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add functions to extract clause from boolean expressions #162

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91 changes: 91 additions & 0 deletions src/query.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,18 @@ void extractClauseFromScalarArrayOpExpr(Relids base_relids,
ScalarArrayOpExpr *node,
List **quals);

void extractClauseFromBooleanTest(Relids base_relids,
BooleanTest *node,
List **quals);

void extractClauseFromBoolExpr(Relids base_relids,
BoolExpr *node,
List **quals);

void extractClauseFromVar(Relids base_relids,
Var *node,
List **quals);

char *getOperatorString(Oid opoid);

MulticornBaseQual *makeQual(AttrNumber varattno, char *opname, Expr *value,
Expand Down Expand Up @@ -304,6 +316,17 @@ extractRestrictions(Relids base_relids,
(ScalarArrayOpExpr *) node,
quals);
break;
case T_BooleanTest:
extractClauseFromBooleanTest(base_relids,
(BooleanTest *) node, quals);
break;
case T_BoolExpr:
extractClauseFromBoolExpr(base_relids,
(BoolExpr *) node, quals);
break;
case T_Var:
extractClauseFromVar(base_relids, (Var *) node, quals);
break;
default:
{
ereport(WARNING,
Expand Down Expand Up @@ -412,7 +435,75 @@ extractClauseFromNullTest(Relids base_relids,
}
}

/*
* Convert a "BooleanTest" (IS TRUE, IS FALSE, IS NOT FALSE, IS NOT TRUE,
* IS UNKNOWN or IS NOT UNKNOWN) to a suitable intermediate representation.
*/
void
extractClauseFromBooleanTest(Relids base_relids,
BooleanTest *node,
List **quals)
{
if (IsA(node->arg, Var))
{
Var *var = (Var *) node->arg;
char *opname = NULL;

switch (node->booltesttype)
{
case IS_TRUE:
case IS_NOT_FALSE:
case IS_NOT_UNKNOWN:
opname = "=";
break;
default:
opname = "<>";
break;
}

*quals = lappend(*quals,
makeQual(var->varattno, opname,
(Expr *) makeBoolConst(true, false),
false, false));
}
}

/*
* Convert a "BoolExpr" (operator NOT)
* to a suitable intermediate representation.
*/
void
extractClauseFromBoolExpr(Relids base_relids,
BoolExpr *node,
List **quals)
{
if (node->boolop == NOT_EXPR)
{
Var *var = list_nth(node->args, 0);

*quals = lappend(*quals,
makeQual(var->varattno, "<>",
(Expr *) makeBoolConst(true, false),
false, false));
}
}

/*
* Convert a "Var" to a suitable intermediate representation.
*/
void
extractClauseFromVar(Relids base_relids,
Var *node,
List **quals)
{
if (node->vartype == BOOLOID)
{
*quals = lappend(*quals,
makeQual(node->varattno, "=",
(Expr *) makeBoolConst(true, false),
false, false));
}
}

/*
* Returns a "Value" node containing the string name of the column from a var.
Expand Down