//////////////////////////////////////////////////////////////////////////////// /// @brief Aql, query AST /// /// @file /// /// DISCLAIMER /// /// Copyright 2014 ArangoDB GmbH, Cologne, Germany /// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany /// /// 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. /// /// Copyright holder is ArangoDB GmbH, Cologne, Germany /// /// @author Jan Steemann /// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany /// @author Copyright 2012-2013, triAGENS GmbH, Cologne, Germany //////////////////////////////////////////////////////////////////////////////// #include "Aql/Ast.h" #include "Aql/Arithmetic.h" #include "Aql/Collection.h" #include "Aql/Executor.h" #include "Basics/tri-strings.h" #include "Utils/Exception.h" #include "VocBase/collection.h" using namespace triagens::aql; // ----------------------------------------------------------------------------- // --SECTION-- static initialisation // ----------------------------------------------------------------------------- //////////////////////////////////////////////////////////////////////////////// /// @brief initialise a singleton no-op node instance //////////////////////////////////////////////////////////////////////////////// AstNode const Ast::NopNode{ NODE_TYPE_NOP }; //////////////////////////////////////////////////////////////////////////////// /// @brief initialise a singleton null node instance //////////////////////////////////////////////////////////////////////////////// AstNode const Ast::NullNode{ NODE_TYPE_VALUE, VALUE_TYPE_NULL }; //////////////////////////////////////////////////////////////////////////////// /// @brief initialise a singleton false node instance //////////////////////////////////////////////////////////////////////////////// AstNode const Ast::FalseNode{ false }; //////////////////////////////////////////////////////////////////////////////// /// @brief initialise a singleton true node instance //////////////////////////////////////////////////////////////////////////////// AstNode const Ast::TrueNode{ true }; //////////////////////////////////////////////////////////////////////////////// /// @brief inverse comparison operators //////////////////////////////////////////////////////////////////////////////// std::unordered_map const Ast::ReverseOperators{ { static_cast(NODE_TYPE_OPERATOR_BINARY_EQ), NODE_TYPE_OPERATOR_BINARY_NE }, { static_cast(NODE_TYPE_OPERATOR_BINARY_NE), NODE_TYPE_OPERATOR_BINARY_EQ }, { static_cast(NODE_TYPE_OPERATOR_BINARY_GT), NODE_TYPE_OPERATOR_BINARY_LE }, { static_cast(NODE_TYPE_OPERATOR_BINARY_GE), NODE_TYPE_OPERATOR_BINARY_LT }, { static_cast(NODE_TYPE_OPERATOR_BINARY_LT), NODE_TYPE_OPERATOR_BINARY_GE }, { static_cast(NODE_TYPE_OPERATOR_BINARY_LE), NODE_TYPE_OPERATOR_BINARY_GT }, { static_cast(NODE_TYPE_OPERATOR_BINARY_IN), NODE_TYPE_OPERATOR_BINARY_NIN }, { static_cast(NODE_TYPE_OPERATOR_BINARY_NIN), NODE_TYPE_OPERATOR_BINARY_IN } }; // ----------------------------------------------------------------------------- // --SECTION-- constructors / destructors // ----------------------------------------------------------------------------- //////////////////////////////////////////////////////////////////////////////// /// @brief create the AST //////////////////////////////////////////////////////////////////////////////// Ast::Ast (Query* query) : _query(query), _scopes(), _variables(), _bindParameters(), _root(nullptr), _queries(), _writeCollection(nullptr) { TRI_ASSERT(_query != nullptr); startSubQuery(); TRI_ASSERT(_root != nullptr); } //////////////////////////////////////////////////////////////////////////////// /// @brief destroy the AST //////////////////////////////////////////////////////////////////////////////// Ast::~Ast () { } // ----------------------------------------------------------------------------- // --SECTION-- public functions // ----------------------------------------------------------------------------- //////////////////////////////////////////////////////////////////////////////// /// @brief convert the AST into JSON /// the caller is responsible for freeing the JSON later //////////////////////////////////////////////////////////////////////////////// TRI_json_t* Ast::toJson (TRI_memory_zone_t* zone, bool verbose) const { TRI_json_t* json = TRI_CreateListJson(zone); try { _root->toJson(json, zone, verbose); } catch (...) { TRI_FreeJson(zone, json); THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } return json; } //////////////////////////////////////////////////////////////////////////////// /// @brief destroy the AST //////////////////////////////////////////////////////////////////////////////// void Ast::addOperation (AstNode* node) { TRI_ASSERT(_root != nullptr); _root->addMember(node); } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST for node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeFor (char const* variableName, AstNode const* expression) { if (variableName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_FOR); AstNode* variable = createNodeVariable(variableName, true); node->addMember(variable); node->addMember(expression); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST let node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeLet (char const* variableName, AstNode const* expression, bool isUserDefinedVariable) { if (variableName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_LET); AstNode* variable = createNodeVariable(variableName, isUserDefinedVariable); node->addMember(variable); node->addMember(expression); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST filter node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeFilter (AstNode const* expression) { AstNode* node = createNode(NODE_TYPE_FILTER); node->addMember(expression); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST return node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeReturn (AstNode const* expression) { AstNode* node = createNode(NODE_TYPE_RETURN); node->addMember(expression); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST remove node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeRemove (AstNode const* expression, AstNode const* collection, AstNode const* options) { AstNode* node = createNode(NODE_TYPE_REMOVE); if (options == nullptr) { // no options given. now use default options options = &NopNode; } node->addMember(options); node->addMember(collection); node->addMember(expression); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST insert node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeInsert (AstNode const* expression, AstNode const* collection, AstNode const* options) { AstNode* node = createNode(NODE_TYPE_INSERT); if (options == nullptr) { // no options given. now use default options options = &NopNode; } node->addMember(options); node->addMember(collection); node->addMember(expression); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST update node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeUpdate (AstNode const* keyExpression, AstNode const* docExpression, AstNode const* collection, AstNode const* options) { AstNode* node = createNode(NODE_TYPE_UPDATE); if (options == nullptr) { // no options given. now use default options options = &NopNode; } node->addMember(options); node->addMember(collection); node->addMember(docExpression); if (keyExpression != nullptr) { node->addMember(keyExpression); } return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST replace node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeReplace (AstNode const* keyExpression, AstNode const* docExpression, AstNode const* collection, AstNode const* options) { AstNode* node = createNode(NODE_TYPE_REPLACE); if (options == nullptr) { // no options given. now use default options options = &NopNode; } node->addMember(options); node->addMember(collection); node->addMember(docExpression); if (keyExpression != nullptr) { node->addMember(keyExpression); } return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST collect node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeCollect (AstNode const* list, char const* name) { AstNode* node = createNode(NODE_TYPE_COLLECT); node->addMember(list); if (name != nullptr) { AstNode* variable = createNodeVariable(name, true); node->addMember(variable); } return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST sort node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeSort (AstNode const* list) { AstNode* node = createNode(NODE_TYPE_SORT); node->addMember(list); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST sort element node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeSortElement (AstNode const* expression, bool ascending) { AstNode* node = createNode(NODE_TYPE_SORT_ELEMENT); node->addMember(expression); node->setBoolValue(ascending); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST limit node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeLimit (AstNode const* offset, AstNode const* count) { AstNode* node = createNode(NODE_TYPE_LIMIT); node->addMember(offset); node->addMember(count); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST assign node, used in COLLECT statements //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeAssign (char const* variableName, AstNode const* expression) { if (variableName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_ASSIGN); AstNode* variable = createNodeVariable(variableName, true); node->addMember(variable); node->addMember(expression); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST variable node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeVariable (char const* name, bool isUserDefined) { if (name == nullptr || *name == '\0') { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } if (isUserDefined && *name == '_') { _query->registerError(TRI_ERROR_QUERY_VARIABLE_NAME_INVALID); return nullptr; } if (_scopes.existsVariable(name)) { _query->registerError(TRI_ERROR_QUERY_VARIABLE_REDECLARED, name); return nullptr; } auto variable = _variables.createVariable(name, isUserDefined); _scopes.addVariable(variable); AstNode* node = createNode(NODE_TYPE_VARIABLE); node->setData(static_cast(variable)); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST collection node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeCollection (char const* name) { if (name == nullptr || *name == '\0') { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } if (! TRI_IsAllowedNameCollection(true, name)) { _query->registerError(TRI_ERROR_ARANGO_ILLEGAL_NAME, name); return nullptr; } AstNode* node = createNode(NODE_TYPE_COLLECTION); node->setStringValue(name); _query->collections()->add(name, TRI_TRANSACTION_READ); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST reference node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeReference (char const* variableName) { if (variableName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_REFERENCE); auto variable = _scopes.getVariable(variableName); if (variable == nullptr) { THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL, "variable not found in reference AstNode"); } node->setData(variable); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST parameter node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeParameter (char const* name) { if (name == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_PARAMETER); node->setStringValue(name); // insert bind parameter name into list of found parameters _bindParameters.emplace(name); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST unary operator node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeUnaryOperator (AstNodeType type, AstNode const* operand) { AstNode* node = createNode(type); node->addMember(operand); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST binary operator node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeBinaryOperator (AstNodeType type, AstNode const* lhs, AstNode const* rhs) { AstNode* node = createNode(type); node->addMember(lhs); node->addMember(rhs); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST ternary operator node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeTernaryOperator (AstNode const* condition, AstNode const* truePart, AstNode const* falsePart) { AstNode* node = createNode(NODE_TYPE_OPERATOR_TERNARY); node->addMember(condition); node->addMember(truePart); node->addMember(falsePart); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST subquery node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeSubquery (char const* variableName, AstNode const* subQuery) { if (variableName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_SUBQUERY); AstNode* variable = createNodeVariable(variableName, false); node->addMember(variable); node->addMember(subQuery); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST attribute access node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeAttributeAccess (AstNode const* accessed, char const* attributeName) { if (attributeName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_ATTRIBUTE_ACCESS); node->addMember(accessed); node->setStringValue(attributeName); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST attribute access node w/ bind parameter //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeBoundAttributeAccess (AstNode const* accessed, AstNode const* parameter) { AstNode* node = createNode(NODE_TYPE_BOUND_ATTRIBUTE_ACCESS); node->setStringValue(parameter->getStringValue()); node->addMember(accessed); node->addMember(parameter); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST indexed access node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeIndexedAccess (AstNode const* accessed, AstNode const* indexValue) { AstNode* node = createNode(NODE_TYPE_INDEXED_ACCESS); node->addMember(accessed); node->addMember(indexValue); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST expand node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeExpand (AstNode const* iterator, AstNode const* expansion) { AstNode* node = createNode(NODE_TYPE_EXPAND); node->addMember(iterator); node->addMember(expansion); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST iterator node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeIterator (char const* variableName, AstNode const* expanded) { if (variableName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_ITERATOR); AstNode* variable = createNodeVariable(variableName, false); node->addMember(variable); node->addMember(expanded); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST null value node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeValueNull () { // return a pointer to the singleton null node // note: this node is never registered nor freed return const_cast(&NullNode); } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST bool value node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeValueBool (bool value) { // return a pointer to the singleton bool nodes // note: these nodes are never registered nor freed if (value) { return const_cast(&TrueNode); } return const_cast(&FalseNode); } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST int value node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeValueInt (int64_t value) { AstNode* node = createNode(NODE_TYPE_VALUE); node->setValueType(VALUE_TYPE_INT); node->setIntValue(value); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST double value node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeValueDouble (double value) { AstNode* node = createNode(NODE_TYPE_VALUE); node->setValueType(VALUE_TYPE_DOUBLE); node->setDoubleValue(value); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST string value node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeValueString (char const* value) { if (value == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_VALUE); node->setValueType(VALUE_TYPE_STRING); node->setStringValue(value); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST list node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeList () { AstNode* node = createNode(NODE_TYPE_LIST); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST array node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeArray () { AstNode* node = createNode(NODE_TYPE_ARRAY); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST array element node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeArrayElement (char const* attributeName, AstNode const* expression) { if (attributeName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* node = createNode(NODE_TYPE_ARRAY_ELEMENT); node->setStringValue(attributeName); node->addMember(expression); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST function call node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeFunctionCall (char const* functionName, AstNode const* arguments) { if (functionName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } auto normalized = normalizeFunctionName(functionName); AstNode* node; if (normalized.second) { // built-in function node = createNode(NODE_TYPE_FCALL); // register a pointer to the function auto func = _query->executor()->getFunctionByName(normalized.first); TRI_ASSERT(func != nullptr); node->setData(static_cast(func)); TRI_ASSERT(arguments != nullptr); TRI_ASSERT(arguments->type == NODE_TYPE_LIST); // validate number of function call arguments size_t const n = arguments->numMembers(); auto numExpectedArguments = func->numArguments(); if (n < numExpectedArguments.first || n > numExpectedArguments.second) { THROW_ARANGO_EXCEPTION_PARAMS(TRI_ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH, functionName, static_cast(numExpectedArguments.first), static_cast(numExpectedArguments.second)); } } else { // user-defined function node = createNode(NODE_TYPE_FCALL_USER); // register the function name char* fname = _query->registerString(normalized.first.c_str(), normalized.first.size(), false); node->setStringValue(fname); } node->addMember(arguments); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST range node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeRange (AstNode const* start, AstNode const* end) { AstNode* node = createNode(NODE_TYPE_RANGE); node->addMember(start); node->addMember(end); return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST nop node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNodeNop () { return const_cast(&NopNode); } //////////////////////////////////////////////////////////////////////////////// /// @brief injects bind parameters into the AST //////////////////////////////////////////////////////////////////////////////// void Ast::injectBindParameters (BindParameters& parameters) { auto p = parameters(); auto func = [&](AstNode* node, void*) -> AstNode* { if (node->type == NODE_TYPE_PARAMETER) { // found a bind parameter in the query string char const* param = node->getStringValue(); if (param == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } auto it = p.find(std::string(param)); if (it == p.end()) { // query uses a bind parameter that was not defined by the user _query->registerError(TRI_ERROR_QUERY_BIND_PARAMETER_MISSING, param); return nullptr; } // mark the bind parameter as being used (*it).second.second = true; auto value = (*it).second.first; if (*param == '@') { // collection parameter TRI_ASSERT(TRI_IsStringJson(value)); bool isWriteCollection = false; if (_writeCollection != nullptr && _writeCollection->type == NODE_TYPE_PARAMETER && strcmp(param, _writeCollection->getStringValue()) == 0) { isWriteCollection = true; } // turn node into a collection node char const* name = _query->registerString(value->_value._string.data, value->_value._string.length - 1, false); node = createNodeCollection(name); if (isWriteCollection) { // this was the bind parameter that contained the collection to update _writeCollection = node; } } else { node = nodeFromJson(value); } } else if (node->type == NODE_TYPE_BOUND_ATTRIBUTE_ACCESS) { // look at second sub-node. this is the (replaced) bind parameter auto name = node->getMember(1); if (name->type != NODE_TYPE_VALUE || name->value.type != VALUE_TYPE_STRING || *name->value.value._string == '\0') { // if no string value was inserted for the parameter name, this is an error THROW_ARANGO_EXCEPTION_PARAMS(TRI_ERROR_QUERY_BIND_PARAMETER_TYPE, node->getStringValue()); } } return node; }; _root = traverse(_root, func, &p); if (_writeCollection != nullptr && _writeCollection->type == NODE_TYPE_COLLECTION) { _query->collections()->add(_writeCollection->getStringValue(), TRI_TRANSACTION_WRITE); } for (auto it = p.begin(); it != p.end(); ++it) { if (! (*it).second.second) { THROW_ARANGO_EXCEPTION_PARAMS(TRI_ERROR_QUERY_BIND_PARAMETER_UNDECLARED, (*it).first.c_str()); } } } //////////////////////////////////////////////////////////////////////////////// /// @brief replace variables //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::replaceVariables (AstNode* node, std::unordered_map const& replacements) { auto func = [&](AstNode* node, void*) -> AstNode* { if (node == nullptr) { return nullptr; } // reference to a variable if (node->type == NODE_TYPE_REFERENCE) { auto variable = static_cast(node->getData()); if (variable != nullptr) { auto it = replacements.find(variable->id); if (it != replacements.end()) { // overwrite the node in place node->setData((*it).second); } } // fall-through intentional } return node; }; return traverse(node, func, nullptr); } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes the AST //////////////////////////////////////////////////////////////////////////////// void Ast::optimize () { auto func = [&](AstNode* node, void*) -> AstNode* { if (node == nullptr) { return nullptr; } // unary operators if (node->type == NODE_TYPE_OPERATOR_UNARY_PLUS || node->type == NODE_TYPE_OPERATOR_UNARY_MINUS) { return optimizeUnaryOperatorArithmetic(node); } if (node->type == NODE_TYPE_OPERATOR_UNARY_NOT) { return optimizeUnaryOperatorLogical(node); } // binary operators if (node->type == NODE_TYPE_OPERATOR_BINARY_AND || node->type == NODE_TYPE_OPERATOR_BINARY_OR) { return optimizeBinaryOperatorLogical(node); } if (node->type == NODE_TYPE_OPERATOR_BINARY_EQ || node->type == NODE_TYPE_OPERATOR_BINARY_NE || node->type == NODE_TYPE_OPERATOR_BINARY_LT || node->type == NODE_TYPE_OPERATOR_BINARY_LE || node->type == NODE_TYPE_OPERATOR_BINARY_GT || node->type == NODE_TYPE_OPERATOR_BINARY_GE || node->type == NODE_TYPE_OPERATOR_BINARY_IN || node->type == NODE_TYPE_OPERATOR_BINARY_NIN) { return optimizeBinaryOperatorRelational(node); } if (node->type == NODE_TYPE_OPERATOR_BINARY_PLUS || node->type == NODE_TYPE_OPERATOR_BINARY_MINUS || node->type == NODE_TYPE_OPERATOR_BINARY_TIMES || node->type == NODE_TYPE_OPERATOR_BINARY_DIV || node->type == NODE_TYPE_OPERATOR_BINARY_MOD) { return optimizeBinaryOperatorArithmetic(node); } // ternary operator if (node->type == NODE_TYPE_OPERATOR_TERNARY) { return optimizeTernaryOperator(node); } // call to built-in function if (node->type == NODE_TYPE_FCALL) { return optimizeFunctionCall(node); } // reference to a variable if (node->type == NODE_TYPE_REFERENCE) { return optimizeReference(node); } // LET if (node->type == NODE_TYPE_LET) { return optimizeLet(node); } return node; }; // optimization _root = traverse(_root, func, nullptr); } //////////////////////////////////////////////////////////////////////////////// /// @brief determines the variables referenced in an expression //////////////////////////////////////////////////////////////////////////////// std::unordered_set Ast::getReferencedVariables (AstNode const* node) { auto func = [&](AstNode const* node, void* data) -> void { if (node == nullptr) { return; } // reference to a variable if (node->type == NODE_TYPE_REFERENCE) { auto variable = static_cast(node->getData()); if (variable == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } if (variable->needsRegister()) { auto result = static_cast*>(data); result->insert(variable); } } }; std::unordered_set result; traverse(node, func, &result); return result; } //////////////////////////////////////////////////////////////////////////////// /// @brief recursively clone a node //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::clone (AstNode const* node) { auto type = node->type; auto copy = createNode(type); // special handling for certain node types // copy payload... if (type == NODE_TYPE_COLLECTION || type == NODE_TYPE_PARAMETER || type == NODE_TYPE_ATTRIBUTE_ACCESS || type == NODE_TYPE_ARRAY_ELEMENT || type == NODE_TYPE_FCALL_USER) { copy->setStringValue(node->getStringValue()); } else if (type == NODE_TYPE_VARIABLE || type == NODE_TYPE_REFERENCE || type == NODE_TYPE_FCALL) { copy->setData(node->getData()); } else if (type == NODE_TYPE_SORT_ELEMENT) { copy->setBoolValue(node->getBoolValue()); } else if (type == NODE_TYPE_VALUE) { switch (node->value.type) { case VALUE_TYPE_BOOL: copy->setBoolValue(node->getBoolValue()); break; case VALUE_TYPE_INT: copy->setIntValue(node->getIntValue()); break; case VALUE_TYPE_DOUBLE: copy->setDoubleValue(node->getDoubleValue()); break; case VALUE_TYPE_STRING: copy->setStringValue(node->getStringValue()); break; default: { } } } // recursively clone subnodes size_t const n = node->numMembers(); for (size_t i = 0; i < n; ++i) { copy->addMember(clone(node->getMember(i))); } return copy; } // ----------------------------------------------------------------------------- // --SECTION-- private methods // ----------------------------------------------------------------------------- //////////////////////////////////////////////////////////////////////////////// /// @brief create a number node for an arithmetic result, integer //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createArithmeticResultNode (int64_t value) { return createNodeValueInt(value); } //////////////////////////////////////////////////////////////////////////////// /// @brief create a number node for an arithmetic result, double //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createArithmeticResultNode (double value) { if (value != value || value == HUGE_VAL || value == - HUGE_VAL) { // IEEE754 NaN values have an interesting property that we can exploit... // if the architecture does not use IEEE754 values then this shouldn't do // any harm either // TODO: log an error: _query->registerError(TRI_ERROR_QUERY_NUMBER_OUT_OF_RANGE); return createNodeValueNull(); } return createNodeValueDouble(value); } //////////////////////////////////////////////////////////////////////////////// /// @brief executes an expression with constant parameters //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::executeConstExpression (AstNode const* node) { // must enter v8 before we can execute any expression v8::HandleScope scope; // do not delete this! _query->enterContext(); TRI_json_t* result = _query->executor()->executeExpression(node); if (result == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } AstNode* value = nullptr; try { value = nodeFromJson(result); } catch (...) { } TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, result); if (value == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } return value; } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes the unary operators + and - /// the unary plus will be converted into a simple value node if the operand of /// the operation is a constant number //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeUnaryOperatorArithmetic (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->type == NODE_TYPE_OPERATOR_UNARY_PLUS || node->type == NODE_TYPE_OPERATOR_UNARY_MINUS); TRI_ASSERT(node->numMembers() == 1); AstNode* operand = node->getMember(0); if (! operand->isConstant()) { // operand is dynamic, cannot statically optimize it return node; } // operand is a constant, now convert it into a number auto converted = operand->castToNumber(this); if (converted->isNullValue()) { return createNodeValueNull(); } if (node->type == NODE_TYPE_OPERATOR_UNARY_PLUS) { // + number => number return converted; } else { // - number if (converted->value.type == VALUE_TYPE_INT) { // int64 return createNodeValueInt(- converted->getIntValue()); } else { // double double const value = - converted->getDoubleValue(); if (value != value || value == HUGE_VAL || value == - HUGE_VAL) { // IEEE754 NaN values have an interesting property that we can exploit... // if the architecture does not use IEEE754 values then this shouldn't do // any harm either return createNodeValueNull(); } return createNodeValueDouble(value); } } TRI_ASSERT(false); } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes the unary operator NOT /// the unary NOT operation will be replaced with the result of the operation //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeNotExpression (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->type == NODE_TYPE_OPERATOR_UNARY_NOT); TRI_ASSERT(node->numMembers() == 1); AstNode* operand = node->getMember(0); if (operand->isComparisonOperator()) { // remove the NOT and reverse the operation, e.g. NOT (a == b) => (a != b) TRI_ASSERT(operand->numMembers() == 2); auto lhs = operand->getMember(0); auto rhs = operand->getMember(1); auto it = ReverseOperators.find(static_cast(operand->type)); TRI_ASSERT(it != ReverseOperators.end()); return createNodeBinaryOperator((*it).second, lhs, rhs); } return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes the unary operator NOT /// the unary NOT operation will be replaced with the result of the operation //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeUnaryOperatorLogical (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->type == NODE_TYPE_OPERATOR_UNARY_NOT); TRI_ASSERT(node->numMembers() == 1); AstNode* operand = node->getMember(0); if (! operand->isConstant()) { // operand is dynamic, cannot statically optimize it return optimizeNotExpression(node); } auto converted = operand->castToBool(this); // replace unary negation operation with result of negation return createNodeValueBool(! converted->getBoolValue()); } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes the binary logical operators && and || //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeBinaryOperatorLogical (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->type == NODE_TYPE_OPERATOR_BINARY_AND || node->type == NODE_TYPE_OPERATOR_BINARY_OR); TRI_ASSERT(node->numMembers() == 2); auto lhs = node->getMember(0); auto rhs = node->getMember(1); if (lhs == nullptr || rhs == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } if (lhs->isConstant()) { if (node->type == NODE_TYPE_OPERATOR_BINARY_AND) { // left operand is a constant value if (lhs->isFalse()) { // return it if it is falsey return lhs; } // left-operand was trueish, now return right operand return rhs; } else if (node->type == NODE_TYPE_OPERATOR_BINARY_OR) { // left operand is a constant value if (lhs->isTrue()) { // return it if it is trueish return lhs; } // left-operand was falsey, now return right operand return rhs; } } // default case return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes the binary relational operators <, <=, >, >=, ==, != and IN //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeBinaryOperatorRelational (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->numMembers() == 2); AstNode* lhs = node->getMember(0); AstNode* rhs = node->getMember(1); if (lhs == nullptr || rhs == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } bool const lhsIsConst = lhs->isConstant(); bool const rhsIsConst = rhs->isConstant(); if (! lhs->canThrow() && rhs->type == NODE_TYPE_LIST && rhs->numMembers() <= 1 && (node->type == NODE_TYPE_OPERATOR_BINARY_IN || node->type == NODE_TYPE_OPERATOR_BINARY_NIN)) { // turn an IN or a NOT IN with few members into an equality comparison if (rhs->numMembers() == 0) { // IN with no members returns false // NOT IN with no members returns true return createNodeValueBool(node->type == NODE_TYPE_OPERATOR_BINARY_NIN); } else if (rhs->numMembers() == 1) { // IN with a single member becomes equality // NOT IN with a single members becomes unequality if (node->type == NODE_TYPE_OPERATOR_BINARY_IN) { node = createNodeBinaryOperator(NODE_TYPE_OPERATOR_BINARY_EQ, lhs, rhs->getMember(0)); } else { node = createNodeBinaryOperator(NODE_TYPE_OPERATOR_BINARY_NE, lhs, rhs->getMember(0)); } // and optimize ourselves... return optimizeBinaryOperatorRelational(node); } // fall-through intentional } if (! rhsIsConst) { return node; } if (rhs->type != NODE_TYPE_LIST && (node->type == NODE_TYPE_OPERATOR_BINARY_IN || node->type == NODE_TYPE_OPERATOR_BINARY_NIN)) { // right operand of IN or NOT IN must be a list, otherwise we return false return createNodeValueBool(false); } if (! lhsIsConst) { return node; } return executeConstExpression(node); } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes the binary arithmetic operators +, -, *, / and % //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeBinaryOperatorArithmetic (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->numMembers() == 2); AstNode* lhs = node->getMember(0); AstNode* rhs = node->getMember(1); if (lhs == nullptr || rhs == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } if (lhs->isConstant() && rhs->isConstant()) { // now calculate the expression result if (node->type == NODE_TYPE_OPERATOR_BINARY_PLUS) { if (lhs->isStringValue() || lhs->isList() || lhs->isArray() || rhs->isStringValue() || rhs->isList() || rhs->isArray()) { // + means string concatenation if one of the operands is a string, a list or an array auto left = lhs->castToString(this); auto right = rhs->castToString(this); TRI_ASSERT(left->type == NODE_TYPE_VALUE && left->value.type == VALUE_TYPE_STRING); TRI_ASSERT(right->type == NODE_TYPE_VALUE && right->value.type == VALUE_TYPE_STRING); if (*left->value.value._string == '\0') { // left side is empty return right; } else if (*right->value.value._string == '\0') { // right side is empty return left; } // must concat char* concatenated = _query->registerStringConcat(left->value.value._string, right->value.value._string); TRI_ASSERT(concatenated != nullptr); return createNodeValueString(concatenated); } // arithmetic + auto left = lhs->castToNumber(this); auto right = rhs->castToNumber(this); bool useDoublePrecision = (left->isDoubleValue() || right->isDoubleValue()); if (! useDoublePrecision) { auto l = left->getIntValue(); auto r = right->getIntValue(); // check if the result would overflow useDoublePrecision = IsUnsafeAddition(l, r); if (! useDoublePrecision) { // can calculate using integers return createArithmeticResultNode(l + r); } } // must use double precision return createArithmeticResultNode(left->getDoubleValue() + right->getDoubleValue()); } else if (node->type == NODE_TYPE_OPERATOR_BINARY_MINUS) { auto left = lhs->castToNumber(this); auto right = rhs->castToNumber(this); bool useDoublePrecision = (left->isDoubleValue() || right->isDoubleValue()); if (! useDoublePrecision) { auto l = left->getIntValue(); auto r = right->getIntValue(); // check if the result would overflow useDoublePrecision = IsUnsafeSubtraction(l, r); if (! useDoublePrecision) { // can calculate using integers return createArithmeticResultNode(l - r); } } // must use double precision return createArithmeticResultNode(left->getDoubleValue() - right->getDoubleValue()); } else if (node->type == NODE_TYPE_OPERATOR_BINARY_TIMES) { auto left = lhs->castToNumber(this); auto right = rhs->castToNumber(this); bool useDoublePrecision = (left->isDoubleValue() || right->isDoubleValue()); if (! useDoublePrecision) { auto l = left->getIntValue(); auto r = right->getIntValue(); // check if the result would overflow useDoublePrecision = IsUnsafeMultiplication(l, r); if (! useDoublePrecision) { // can calculate using integers return createArithmeticResultNode(l * r); } } // must use double precision return createArithmeticResultNode(left->getDoubleValue() * right->getDoubleValue()); } else if (node->type == NODE_TYPE_OPERATOR_BINARY_DIV) { auto left = lhs->castToNumber(this); auto right = rhs->castToNumber(this); bool useDoublePrecision = (left->isDoubleValue() || right->isDoubleValue()); if (! useDoublePrecision) { auto l = left->getIntValue(); auto r = right->getIntValue(); if (r == 0) { // TODO: log an error _query->registerError(TRI_ERROR_QUERY_DIVISION_BY_ZERO); return createNodeValueNull(); } // check if the result would overflow useDoublePrecision = (IsUnsafeDivision(l, r) || r < -1 || r > 1); if (! useDoublePrecision) { // can calculate using integers return createArithmeticResultNode(l / r); } } if (right->getDoubleValue() == 0.0) { // TODO: log an error _query->registerError(TRI_ERROR_QUERY_DIVISION_BY_ZERO); return createNodeValueNull(); } return createArithmeticResultNode(left->getDoubleValue() / right->getDoubleValue()); } else if (node->type == NODE_TYPE_OPERATOR_BINARY_MOD) { auto left = lhs->castToNumber(this); auto right = rhs->castToNumber(this); bool useDoublePrecision = (left->isDoubleValue() || right->isDoubleValue()); if (! useDoublePrecision) { auto l = left->getIntValue(); auto r = right->getIntValue(); if (r == 0) { // TODO: log an error _query->registerError(TRI_ERROR_QUERY_DIVISION_BY_ZERO); return createNodeValueNull(); } // check if the result would overflow useDoublePrecision = IsUnsafeDivision(l, r); if (! useDoublePrecision) { // can calculate using integers return createArithmeticResultNode(l % r); } } if (right->getDoubleValue() == 0.0) { // TODO: log an error _query->registerError(TRI_ERROR_QUERY_DIVISION_BY_ZERO); return createNodeValueNull(); } return createArithmeticResultNode(fmod(left->getDoubleValue(), right->getDoubleValue())); } THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL, "invalid operator"); } return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes the ternary operator /// if the condition is constant, the operator will be replaced with either the /// true part or the false part //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeTernaryOperator (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->type == NODE_TYPE_OPERATOR_TERNARY); TRI_ASSERT(node->numMembers() == 3); AstNode* condition = node->getMember(0); AstNode* truePart = node->getMember(1); AstNode* falsePart = node->getMember(2); if (condition == nullptr || truePart == nullptr || falsePart == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } if (! condition->isConstant()) { return node; } if (condition->isTrue()) { // condition is always true, replace ternary operation with true part return truePart; } // condition is always false, replace ternary operation with false part return falsePart; } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes a call to a built-in function //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeFunctionCall (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->type == NODE_TYPE_FCALL); TRI_ASSERT(node->numMembers() == 1); auto func = static_cast(node->getData()); TRI_ASSERT(func != nullptr); if (! func->isDeterministic) { // non-deterministic function return node; } if (! node->getMember(0)->isConstant()) { // arguments to function call are not constant return node; } return executeConstExpression(node); } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes a reference to a variable /// references are replaced with constants if possible //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeReference (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->type == NODE_TYPE_REFERENCE); auto variable = static_cast(node->getData()); if (variable == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } // constant propagation if (variable->constValue() == nullptr) { return node; } return static_cast(variable->constValue()); } //////////////////////////////////////////////////////////////////////////////// /// @brief optimizes the LET statement //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::optimizeLet (AstNode* node) { TRI_ASSERT(node != nullptr); TRI_ASSERT(node->type == NODE_TYPE_LET); TRI_ASSERT(node->numMembers() == 2); AstNode* variable = node->getMember(0); AstNode* expression = node->getMember(1); auto v = static_cast(variable->getData()); TRI_ASSERT(v != nullptr); if (expression->isConstant()) { // if the expression assigned to the LET variable is constant, we'll store // a pointer to the const value in the variable // further optimizations can then use this pointer and optimize further, e.g. // LET a = 1 LET b = a + 1, c = b + a can be optimized to LET a = 1 LET b = 2 LET c = 4 v->constValue(static_cast(expression)); } return node; } //////////////////////////////////////////////////////////////////////////////// /// @brief create an AST node from JSON //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::nodeFromJson (TRI_json_t const* json) { TRI_ASSERT(json != nullptr); if (json->_type == TRI_JSON_BOOLEAN) { return createNodeValueBool(json->_value._boolean); } if (json->_type == TRI_JSON_NUMBER) { return createNodeValueDouble(json->_value._number); } if (json->_type == TRI_JSON_STRING) { char const* value = _query->registerString(json->_value._string.data, json->_value._string.length - 1, false); return createNodeValueString(value); } if (json->_type == TRI_JSON_LIST) { auto node = createNodeList(); size_t const n = json->_value._objects._length; for (size_t i = 0; i < n; ++i) { node->addMember(nodeFromJson(static_cast(TRI_AtVector(&json->_value._objects, i)))); } return node; } if (json->_type == TRI_JSON_ARRAY) { auto node = createNodeArray(); size_t const n = json->_value._objects._length; for (size_t i = 0; i < n; i += 2) { TRI_json_t const* key = static_cast(TRI_AtVector(&json->_value._objects, i)); TRI_json_t const* value = static_cast(TRI_AtVector(&json->_value._objects, i + 1)); if (! TRI_IsStringJson(key) || value == nullptr) { THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL, "unexpected type found in array node"); } char const* attributeName = _query->registerString(key->_value._string.data, key->_value._string.length - 1, false); node->addMember(createNodeArrayElement(attributeName, nodeFromJson(value))); } return node; } return createNodeValueNull(); } //////////////////////////////////////////////////////////////////////////////// /// @brief traverse the AST //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::traverse (AstNode* node, std::function func, void* data) { if (node == nullptr) { return nullptr; } size_t const n = node->numMembers(); for (size_t i = 0; i < n; ++i) { auto member = node->getMember(i); if (member != nullptr) { AstNode* result = traverse(member, func, data); if (result != node) { node->changeMember(i, result); } } } return func(node, data); } //////////////////////////////////////////////////////////////////////////////// /// @brief traverse the AST, with const nodes //////////////////////////////////////////////////////////////////////////////// void Ast::traverse (AstNode const* node, std::function func, void* data) { if (node == nullptr) { return; } size_t const n = node->numMembers(); for (size_t i = 0; i < n; ++i) { auto member = node->getMember(i); if (member != nullptr) { traverse(const_cast(member), func, data); } } func(node, data); } //////////////////////////////////////////////////////////////////////////////// /// @brief normalize a function name //////////////////////////////////////////////////////////////////////////////// std::pair Ast::normalizeFunctionName (char const* name) { TRI_ASSERT(name != nullptr); char* upperName = TRI_UpperAsciiStringZ(TRI_UNKNOWN_MEM_ZONE, name); if (upperName == nullptr) { THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } std::string functionName(upperName); TRI_FreeString(TRI_UNKNOWN_MEM_ZONE, upperName); if (functionName.find(':') == std::string::npos) { // prepend default namespace for internal functions return std::make_pair(functionName, true); } // user-defined function return std::make_pair(functionName, false); } //////////////////////////////////////////////////////////////////////////////// /// @brief create a node of the specified type //////////////////////////////////////////////////////////////////////////////// AstNode* Ast::createNode (AstNodeType type) { auto node = new AstNode(type); try { // register the node so it gets freed automatically later _query->addNode(node); } catch (...) { delete node; THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY); } return node; } // ----------------------------------------------------------------------------- // --SECTION-- END-OF-FILE // ----------------------------------------------------------------------------- // Local Variables: // mode: outline-minor // outline-regexp: "/// @brief\\|/// {@inheritDoc}\\|/// @page\\|// --SECTION--\\|/// @\\}" // End: