hdfs-scanner-ir.cc

Go to the documentation of this file.

// Copyright 2012 Cloudera Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 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 "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "exec/hdfs-scanner.h"
#include "runtime/row-batch.h"
#include "util/string-parser.h"
#include "runtime/string-value.inline.h"

#include "common/names.h"

using namespace impala;

// Functions in this file are cross compiled to IR with clang.  These functions
// are modified at runtime with a query specific codegen'd WriteTuple

// This function will output tuples to the row batch from parsed field locations.
// The fields locations should be aligned to the start of the tuple (field at 0 is
// the first materialized slot).
// This function takes more arguments than are strictly necessary (they could be
// computed inside this function) but this is done to minimize the clang dependencies,
// specifically, calling function on the scan node.
int HdfsScanner::WriteAlignedTuples(MemPool* pool, TupleRow* tuple_row, int row_size,
    FieldLocation* fields, int num_tuples, int max_added_tuples,
    int slots_per_tuple, int row_idx_start) {

  DCHECK(tuple_ != NULL);
  uint8_t* tuple_row_mem = reinterpret_cast<uint8_t*>(tuple_row);
  uint8_t* tuple_mem = reinterpret_cast<uint8_t*>(tuple_);
  Tuple* tuple = reinterpret_cast<Tuple*>(tuple_mem);

  uint8_t error[slots_per_tuple];
  memset(error, 0, sizeof(error));

  int tuples_returned = 0;

  // Loop through the fields and materialize all the tuples
  for (int i = 0; i < num_tuples; ++i) {
    uint8_t error_in_row = false;
    // Materialize a single tuple.  This function will be replaced by a codegen'd
    // function.
    if (WriteCompleteTuple(pool, fields, tuple, tuple_row, template_tuple_,
          error, &error_in_row)) {
      ++tuples_returned;
      tuple_mem += tuple_byte_size_;
      tuple_row_mem += row_size;
      tuple = reinterpret_cast<Tuple*>(tuple_mem);
      tuple_row = reinterpret_cast<TupleRow*>(tuple_row_mem);
    }

    // Report parse errors
    if (UNLIKELY(error_in_row)) {
      if (!ReportTupleParseError(fields, error, i + row_idx_start)) {
        return -1;
      }
    }

    // Advance to the start of the next tuple
    fields += slots_per_tuple;

    if (tuples_returned == max_added_tuples) {
      break;
    }
  }

  return tuples_returned;
}

ExprContext* HdfsScanner::GetConjunctCtx (int idx) const {
  return conjunct_ctxs_[idx];
}

// Define the string parsing functions for llvm.  Stamp out the templated functions
#ifdef IR_COMPILE
extern "C"
bool IrStringToBool(const char* s, int len, StringParser::ParseResult* result) {
  return StringParser::StringToBool(s, len, result);
}

int8_t IrStringToInt8(const char* s, int len, StringParser::ParseResult* result) {
  return StringParser::StringToInt<int8_t>(s, len, result);
}

extern "C"
int16_t IrStringToInt16(const char* s, int len, StringParser::ParseResult* result) {
  return StringParser::StringToInt<int16_t>(s, len, result);
}

extern "C"
int32_t IrStringToInt32(const char* s, int len, StringParser::ParseResult* result) {
  return StringParser::StringToInt<int32_t>(s, len, result);
}

extern "C"
int64_t IrStringToInt64(const char* s, int len, StringParser::ParseResult* result) {
  return StringParser::StringToInt<int64_t>(s, len, result);
}

extern "C"
float IrStringToFloat(const char* s, int len, StringParser::ParseResult* result) {
  return StringParser::StringToFloat<float>(s, len, result);
}

extern "C"
double IrStringToDouble(const char* s, int len, StringParser::ParseResult* result) {
  return StringParser::StringToFloat<double>(s, len, result);
}

extern "C"
bool IrIsNullString(const char* data, int len) {
  return data == NULL || (len == 2 && data[0] == '\\' && data[1] == 'N');
}

extern "C"
bool IrGenericIsNullString(const char* s, int slen, const char* n, int nlen) {
  return s == NULL || (slen == nlen && StringCompare(s, slen, n, nlen, slen) == 0);
}
#endif