YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

//--------------------------------------------------------------------------------------------------

// Copyright (c) YugaByte, 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 "yb/bfpg/bfpg.h"

#include <functional>

#include <unordered_map>

#include "yb/common/ql_type.h"

using std::function;

using std::vector;

using std::unordered_map;

using strings::Substitute;

namespace yb {

namespace bfpg {

//--------------------------------------------------------------------------------------------------

bool IsAggregateOpcode(TSOpcode op) {

  switch (op) {

  case TSOpcode::kAvg: FALLTHROUGH_INTENDED;

  case TSOpcode::kCount: FALLTHROUGH_INTENDED;

  case TSOpcode::kMax: FALLTHROUGH_INTENDED;

  case TSOpcode::kMin: FALLTHROUGH_INTENDED;

  case TSOpcode::kSumInt8: FALLTHROUGH_INTENDED;

  case TSOpcode::kSumInt16: FALLTHROUGH_INTENDED;

  case TSOpcode::kSumInt32: FALLTHROUGH_INTENDED;

  case TSOpcode::kSumInt64: FALLTHROUGH_INTENDED;

  case TSOpcode::kSumFloat: FALLTHROUGH_INTENDED;

  case TSOpcode::kSumDouble:

    return true;

  default:

    return false;

  }

}

//--------------------------------------------------------------------------------------------------

// Check compatible type in function call.

inline bool IsCompatible(DataType left, DataType right) {

  return QLType::IsPotentiallyConvertible(left, right);

}

//--------------------------------------------------------------------------------------------------

// HasExactSignature() is a predicate to check if the datatypes of actual parameters (arguments)

// and formal parameters (signature) are identical.

// NOTES:

//   PTypePtr can be a (shared_ptr<MyClass>) or a raw pointer (MyClass*)

static bool HasExactTypeSignature(const std::vector<DataType>& signature,

                                  const std::vector<DataType>& actual_types) {

  // Check parameter count.

  const auto formal_count = signature.size();

  const auto actual_count = actual_types.size();

  // Check for exact match.

  size_t index;

  for (index = 0; index < formal_count; index++) {

    // Check if the signature accept varargs which can be matched with the rest of arguments.

    if (signature[index] == DataType::TYPEARGS) {

      return true;

    }

    // Return false if one of the following is true.

    // - The number of arguments is less than the formal count.

    // - The datatype of an argument is not an exact match of the signature type.

    if (index >= actual_count || signature[index] != actual_types[index]) {

      return false;

    }

  }

  // Assert that the number of arguments is the same as the formal count.

  if (index < actual_count) {

    return false;

  }

  return true;

}

//--------------------------------------------------------------------------------------------------

// HasSimilarSignature() is a predicate to check if the datatypes of actual parameters (arguments)

// and formal parameters (signature) are similar.

//

// Similar is mainly used for integers vs floating point values.

//   INT8 is "similar" to INT64.

//   INT8 is NOT "similar" to DOUBLE.

//   FLOAT is "similar" to DOUBLE.

// This rule is to help resolve the overloading functions between integers and float point data.

//

// NOTES:

//   PTypePtr and RTypePtr can be either a (shared_ptr<MyClass>) or a raw pointer (MyClass*)

static bool HasSimilarTypeSignature(const std::vector<DataType>& signature,

                                    const std::vector<DataType>& actual_types) {

  const auto formal_count = signature.size();

  const auto actual_count = actual_types.size();

  // Check for exact match.

  size_t index;

  for (index = 0; index < formal_count; index++) {

    // Check if the signature accept varargs which can be matched with the rest of arguments.

    if (signature[index] == DataType::TYPEARGS) {

      return true;

    }

    // Return false if one of the following is true.

    // - The number of arguments is less than the formal count.

    // - The datatype of an argument is not an similar match of the signature type.

    if (index >= actual_count || !QLType::IsSimilar(signature[index], actual_types[index])) {

      return false;

    }

  }

  // Assert that the number of arguments is the same as the formal count.

  if (index < actual_count) {

    return false;

  }

  return true;

}

//--------------------------------------------------------------------------------------------------

// HasCompatibleSignature() is a predicate to check if the arguments is convertible to the

// signature.

//

// TODO(neil) Needs to allow passing double to int.

// NOTES:

//   PTypePtr and RTypePtr can be either a (shared_ptr<MyClass>) or a raw pointer (MyClass*).

static bool HasCompatibleTypeSignature(const std::vector<DataType>& signature,

                                       const std::vector<DataType>& actual_types) {

  const auto formal_count = signature.size();

  const auto actual_count = actual_types.size();

  // Check for compatible match.

  size_t index;

  for (index = 0; index < formal_count; index++) {

    // Check if the signature accept varargs which can be matched with the rest of arguments.

    if (signature[index] == DataType::TYPEARGS) {

      return true;

    }

    // Return false if one of the following is true.

    // - The number of arguments is less than the formal count.

    // - The datatype of an argument is not a compatible match of the signature type.

    if (index >= actual_count || !IsCompatible(signature[index], actual_types[index])) {

      return false;

    }

  }

  // Assert that the number of arguments is the same as the formal count.

  if (index < actual_count) {

    return false;

  }

  return true;

}

//--------------------------------------------------------------------------------------------------

// Searches all overloading versions of a function and finds exactly one function specification

// whose signature matches with the datatypes of the arguments.

// NOTES:

//   "compare_signature" is a predicate to compare datatypes of formal and actual parameters.

//   PTypePtr and RTypePtr can be either a (shared_ptr<MyClass>) or a raw pointer (MyClass*)

static Status FindMatch(

    const string& ql_name,

    function<bool(const std::vector<DataType>&, const std::vector<DataType>&)> compare_signature,

    BFOpcode max_opcode,

    const std::vector<DataType>& actual_types,

    BFOpcode *found_opcode,

    const BFDecl **found_decl,

    DataType *return_type) {

  // Find a compatible operator, and raise error if there's more than one match.

  const BFOperator *compatible_operator = nullptr;

  while (true) {

    const BFOperator *bf_operator = kBFOperators[static_cast<int>(max_opcode)].get();

    DCHECK(max_opcode == bf_operator->opcode());

    // Check if each parameter has compatible type match.

    if (compare_signature(bf_operator->param_types(), actual_types)) {

      // Found a compatible match. Make sure that it is the only match.

      if (compatible_operator != nullptr) {

        return STATUS(InvalidArgument,

                      Substitute("Found too many matches for builtin function '$0'", ql_name));

      }

      compatible_operator = bf_operator;

    }

    // Break the loop if we have processed all operators in the overloading chain.

    if (max_opcode == bf_operator->overloaded_opcode()) {

      break;

    }

    // Jump to the next overloading opcode.

    max_opcode = bf_operator->overloaded_opcode();

  }

  // Returns error if no match is found.

  if (compatible_operator == nullptr) {

    return STATUS(NotFound,

                  Substitute("Signature mismatch in call to builtin function '$0'", ql_name));

  }

  // Returns error if the return type is not compatible.

  if (return_type != nullptr) {

    if (QLType::IsUnknown(*return_type)) {

      *return_type = compatible_operator->return_type();

    } else if (!IsCompatible(*return_type, compatible_operator->return_type())) {

      return STATUS(InvalidArgument,

                    Substitute("Return-type mismatch in call to builtin function '$0'", ql_name));

    }

  }

  // Raise error if the function execution was not yet implemented.

  if (!compatible_operator->op_decl()->implemented()) {

    return STATUS(NotSupported,

                  Substitute("Builtin function '$0' is not yet implemented", ql_name));

  }

  *found_opcode = compatible_operator->opcode();

  *found_decl = compatible_operator->op_decl();

  return Status::OK();

}

//--------------------------------------------------------------------------------------------------

// Find the builtin opcode, declaration, and return type for a builtin call.

// Inputs: Builtin function name and parameter types.

// Outputs: opcode and bfdecl.

// In/Out parameter: return_type

//   If return_type is given, check if it is compatible with the declaration.

//   If not, return_type is an output parameter whose value is the return type of the builtin.

Status FindOpcodeByType(const string& ql_name,

                        const std::vector<DataType>& actual_types,

                        BFOpcode *opcode,

                        const BFDecl **bfdecl,

                        DataType *return_type) {

  auto entry = kBfPgsqlName2Opcode.find(ql_name);

  if (entry == kBfPgsqlName2Opcode.end()) {

    VLOG(3) << strings::Substitute("Function '$0' does not exist", ql_name);

    return STATUS(NotFound, strings::Substitute("Function '$0' does not exist", ql_name));

  }

  // Seek the correct overload functions in the following order:

  // - Find the exact signature match.

  //   Example:

  //   . Overload #1: FuncX(int8_t i) would be used for the call FuncX(int8_t(7)).

  //   . Overload #2: FuncX(int16_t i) would be used for the call FuncX(int16_t(7)).

  //

  // - For "cast" operator, if exact match is not found, return error. For all other operators,

  //   continue to the next steps.

  //

  // - Find the similar signature match.

  //   Example:

  //   . Overload #2: FuncY(int64_t i) would be used for FuncY(int8_t(7)).

  //       int64_t and int8_t are both integer values.

  //   . Overload #1: FuncY(double d) would be used for FuncY(float(7)).

  //       double & float are both floating values.

  //

  // - Find the compatible match. Signatures are of convertible datatypes.

  Status s = FindMatch(ql_name, HasExactTypeSignature, entry->second, actual_types,

                       opcode, bfdecl, return_type);

  VLOG(3) << "Seek exact match for function call " << ql_name << "(): " << s.ToString();

  if (ql_name != kCastFuncName && s.IsNotFound()) {

    s = FindMatch(ql_name, HasSimilarTypeSignature, entry->second, actual_types,

                  opcode, bfdecl, return_type);

    VLOG(3) << "Seek similar match for function call " << ql_name << "(): " << s.ToString();

    if (s.IsNotFound()) {

      s = FindMatch(ql_name, HasCompatibleTypeSignature, entry->second, actual_types,

                    opcode, bfdecl, return_type);

      VLOG(3) << "Seek compatible match for function call " << ql_name << "(): " << s.ToString();

    }

  }

  return s;

}

} // namespace bfpg

} // namespace yb