/**
* Determines whether a {@link RexCall} requires decimal expansion. It usually requires expansion
* if it has decimal operands.
*
* <p>Exceptions to this rule are:
*
* <ul>
* <li>isNull doesn't require expansion
* <li>It's okay to cast decimals to and from char types
* <li>It's okay to cast nulls as decimals
* <li>Casts require expansion if their return type is decimal
* <li>Reinterpret casts can handle a decimal operand
* </ul>
*
* @param expr expression possibly in need of expansion
* @param recurse whether to check nested calls
* @return whether the expression requires expansion
*/
public static boolean requiresDecimalExpansion(RexNode expr, boolean recurse) {
if (!(expr instanceof RexCall)) {
return false;
}
RexCall call = (RexCall) expr;
boolean localCheck = true;
switch (call.getKind()) {
case Reinterpret:
case IsNull:
localCheck = false;
break;
case Cast:
RelDataType lhsType = call.getType();
RelDataType rhsType = call.operands[0].getType();
if (rhsType.getSqlTypeName() == SqlTypeName.NULL) {
return false;
}
if (SqlTypeUtil.inCharFamily(lhsType) || SqlTypeUtil.inCharFamily(rhsType)) {
localCheck = false;
} else if (SqlTypeUtil.isDecimal(lhsType) && (lhsType != rhsType)) {
return true;
}
break;
default:
localCheck = call.getOperator().requiresDecimalExpansion();
}
if (localCheck) {
if (SqlTypeUtil.isDecimal(call.getType())) {
// NOTE jvs 27-Mar-2007: Depending on the type factory, the
// result of a division may be decimal, even though both inputs
// are integer.
return true;
}
for (int i = 0; i < call.operands.length; i++) {
if (SqlTypeUtil.isDecimal(call.operands[i].getType())) {
return true;
}
}
}
return (recurse && requiresDecimalExpansion(call.operands, recurse));
}
// override RexShuttle
public RexNode visitCall(final RexCall call) {
int i = reducibleExps.indexOf(call);
if (i == -1) {
return super.visitCall(call);
}
RexNode replacement = reducedValues.get(i);
if (addCasts.get(i) && (replacement.getType() != call.getType())) {
// Handle change from nullable to NOT NULL by claiming
// that the result is still nullable, even though
// we know it isn't.
//
// Also, we cannot reduce CAST('abc' AS VARCHAR(4)) to 'abc'.
// If we make 'abc' of type VARCHAR(4), we may later encounter
// the same expression in a ProjectRel's digest where it has
// type VARCHAR(3), and that's wrong.
replacement = rexBuilder.makeCast(call.getType(), replacement);
}
return replacement;
}
/**
* Replaces the operands of a call. The new operands' types must match the old operands' types.
*/
public static RexCall replaceOperands(RexCall call, RexNode[] operands) {
if (call.operands == operands) {
return call;
}
for (int i = 0; i < operands.length; i++) {
RelDataType oldType = call.operands[i].getType();
RelDataType newType = operands[i].getType();
if (!oldType.isNullable() && newType.isNullable()) {
throw Util.newInternal("invalid nullability");
}
assert (oldType.toString().equals(newType.toString()));
}
return new RexCall(call.getType(), call.getOperator(), operands);
}
public RexNode visitCall(RexCall call) {
List<RexNode> normalizedOperands = new ArrayList<RexNode>();
int diffCount = 0;
for (RexNode operand : call.getOperands()) {
operand.accept(this);
final RexNode normalizedOperand = lookup(operand);
normalizedOperands.add(normalizedOperand);
if (normalizedOperand != operand) {
++diffCount;
}
}
if (diffCount > 0) {
call = call.clone(call.getType(), normalizedOperands);
}
return register(call);
}
@Override
public String translate(ExprCompiler compiler, RexCall call) {
String val = compiler.reserveName();
PrintWriter pw = compiler.pw;
RexNode op = call.getOperands().get(0);
String lhs = op.accept(compiler);
boolean nullable = call.getType().isNullable();
pw.print(String.format("final %s %s;\n", compiler.javaTypeName(call), val));
if (!nullable) {
pw.print(String.format("%1$s = !(%2$s);\n", val, lhs));
} else {
String s =
foldNullExpr(String.format("%1$s == null ? null : !(%1$s)", lhs), "null", op);
pw.print(String.format("%1$s = %2$s;\n", val, s));
}
return val;
}
private void reduceCasts(RexCall outerCast) {
RexNode[] operands = outerCast.getOperands();
if (operands.length != 1) {
return;
}
RelDataType outerCastType = outerCast.getType();
RelDataType operandType = operands[0].getType();
if (operandType.equals(outerCastType)) {
removableCasts.add(outerCast);
return;
}
// See if the reduction
// CAST((CAST x AS type) AS type NOT NULL)
// -> CAST(x AS type NOT NULL)
// applies. TODO jvs 15-Dec-2008: consider
// similar cases for precision changes.
if (!(operands[0] instanceof RexCall)) {
return;
}
RexCall innerCast = (RexCall) operands[0];
if (innerCast.getOperator() != SqlStdOperatorTable.castFunc) {
return;
}
if (innerCast.getOperands().length != 1) {
return;
}
RelDataTypeFactory typeFactory = preparingStmt.getFarragoTypeFactory();
RelDataType outerTypeNullable = typeFactory.createTypeWithNullability(outerCastType, true);
RelDataType innerTypeNullable = typeFactory.createTypeWithNullability(operandType, true);
if (outerTypeNullable != innerTypeNullable) {
return;
}
if (operandType.isNullable()) {
removableCasts.add(innerCast);
}
}
// implement FarragoOJRexImplementor
public Expression implementFarrago(
FarragoRexToOJTranslator translator, RexCall call, Expression[] operands) {
RelDataType lhsType = call.getType();
RelDataType rhsType = call.operands[0].getType();
Expression rhsExp = operands[0];
SqlTypeName lhsTypeName = lhsType.getSqlTypeName();
if ((lhsTypeName == SqlTypeName.CURSOR) || (lhsTypeName == SqlTypeName.COLUMN_LIST)) {
// Conversion should already have been taken care of outside.
return rhsExp;
}
// NOTE jvs 19-Nov-2008: In some cases (e.g. FRG-273) a cast
// may be illegal at the SQL level, but allowable as part of
// implementation, so don't try to enforce
// SqlTypeUtil.canCastFrom here. Anything which was supposed
// to have been prevented should already have been caught
// by the validator.
CastHelper helper =
new CastHelper(translator, null, call.toString(), lhsType, rhsType, null, rhsExp);
return helper.implement();
}
/** Converts an expression from {@link RexNode} to {@link SqlNode} format. */
SqlNode toSql(RexProgram program, RexNode rex) {
if (rex instanceof RexLocalRef) {
final int index = ((RexLocalRef) rex).getIndex();
return toSql(program, program.getExprList().get(index));
} else if (rex instanceof RexInputRef) {
return field(((RexInputRef) rex).getIndex());
} else if (rex instanceof RexLiteral) {
final RexLiteral literal = (RexLiteral) rex;
switch (literal.getTypeName().getFamily()) {
case CHARACTER:
return SqlLiteral.createCharString((String) literal.getValue2(), POS);
case NUMERIC:
case EXACT_NUMERIC:
return SqlLiteral.createExactNumeric(literal.getValue().toString(), POS);
case APPROXIMATE_NUMERIC:
return SqlLiteral.createApproxNumeric(literal.getValue().toString(), POS);
case BOOLEAN:
return SqlLiteral.createBoolean((Boolean) literal.getValue(), POS);
case DATE:
return SqlLiteral.createDate((Calendar) literal.getValue(), POS);
case TIME:
return SqlLiteral.createTime(
(Calendar) literal.getValue(), literal.getType().getPrecision(), POS);
case TIMESTAMP:
return SqlLiteral.createTimestamp(
(Calendar) literal.getValue(), literal.getType().getPrecision(), POS);
case ANY:
switch (literal.getTypeName()) {
case NULL:
return SqlLiteral.createNull(POS);
// fall through
}
default:
throw new AssertionError(literal + ": " + literal.getTypeName());
}
} else if (rex instanceof RexCall) {
final RexCall call = (RexCall) rex;
final SqlOperator op = call.getOperator();
final List<SqlNode> nodeList = toSql(program, call.getOperands());
if (op == SqlStdOperatorTable.CAST) {
RelDataType type = call.getType();
if (type.getSqlTypeName() == SqlTypeName.VARCHAR
&& dialect.getDatabaseProduct() == SqlDialect.DatabaseProduct.MYSQL) {
// MySQL doesn't have a VARCHAR type, only CHAR.
nodeList.add(
new SqlDataTypeSpec(
new SqlIdentifier("CHAR", POS), type.getPrecision(), -1, null, null, POS));
} else {
nodeList.add(toSql(type));
}
}
if (op == SqlStdOperatorTable.CASE) {
final SqlNode valueNode;
final List<SqlNode> whenList = Expressions.list();
final List<SqlNode> thenList = Expressions.list();
final SqlNode elseNode;
if (nodeList.size() % 2 == 0) {
// switched:
// "case x when v1 then t1 when v2 then t2 ... else e end"
valueNode = nodeList.get(0);
for (int i = 1; i < nodeList.size() - 1; i += 2) {
whenList.add(nodeList.get(i));
thenList.add(nodeList.get(i + 1));
}
} else {
// other: "case when w1 then t1 when w2 then t2 ... else e end"
valueNode = null;
for (int i = 0; i < nodeList.size() - 1; i += 2) {
whenList.add(nodeList.get(i));
thenList.add(nodeList.get(i + 1));
}
}
elseNode = nodeList.get(nodeList.size() - 1);
return op.createCall(
POS,
valueNode,
new SqlNodeList(whenList, POS),
new SqlNodeList(thenList, POS),
elseNode);
}
if (op instanceof SqlBinaryOperator && nodeList.size() > 2) {
// In RexNode trees, OR and AND have any number of children;
// SqlCall requires exactly 2. So, convert to a left-deep binary tree.
return createLeftCall(op, nodeList);
}
return op.createCall(new SqlNodeList(nodeList, POS));
} else {
throw new AssertionError(rex);
}
}
