf, 'D');
+	pq_sendint16(&buf, tupdesc->natts);
+
+	for (i = 0; i < tupdesc->natts; ++i)
+	{
+		Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+		Datum		value;
+
+		if (slot->tts_isnull[i])
+		{
+			pq_sendint32(&buf, -1);
+			continue;
+		}
+
+		value = slot->tts_values[i];
+
+		/*
+		 * We can't call the regular type output functions here because we
+		 * might not have catalog access.  Instead, we must hard-wire
+		 * knowledge of the required types.
+		 */
+		switch (attr->atttypid)
+		{
+			case TEXTOID:
+				{
+					text	   *t = DatumGetTextPP(value);
+
+					pq_sendcountedtext(&buf,
+									   VARDATA_ANY(t),
+									   VARSIZE_ANY_EXHDR(t),
+									   false);
+				}
+				break;
+
+			case INT4OID:
+				{
+					int32		num = DatumGetInt32(value);
+					char		str[12];	/* sign, 10 digits and '\0' */
+					int			len;
+
+					len = pg_ltoa(num, str);
+					pq_sendcountedtext(&buf, str, len, false);
+				}
+				break;
+
+			case INT8OID:
+				{
+					int64		num = DatumGetInt64(value);
+					char		str[MAXINT8LEN + 1];
+					int			len;
+
+					len = pg_lltoa(num, str);
+					pq_sendcountedtext(&buf, str, len, false);
+				}
+				break;
+
+			default:
+				elog(ERROR, "unsupported type OID: %u", attr->atttypid);
+		}
+	}
+
+	pq_endmessage(&buf);
+
+	return true;
+}