ClickHouse/dbms/src/Formats/CapnProtoRowInputStream.cpp
2019-01-17 21:49:56 +03:00

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#include <Common/config.h>
#if USE_CAPNP
#include <Common/escapeForFileName.h>
#include <IO/ReadBuffer.h>
#include <Interpreters/Context.h>
#include <Formats/CapnProtoRowInputStream.h> // Y_IGNORE
#include <Formats/FormatFactory.h>
#include <Formats/BlockInputStreamFromRowInputStream.h>
#include <capnp/serialize.h> // Y_IGNORE
#include <capnp/dynamic.h> // Y_IGNORE
#include <capnp/common.h> // Y_IGNORE
#include <boost/algorithm/string.hpp>
#include <boost/range/join.hpp>
#include <common/logger_useful.h>
namespace DB
{
namespace ErrorCodes
{
extern const int BAD_TYPE_OF_FIELD;
extern const int BAD_ARGUMENTS;
extern const int THERE_IS_NO_COLUMN;
extern const int LOGICAL_ERROR;
}
static String getSchemaPath(const String & schema_dir, const String & schema_file)
{
return schema_dir + escapeForFileName(schema_file) + ".capnp";
}
CapnProtoRowInputStream::NestedField split(const Block & header, size_t i)
{
CapnProtoRowInputStream::NestedField field = {{}, i};
// Remove leading dot in field definition, e.g. ".msg" -> "msg"
String name(header.safeGetByPosition(i).name);
if (name.size() > 0 && name[0] == '.')
name.erase(0, 1);
boost::split(field.tokens, name, boost::is_any_of("._"));
return field;
}
Field convertNodeToField(capnp::DynamicValue::Reader value)
{
switch (value.getType())
{
case capnp::DynamicValue::UNKNOWN:
throw Exception("Unknown field type", ErrorCodes::BAD_TYPE_OF_FIELD);
case capnp::DynamicValue::VOID:
return Field();
case capnp::DynamicValue::BOOL:
return value.as<bool>() ? 1u : 0u;
case capnp::DynamicValue::INT:
return value.as<int64_t>();
case capnp::DynamicValue::UINT:
return value.as<uint64_t>();
case capnp::DynamicValue::FLOAT:
return value.as<double>();
case capnp::DynamicValue::TEXT:
{
auto arr = value.as<capnp::Text>();
return String(arr.begin(), arr.size());
}
case capnp::DynamicValue::DATA:
{
auto arr = value.as<capnp::Data>().asChars();
return String(arr.begin(), arr.size());
}
case capnp::DynamicValue::LIST:
{
auto listValue = value.as<capnp::DynamicList>();
Array res(listValue.size());
for (auto i : kj::indices(listValue))
res[i] = convertNodeToField(listValue[i]);
return res;
}
case capnp::DynamicValue::ENUM:
return value.as<capnp::DynamicEnum>().getRaw();
case capnp::DynamicValue::STRUCT:
{
auto structValue = value.as<capnp::DynamicStruct>();
const auto & fields = structValue.getSchema().getFields();
Field field = Tuple(TupleBackend(fields.size()));
TupleBackend & tuple = get<Tuple &>(field).toUnderType();
for (auto i : kj::indices(fields))
tuple[i] = convertNodeToField(structValue.get(fields[i]));
return field;
}
case capnp::DynamicValue::CAPABILITY:
throw Exception("CAPABILITY type not supported", ErrorCodes::BAD_TYPE_OF_FIELD);
case capnp::DynamicValue::ANY_POINTER:
throw Exception("ANY_POINTER type not supported", ErrorCodes::BAD_TYPE_OF_FIELD);
}
return Field();
}
capnp::StructSchema::Field getFieldOrThrow(capnp::StructSchema node, const std::string & field)
{
KJ_IF_MAYBE(child, node.findFieldByName(field))
return *child;
else
throw Exception("Field " + field + " doesn't exist in schema " + node.getShortDisplayName().cStr(), ErrorCodes::THERE_IS_NO_COLUMN);
}
void CapnProtoRowInputStream::createActions(const NestedFieldList & sorted_fields, capnp::StructSchema reader)
{
/// Columns in a table can map to fields in Cap'n'Proto or to structs.
/// Store common parents and their tokens in order to backtrack.
std::vector<capnp::StructSchema::Field> parents;
std::vector<std::string> parent_tokens;
capnp::StructSchema cur_reader = reader;
for (const auto & field : sorted_fields)
{
if (field.tokens.empty())
throw Exception("Logical error in CapnProtoRowInputStream", ErrorCodes::LOGICAL_ERROR);
// Backtrack to common parent
while (field.tokens.size() < parent_tokens.size() + 1
|| !std::equal(parent_tokens.begin(), parent_tokens.end(), field.tokens.begin()))
{
actions.push_back({Action::POP});
parents.pop_back();
parent_tokens.pop_back();
if (parents.empty())
{
cur_reader = reader;
break;
}
else
cur_reader = parents.back().getType().asStruct();
}
// Go forward
while (parent_tokens.size() + 1 < field.tokens.size())
{
const auto & token = field.tokens[parents.size()];
auto node = getFieldOrThrow(cur_reader, token);
if (node.getType().isStruct())
{
// Descend to field structure
parents.emplace_back(node);
parent_tokens.emplace_back(token);
cur_reader = node.getType().asStruct();
actions.push_back({Action::PUSH, node});
}
else if (node.getType().isList())
{
break; // Collect list
}
else
throw Exception("Field " + token + " is neither Struct nor List", ErrorCodes::BAD_TYPE_OF_FIELD);
}
// Read field from the structure
auto node = getFieldOrThrow(cur_reader, field.tokens[parents.size()]);
if (node.getType().isList() && actions.size() > 0 && actions.back().field == node)
{
// The field list here flattens Nested elements into multiple arrays
// In order to map Nested types in Cap'nProto back, they need to be collected
// Since the field names are sorted, the order of field positions must be preserved
// For example, if the fields are { b @0 :Text, a @1 :Text }, the `a` would come first
// even though it's position is second.
auto & columns = actions.back().columns;
auto it = std::upper_bound(columns.cbegin(), columns.cend(), field.pos);
columns.insert(it, field.pos);
}
else
{
actions.push_back({Action::READ, node, {field.pos}});
}
}
}
CapnProtoRowInputStream::CapnProtoRowInputStream(ReadBuffer & istr_, const Block & header_, const String & schema_dir, const String & schema_file, const String & root_object)
: istr(istr_), header(header_), parser(std::make_shared<SchemaParser>())
{
// Parse the schema and fetch the root object
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
auto schema = parser->impl.parseDiskFile(schema_file, getSchemaPath(schema_dir, schema_file), {});
#pragma GCC diagnostic pop
root = schema.getNested(root_object).asStruct();
/**
* The schema typically consists of fields in various nested structures.
* Here we gather the list of fields and sort them in a way so that fields in the same structure are adjacent,
* and the nesting level doesn't decrease to make traversal easier.
*/
NestedFieldList list;
size_t num_columns = header.columns();
for (size_t i = 0; i < num_columns; ++i)
list.push_back(split(header, i));
// Order list first by value of strings then by length of string vector.
std::sort(list.begin(), list.end(), [](const NestedField & a, const NestedField & b) { return a.tokens < b.tokens; });
createActions(list, root);
}
bool CapnProtoRowInputStream::read(MutableColumns & columns, RowReadExtension &)
{
if (istr.eof())
return false;
// Read from underlying buffer directly
auto buf = istr.buffer();
auto base = reinterpret_cast<const capnp::word *>(istr.position());
// Check if there's enough bytes in the buffer to read the full message
kj::Array<capnp::word> heap_array;
auto array = kj::arrayPtr(base, buf.size() - istr.offset());
auto expected_words = capnp::expectedSizeInWordsFromPrefix(array);
if (expected_words * sizeof(capnp::word) > array.size())
{
// We'll need to reassemble the message in a contiguous buffer
heap_array = kj::heapArray<capnp::word>(expected_words);
istr.readStrict(heap_array.asChars().begin(), heap_array.asChars().size());
array = heap_array.asPtr();
}
#if CAPNP_VERSION >= 8000
capnp::UnalignedFlatArrayMessageReader msg(array);
#else
capnp::FlatArrayMessageReader msg(array);
#endif
std::vector<capnp::DynamicStruct::Reader> stack;
stack.push_back(msg.getRoot<capnp::DynamicStruct>(root));
for (auto action : actions)
{
switch (action.type)
{
case Action::READ:
{
Field value = convertNodeToField(stack.back().get(action.field));
if (action.columns.size() > 1)
{
// Nested columns must be flattened into several arrays
// e.g. Array(Tuple(x ..., y ...)) -> Array(x ...), Array(y ...)
const Array & collected = DB::get<const Array &>(value);
size_t size = collected.size();
// The flattened array contains an array of a part of the nested tuple
Array flattened(size);
for (size_t column_index = 0; column_index < action.columns.size(); ++column_index)
{
// Populate array with a single tuple elements
for (size_t off = 0; off < size; ++off)
{
const TupleBackend & tuple = DB::get<const Tuple &>(collected[off]).toUnderType();
flattened[off] = tuple[column_index];
}
auto & col = columns[action.columns[column_index]];
col->insert(flattened);
}
}
else
{
auto & col = columns[action.columns[0]];
col->insert(value);
}
break;
}
case Action::POP:
stack.pop_back();
break;
case Action::PUSH:
stack.push_back(stack.back().get(action.field).as<capnp::DynamicStruct>());
break;
}
}
// Advance buffer position if used directly
if (heap_array.size() == 0)
{
auto parsed = (msg.getEnd() - base) * sizeof(capnp::word);
istr.position() += parsed;
}
return true;
}
void registerInputFormatCapnProto(FormatFactory & factory)
{
factory.registerInputFormat("CapnProto", [](
ReadBuffer & buf,
const Block & sample,
const Context & context,
size_t max_block_size,
const FormatSettings & settings)
{
std::vector<String> tokens;
auto schema_and_root = context.getSettingsRef().format_schema.toString();
boost::split(tokens, schema_and_root, boost::is_any_of(":"));
if (tokens.size() != 2)
throw Exception("Format CapnProto requires 'format_schema' setting to have a schema_file:root_object format, e.g. 'schema.capnp:Message'",
ErrorCodes::BAD_ARGUMENTS);
const String & schema_dir = context.getFormatSchemaPath();
return std::make_shared<BlockInputStreamFromRowInputStream>(
std::make_shared<CapnProtoRowInputStream>(buf, sample, schema_dir, tokens[0], tokens[1]),
sample, max_block_size, settings);
});
}
}
#else
namespace DB
{
class FormatFactory;
void registerInputFormatCapnProto(FormatFactory &) {}
}
#endif // USE_CAPNP