greenplumn extensible 源码

greenplumn extensible 代码

文件路径：/src/include/nodes/extensible.h

/*-------------------------------------------------------------------------
 *
 * extensible.h
 *	  Definitions for extensible nodes and custom scans
 *
 *
 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/nodes/extensible.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef EXTENSIBLE_H
#define EXTENSIBLE_H

#include "access/parallel.h"
#include "commands/explain.h"
#include "nodes/execnodes.h"
#include "nodes/pathnodes.h"
#include "nodes/plannodes.h"

/* maximum length of an extensible node identifier */
#define EXTNODENAME_MAX_LEN					64

/*
 * An extensible node is a new type of node defined by an extension.  The
 * type is always T_ExtensibleNode, while the extnodename identifies the
 * specific type of node.  extnodename can be looked up to find the
 * ExtensibleNodeMethods for this node type.
 */
typedef struct ExtensibleNode
{
	NodeTag		type;
	const char *extnodename;	/* identifier of ExtensibleNodeMethods */
} ExtensibleNode;

/*
 * node_size is the size of an extensible node of this type in bytes.
 *
 * nodeCopy is a function which performs a deep copy from oldnode to newnode.
 * It does not need to copy type or extnodename, which are copied by the
 * core system.
 *
 * nodeEqual is a function which performs a deep equality comparison between
 * a and b and returns true or false accordingly.  It does not need to compare
 * type or extnodename, which are compared by the core system.
 *
 * nodeOut is a serialization function for the node type.  It should use the
 * output conventions typical for outfuncs.c.  It does not need to output
 * type or extnodename; the core system handles those.
 *
 * nodeRead is a deserialization function for the node type.  It does not need
 * to read type or extnodename; the core system handles those.  It should fetch
 * the next token using pg_strtok() from the current input stream, and then
 * reconstruct the private fields according to the manner in readfuncs.c.
 *
 * All callbacks are mandatory.
 */
typedef struct ExtensibleNodeMethods
{
	const char *extnodename;
	Size		node_size;
	void		(*nodeCopy) (struct ExtensibleNode *newnode,
							 const struct ExtensibleNode *oldnode);
	bool		(*nodeEqual) (const struct ExtensibleNode *a,
							  const struct ExtensibleNode *b);
	void		(*nodeOut) (struct StringInfoData *str,
							const struct ExtensibleNode *node);
	void		(*nodeRead) (struct ExtensibleNode *node);
} ExtensibleNodeMethods;

extern void RegisterExtensibleNodeMethods(const ExtensibleNodeMethods *method);
extern const ExtensibleNodeMethods *GetExtensibleNodeMethods(const char *name,
															 bool missing_ok);

/*
 * Flags for custom paths, indicating what capabilities the resulting scan
 * will have.
 */
#define CUSTOMPATH_SUPPORT_BACKWARD_SCAN	0x0001
#define CUSTOMPATH_SUPPORT_MARK_RESTORE		0x0002

/*
 * Custom path methods.  Mostly, we just need to know how to convert a
 * CustomPath to a plan.
 */
typedef struct CustomPathMethods
{
	const char *CustomName;

	/* Convert Path to a Plan */
	struct Plan *(*PlanCustomPath) (PlannerInfo *root,
									RelOptInfo *rel,
									struct CustomPath *best_path,
									List *tlist,
									List *clauses,
									List *custom_plans);
	struct List *(*ReparameterizeCustomPathByChild) (PlannerInfo *root,
													 List *custom_private,
													 RelOptInfo *child_rel);
}			CustomPathMethods;

/*
 * Custom scan.  Here again, there's not much to do: we need to be able to
 * generate a ScanState corresponding to the scan.
 */
typedef struct CustomScanMethods
{
	const char *CustomName;

	/* Create execution state (CustomScanState) from a CustomScan plan node */
	Node	   *(*CreateCustomScanState) (CustomScan *cscan);
} CustomScanMethods;

/*
 * Execution-time methods for a CustomScanState.  This is more complex than
 * what we need for a custom path or scan.
 */
typedef struct CustomExecMethods
{
	const char *CustomName;

	/* Required executor methods */
	void		(*BeginCustomScan) (CustomScanState *node,
									EState *estate,
									int eflags);
	TupleTableSlot *(*ExecCustomScan) (CustomScanState *node);
	void		(*EndCustomScan) (CustomScanState *node);
	void		(*ReScanCustomScan) (CustomScanState *node);

	/* Optional methods: needed if mark/restore is supported */
	void		(*MarkPosCustomScan) (CustomScanState *node);
	void		(*RestrPosCustomScan) (CustomScanState *node);

	/* Optional methods: needed if parallel execution is supported */
	Size		(*EstimateDSMCustomScan) (CustomScanState *node,
										  ParallelContext *pcxt);
	void		(*InitializeDSMCustomScan) (CustomScanState *node,
											ParallelContext *pcxt,
											void *coordinate);
	void		(*ReInitializeDSMCustomScan) (CustomScanState *node,
											  ParallelContext *pcxt,
											  void *coordinate);
	void		(*InitializeWorkerCustomScan) (CustomScanState *node,
											   shm_toc *toc,
											   void *coordinate);
	void		(*ShutdownCustomScan) (CustomScanState *node);

	/* Optional: print additional information in EXPLAIN */
	void		(*ExplainCustomScan) (CustomScanState *node,
									  List *ancestors,
									  ExplainState *es);
} CustomExecMethods;

extern void RegisterCustomScanMethods(const CustomScanMethods *methods);
extern const CustomScanMethods *GetCustomScanMethods(const char *CustomName,
													 bool missing_ok);

#endif							/* EXTENSIBLE_H */

相关信息

greenplumn 源码目录

相关文章

greenplumn altertablenodes 源码

greenplumn bitmapset 源码

greenplumn execnodes 源码

greenplumn lockoptions 源码

greenplumn makefuncs 源码

greenplumn memnodes 源码

greenplumn nodeFuncs 源码

greenplumn nodes 源码

greenplumn params 源码

greenplumn parsenodes 源码