path: root/NameAndTypeResolver.cpp

/*
    This file is part of cpp-ethereum.

    cpp-ethereum is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    cpp-ethereum is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
/**
 * @author Christian <c@ethdev.com>
 * @date 2014
 * Parser part that determines the declarations corresponding to names and the types of expressions.
 */

#include <libsolidity/NameAndTypeResolver.h>
#include <libsolidity/AST.h>
#include <libsolidity/Exceptions.h>

using namespace std;

namespace dev
{
namespace solidity
{

NameAndTypeResolver::NameAndTypeResolver(std::vector<Declaration const*> const& _globals)
{
    for (Declaration const* declaration: _globals)
        m_scopes[nullptr].registerDeclaration(*declaration);
}

void NameAndTypeResolver::registerDeclarations(SourceUnit& _sourceUnit)
{
    // The helper registers all declarations in m_scopes as a side-effect of its construction.
    DeclarationRegistrationHelper registrar(m_scopes, _sourceUnit);
}

void NameAndTypeResolver::resolveNamesAndTypes(ContractDefinition& _contract)
{
    m_currentScope = &m_scopes[nullptr];

    for (ASTPointer<InheritanceSpecifier> const& baseContract: _contract.getBaseContracts())
        ReferencesResolver resolver(*baseContract, *this, &_contract, nullptr);

    m_currentScope = &m_scopes[&_contract];

    linearizeBaseContracts(_contract);
    for (ContractDefinition const* base: _contract.getLinearizedBaseContracts())
        importInheritedScope(*base);

    for (ASTPointer<StructDefinition> const& structDef: _contract.getDefinedStructs())
        ReferencesResolver resolver(*structDef, *this, &_contract, nullptr);
    for (ASTPointer<VariableDeclaration> const& variable: _contract.getStateVariables())
        ReferencesResolver resolver(*variable, *this, &_contract, nullptr);
    for (ASTPointer<EventDefinition> const& event: _contract.getEvents())
        ReferencesResolver resolver(*event, *this, &_contract, nullptr);
    for (ASTPointer<ModifierDefinition> const& modifier: _contract.getFunctionModifiers())
    {
        m_currentScope = &m_scopes[modifier.get()];
        ReferencesResolver resolver(*modifier, *this, &_contract, nullptr);
    }
    for (ASTPointer<FunctionDefinition> const& function: _contract.getDefinedFunctions())
    {
        m_currentScope = &m_scopes[function.get()];
        ReferencesResolver referencesResolver(*function, *this, &_contract,
                                              function->getReturnParameterList().get());
    }
}

void NameAndTypeResolver::checkTypeRequirements(ContractDefinition& _contract)
{
    for (ASTPointer<StructDefinition> const& structDef: _contract.getDefinedStructs())
        structDef->checkValidityOfMembers();
    _contract.checkTypeRequirements();
}

void NameAndTypeResolver::updateDeclaration(Declaration const& _declaration)
{
    m_scopes[nullptr].registerDeclaration(_declaration, true);
    solAssert(_declaration.getScope() == nullptr, "Updated declaration outside global scope.");
}

Declaration const* NameAndTypeResolver::resolveName(ASTString const& _name, Declaration const* _scope) const
{
    auto iterator = m_scopes.find(_scope);
    if (iterator == end(m_scopes))
        return nullptr;
    return iterator->second.resolveName(_name, false);
}

Declaration const* NameAndTypeResolver::getNameFromCurrentScope(ASTString const& _name, bool _recursive)
{
    return m_currentScope->resolveName(_name, _recursive);
}

void NameAndTypeResolver::importInheritedScope(ContractDefinition const& _base)
{
    auto iterator = m_scopes.find(&_base);
    solAssert(iterator != end(m_scopes), "");
    for (auto const& nameAndDeclaration: iterator->second.getDeclarations())
    {
        Declaration const* declaration = nameAndDeclaration.second;
        // Import if it was declared in the base and is not the constructor
        if (declaration->getScope() == &_base && declaration->getName() != _base.getName())
            m_currentScope->registerDeclaration(*declaration);
    }
}

void NameAndTypeResolver::linearizeBaseContracts(ContractDefinition& _contract) const
{
    // order in the lists is from derived to base
    // list of lists to linearize, the last element is the list of direct bases
    list<list<ContractDefinition const*>> input(1, {});
    for (ASTPointer<InheritanceSpecifier> const& baseSpecifier: _contract.getBaseContracts())
    {
        ASTPointer<Identifier> baseName = baseSpecifier->getName();
        ContractDefinition const* base = dynamic_cast<ContractDefinition const*>(
                                                        baseName->getReferencedDeclaration());
        if (!base)
            BOOST_THROW_EXCEPTION(baseName->createTypeError("Contract expected."));
        // "push_front" has the effect that bases mentioned later can overwrite members of bases
        // mentioned earlier
        input.back().push_front(base);
        vector<ContractDefinition const*> const& basesBases = base->getLinearizedBaseContracts();
        if (basesBases.empty())
            BOOST_THROW_EXCEPTION(baseName->createTypeError("Definition of base has to precede definition of derived contract"));
        input.push_front(list<ContractDefinition const*>(basesBases.begin(), basesBases.end()));
    }
    input.back().push_front(&_contract);
    vector<ContractDefinition const*> result = cThreeMerge(input);
    if (result.empty())
        BOOST_THROW_EXCEPTION(_contract.createTypeError("Linearization of inheritance graph impossible"));
    _contract.setLinearizedBaseContracts(result);
}

template <class _T>
vector<_T const*> NameAndTypeResolver::cThreeMerge(list<list<_T const*>>& _toMerge)
{
    // returns true iff _candidate appears only as last element of the lists
    auto appearsOnlyAtHead = [&](_T const* _candidate) -> bool
    {
        for (list<_T const*> const& bases: _toMerge)
        {
            solAssert(!bases.empty(), "");
            if (find(++bases.begin(), bases.end(), _candidate) != bases.end())
                return false;
        }
        return true;
    };
    // returns the next candidate to append to the linearized list or nullptr on failure
    auto nextCandidate = [&]() -> _T const*
    {
        for (list<_T const*> const& bases: _toMerge)
        {
            solAssert(!bases.empty(), "");
            if (appearsOnlyAtHead(bases.front()))
                return bases.front();
        }
        return nullptr;
    };
    // removes the given contract from all lists
    auto removeCandidate = [&](_T const* _candidate)
    {
        for (auto it = _toMerge.begin(); it != _toMerge.end();)
        {
            it->remove(_candidate);
            if (it->empty())
                it = _toMerge.erase(it);
            else
                ++it;
        }
    };

    _toMerge.remove_if([](list<_T const*> const& _bases) { return _bases.empty(); });
    vector<_T const*> result;
    while (!_toMerge.empty())
    {
        _T const* candidate = nextCandidate();
        if (!candidate)
            return vector<_T const*>();
        result.push_back(candidate);
        removeCandidate(candidate);
    }
    return result;
}

DeclarationRegistrationHelper::DeclarationRegistrationHelper(map<ASTNode const*, DeclarationContainer>& _scopes,
                                                             ASTNode& _astRoot):
    m_scopes(_scopes), m_currentScope(nullptr)
{
    _astRoot.accept(*this);
}

bool DeclarationRegistrationHelper::visit(ContractDefinition& _contract)
{
    registerDeclaration(_contract, true);
    return true;
}

void DeclarationRegistrationHelper::endVisit(ContractDefinition&)
{
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(StructDefinition& _struct)
{
    registerDeclaration(_struct, true);
    return true;
}

void DeclarationRegistrationHelper::endVisit(StructDefinition&)
{
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(FunctionDefinition& _function)
{
    registerDeclaration(_function, true);
    m_currentFunction = &_function;
    return true;
}

void DeclarationRegistrationHelper::endVisit(FunctionDefinition&)
{
    m_currentFunction = nullptr;
    closeCurrentScope();
}

bool DeclarationRegistrationHelper::visit(ModifierDefinition& _modifier)
{
    registerDeclaration(_modifier, true);
    m_currentFunction = &_modifier;
    return true;
}

void DeclarationRegistrationHelper::endVisit(ModifierDefinition&)
{
    m_currentFunction = nullptr;
    closeCurrentScope();
}

void DeclarationRegistrationHelper::endVisit(VariableDefinition& _variableDefinition)
{
    // Register the local variables with the function
    // This does not fit here perfectly, but it saves us another AST visit.
    solAssert(m_currentFunction, "Variable definition without function.");
    m_currentFunction->addLocalVariable(_variableDefinition.getDeclaration());
}

bool DeclarationRegistrationHelper::visit(VariableDeclaration& _declaration)
{
    registerDeclaration(_declaration, false);
    return true;
}

bool DeclarationRegistrationHelper::visit(EventDefinition& _event)
{
    registerDeclaration(_event, true);
    return true;
}

void DeclarationRegistrationHelper::endVisit(EventDefinition&)
{
    closeCurrentScope();
}

void DeclarationRegistrationHelper::enterNewSubScope(Declaration const& _declaration)
{
    map<ASTNode const*, DeclarationContainer>::iterator iter;
    bool newlyAdded;
    tie(iter, newlyAdded) = m_scopes.emplace(&_declaration, DeclarationContainer(m_currentScope, &m_scopes[m_currentScope]));
    solAssert(newlyAdded, "Unable to add new scope.");
    m_currentScope = &_declaration;
}

void DeclarationRegistrationHelper::closeCurrentScope()
{
    solAssert(m_currentScope, "Closed non-existing scope.");
    m_currentScope = m_scopes[m_currentScope].getEnclosingDeclaration();
}

void DeclarationRegistrationHelper::registerDeclaration(Declaration& _declaration, bool _opensScope)
{
    if (!m_scopes[m_currentScope].registerDeclaration(_declaration))
        BOOST_THROW_EXCEPTION(DeclarationError() << errinfo_sourceLocation(_declaration.getLocation())
                                                 << errinfo_comment("Identifier already declared."));
    //@todo the exception should also contain the location of the first declaration
    _declaration.setScope(m_currentScope);
    if (_opensScope)
        enterNewSubScope(_declaration);
}

ReferencesResolver::ReferencesResolver(ASTNode& _root, NameAndTypeResolver& _resolver,
                                       ContractDefinition const* _currentContract,
                                       ParameterList const* _returnParameters, bool _allowLazyTypes):
    m_resolver(_resolver), m_currentContract(_currentContract),
    m_returnParameters(_returnParameters), m_allowLazyTypes(_allowLazyTypes)
{
    _root.accept(*this);
}

void ReferencesResolver::endVisit(VariableDeclaration& _variable)
{
    // endVisit because the internal type needs resolving if it is a user defined type
    // or mapping
    if (_variable.getTypeName())
    {
        _variable.setType(_variable.getTypeName()->toType());
        if (!_variable.getType())
            BOOST_THROW_EXCEPTION(_variable.getTypeName()->createTypeError("Invalid type name"));
    }
    else if (!m_allowLazyTypes)
        BOOST_THROW_EXCEPTION(_variable.createTypeError("Explicit type needed."));
    // otherwise we have a "var"-declaration whose type is resolved by the first assignment
}

bool ReferencesResolver::visit(Return& _return)
{
    _return.setFunctionReturnParameters(m_returnParameters);
    return true;
}

bool ReferencesResolver::visit(Mapping&)
{
    return true;
}

bool ReferencesResolver::visit(UserDefinedTypeName& _typeName)
{
    Declaration const* declaration = m_resolver.getNameFromCurrentScope(_typeName.getName());
    if (!declaration)
        BOOST_THROW_EXCEPTION(DeclarationError() << errinfo_sourceLocation(_typeName.getLocation())
                                                 << errinfo_comment("Undeclared identifier."));
    _typeName.setReferencedDeclaration(*declaration);
    return false;
}

bool ReferencesResolver::visit(Identifier& _identifier)
{
    Declaration const* declaration = m_resolver.getNameFromCurrentScope(_identifier.getName());
    if (!declaration)
        BOOST_THROW_EXCEPTION(DeclarationError() << errinfo_sourceLocation(_identifier.getLocation())
                                                 << errinfo_comment("Undeclared identifier."));
    _identifier.setReferencedDeclaration(*declaration, m_currentContract);
    return false;
}


}
}