init

db_include/executor/tablefunc.h

@@ -0,0 +1,67 @@
+/*-------------------------------------------------------------------------
+ *
+ * tablefunc.h
+ *				interface for TableFunc executor node
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/executor/tablefunc.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _TABLEFUNC_H
+#define _TABLEFUNC_H
+
+/* Forward-declare this to avoid including execnodes.h here */
+struct TableFuncScanState;
+
+/*
+ * TableFuncRoutine holds function pointers used for generating content of
+ * table-producer functions, such as XMLTABLE.
+ *
+ * InitOpaque initializes table builder private objects.  The output tuple
+ * descriptor, input functions for the columns, and typioparams are passed
+ * from executor state.
+ *
+ * SetDocument is called to define the input document.  The table builder may
+ * apply additional transformations not exposed outside the table builder
+ * context.
+ *
+ * SetNamespace is called to pass namespace declarations from the table
+ * expression.  This function may be NULL if namespaces are not supported by
+ * the table builder.  Namespaces must be given before setting the row and
+ * column filters.  If the name is given as NULL, the entry shall be for the
+ * default namespace.
+ *
+ * SetRowFilter is called do define the row-generating filter, which shall be
+ * used to extract each row from the input document.
+ *
+ * SetColumnFilter is called once for each column, to define the column-
+ * generating filter for the given column.
+ *
+ * FetchRow shall be called repeatedly until it returns that no more rows are
+ * found in the document.  On each invocation it shall set state in the table
+ * builder context such that each subsequent GetValue call returns the values
+ * for the indicated column for the row being processed.
+ *
+ * DestroyOpaque shall release all resources associated with a table builder
+ * context.  It may be called either because all rows have been consumed, or
+ * because an error occurred while processing the table expression.
+ */
+typedef struct TableFuncRoutine
+{
+	void		(*InitOpaque) (struct TableFuncScanState *state, int natts);
+	void		(*SetDocument) (struct TableFuncScanState *state, Datum value);
+	void		(*SetNamespace) (struct TableFuncScanState *state, const char *name,
+								 const char *uri);
+	void		(*SetRowFilter) (struct TableFuncScanState *state, const char *path);
+	void		(*SetColumnFilter) (struct TableFuncScanState *state,
+									const char *path, int colnum);
+	bool		(*FetchRow) (struct TableFuncScanState *state);
+	Datum		(*GetValue) (struct TableFuncScanState *state, int colnum,
+							 Oid typid, int32 typmod, bool *isnull);
+	void		(*DestroyOpaque) (struct TableFuncScanState *state);
+} TableFuncRoutine;
+
+#endif							/* _TABLEFUNC_H */