ClickHouse/src/Parsers/ASTColumnsTransformers.cpp
2022-08-29 01:21:12 +08:00

416 lines
12 KiB
C++

#include <map>
#include "ASTColumnsTransformers.h"
#include <IO/WriteHelpers.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTIdentifier.h>
#include <Common/SipHash.h>
#include <Common/quoteString.h>
#include <IO/Operators.h>
#include <re2/re2.h>
#include <stack>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int NO_SUCH_COLUMN_IN_TABLE;
extern const int CANNOT_COMPILE_REGEXP;
}
void IASTColumnsTransformer::transform(const ASTPtr & transformer, ASTs & nodes)
{
if (const auto * apply = transformer->as<ASTColumnsApplyTransformer>())
{
apply->transform(nodes);
}
else if (const auto * except = transformer->as<ASTColumnsExceptTransformer>())
{
except->transform(nodes);
}
else if (const auto * replace = transformer->as<ASTColumnsReplaceTransformer>())
{
replace->transform(nodes);
}
}
void ASTColumnsApplyTransformer::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
{
settings.ostr << (settings.hilite ? hilite_keyword : "") << "APPLY" << (settings.hilite ? hilite_none : "") << " ";
if (!column_name_prefix.empty())
settings.ostr << "(";
if (lambda)
{
lambda->formatImpl(settings, state, frame);
}
else
{
settings.ostr << func_name;
if (parameters)
{
auto nested_frame = frame;
nested_frame.expression_list_prepend_whitespace = false;
settings.ostr << "(";
parameters->formatImpl(settings, state, nested_frame);
settings.ostr << ")";
}
}
if (!column_name_prefix.empty())
settings.ostr << ", '" << column_name_prefix << "')";
}
void ASTColumnsApplyTransformer::transform(ASTs & nodes) const
{
for (auto & column : nodes)
{
String name;
auto alias = column->tryGetAlias();
if (!alias.empty())
name = alias;
else
{
if (const auto * id = column->as<ASTIdentifier>())
name = id->shortName();
else
name = column->getColumnName();
}
if (lambda)
{
auto body = lambda->as<const ASTFunction &>().arguments->children.at(1)->clone();
std::stack<ASTPtr> stack;
stack.push(body);
while (!stack.empty())
{
auto ast = stack.top();
stack.pop();
for (auto & child : ast->children)
{
if (auto arg_name = tryGetIdentifierName(child); arg_name && arg_name == lambda_arg)
{
child = column->clone();
continue;
}
stack.push(child);
}
}
column = body;
}
else
{
auto function = makeASTFunction(func_name, column);
function->parameters = parameters;
column = function;
}
if (!column_name_prefix.empty())
column->setAlias(column_name_prefix + name);
}
}
void ASTColumnsApplyTransformer::appendColumnName(WriteBuffer & ostr) const
{
writeCString("APPLY ", ostr);
if (!column_name_prefix.empty())
writeChar('(', ostr);
if (lambda)
lambda->appendColumnName(ostr);
else
{
writeString(func_name, ostr);
if (parameters)
parameters->appendColumnName(ostr);
}
if (!column_name_prefix.empty())
{
writeCString(", '", ostr);
writeString(column_name_prefix, ostr);
writeCString("')", ostr);
}
}
void ASTColumnsApplyTransformer::updateTreeHashImpl(SipHash & hash_state) const
{
hash_state.update(func_name.size());
hash_state.update(func_name);
if (parameters)
parameters->updateTreeHashImpl(hash_state);
if (lambda)
lambda->updateTreeHashImpl(hash_state);
hash_state.update(lambda_arg.size());
hash_state.update(lambda_arg);
hash_state.update(column_name_prefix.size());
hash_state.update(column_name_prefix);
IAST::updateTreeHashImpl(hash_state);
}
void ASTColumnsExceptTransformer::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
{
settings.ostr << (settings.hilite ? hilite_keyword : "") << "EXCEPT" << (is_strict ? " STRICT " : " ") << (settings.hilite ? hilite_none : "");
if (children.size() > 1)
settings.ostr << "(";
for (ASTs::const_iterator it = children.begin(); it != children.end(); ++it)
{
if (it != children.begin())
{
settings.ostr << ", ";
}
(*it)->formatImpl(settings, state, frame);
}
if (!original_pattern.empty())
settings.ostr << quoteString(original_pattern);
if (children.size() > 1)
settings.ostr << ")";
}
void ASTColumnsExceptTransformer::appendColumnName(WriteBuffer & ostr) const
{
writeCString("EXCEPT ", ostr);
if (is_strict)
writeCString("STRICT ", ostr);
if (children.size() > 1)
writeChar('(', ostr);
for (ASTs::const_iterator it = children.begin(); it != children.end(); ++it)
{
if (it != children.begin())
writeCString(", ", ostr);
(*it)->appendColumnName(ostr);
}
if (!original_pattern.empty())
writeQuotedString(original_pattern, ostr);
if (children.size() > 1)
writeChar(')', ostr);
}
void ASTColumnsExceptTransformer::updateTreeHashImpl(SipHash & hash_state) const
{
hash_state.update(is_strict);
hash_state.update(original_pattern.size());
hash_state.update(original_pattern);
IAST::updateTreeHashImpl(hash_state);
}
void ASTColumnsExceptTransformer::transform(ASTs & nodes) const
{
std::set<String> expected_columns;
if (original_pattern.empty())
{
for (const auto & child : children)
expected_columns.insert(child->as<const ASTIdentifier &>().name());
for (auto it = nodes.begin(); it != nodes.end();)
{
if (const auto * id = it->get()->as<ASTIdentifier>())
{
auto expected_column = expected_columns.find(id->shortName());
if (expected_column != expected_columns.end())
{
expected_columns.erase(expected_column);
it = nodes.erase(it);
continue;
}
}
++it;
}
}
else
{
for (auto it = nodes.begin(); it != nodes.end();)
{
if (const auto * id = it->get()->as<ASTIdentifier>())
{
if (isColumnMatching(id->shortName()))
{
it = nodes.erase(it);
continue;
}
}
++it;
}
}
if (is_strict && !expected_columns.empty())
{
String expected_columns_str;
std::for_each(expected_columns.begin(), expected_columns.end(),
[&](String x) { expected_columns_str += (" " + x) ; });
throw Exception(
"Columns transformer EXCEPT expects following column(s) :" + expected_columns_str,
ErrorCodes::NO_SUCH_COLUMN_IN_TABLE);
}
}
void ASTColumnsExceptTransformer::setPattern(String pattern)
{
original_pattern = std::move(pattern);
column_matcher = std::make_shared<RE2>(original_pattern, RE2::Quiet);
if (!column_matcher->ok())
throw DB::Exception(
"COLUMNS pattern " + original_pattern + " cannot be compiled: " + column_matcher->error(),
DB::ErrorCodes::CANNOT_COMPILE_REGEXP);
}
bool ASTColumnsExceptTransformer::isColumnMatching(const String & column_name) const
{
return RE2::PartialMatch(column_name, *column_matcher);
}
void ASTColumnsReplaceTransformer::Replacement::formatImpl(
const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
{
expr->formatImpl(settings, state, frame);
settings.ostr << (settings.hilite ? hilite_keyword : "") << " AS " << (settings.hilite ? hilite_none : "") << backQuoteIfNeed(name);
}
void ASTColumnsReplaceTransformer::Replacement::appendColumnName(WriteBuffer & ostr) const
{
expr->appendColumnName(ostr);
writeCString(" AS ", ostr);
writeProbablyBackQuotedString(name, ostr);
}
void ASTColumnsReplaceTransformer::Replacement::updateTreeHashImpl(SipHash & hash_state) const
{
hash_state.update(name.size());
hash_state.update(name);
expr->updateTreeHashImpl(hash_state);
IAST::updateTreeHashImpl(hash_state);
}
void ASTColumnsReplaceTransformer::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
{
settings.ostr << (settings.hilite ? hilite_keyword : "") << "REPLACE" << (is_strict ? " STRICT " : " ") << (settings.hilite ? hilite_none : "");
if (children.size() > 1)
settings.ostr << "(";
for (ASTs::const_iterator it = children.begin(); it != children.end(); ++it)
{
if (it != children.begin())
settings.ostr << ", ";
(*it)->formatImpl(settings, state, frame);
}
if (children.size() > 1)
settings.ostr << ")";
}
void ASTColumnsReplaceTransformer::appendColumnName(WriteBuffer & ostr) const
{
writeCString("REPLACE ", ostr);
if (is_strict)
writeCString("STRICT ", ostr);
if (children.size() > 1)
writeChar('(', ostr);
for (ASTs::const_iterator it = children.begin(); it != children.end(); ++it)
{
if (it != children.begin())
writeCString(", ", ostr);
(*it)->appendColumnName(ostr);
}
if (children.size() > 1)
writeChar(')', ostr);
}
void ASTColumnsReplaceTransformer::updateTreeHashImpl(SipHash & hash_state) const
{
hash_state.update(is_strict);
IAST::updateTreeHashImpl(hash_state);
}
void ASTColumnsReplaceTransformer::replaceChildren(ASTPtr & node, const ASTPtr & replacement, const String & name)
{
for (auto & child : node->children)
{
if (const auto * id = child->as<ASTIdentifier>())
{
if (id->shortName() == name)
child = replacement->clone();
}
else
replaceChildren(child, replacement, name);
}
}
void ASTColumnsReplaceTransformer::transform(ASTs & nodes) const
{
std::map<String, ASTPtr> replace_map;
for (const auto & replace_child : children)
{
auto & replacement = replace_child->as<Replacement &>();
if (replace_map.find(replacement.name) != replace_map.end())
throw Exception(
"Expressions in columns transformer REPLACE should not contain the same replacement more than once",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
replace_map.emplace(replacement.name, replacement.expr);
}
for (auto & column : nodes)
{
if (const auto * id = column->as<ASTIdentifier>())
{
auto replace_it = replace_map.find(id->shortName());
if (replace_it != replace_map.end())
{
column = replace_it->second;
column->setAlias(replace_it->first);
replace_map.erase(replace_it);
}
}
else if (auto * ast_with_alias = dynamic_cast<ASTWithAlias *>(column.get()))
{
auto replace_it = replace_map.find(ast_with_alias->alias);
if (replace_it != replace_map.end())
{
auto new_ast = replace_it->second->clone();
ast_with_alias->alias = ""; // remove the old alias as it's useless after replace transformation
replaceChildren(new_ast, column, replace_it->first);
column = new_ast;
column->setAlias(replace_it->first);
replace_map.erase(replace_it);
}
}
}
if (is_strict && !replace_map.empty())
{
String expected_columns;
for (auto & elem: replace_map)
{
if (!expected_columns.empty())
expected_columns += ", ";
expected_columns += elem.first;
}
throw Exception(
"Columns transformer REPLACE expects following column(s) : " + expected_columns,
ErrorCodes::NO_SUCH_COLUMN_IN_TABLE);
}
}
}