Function TidExprListCreate

src/backend/executor/nodeTidscan.c:66–122

* Extract the qual subexpressions that yield TIDs to search for, * and compile them into ExprStates if they're ordinary expressions. * * CURRENT OF is a special case that we can't compile usefully; * just drop it into the TidExpr list as-is. */

 * just drop it into the TidExpr list as-is.
 */
static void
TidExprListCreate(TidScanState *tidstate)
{
	TidScan    *node = (TidScan *) tidstate->ss.ps.plan;
	ListCell   *l;

	tidstate->tss_tidexprs = NIL;
	tidstate->tss_isCurrentOf = false;

	foreach(l, node->tidquals)
	{
		Expr	   *expr = (Expr *) lfirst(l);
		TidExpr    *tidexpr = (TidExpr *) palloc0(sizeof(TidExpr));

		if (is_opclause(expr))
		{
			Node	   *arg1;
			Node	   *arg2;

			arg1 = get_leftop(expr);
			arg2 = get_rightop(expr);
			if (IsCTIDVar(arg1))
				tidexpr->exprstate = ExecInitExpr((Expr *) arg2,
												  &tidstate->ss.ps);
			else if (IsCTIDVar(arg2))
				tidexpr->exprstate = ExecInitExpr((Expr *) arg1,
												  &tidstate->ss.ps);
			else
				elog(ERROR, "could not identify CTID variable");
			tidexpr->isarray = false;
		}
		else if (expr && IsA(expr, ScalarArrayOpExpr))
		{
			ScalarArrayOpExpr *saex = (ScalarArrayOpExpr *) expr;

			Assert(IsCTIDVar(linitial(saex->args)));
			tidexpr->exprstate = ExecInitExpr(lsecond(saex->args),
											  &tidstate->ss.ps);
			tidexpr->isarray = true;
		}
		else if (expr && IsA(expr, CurrentOfExpr))
		{
			CurrentOfExpr *cexpr = (CurrentOfExpr *) expr;

			tidexpr->cexpr = cexpr;
			tidstate->tss_isCurrentOf = true;
		}
		else
			elog(ERROR, "could not identify CTID expression");

		tidstate->tss_tidexprs = lappend(tidstate->tss_tidexprs, tidexpr);
	}

	/* CurrentOfExpr could never appear OR'd with something else */
	Assert(list_length(tidstate->tss_tidexprs) == 1 ||
		   !tidstate->tss_isCurrentOf);
}