copyfuncs.c

PostgreSQL7.4.6 for Linux

/*-------------------------------------------------------------------------
 *
 * copyfuncs.c
 *	  Copy functions for Postgres tree nodes.
 *
 * NOTE: we currently support copying all node types found in parse and
 * plan trees.	We do not support copying executor state trees; there
 * is no need for that, and no point in maintaining all the code that
 * would be needed.  We also do not support copying Path trees, mainly
 * because the circular linkages between RelOptInfo and Path nodes can't
 * be handled easily in a simple depth-first traversal.
 *
 *
 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.265 2003/08/17 23:43:25 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include "nodes/parsenodes.h"
#include "nodes/plannodes.h"
#include "nodes/relation.h"
#include "utils/datum.h"


/*
 * Macros to simplify copying of different kinds of fields.  Use these
 * wherever possible to reduce the chance for silly typos.	Note that these
 * hard-wire the convention that the local variables in a Copy routine are
 * named 'newnode' and 'from'.
 */

/* Copy a simple scalar field (int, float, bool, enum, etc) */
#define COPY_SCALAR_FIELD(fldname) \
	(newnode->fldname = from->fldname)

/* Copy a field that is a pointer to some kind of Node or Node tree */
#define COPY_NODE_FIELD(fldname) \
	(newnode->fldname = copyObject(from->fldname))

/* Copy a field that is a pointer to a list of integers */
#define COPY_INTLIST_FIELD(fldname) \
	(newnode->fldname = listCopy(from->fldname))

/* Copy a field that is a pointer to a list of Oids */
#define COPY_OIDLIST_FIELD(fldname) \
	(newnode->fldname = listCopy(from->fldname))

/* Copy a field that is a pointer to a Bitmapset */
#define COPY_BITMAPSET_FIELD(fldname) \
	(newnode->fldname = bms_copy(from->fldname))

/* Copy a field that is a pointer to a C string, or perhaps NULL */
#define COPY_STRING_FIELD(fldname) \
	(newnode->fldname = from->fldname ? pstrdup(from->fldname) : (char *) NULL)

/* Copy a field that is a pointer to a simple palloc'd object of size sz */
#define COPY_POINTER_FIELD(fldname, sz) \
	do { \
		Size	_size = (sz); \
		newnode->fldname = palloc(_size); \
		memcpy(newnode->fldname, from->fldname, _size); \
	} while (0)


/*
 * listCopy
 *	  This copy function only copies the "cons-cells" of the list, not the
 *	  pointed-to objects.  (Use copyObject if you want a "deep" copy.)
 *
 *	  We also use this function for copying lists of integers and Oids,
 *	  which is notationally a bit ugly, but perfectly safe.
 *
 *	  Note that copyObject will surely coredump if applied to a list
 *	  of integers or Oids!
 */
List *
listCopy(List *list)
{
	List	   *newlist,
			   *oldl,
			   *newcell,
			   *prev;

	/* rather ugly coding for speed... */
	if (list == NIL)
		return NIL;

	newcell = makeNode(List);
	newcell->elem = list->elem;

	newlist = prev = newcell;

	foreach(oldl, lnext(list))
	{
		newcell = makeNode(List);
		newcell->elem = oldl->elem;
		prev->next = newcell;
		prev = newcell;
	}
	prev->next = NIL;

	return newlist;
}

/* ****************************************************************
 *					 plannodes.h copy functions
 * ****************************************************************
 */

/*
 * CopyPlanFields
 *
 *		This function copies the fields of the Plan node.  It is used by
 *		all the copy functions for classes which inherit from Plan.
 */
static void
CopyPlanFields(Plan *from, Plan *newnode)
{
	COPY_SCALAR_FIELD(startup_cost);
	COPY_SCALAR_FIELD(total_cost);
	COPY_SCALAR_FIELD(plan_rows);
	COPY_SCALAR_FIELD(plan_width);
	COPY_NODE_FIELD(targetlist);
	COPY_NODE_FIELD(qual);
	COPY_NODE_FIELD(lefttree);
	COPY_NODE_FIELD(righttree);
	COPY_NODE_FIELD(initPlan);
	COPY_BITMAPSET_FIELD(extParam);
	COPY_BITMAPSET_FIELD(allParam);
	COPY_SCALAR_FIELD(nParamExec);
}

/*
 * _copyPlan
 */
static Plan *
_copyPlan(Plan *from)
{
	Plan	   *newnode = makeNode(Plan);

	/*
	 * copy node superclass fields
	 */
	CopyPlanFields(from, newnode);

	return newnode;
}


/*
 * _copyResult
 */
static Result *
_copyResult(Result *from)
{
	Result	   *newnode = makeNode(Result);

	/*
	 * copy node superclass fields
	 */
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_NODE_FIELD(resconstantqual);

	return newnode;
}

/*
 * _copyAppend
 */
static Append *
_copyAppend(Append *from)
{
	Append	   *newnode = makeNode(Append);

	/*
	 * copy node superclass fields
	 */
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_NODE_FIELD(appendplans);
	COPY_SCALAR_FIELD(isTarget);

	return newnode;
}


/*
 * CopyScanFields
 *
 *		This function copies the fields of the Scan node.  It is used by
 *		all the copy functions for classes which inherit from Scan.
 */
static void
CopyScanFields(Scan *from, Scan *newnode)
{
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	COPY_SCALAR_FIELD(scanrelid);
}

/*
 * _copyScan
 */
static Scan *
_copyScan(Scan *from)
{
	Scan	   *newnode = makeNode(Scan);

	/*
	 * copy node superclass fields
	 */
	CopyScanFields((Scan *) from, (Scan *) newnode);

	return newnode;
}

/*
 * _copySeqScan
 */
static SeqScan *
_copySeqScan(SeqScan *from)
{
	SeqScan    *newnode = makeNode(SeqScan);

	/*
	 * copy node superclass fields
	 */
	CopyScanFields((Scan *) from, (Scan *) newnode);

	return newnode;
}

/*
 * _copyIndexScan
 */
static IndexScan *
_copyIndexScan(IndexScan *from)
{
	IndexScan  *newnode = makeNode(IndexScan);

	/*
	 * copy node superclass fields
	 */
	CopyScanFields((Scan *) from, (Scan *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_OIDLIST_FIELD(indxid);
	COPY_NODE_FIELD(indxqual);
	COPY_NODE_FIELD(indxqualorig);
	COPY_SCALAR_FIELD(indxorderdir);

	return newnode;
}

/*
 * _copyTidScan
 */
static TidScan *
_copyTidScan(TidScan *from)
{
	TidScan    *newnode = makeNode(TidScan);

	/*
	 * copy node superclass fields
	 */
	CopyScanFields((Scan *) from, (Scan *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_NODE_FIELD(tideval);

	return newnode;
}

/*
 * _copySubqueryScan
 */
static SubqueryScan *
_copySubqueryScan(SubqueryScan *from)
{
	SubqueryScan *newnode = makeNode(SubqueryScan);

	/*
	 * copy node superclass fields
	 */
	CopyScanFields((Scan *) from, (Scan *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_NODE_FIELD(subplan);

	return newnode;
}

/*
 * _copyFunctionScan
 */
static FunctionScan *
_copyFunctionScan(FunctionScan *from)
{
	FunctionScan *newnode = makeNode(FunctionScan);

	/*
	 * copy node superclass fields
	 */
	CopyScanFields((Scan *) from, (Scan *) newnode);

	return newnode;
}

/*
 * CopyJoinFields
 *
 *		This function copies the fields of the Join node.  It is used by
 *		all the copy functions for classes which inherit from Join.
 */
static void
CopyJoinFields(Join *from, Join *newnode)
{
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	COPY_SCALAR_FIELD(jointype);
	COPY_NODE_FIELD(joinqual);
}


/*
 * _copyJoin
 */
static Join *
_copyJoin(Join *from)
{
	Join	   *newnode = makeNode(Join);

	/*
	 * copy node superclass fields
	 */
	CopyJoinFields(from, newnode);

	return newnode;
}


/*
 * _copyNestLoop
 */
static NestLoop *
_copyNestLoop(NestLoop *from)
{
	NestLoop   *newnode = makeNode(NestLoop);

	/*
	 * copy node superclass fields
	 */
	CopyJoinFields((Join *) from, (Join *) newnode);

	return newnode;
}


/*
 * _copyMergeJoin
 */
static MergeJoin *
_copyMergeJoin(MergeJoin *from)
{
	MergeJoin  *newnode = makeNode(MergeJoin);

	/*
	 * copy node superclass fields
	 */
	CopyJoinFields((Join *) from, (Join *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_NODE_FIELD(mergeclauses);

	return newnode;
}

/*
 * _copyHashJoin
 */
static HashJoin *
_copyHashJoin(HashJoin *from)
{
	HashJoin   *newnode = makeNode(HashJoin);

	/*
	 * copy node superclass fields
	 */
	CopyJoinFields((Join *) from, (Join *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_NODE_FIELD(hashclauses);

	return newnode;
}


/*
 * _copyMaterial
 */
static Material *
_copyMaterial(Material *from)
{
	Material   *newnode = makeNode(Material);

	/*
	 * copy node superclass fields
	 */
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	return newnode;
}


/*
 * _copySort
 */
static Sort *
_copySort(Sort *from)
{
	Sort	   *newnode = makeNode(Sort);

	/*
	 * copy node superclass fields
	 */
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	COPY_SCALAR_FIELD(numCols);
	COPY_POINTER_FIELD(sortColIdx, from->numCols * sizeof(AttrNumber));
	COPY_POINTER_FIELD(sortOperators, from->numCols * sizeof(Oid));

	return newnode;
}


/*
 * _copyGroup
 */
static Group *
_copyGroup(Group *from)
{
	Group	   *newnode = makeNode(Group);

	CopyPlanFields((Plan *) from, (Plan *) newnode);

	COPY_SCALAR_FIELD(numCols);
	COPY_POINTER_FIELD(grpColIdx, from->numCols * sizeof(AttrNumber));

	return newnode;
}

/*
 * _copyAgg
 */
static Agg *
_copyAgg(Agg *from)
{
	Agg		   *newnode = makeNode(Agg);

	CopyPlanFields((Plan *) from, (Plan *) newnode);

	COPY_SCALAR_FIELD(aggstrategy);
	COPY_SCALAR_FIELD(numCols);
	if (from->numCols > 0)
		COPY_POINTER_FIELD(grpColIdx, from->numCols * sizeof(AttrNumber));
	COPY_SCALAR_FIELD(numGroups);

	return newnode;
}

/*
 * _copyUnique
 */
static Unique *
_copyUnique(Unique *from)
{
	Unique	   *newnode = makeNode(Unique);

	/*
	 * copy node superclass fields
	 */
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_SCALAR_FIELD(numCols);
	COPY_POINTER_FIELD(uniqColIdx, from->numCols * sizeof(AttrNumber));

	return newnode;
}

/*
 * _copyHash
 */
static Hash *
_copyHash(Hash *from)
{
	Hash	   *newnode = makeNode(Hash);

	/*
	 * copy node superclass fields
	 */
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_NODE_FIELD(hashkeys);

	return newnode;
}

/*
 * _copySetOp
 */
static SetOp *
_copySetOp(SetOp *from)
{
	SetOp	   *newnode = makeNode(SetOp);

	/*
	 * copy node superclass fields
	 */
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_SCALAR_FIELD(cmd);
	COPY_SCALAR_FIELD(numCols);
	COPY_POINTER_FIELD(dupColIdx, from->numCols * sizeof(AttrNumber));
	COPY_SCALAR_FIELD(flagColIdx);

	return newnode;
}

/*
 * _copyLimit
 */
static Limit *
_copyLimit(Limit *from)
{
	Limit	   *newnode = makeNode(Limit);

	/*
	 * copy node superclass fields
	 */
	CopyPlanFields((Plan *) from, (Plan *) newnode);

	/*
	 * copy remainder of node
	 */
	COPY_NODE_FIELD(limitOffset);
	COPY_NODE_FIELD(limitCount);

	return newnode;
}

/* ****************************************************************
 *					   primnodes.h copy functions
 * ****************************************************************
 */

/*
 * _copyResdom
 */
static Resdom *
_copyResdom(Resdom *from)
{
	Resdom	   *newnode = makeNode(Resdom);

	COPY_SCALAR_FIELD(resno);
	COPY_SCALAR_FIELD(restype);
	COPY_SCALAR_FIELD(restypmod);
	COPY_STRING_FIELD(resname);
	COPY_SCALAR_FIELD(ressortgroupref);
	COPY_SCALAR_FIELD(resorigtbl);
	COPY_SCALAR_FIELD(resorigcol);
	COPY_SCALAR_FIELD(resjunk);

	return newnode;
}

/*
 * _copyAlias
 */
static Alias *
_copyAlias(Alias *from)
{
	Alias	   *newnode = makeNode(Alias);

	COPY_STRING_FIELD(aliasname);
	COPY_NODE_FIELD(colnames);

	return newnode;
}

/*
 * _copyRangeVar
 */
static RangeVar *
_copyRangeVar(RangeVar *from)
{
	RangeVar   *newnode = makeNode(RangeVar);

	COPY_STRING_FIELD(catalogname);
	COPY_STRING_FIELD(schemaname);
	COPY_STRING_FIELD(relname);
	COPY_SCALAR_FIELD(inhOpt);
	COPY_SCALAR_FIELD(istemp);
	COPY_NODE_FIELD(alias);

	return newnode;
}

/*
 * We don't need a _copyExpr because Expr is an abstract supertype which
 * should never actually get instantiated.	Also, since it has no common
 * fields except NodeTag, there's no need for a helper routine to factor
 * out copying the common fields...
 */

/*
 * _copyVar
 */
static Var *
_copyVar(Var *from)
{
	Var		   *newnode = makeNode(Var);

	COPY_SCALAR_FIELD(varno);
	COPY_SCALAR_FIELD(varattno);
	COPY_SCALAR_FIELD(vartype);
	COPY_SCALAR_FIELD(vartypmod);
	COPY_SCALAR_FIELD(varlevelsup);
	COPY_SCALAR_FIELD(varnoold);
	COPY_SCALAR_FIELD(varoattno);

	return newnode;
}

/*
 * _copyConst
 */
static Const *
_copyConst(Const *from)
{
	Const	   *newnode = makeNode(Const);

	COPY_SCALAR_FIELD(consttype);
	COPY_SCALAR_FIELD(constlen);

	if (from->constbyval || from->constisnull)
	{
		/*
		 * passed by value so just copy the datum. Also, don't try to copy
		 * struct when value is null!
		 */
		newnode->constvalue = from->constvalue;
	}
	else
	{
		/*
		 * passed by reference.  We need a palloc'd copy.
		 */
		newnode->constvalue = datumCopy(from->constvalue,
										from->constbyval,
										from->constlen);
	}

	COPY_SCALAR_FIELD(constisnull);
	COPY_SCALAR_FIELD(constbyval);

	return newnode;
}

/*
 * _copyParam
 */
static Param *
_copyParam(Param *from)
{
	Param	   *newnode = makeNode(Param);

	COPY_SCALAR_FIELD(paramkind);
	COPY_SCALAR_FIELD(paramid);
	COPY_STRING_FIELD(paramname);
	COPY_SCALAR_FIELD(paramtype);

	return newnode;
}

/*
 * _copyAggref
 */
static Aggref *
_copyAggref(Aggref *from)
{
	Aggref	   *newnode = makeNode(Aggref);

	COPY_SCALAR_FIELD(aggfnoid);
	COPY_SCALAR_FIELD(aggtype);
	COPY_NODE_FIELD(target);
	COPY_SCALAR_FIELD(agglevelsup);
	COPY_SCALAR_FIELD(aggstar);
	COPY_SCALAR_FIELD(aggdistinct);

	return newnode;
}

/*
 * _copyArrayRef
 */
static ArrayRef *
_copyArrayRef(ArrayRef *from)
{
	ArrayRef   *newnode = makeNode(ArrayRef);

	COPY_SCALAR_FIELD(refrestype);
	COPY_SCALAR_FIELD(refarraytype);
	COPY_SCALAR_FIELD(refelemtype);