execnodes.h

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/* es_rowMarks is a list of these structs: */
typedef struct ExecRowMark
{
	Relation	relation;		/* opened and RowShareLock'd relation */
	Index		rti;			/* its range table index */
	bool		forUpdate;		/* true = FOR UPDATE, false = FOR SHARE */
	bool		noWait;			/* NOWAIT option */
	char		resname[32];	/* name for its ctid junk attribute */
} ExecRowMark;


/* ----------------------------------------------------------------
 *				 Tuple Hash Tables
 *
 * All-in-memory tuple hash tables are used for a number of purposes.
 * ----------------------------------------------------------------
 */
typedef struct TupleHashEntryData *TupleHashEntry;
typedef struct TupleHashTableData *TupleHashTable;

typedef struct TupleHashEntryData
{
	/* firstTuple must be the first field in this struct! */
	MinimalTuple firstTuple;	/* copy of first tuple in this group */
	/* there may be additional data beyond the end of this struct */
} TupleHashEntryData;			/* VARIABLE LENGTH STRUCT */

typedef struct TupleHashTableData
{
	HTAB	   *hashtab;		/* underlying dynahash table */
	int			numCols;		/* number of columns in lookup key */
	AttrNumber *keyColIdx;		/* attr numbers of key columns */
	FmgrInfo   *eqfunctions;	/* lookup data for comparison functions */
	FmgrInfo   *hashfunctions;	/* lookup data for hash functions */
	MemoryContext tablecxt;		/* memory context containing table */
	MemoryContext tempcxt;		/* context for function evaluations */
	Size		entrysize;		/* actual size to make each hash entry */
	TupleTableSlot *tableslot;	/* slot for referencing table entries */
	TupleTableSlot *inputslot;	/* current input tuple's slot */
} TupleHashTableData;

typedef HASH_SEQ_STATUS TupleHashIterator;

/*
 * Use InitTupleHashIterator/TermTupleHashIterator for a read/write scan.
 * Use ResetTupleHashIterator if the table can be frozen (in this case no
 * explicit scan termination is needed).
 */
#define InitTupleHashIterator(htable, iter) \
	hash_seq_init(iter, (htable)->hashtab)
#define TermTupleHashIterator(iter) \
	hash_seq_term(iter)
#define ResetTupleHashIterator(htable, iter) \
	do { \
		hash_freeze((htable)->hashtab); \
		hash_seq_init(iter, (htable)->hashtab); \
	} while (0)
#define ScanTupleHashTable(iter) \
	((TupleHashEntry) hash_seq_search(iter))


/* ----------------------------------------------------------------
 *				 Expression State Trees
 *
 * Each executable expression tree has a parallel ExprState tree.
 *
 * Unlike PlanState, there is not an exact one-for-one correspondence between
 * ExprState node types and Expr node types.  Many Expr node types have no
 * need for node-type-specific run-time state, and so they can use plain
 * ExprState or GenericExprState as their associated ExprState node type.
 * ----------------------------------------------------------------
 */

/* ----------------
 *		ExprState node
 *
 * ExprState is the common superclass for all ExprState-type nodes.
 *
 * It can also be instantiated directly for leaf Expr nodes that need no
 * local run-time state (such as Var, Const, or Param).
 *
 * To save on dispatch overhead, each ExprState node contains a function
 * pointer to the routine to execute to evaluate the node.
 * ----------------
 */

typedef struct ExprState ExprState;

typedef Datum (*ExprStateEvalFunc) (ExprState *expression,
												ExprContext *econtext,
												bool *isNull,
												ExprDoneCond *isDone);

struct ExprState
{
	NodeTag		type;
	Expr	   *expr;			/* associated Expr node */
	ExprStateEvalFunc evalfunc; /* routine to run to execute node */
};

/* ----------------
 *		GenericExprState node
 *
 * This is used for Expr node types that need no local run-time state,
 * but have one child Expr node.
 * ----------------
 */
typedef struct GenericExprState
{
	ExprState	xprstate;
	ExprState  *arg;			/* state of my child node */
} GenericExprState;

/* ----------------
 *		AggrefExprState node
 * ----------------
 */
typedef struct AggrefExprState
{
	ExprState	xprstate;
	List	   *args;			/* states of argument expressions */
	int			aggno;			/* ID number for agg within its plan node */
} AggrefExprState;

/* ----------------
 *		ArrayRefExprState node
 *
 * Note: array types can be fixed-length (typlen > 0), but only when the
 * element type is itself fixed-length.  Otherwise they are varlena structures
 * and have typlen = -1.  In any case, an array type is never pass-by-value.
 * ----------------
 */
typedef struct ArrayRefExprState
{
	ExprState	xprstate;
	List	   *refupperindexpr;	/* states for child nodes */
	List	   *reflowerindexpr;
	ExprState  *refexpr;
	ExprState  *refassgnexpr;
	int16		refattrlength;	/* typlen of array type */
	int16		refelemlength;	/* typlen of the array element type */
	bool		refelembyval;	/* is the element type pass-by-value? */
	char		refelemalign;	/* typalign of the element type */
} ArrayRefExprState;

/* ----------------
 *		FuncExprState node
 *
 * Although named for FuncExpr, this is also used for OpExpr, DistinctExpr,
 * and NullIf nodes; be careful to check what xprstate.expr is actually
 * pointing at!
 * ----------------
 */
typedef struct FuncExprState
{
	ExprState	xprstate;
	List	   *args;			/* states of argument expressions */

	/*
	 * Function manager's lookup info for the target function.  If func.fn_oid
	 * is InvalidOid, we haven't initialized it yet.
	 */
	FmgrInfo	func;

	/*
	 * We also need to store argument values across calls when evaluating a
	 * function-returning-set.
	 *
	 * setArgsValid is true when we are evaluating a set-valued function and
	 * we are in the middle of a call series; we want to pass the same
	 * argument values to the function again (and again, until it returns
	 * ExprEndResult).
	 */
	bool		setArgsValid;

	/*
	 * Flag to remember whether we found a set-valued argument to the
	 * function. This causes the function result to be a set as well. Valid
	 * only when setArgsValid is true.
	 */
	bool		setHasSetArg;	/* some argument returns a set */

	/*
	 * Flag to remember whether we have registered a shutdown callback for
	 * this FuncExprState.	We do so only if setArgsValid has been true at
	 * least once (since all the callback is for is to clear setArgsValid).
	 */
	bool		shutdown_reg;	/* a shutdown callback is registered */

	/*
	 * Current argument data for a set-valued function; contains valid data
	 * only if setArgsValid is true.
	 */
	FunctionCallInfoData setArgs;
} FuncExprState;

/* ----------------
 *		ScalarArrayOpExprState node
 *
 * This is a FuncExprState plus some additional data.
 * ----------------
 */
typedef struct ScalarArrayOpExprState
{
	FuncExprState fxprstate;
	/* Cached info about array element type */
	Oid			element_type;
	int16		typlen;
	bool		typbyval;
	char		typalign;
} ScalarArrayOpExprState;

/* ----------------
 *		BoolExprState node
 * ----------------
 */
typedef struct BoolExprState
{
	ExprState	xprstate;
	List	   *args;			/* states of argument expression(s) */
} BoolExprState;

/* ----------------
 *		SubPlanState node
 * ----------------
 */
typedef struct SubPlanState
{
	ExprState	xprstate;
	EState	   *sub_estate;		/* subselect plan has its own EState */
	struct PlanState *planstate;	/* subselect plan's state tree */
	ExprState  *testexpr;		/* state of combining expression */
	List	   *args;			/* states of argument expression(s) */
	bool		needShutdown;	/* TRUE = need to shutdown subplan */
	HeapTuple	curTuple;		/* copy of most recent tuple from subplan */
	/* these are used when hashing the subselect's output: */
	ProjectionInfo *projLeft;	/* for projecting lefthand exprs */
	ProjectionInfo *projRight;	/* for projecting subselect output */
	TupleHashTable hashtable;	/* hash table for no-nulls subselect rows */
	TupleHashTable hashnulls;	/* hash table for rows with null(s) */
	bool		havehashrows;	/* TRUE if hashtable is not empty */
	bool		havenullrows;	/* TRUE if hashnulls is not empty */
	MemoryContext tablecxt;		/* memory context containing tables */
	ExprContext *innerecontext; /* working context for comparisons */
	AttrNumber *keyColIdx;		/* control data for hash tables */
	FmgrInfo   *eqfunctions;	/* comparison functions for hash tables */
	FmgrInfo   *hashfunctions;	/* lookup data for hash functions */
} SubPlanState;

/* ----------------
 *		FieldSelectState node
 * ----------------
 */
typedef struct FieldSelectState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input expression */
	TupleDesc	argdesc;		/* tupdesc for most recent input */
} FieldSelectState;

/* ----------------
 *		FieldStoreState node
 * ----------------
 */
typedef struct FieldStoreState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input tuple value */
	List	   *newvals;		/* new value(s) for field(s) */
	TupleDesc	argdesc;		/* tupdesc for most recent input */
} FieldStoreState;

/* ----------------
 *		ConvertRowtypeExprState node
 * ----------------
 */
typedef struct ConvertRowtypeExprState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input tuple value */
	TupleDesc	indesc;			/* tupdesc for source rowtype */
	TupleDesc	outdesc;		/* tupdesc for result rowtype */
	AttrNumber *attrMap;		/* indexes of input fields, or 0 for null */
	Datum	   *invalues;		/* workspace for deconstructing source */
	bool	   *inisnull;
	Datum	   *outvalues;		/* workspace for constructing result */
	bool	   *outisnull;
} ConvertRowtypeExprState;

/* ----------------
 *		CaseExprState node
 * ----------------
 */
typedef struct CaseExprState
{
	ExprState	xprstate;
	ExprState  *arg;			/* implicit equality comparison argument */
	List	   *args;			/* the arguments (list of WHEN clauses) */
	ExprState  *defresult;		/* the default result (ELSE clause) */
} CaseExprState;

/* ----------------
 *		CaseWhenState node
 * ----------------
 */
typedef struct CaseWhenState
{
	ExprState	xprstate;
	ExprState  *expr;			/* condition expression */
	ExprState  *result;			/* substitution result */
} CaseWhenState;

/* ----------------
 *		ArrayExprState node
 *
 * Note: ARRAY[] expressions always produce varlena arrays, never fixed-length
 * arrays.
 * ----------------
 */
typedef struct ArrayExprState
{
	ExprState	xprstate;
	List	   *elements;		/* states for child nodes */
	int16		elemlength;		/* typlen of the array element type */
	bool		elembyval;		/* is the element type pass-by-value? */
	char		elemalign;		/* typalign of the element type */
} ArrayExprState;

/* ----------------
 *		RowExprState node
 * ----------------
 */
typedef struct RowExprState
{
	ExprState	xprstate;
	List	   *args;			/* the arguments */
	TupleDesc	tupdesc;		/* descriptor for result tuples */
} RowExprState;

/* ----------------
 *		RowCompareExprState node
 * ----------------
 */
typedef struct RowCompareExprState
{
	ExprState	xprstate;
	List	   *largs;			/* the left-hand input arguments */
	List	   *rargs;			/* the right-hand input arguments */
	FmgrInfo   *funcs;			/* array of comparison function info */