execExpr.h 20.2 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747
/*-------------------------------------------------------------------------
 *
 * execExpr.h
 *	  Low level infrastructure related to expression evaluation
 *
 *
 * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/executor/execExpr.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef EXEC_EXPR_H
#define EXEC_EXPR_H

#include "executor/nodeAgg.h"
#include "nodes/execnodes.h"

/* forward references to avoid circularity */
struct ExprEvalStep;
struct ArrayRefState;

/* Bits in ExprState->flags (see also execnodes.h for public flag bits): */
/* expression's interpreter has been initialized */
#define EEO_FLAG_INTERPRETER_INITIALIZED	(1 << 1)
/* jump-threading is in use */
#define EEO_FLAG_DIRECT_THREADED			(1 << 2)

/* Typical API for out-of-line evaluation subroutines */
typedef void (*ExecEvalSubroutine) (ExprState *state,
									struct ExprEvalStep *op,
									ExprContext *econtext);

/*
 * Discriminator for ExprEvalSteps.
 *
 * Identifies the operation to be executed and which member in the
 * ExprEvalStep->d union is valid.
 *
 * The order of entries needs to be kept in sync with the dispatch_table[]
 * array in execExprInterp.c:ExecInterpExpr().
 */
typedef enum ExprEvalOp
{
	/* entire expression has been evaluated completely, return */
	EEOP_DONE,

	/* apply slot_getsomeattrs on corresponding tuple slot */
	EEOP_INNER_FETCHSOME,
	EEOP_OUTER_FETCHSOME,
	EEOP_SCAN_FETCHSOME,

	/* compute non-system Var value */
	EEOP_INNER_VAR,
	EEOP_OUTER_VAR,
	EEOP_SCAN_VAR,

	/* compute system Var value */
	EEOP_INNER_SYSVAR,
	EEOP_OUTER_SYSVAR,
	EEOP_SCAN_SYSVAR,

	/* compute wholerow Var */
	EEOP_WHOLEROW,

	/*
	 * Compute non-system Var value, assign it into ExprState's resultslot.
	 * These are not used if a CheckVarSlotCompatibility() check would be
	 * needed.
	 */
	EEOP_ASSIGN_INNER_VAR,
	EEOP_ASSIGN_OUTER_VAR,
	EEOP_ASSIGN_SCAN_VAR,

	/* assign ExprState's resvalue/resnull to a column of its resultslot */
	EEOP_ASSIGN_TMP,
	/* ditto, applying MakeExpandedObjectReadOnly() */
	EEOP_ASSIGN_TMP_MAKE_RO,

	/* evaluate Const value */
	EEOP_CONST,

	/*
	 * Evaluate function call (including OpExprs etc).  For speed, we
	 * distinguish in the opcode whether the function is strict and/or
	 * requires usage stats tracking.
	 */
	EEOP_FUNCEXPR,
	EEOP_FUNCEXPR_STRICT,
	EEOP_FUNCEXPR_FUSAGE,
	EEOP_FUNCEXPR_STRICT_FUSAGE,

	/*
	 * Evaluate boolean AND expression, one step per subexpression. FIRST/LAST
	 * subexpressions are special-cased for performance.  Since AND always has
	 * at least two subexpressions, FIRST and LAST never apply to the same
	 * subexpression.
	 */
	EEOP_BOOL_AND_STEP_FIRST,
	EEOP_BOOL_AND_STEP,
	EEOP_BOOL_AND_STEP_LAST,

	/* similarly for boolean OR expression */
	EEOP_BOOL_OR_STEP_FIRST,
	EEOP_BOOL_OR_STEP,
	EEOP_BOOL_OR_STEP_LAST,

	/* evaluate boolean NOT expression */
	EEOP_BOOL_NOT_STEP,

	/* simplified version of BOOL_AND_STEP for use by ExecQual() */
	EEOP_QUAL,

	/* unconditional jump to another step */
	EEOP_JUMP,

	/* conditional jumps based on current result value */
	EEOP_JUMP_IF_NULL,
	EEOP_JUMP_IF_NOT_NULL,
	EEOP_JUMP_IF_NOT_TRUE,

	/* perform NULL tests for scalar values */
	EEOP_NULLTEST_ISNULL,
	EEOP_NULLTEST_ISNOTNULL,

	/* perform NULL tests for row values */
	EEOP_NULLTEST_ROWISNULL,
	EEOP_NULLTEST_ROWISNOTNULL,

	/* evaluate a BooleanTest expression */
	EEOP_BOOLTEST_IS_TRUE,
	EEOP_BOOLTEST_IS_NOT_TRUE,
	EEOP_BOOLTEST_IS_FALSE,
	EEOP_BOOLTEST_IS_NOT_FALSE,

	/* evaluate PARAM_EXEC/EXTERN parameters */
	EEOP_PARAM_EXEC,
	EEOP_PARAM_EXTERN,
	EEOP_PARAM_CALLBACK,

	/* return CaseTestExpr value */
	EEOP_CASE_TESTVAL,

	/* apply MakeExpandedObjectReadOnly() to target value */
	EEOP_MAKE_READONLY,

	/* evaluate assorted special-purpose expression types */
	EEOP_IOCOERCE,
	EEOP_DISTINCT,
	EEOP_NOT_DISTINCT,
	EEOP_NULLIF,
	EEOP_SQLVALUEFUNCTION,
	EEOP_CURRENTOFEXPR,
	EEOP_NEXTVALUEEXPR,
	EEOP_ARRAYEXPR,
	EEOP_ARRAYCOERCE,
	EEOP_ROW,

	/*
	 * Compare two individual elements of each of two compared ROW()
	 * expressions.  Skip to ROWCOMPARE_FINAL if elements are not equal.
	 */
	EEOP_ROWCOMPARE_STEP,

	/* evaluate boolean value based on previous ROWCOMPARE_STEP operations */
	EEOP_ROWCOMPARE_FINAL,

	/* evaluate GREATEST() or LEAST() */
	EEOP_MINMAX,

	/* evaluate FieldSelect expression */
	EEOP_FIELDSELECT,

	/*
	 * Deform tuple before evaluating new values for individual fields in a
	 * FieldStore expression.
	 */
	EEOP_FIELDSTORE_DEFORM,

	/*
	 * Form the new tuple for a FieldStore expression.  Individual fields will
	 * have been evaluated into columns of the tuple deformed by the preceding
	 * DEFORM step.
	 */
	EEOP_FIELDSTORE_FORM,

	/* Process an array subscript; short-circuit expression to NULL if NULL */
	EEOP_ARRAYREF_SUBSCRIPT,

	/*
	 * Compute old array element/slice when an ArrayRef assignment expression
	 * contains ArrayRef/FieldStore subexpressions.  Value is accessed using
	 * the CaseTest mechanism.
	 */
	EEOP_ARRAYREF_OLD,

	/* compute new value for ArrayRef assignment expression */
	EEOP_ARRAYREF_ASSIGN,

	/* compute element/slice for ArrayRef fetch expression */
	EEOP_ARRAYREF_FETCH,

	/* evaluate value for CoerceToDomainValue */
	EEOP_DOMAIN_TESTVAL,

	/* evaluate a domain's NOT NULL constraint */
	EEOP_DOMAIN_NOTNULL,

	/* evaluate a single domain CHECK constraint */
	EEOP_DOMAIN_CHECK,

	/* evaluate assorted special-purpose expression types */
	EEOP_CONVERT_ROWTYPE,
	EEOP_SCALARARRAYOP,
	EEOP_XMLEXPR,
	EEOP_AGGREF,
	EEOP_GROUPING_FUNC,
	EEOP_WINDOW_FUNC,
	EEOP_SUBPLAN,
	EEOP_ALTERNATIVE_SUBPLAN,

	/* aggregation related nodes */
	EEOP_AGG_STRICT_DESERIALIZE,
	EEOP_AGG_DESERIALIZE,
	EEOP_AGG_STRICT_INPUT_CHECK,
	EEOP_AGG_INIT_TRANS,
	EEOP_AGG_STRICT_TRANS_CHECK,
	EEOP_AGG_PLAIN_TRANS_BYVAL,
	EEOP_AGG_PLAIN_TRANS,
	EEOP_AGG_ORDERED_TRANS_DATUM,
	EEOP_AGG_ORDERED_TRANS_TUPLE,

	/* non-existent operation, used e.g. to check array lengths */
	EEOP_LAST
} ExprEvalOp;


typedef struct ExprEvalStep
{
	/*
	 * Instruction to be executed.  During instruction preparation this is an
	 * enum ExprEvalOp, but later it can be changed to some other type, e.g. a
	 * pointer for computed goto (that's why it's an intptr_t).
	 */
	intptr_t	opcode;

	/* where to store the result of this step */
	Datum	   *resvalue;
	bool	   *resnull;

	/*
	 * Inline data for the operation.  Inline data is faster to access, but
	 * also bloats the size of all instructions.  The union should be kept to
	 * no more than 40 bytes on 64-bit systems (so that the entire struct is
	 * no more than 64 bytes, a single cacheline on common systems).
	 */
	union
	{
		/* for EEOP_INNER/OUTER/SCAN_FETCHSOME */
		struct
		{
			/* attribute number up to which to fetch (inclusive) */
			int			last_var;
			TupleDesc	known_desc;
		}			fetch;

		/* for EEOP_INNER/OUTER/SCAN_[SYS]VAR[_FIRST] */
		struct
		{
			/* attnum is attr number - 1 for regular VAR ... */
			/* but it's just the normal (negative) attr number for SYSVAR */
			int			attnum;
			Oid			vartype;	/* type OID of variable */
		}			var;

		/* for EEOP_WHOLEROW */
		struct
		{
			Var		   *var;	/* original Var node in plan tree */
			bool		first;	/* first time through, need to initialize? */
			bool		slow;	/* need runtime check for nulls? */
			TupleDesc	tupdesc;	/* descriptor for resulting tuples */
			JunkFilter *junkFilter; /* JunkFilter to remove resjunk cols */
		}			wholerow;

		/* for EEOP_ASSIGN_*_VAR */
		struct
		{
			/* target index in ExprState->resultslot->tts_values/nulls */
			int			resultnum;
			/* source attribute number - 1 */
			int			attnum;
		}			assign_var;

		/* for EEOP_ASSIGN_TMP[_MAKE_RO] */
		struct
		{
			/* target index in ExprState->resultslot->tts_values/nulls */
			int			resultnum;
		}			assign_tmp;

		/* for EEOP_CONST */
		struct
		{
			/* constant's value */
			Datum		value;
			bool		isnull;
		}			constval;

		/* for EEOP_FUNCEXPR_* / NULLIF / DISTINCT */
		struct
		{
			FmgrInfo   *finfo;	/* function's lookup data */
			FunctionCallInfo fcinfo_data;	/* arguments etc */
			/* faster to access without additional indirection: */
			PGFunction	fn_addr;	/* actual call address */
			int			nargs;	/* number of arguments */
		}			func;

		/* for EEOP_BOOL_*_STEP */
		struct
		{
			bool	   *anynull;	/* track if any input was NULL */
			int			jumpdone;	/* jump here if result determined */
		}			boolexpr;

		/* for EEOP_QUAL */
		struct
		{
			int			jumpdone;	/* jump here on false or null */
		}			qualexpr;

		/* for EEOP_JUMP[_CONDITION] */
		struct
		{
			int			jumpdone;	/* target instruction's index */
		}			jump;

		/* for EEOP_NULLTEST_ROWIS[NOT]NULL */
		struct
		{
			/* cached tupdesc pointer - filled at runtime */
			TupleDesc	argdesc;
		}			nulltest_row;

		/* for EEOP_PARAM_EXEC/EXTERN */
		struct
		{
			int			paramid;	/* numeric ID for parameter */
			Oid			paramtype;	/* OID of parameter's datatype */
		}			param;

		/* for EEOP_PARAM_CALLBACK */
		struct
		{
			ExecEvalSubroutine paramfunc;	/* add-on evaluation subroutine */
			void	   *paramarg;	/* private data for same */
			int			paramid;	/* numeric ID for parameter */
			Oid			paramtype;	/* OID of parameter's datatype */
		}			cparam;

		/* for EEOP_CASE_TESTVAL/DOMAIN_TESTVAL */
		struct
		{
			Datum	   *value;	/* value to return */
			bool	   *isnull;
		}			casetest;

		/* for EEOP_MAKE_READONLY */
		struct
		{
			Datum	   *value;	/* value to coerce to read-only */
			bool	   *isnull;
		}			make_readonly;

		/* for EEOP_IOCOERCE */
		struct
		{
			/* lookup and call info for source type's output function */
			FmgrInfo   *finfo_out;
			FunctionCallInfo fcinfo_data_out;
			/* lookup and call info for result type's input function */
			FmgrInfo   *finfo_in;
			FunctionCallInfo fcinfo_data_in;
		}			iocoerce;

		/* for EEOP_SQLVALUEFUNCTION */
		struct
		{
			SQLValueFunction *svf;
		}			sqlvaluefunction;

		/* for EEOP_NEXTVALUEEXPR */
		struct
		{
			Oid			seqid;
			Oid			seqtypid;
		}			nextvalueexpr;

		/* for EEOP_ARRAYEXPR */
		struct
		{
			Datum	   *elemvalues; /* element values get stored here */
			bool	   *elemnulls;
			int			nelems; /* length of the above arrays */
			Oid			elemtype;	/* array element type */
			int16		elemlength; /* typlen of the array element type */
			bool		elembyval;	/* is the element type pass-by-value? */
			char		elemalign;	/* typalign of the element type */
			bool		multidims;	/* is array expression multi-D? */
		}			arrayexpr;

		/* for EEOP_ARRAYCOERCE */
		struct
		{
			ExprState  *elemexprstate;	/* null if no per-element work */
			Oid			resultelemtype; /* element type of result array */
			struct ArrayMapState *amstate;	/* workspace for array_map */
		}			arraycoerce;

		/* for EEOP_ROW */
		struct
		{
			TupleDesc	tupdesc;	/* descriptor for result tuples */
			/* workspace for the values constituting the row: */
			Datum	   *elemvalues;
			bool	   *elemnulls;
		}			row;

		/* for EEOP_ROWCOMPARE_STEP */
		struct
		{
			/* lookup and call data for column comparison function */
			FmgrInfo   *finfo;
			FunctionCallInfo fcinfo_data;
			PGFunction	fn_addr;
			/* target for comparison resulting in NULL */
			int			jumpnull;
			/* target for comparison yielding inequality */
			int			jumpdone;
		}			rowcompare_step;

		/* for EEOP_ROWCOMPARE_FINAL */
		struct
		{
			RowCompareType rctype;
		}			rowcompare_final;

		/* for EEOP_MINMAX */
		struct
		{
			/* workspace for argument values */
			Datum	   *values;
			bool	   *nulls;
			int			nelems;
			/* is it GREATEST or LEAST? */
			MinMaxOp	op;
			/* lookup and call data for comparison function */
			FmgrInfo   *finfo;
			FunctionCallInfo fcinfo_data;
		}			minmax;

		/* for EEOP_FIELDSELECT */
		struct
		{
			AttrNumber	fieldnum;	/* field number to extract */
			Oid			resulttype; /* field's type */
			/* cached tupdesc pointer - filled at runtime */
			TupleDesc	argdesc;
		}			fieldselect;

		/* for EEOP_FIELDSTORE_DEFORM / FIELDSTORE_FORM */
		struct
		{
			/* original expression node */
			FieldStore *fstore;

			/* cached tupdesc pointer - filled at runtime */
			/* note that a DEFORM and FORM pair share the same tupdesc */
			TupleDesc  *argdesc;

			/* workspace for column values */
			Datum	   *values;
			bool	   *nulls;
			int			ncolumns;
		}			fieldstore;

		/* for EEOP_ARRAYREF_SUBSCRIPT */
		struct
		{
			/* too big to have inline */
			struct ArrayRefState *state;
			int			off;	/* 0-based index of this subscript */
			bool		isupper;	/* is it upper or lower subscript? */
			int			jumpdone;	/* jump here on null */
		}			arrayref_subscript;

		/* for EEOP_ARRAYREF_OLD / ASSIGN / FETCH */
		struct
		{
			/* too big to have inline */
			struct ArrayRefState *state;
		}			arrayref;

		/* for EEOP_DOMAIN_NOTNULL / DOMAIN_CHECK */
		struct
		{
			/* name of constraint */
			char	   *constraintname;
			/* where the result of a CHECK constraint will be stored */
			Datum	   *checkvalue;
			bool	   *checknull;
			/* OID of domain type */
			Oid			resulttype;
		}			domaincheck;

		/* for EEOP_CONVERT_ROWTYPE */
		struct
		{
			ConvertRowtypeExpr *convert;	/* original expression */
			/* these three fields are filled at runtime: */
			TupleDesc	indesc; /* tupdesc for input type */
			TupleDesc	outdesc;	/* tupdesc for output type */
			TupleConversionMap *map;	/* column mapping */
			bool		initialized;	/* initialized for current types? */
		}			convert_rowtype;

		/* for EEOP_SCALARARRAYOP */
		struct
		{
			/* element_type/typlen/typbyval/typalign are filled at runtime */
			Oid			element_type;	/* InvalidOid if not yet filled */
			bool		useOr;	/* use OR or AND semantics? */
			int16		typlen; /* array element type storage info */
			bool		typbyval;
			char		typalign;
			FmgrInfo   *finfo;	/* function's lookup data */
			FunctionCallInfo fcinfo_data;	/* arguments etc */
			/* faster to access without additional indirection: */
			PGFunction	fn_addr;	/* actual call address */
		}			scalararrayop;

		/* for EEOP_XMLEXPR */
		struct
		{
			XmlExpr    *xexpr;	/* original expression node */
			/* workspace for evaluating named args, if any */
			Datum	   *named_argvalue;
			bool	   *named_argnull;
			/* workspace for evaluating unnamed args, if any */
			Datum	   *argvalue;
			bool	   *argnull;
		}			xmlexpr;

		/* for EEOP_AGGREF */
		struct
		{
			/* out-of-line state, modified by nodeAgg.c */
			AggrefExprState *astate;
		}			aggref;

		/* for EEOP_GROUPING_FUNC */
		struct
		{
			AggState   *parent; /* parent Agg */
			List	   *clauses;	/* integer list of column numbers */
		}			grouping_func;

		/* for EEOP_WINDOW_FUNC */
		struct
		{
			/* out-of-line state, modified by nodeWindowFunc.c */
			WindowFuncExprState *wfstate;
		}			window_func;

		/* for EEOP_SUBPLAN */
		struct
		{
			/* out-of-line state, created by nodeSubplan.c */
			SubPlanState *sstate;
		}			subplan;

		/* for EEOP_ALTERNATIVE_SUBPLAN */
		struct
		{
			/* out-of-line state, created by nodeSubplan.c */
			AlternativeSubPlanState *asstate;
		}			alternative_subplan;

		/* for EEOP_AGG_*DESERIALIZE */
		struct
		{
			AggState   *aggstate;
			FunctionCallInfo fcinfo_data;
			int			jumpnull;
		}			agg_deserialize;

		/* for EEOP_AGG_STRICT_INPUT_CHECK */
		struct
		{
			bool	   *nulls;
			int			nargs;
			int			jumpnull;
		}			agg_strict_input_check;

		/* for EEOP_AGG_INIT_TRANS */
		struct
		{
			AggState   *aggstate;
			AggStatePerTrans pertrans;
			ExprContext *aggcontext;
			int			setno;
			int			transno;
			int			setoff;
			int			jumpnull;
		}			agg_init_trans;

		/* for EEOP_AGG_STRICT_TRANS_CHECK */
		struct
		{
			AggState   *aggstate;
			int			setno;
			int			transno;
			int			setoff;
			int			jumpnull;
		}			agg_strict_trans_check;

		/* for EEOP_AGG_{PLAIN,ORDERED}_TRANS* */
		struct
		{
			AggState   *aggstate;
			AggStatePerTrans pertrans;
			ExprContext *aggcontext;
			int			setno;
			int			transno;
			int			setoff;
		}			agg_trans;
	}			d;
} ExprEvalStep;


/* Non-inline data for array operations */
typedef struct ArrayRefState
{
	bool		isassignment;	/* is it assignment, or just fetch? */

	Oid			refelemtype;	/* OID of the array element type */
	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 */

	/* numupper and upperprovided[] are filled at compile time */
	/* at runtime, extracted subscript datums get stored in upperindex[] */
	int			numupper;
	bool		upperprovided[MAXDIM];
	int			upperindex[MAXDIM];

	/* similarly for lower indexes, if any */
	int			numlower;
	bool		lowerprovided[MAXDIM];
	int			lowerindex[MAXDIM];

	/* subscript expressions get evaluated into here */
	Datum		subscriptvalue;
	bool		subscriptnull;

	/* for assignment, new value to assign is evaluated into here */
	Datum		replacevalue;
	bool		replacenull;

	/* if we have a nested assignment, ARRAYREF_OLD puts old value here */
	Datum		prevvalue;
	bool		prevnull;
} ArrayRefState;


/* functions in execExpr.c */
extern void ExprEvalPushStep(ExprState *es, const ExprEvalStep *s);

/* functions in execExprInterp.c */
extern void ExecReadyInterpretedExpr(ExprState *state);
extern ExprEvalOp ExecEvalStepOp(ExprState *state, ExprEvalStep *op);

extern Datum ExecInterpExprStillValid(ExprState *state, ExprContext *econtext, bool *isNull);
extern void CheckExprStillValid(ExprState *state, ExprContext *econtext);

/*
 * Non fast-path execution functions. These are externs instead of statics in
 * execExprInterp.c, because that allows them to be used by other methods of
 * expression evaluation, reducing code duplication.
 */
extern void ExecEvalFuncExprFusage(ExprState *state, ExprEvalStep *op,
					   ExprContext *econtext);
extern void ExecEvalFuncExprStrictFusage(ExprState *state, ExprEvalStep *op,
							 ExprContext *econtext);
extern void ExecEvalParamExec(ExprState *state, ExprEvalStep *op,
				  ExprContext *econtext);
extern void ExecEvalParamExtern(ExprState *state, ExprEvalStep *op,
					ExprContext *econtext);
extern void ExecEvalSQLValueFunction(ExprState *state, ExprEvalStep *op);
extern void ExecEvalCurrentOfExpr(ExprState *state, ExprEvalStep *op);
extern void ExecEvalNextValueExpr(ExprState *state, ExprEvalStep *op);
extern void ExecEvalRowNull(ExprState *state, ExprEvalStep *op,
				ExprContext *econtext);
extern void ExecEvalRowNotNull(ExprState *state, ExprEvalStep *op,
				   ExprContext *econtext);
extern void ExecEvalArrayExpr(ExprState *state, ExprEvalStep *op);
extern void ExecEvalArrayCoerce(ExprState *state, ExprEvalStep *op,
					ExprContext *econtext);
extern void ExecEvalRow(ExprState *state, ExprEvalStep *op);
extern void ExecEvalMinMax(ExprState *state, ExprEvalStep *op);
extern void ExecEvalFieldSelect(ExprState *state, ExprEvalStep *op,
					ExprContext *econtext);
extern void ExecEvalFieldStoreDeForm(ExprState *state, ExprEvalStep *op,
						 ExprContext *econtext);
extern void ExecEvalFieldStoreForm(ExprState *state, ExprEvalStep *op,
					   ExprContext *econtext);
extern bool ExecEvalArrayRefSubscript(ExprState *state, ExprEvalStep *op);
extern void ExecEvalArrayRefFetch(ExprState *state, ExprEvalStep *op);
extern void ExecEvalArrayRefOld(ExprState *state, ExprEvalStep *op);
extern void ExecEvalArrayRefAssign(ExprState *state, ExprEvalStep *op);
extern void ExecEvalConvertRowtype(ExprState *state, ExprEvalStep *op,
					   ExprContext *econtext);
extern void ExecEvalScalarArrayOp(ExprState *state, ExprEvalStep *op);
extern void ExecEvalConstraintNotNull(ExprState *state, ExprEvalStep *op);
extern void ExecEvalConstraintCheck(ExprState *state, ExprEvalStep *op);
extern void ExecEvalXmlExpr(ExprState *state, ExprEvalStep *op);
extern void ExecEvalGroupingFunc(ExprState *state, ExprEvalStep *op);
extern void ExecEvalSubPlan(ExprState *state, ExprEvalStep *op,
				ExprContext *econtext);
extern void ExecEvalAlternativeSubPlan(ExprState *state, ExprEvalStep *op,
						   ExprContext *econtext);
extern void ExecEvalWholeRowVar(ExprState *state, ExprEvalStep *op,
					ExprContext *econtext);

extern void ExecAggInitGroup(AggState *aggstate, AggStatePerTrans pertrans, AggStatePerGroup pergroup);
extern Datum ExecAggTransReparent(AggState *aggstate, AggStatePerTrans pertrans,
					 Datum newValue, bool newValueIsNull,
					 Datum oldValue, bool oldValueIsNull);
extern void ExecEvalAggOrderedTransDatum(ExprState *state, ExprEvalStep *op,
							 ExprContext *econtext);
extern void ExecEvalAggOrderedTransTuple(ExprState *state, ExprEvalStep *op,
							 ExprContext *econtext);

#endif							/* EXEC_EXPR_H */