readfuncs.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/*-------------------------------------------------------------------------
 *
 * readfuncs.c
 *	  Reader functions for Postgres tree nodes.
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.182 2005/10/15 02:49:19 momjian Exp $
 *
 * NOTES
 *	  Path and Plan nodes do not have any readfuncs support, because we
 *	  never have occasion to read them in.	(There was once code here that
 *	  claimed to read them, but it was broken as well as unused.)  We
 *	  never read executor state trees, either.
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <math.h>

#include "nodes/parsenodes.h"
#include "nodes/readfuncs.h"


/*
 * Macros to simplify reading of different kinds of fields.  Use these
 * wherever possible to reduce the chance for silly typos.	Note that these
 * hard-wire conventions about the names of the local variables in a Read
 * routine.
 */

/* Macros for declaring appropriate local variables */

/* A few guys need only local_node */
#define READ_LOCALS_NO_FIELDS(nodeTypeName) \
	nodeTypeName *local_node = makeNode(nodeTypeName)

/* And a few guys need only the pg_strtok support fields */
#define READ_TEMP_LOCALS()	\
	char	   *token;		\
	int			length

/* ... but most need both */
#define READ_LOCALS(nodeTypeName)			\
	READ_LOCALS_NO_FIELDS(nodeTypeName);	\
	READ_TEMP_LOCALS()

/* Read an integer field (anything written as ":fldname %d") */
#define READ_INT_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = atoi(token)

/* Read an unsigned integer field (anything written as ":fldname %u") */
#define READ_UINT_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = atoui(token)

/* Read an OID field (don't hard-wire assumption that OID is same as uint) */
#define READ_OID_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = atooid(token)

/* Read a char field (ie, one ascii character) */
#define READ_CHAR_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = token[0]

/* Read an enumerated-type field that was written as an integer code */
#define READ_ENUM_FIELD(fldname, enumtype) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = (enumtype) atoi(token)

/* Read a float field */
#define READ_FLOAT_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = atof(token)

/* Read a boolean field */
#define READ_BOOL_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = strtobool(token)

/* Read a character-string field */
#define READ_STRING_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = nullable_string(token, length)

/* Read a Node field */
#define READ_NODE_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	local_node->fldname = nodeRead(NULL, 0)

/* Routine exit */
#define READ_DONE() \
	return local_node


/*
 * NOTE: use atoi() to read values written with %d, or atoui() to read
 * values written with %u in outfuncs.c.  An exception is OID values,
 * for which use atooid().	(As of 7.1, outfuncs.c writes OIDs as %u,
 * but this will probably change in the future.)
 */
#define atoui(x)  ((unsigned int) strtoul((x), NULL, 10))

#define atooid(x)  ((Oid) strtoul((x), NULL, 10))

#define strtobool(x)  ((*(x) == 't') ? true : false)

#define nullable_string(token,length)  \
	((length) == 0 ? NULL : debackslash(token, length))


static Datum readDatum(bool typbyval);


/*
 * _readQuery
 */
static Query *
_readQuery(void)
{
	READ_LOCALS(Query);

	READ_ENUM_FIELD(commandType, CmdType);
	READ_ENUM_FIELD(querySource, QuerySource);
	READ_BOOL_FIELD(canSetTag);
	READ_NODE_FIELD(utilityStmt);
	READ_INT_FIELD(resultRelation);
	READ_NODE_FIELD(into);
	READ_BOOL_FIELD(hasAggs);
	READ_BOOL_FIELD(hasSubLinks);
	READ_NODE_FIELD(rtable);
	READ_NODE_FIELD(jointree);
	READ_NODE_FIELD(rowMarks);
	READ_BOOL_FIELD(forUpdate);
	READ_BOOL_FIELD(rowNoWait);
	READ_NODE_FIELD(targetList);
	READ_NODE_FIELD(groupClause);
	READ_NODE_FIELD(havingQual);
	READ_NODE_FIELD(distinctClause);
	READ_NODE_FIELD(sortClause);
	READ_NODE_FIELD(limitOffset);
	READ_NODE_FIELD(limitCount);
	READ_NODE_FIELD(setOperations);
	READ_NODE_FIELD(resultRelations);

	READ_DONE();
}

/*
 * _readNotifyStmt
 */
static NotifyStmt *
_readNotifyStmt(void)
{
	READ_LOCALS(NotifyStmt);

	READ_NODE_FIELD(relation);

	READ_DONE();
}

/*
 * _readDeclareCursorStmt
 */
static DeclareCursorStmt *
_readDeclareCursorStmt(void)
{
	READ_LOCALS(DeclareCursorStmt);

	READ_STRING_FIELD(portalname);
	READ_INT_FIELD(options);
	READ_NODE_FIELD(query);

	READ_DONE();
}

/*
 * _readSortClause
 */
static SortClause *
_readSortClause(void)
{
	READ_LOCALS(SortClause);

	READ_UINT_FIELD(tleSortGroupRef);
	READ_OID_FIELD(sortop);

	READ_DONE();
}

/*
 * _readGroupClause
 */
static GroupClause *
_readGroupClause(void)
{
	READ_LOCALS(GroupClause);

	READ_UINT_FIELD(tleSortGroupRef);
	READ_OID_FIELD(sortop);

	READ_DONE();
}

/*
 * _readSetOperationStmt
 */
static SetOperationStmt *
_readSetOperationStmt(void)
{
	READ_LOCALS(SetOperationStmt);

	READ_ENUM_FIELD(op, SetOperation);
	READ_BOOL_FIELD(all);
	READ_NODE_FIELD(larg);
	READ_NODE_FIELD(rarg);
	READ_NODE_FIELD(colTypes);

	READ_DONE();
}


/*
 *	Stuff from primnodes.h.
 */

static Alias *
_readAlias(void)
{
	READ_LOCALS(Alias);

	READ_STRING_FIELD(aliasname);
	READ_NODE_FIELD(colnames);

	READ_DONE();
}

static RangeVar *
_readRangeVar(void)
{
	READ_LOCALS(RangeVar);

	local_node->catalogname = NULL;		/* not currently saved in output
										 * format */

	READ_STRING_FIELD(schemaname);
	READ_STRING_FIELD(relname);
	READ_ENUM_FIELD(inhOpt, InhOption);
	READ_BOOL_FIELD(istemp);
	READ_NODE_FIELD(alias);

	READ_DONE();
}

/*
 * _readVar
 */
static Var *
_readVar(void)
{
	READ_LOCALS(Var);

	READ_UINT_FIELD(varno);
	READ_INT_FIELD(varattno);
	READ_OID_FIELD(vartype);
	READ_INT_FIELD(vartypmod);
	READ_UINT_FIELD(varlevelsup);
	READ_UINT_FIELD(varnoold);
	READ_INT_FIELD(varoattno);

	READ_DONE();
}

/*
 * _readConst
 */
static Const *
_readConst(void)
{
	READ_LOCALS(Const);

	READ_OID_FIELD(consttype);
	READ_INT_FIELD(constlen);
	READ_BOOL_FIELD(constbyval);
	READ_BOOL_FIELD(constisnull);

	token = pg_strtok(&length); /* skip :constvalue */
	if (local_node->constisnull)
		token = pg_strtok(&length);		/* skip "<>" */
	else
		local_node->constvalue = readDatum(local_node->constbyval);

	READ_DONE();
}

/*
 * _readParam
 */
static Param *
_readParam(void)
{
	READ_LOCALS(Param);

	READ_INT_FIELD(paramkind);
	READ_INT_FIELD(paramid);
	READ_STRING_FIELD(paramname);
	READ_OID_FIELD(paramtype);

	READ_DONE();
}

/*
 * _readAggref
 */
static Aggref *
_readAggref(void)
{
	READ_LOCALS(Aggref);

	READ_OID_FIELD(aggfnoid);
	READ_OID_FIELD(aggtype);
	READ_NODE_FIELD(target);
	READ_UINT_FIELD(agglevelsup);
	READ_BOOL_FIELD(aggstar);
	READ_BOOL_FIELD(aggdistinct);

	READ_DONE();
}

/*
 * _readArrayRef
 */
static ArrayRef *
_readArrayRef(void)
{
	READ_LOCALS(ArrayRef);

	READ_OID_FIELD(refrestype);
	READ_OID_FIELD(refarraytype);
	READ_OID_FIELD(refelemtype);
	READ_NODE_FIELD(refupperindexpr);
	READ_NODE_FIELD(reflowerindexpr);
	READ_NODE_FIELD(refexpr);
	READ_NODE_FIELD(refassgnexpr);

	READ_DONE();
}

/*
 * _readFuncExpr
 */
static FuncExpr *
_readFuncExpr(void)
{
	READ_LOCALS(FuncExpr);

	READ_OID_FIELD(funcid);
	READ_OID_FIELD(funcresulttype);
	READ_BOOL_FIELD(funcretset);
	READ_ENUM_FIELD(funcformat, CoercionForm);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readOpExpr
 */
static OpExpr *
_readOpExpr(void)
{
	READ_LOCALS(OpExpr);

	READ_OID_FIELD(opno);
	READ_OID_FIELD(opfuncid);

	/*
	 * The opfuncid is stored in the textual format primarily for debugging
	 * and documentation reasons.  We want to always read it as zero to force
	 * it to be re-looked-up in the pg_operator entry.	This ensures that
	 * stored rules don't have hidden dependencies on operators' functions.
	 * (We don't currently support an ALTER OPERATOR command, but might
	 * someday.)
	 */
	local_node->opfuncid = InvalidOid;

	READ_OID_FIELD(opresulttype);
	READ_BOOL_FIELD(opretset);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readDistinctExpr
 */
static DistinctExpr *
_readDistinctExpr(void)
{
	READ_LOCALS(DistinctExpr);

	READ_OID_FIELD(opno);
	READ_OID_FIELD(opfuncid);

	/*
	 * The opfuncid is stored in the textual format primarily for debugging
	 * and documentation reasons.  We want to always read it as zero to force
	 * it to be re-looked-up in the pg_operator entry.	This ensures that
	 * stored rules don't have hidden dependencies on operators' functions.
	 * (We don't currently support an ALTER OPERATOR command, but might
	 * someday.)
	 */
	local_node->opfuncid = InvalidOid;

	READ_OID_FIELD(opresulttype);
	READ_BOOL_FIELD(opretset);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readScalarArrayOpExpr
 */
static ScalarArrayOpExpr *
_readScalarArrayOpExpr(void)
{
	READ_LOCALS(ScalarArrayOpExpr);

	READ_OID_FIELD(opno);
	READ_OID_FIELD(opfuncid);

	/*
	 * The opfuncid is stored in the textual format primarily for debugging
	 * and documentation reasons.  We want to always read it as zero to force
	 * it to be re-looked-up in the pg_operator entry.	This ensures that
	 * stored rules don't have hidden dependencies on operators' functions.
	 * (We don't currently support an ALTER OPERATOR command, but might
	 * someday.)
	 */
	local_node->opfuncid = InvalidOid;

	READ_BOOL_FIELD(useOr);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readBoolExpr
 */
static BoolExpr *
_readBoolExpr(void)
{
	READ_LOCALS(BoolExpr);

	/* do-it-yourself enum representation */
	token = pg_strtok(&length); /* skip :boolop */
	token = pg_strtok(&length); /* get field value */
	if (strncmp(token, "and", 3) == 0)
		local_node->boolop = AND_EXPR;
	else if (strncmp(token, "or", 2) == 0)
		local_node->boolop = OR_EXPR;
	else if (strncmp(token, "not", 3) == 0)
		local_node->boolop = NOT_EXPR;
	else
		elog(ERROR, "unrecognized boolop \"%.*s\"", length, token);

	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readSubLink
 */
static SubLink *
_readSubLink(void)
{
	READ_LOCALS(SubLink);

	READ_ENUM_FIELD(subLinkType, SubLinkType);
	READ_BOOL_FIELD(useOr);
	READ_NODE_FIELD(lefthand);
	READ_NODE_FIELD(operName);
	READ_NODE_FIELD(operOids);
	READ_NODE_FIELD(subselect);

	READ_DONE();
}

/*
 * _readSubPlan is not needed since it doesn't appear in stored rules.
 */

/*
 * _readFieldSelect
 */
static FieldSelect *
_readFieldSelect(void)
{
	READ_LOCALS(FieldSelect);

	READ_NODE_FIELD(arg);
	READ_INT_FIELD(fieldnum);
	READ_OID_FIELD(resulttype);
	READ_INT_FIELD(resulttypmod);

	READ_DONE();
}

/*
 * _readFieldStore
 */
static FieldStore *
_readFieldStore(void)
{
	READ_LOCALS(FieldStore);

	READ_NODE_FIELD(arg);
	READ_NODE_FIELD(newvals);
	READ_NODE_FIELD(fieldnums);
	READ_OID_FIELD(resulttype);

	READ_DONE();
}

/*
 * _readRelabelType
 */
static RelabelType *
_readRelabelType(void)
{
	READ_LOCALS(RelabelType);

	READ_NODE_FIELD(arg);
	READ_OID_FIELD(resulttype);
	READ_INT_FIELD(resulttypmod);
	READ_ENUM_FIELD(relabelformat, CoercionForm);