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// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
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//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
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#include "exprs/tuple-is-null-predicate.h"

#include <sstream>

#include "gen-cpp/Exprs_types.h"

#include "common/names.h"
#include "runtime/descriptors.h"
#include "runtime/tuple-row.h"

namespace impala {

BooleanVal TupleIsNullPredicate::GetBooleanValInterpreted(
    ScalarExprEvaluator* evaluator, const TupleRow* row) const {
  int count = 0;
  for (int i = 0; i < tuple_idxs_.size(); ++i) {
    count += row->GetTuple(tuple_idxs_[i]) == NULL;
  }
  // Return true only if all originally specified tuples are NULL. Return false if any
  // tuple is non-nullable.
  return BooleanVal(count == tuple_ids_.size());
}

TupleIsNullPredicate::TupleIsNullPredicate(const TExprNode& node)
  : Predicate(node),
    tuple_ids_(node.tuple_is_null_pred.tuple_ids.begin(),
        node.tuple_is_null_pred.tuple_ids.end()) {}

Status TupleIsNullPredicate::Init(
    const RowDescriptor& row_desc, bool is_entry_point, RuntimeState* state) {
  RETURN_IF_ERROR(ScalarExpr::Init(row_desc, is_entry_point, state));
  DCHECK_EQ(0, children_.size());
  // Resolve tuple ids to tuple indexes.
  for (int i = 0; i < tuple_ids_.size(); ++i) {
    int32_t tuple_idx = row_desc.GetTupleIdx(tuple_ids_[i]);
    if (tuple_idx == RowDescriptor::INVALID_IDX) {
      // This should not happen and indicates a planner issue. This code is tricky
      // so rather than crashing, do this as a stop gap.
      // TODO: remove this code and replace with DCHECK.
      return Status("Invalid plan. TupleIsNullPredicate has invalid tuple idx.");
    }
    if (row_desc.TupleIsNullable(tuple_idx)) tuple_idxs_.push_back(tuple_idx);
  }
  return Status::OK();
}

Status TupleIsNullPredicate::GetCodegendComputeFnImpl(LlvmCodeGen* codegen,
    llvm::Function** fn) {
  return GetCodegendComputeFnWrapper(codegen, fn);
}

string TupleIsNullPredicate::DebugString() const {
  stringstream out;
  out << "TupleIsNullPredicate(tupleids=[";
  for (int i = 0; i < tuple_ids_.size(); ++i) {
    out << (i == 0 ? "" : " ") << tuple_ids_[i];
  }
  out << "])";
  return out.str();
}

}