greenplumn tablefunc 源码
greenplumn tablefunc 代码
文件路径：/src/include/executor/tablefunc.h
/*-------------------------------------------------------------------------
*
* tablefunc.h
* interface for TableFunc executor node
*
* Portions Copyright (c) 1996-2019, 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.
*
* InitBuilder initialize table builder private objects. The output tuple
* descriptor, input functions for the columns, and typioparams are passed
* from executor state.
*
* SetDoc 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.
*
* DestroyBuilder 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 */
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