ClickHouse/src/Functions/synonyms.cpp
2021-06-19 18:52:09 +00:00

117 lines
4.0 KiB
C++

#include <Columns/ColumnArray.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnVector.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypeString.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/IFunction.h>
#include <Interpreters/Context.h>
#include <Interpreters/SynonymsExtensions.h>
#include <string_view>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
class FunctionSynonyms : public IFunction
{
public:
static constexpr auto name = "synonyms";
static FunctionPtr create(ContextPtr context)
{
return std::make_shared<FunctionSynonyms>(context->getSynonymsExtensions());
}
private:
SynonymsExtensions & extensions;
public:
FunctionSynonyms(SynonymsExtensions & extensions_)
: extensions(extensions_) {}
String getName() const override { return name; }
size_t getNumberOfArguments() const override { return 2; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
if (!isString(arguments[0]))
throw Exception(
"Illegal type " + arguments[0]->getName() + " of argument of function " + getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
if (!isString(arguments[1]))
throw Exception(
"Illegal type " + arguments[1]->getName() + " of argument of function " + getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>());
}
bool useDefaultImplementationForConstants() const override { return true; }
ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {0}; }
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
{
const auto & extcolumn = arguments[0].column;
const auto & strcolumn = arguments[1].column;
const ColumnConst * ext_col = checkAndGetColumn<ColumnConst>(extcolumn.get());
const ColumnString * word_col = checkAndGetColumn<ColumnString>(strcolumn.get());
if (!ext_col)
throw Exception(
"Illegal column " + arguments[0].column->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
if (!word_col)
throw Exception(
"Illegal column " + arguments[1].column->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
String ext_name = ext_col->getValue<String>();
auto extension = extensions.getExtension(ext_name);
/// Create and fill the result array.
const DataTypePtr & elem_type = static_cast<const DataTypeArray &>(*result_type).getNestedType();
auto out = ColumnArray::create(elem_type->createColumn());
IColumn & out_data = out->getData();
IColumn::Offsets & out_offsets = out->getOffsets();
const ColumnString::Chars & data = word_col->getChars();
const ColumnString::Offsets & offsets = word_col->getOffsets();
out_data.reserve(input_rows_count);
out_offsets.resize(input_rows_count);
IColumn::Offset current_offset = 0;
for (size_t i = 0; i < offsets.size(); ++i)
{
std::string_view word(reinterpret_cast<const char *>(data.data() + offsets[i - 1]), offsets[i] - offsets[i - 1] - 1);
auto synset = extension->getSynonyms(word);
if (synset)
{
for (const auto &token : *synset)
out_data.insert(Field(token.data(), token.size()));
current_offset += synset->size();
}
out_offsets[i] = current_offset;
}
return out;
}
};
void registerFunctionSynonyms(FunctionFactory & factory)
{
factory.registerFunction<FunctionSynonyms>(FunctionFactory::CaseInsensitive);
}
}