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#include <Formats/StructureToFormatSchemaUtils.h>
#include <IO/WriteHelpers.h>
namespace DB
{
namespace StructureToFormatSchemaUtils
{
void writeIndent(WriteBuffer & buf, size_t indent)
{
writeChar(' ', indent * 4, buf);
}
void startNested(WriteBuffer & buf, const String & nested_name, const String & nested_type, size_t indent)
{
writeIndent(buf, indent);
writeString(nested_type, buf);
if (!nested_name.empty())
{
writeChar(' ', buf);
writeString(nested_name, buf);
}
writeChar('\n', buf);
writeIndent(buf, indent);
writeCString("{\n", buf);
}
void endNested(WriteBuffer & buf, size_t indent)
{
writeIndent(buf, indent);
writeCString("}\n", buf);
}
String getSchemaFieldName(const String & column_name)
{
String result = column_name;
/// Replace all first uppercase letters to lower-case,
/// because fields in CapnProto schema must begin with a lower-case letter.
/// Don't replace all letters to lower-case to remain camelCase field names.
for (auto & symbol : result)
{
if (islower(symbol))
break;
symbol = tolower(symbol);
}
return result;
}
String getSchemaMessageName(const String & column_name)
{
String result = column_name;
if (!column_name.empty() && isalpha(column_name[0]))
result[0] = toupper(column_name[0]);
return result;
}
namespace
{
std::pair<String, String> splitName(const String & name)
{
const auto * begin = name.data();
const auto * end = name.data() + name.size();
const auto * it = find_first_symbols<'_', '.'>(begin, end);
String first = String(begin, it);
String second = it == end ? "" : String(it + 1, end);
return {std::move(first), std::move(second)};
}
}
NamesAndTypesList collectNested(const NamesAndTypesList & names_and_types)
{
/// Find all columns with dots '.' or underscores '_' and move them into a tuple.
/// For example if we have columns 'a.b UInt32, a.c UInt32, x_y String' we will
/// change it to 'a Tuple(b UInt32, c UInt32), x Tuple(y String)'
NamesAndTypesList result;
std::unordered_map<String, NamesAndTypesList> nested;
for (const auto & [name, type] : names_and_types)
{
auto [field_name, nested_name] = splitName(name);
if (nested_name.empty())
result.emplace_back(name, type);
else
nested[field_name].emplace_back(nested_name, type);
}
for (const auto & [field_name, elements]: nested)
result.emplace_back(field_name, std::make_shared<DataTypeTuple>(elements.getTypes(), elements.getNames()));
return result;
}
NamesAndTypesList getCollectedTupleElements(const DataTypeTuple & tuple_type)
{
const auto & nested_types = tuple_type.getElements();
Names nested_names;
if (tuple_type.haveExplicitNames())
{
nested_names = tuple_type.getElementNames();
}
else
{
nested_names.reserve(nested_types.size());
for (size_t i = 0; i != nested_types.size(); ++i)
nested_names.push_back("e" + std::to_string(i + 1));
}
NamesAndTypesList result;
for (size_t i = 0; i != nested_names.size(); ++i)
result.emplace_back(nested_names[i], nested_types[i]);
return collectNested(result);
}
}
}
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