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/*
This file is part of solidity.
solidity 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.
solidity 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 solidity. If not, see <http://www.gnu.org/licenses/>.
*/
#include <libsolidity/analysis/ViewPureChecker.h>
using namespace std;
using namespace dev;
using namespace dev::solidity;
bool ViewPureChecker::check()
{
vector<ContractDefinition const*> contracts;
for (auto const& node: m_ast)
{
SourceUnit const* source = dynamic_cast<SourceUnit const*>(node.get());
solAssert(source, "");
for (auto const& topLevelNode: source->nodes())
{
ContractDefinition const* contract = dynamic_cast<ContractDefinition const*>(topLevelNode.get());
if (contract)
contracts.push_back(contract);
}
}
// Check modifiers first to infer their state mutability.
for (auto const* contract: contracts)
for (ModifierDefinition const* mod: contract->functionModifiers())
mod->accept(*this);
for (auto const* contract: contracts)
contract->accept(*this);
return !m_errors;
}
bool ViewPureChecker::visit(FunctionDefinition const& _funDef)
{
solAssert(!m_currentFunction, "");
m_currentFunction = &_funDef;
m_currentBestMutability = StateMutability::Pure;
return true;
}
void ViewPureChecker::endVisit(FunctionDefinition const& _funDef)
{
solAssert(m_currentFunction == &_funDef, "");
if (
m_currentBestMutability < _funDef.stateMutability() &&
_funDef.stateMutability() != StateMutability::Payable &&
_funDef.isImplemented() &&
!_funDef.isConstructor() &&
!_funDef.isFallback() &&
!_funDef.isConstructor() &&
!_funDef.annotation().superFunction
)
m_errorReporter.warning(
_funDef.location(),
"Function state mutability can be restricted to " + stateMutabilityToString(m_currentBestMutability)
);
m_currentFunction = nullptr;
}
bool ViewPureChecker::visit(ModifierDefinition const&)
{
solAssert(m_currentFunction == nullptr, "");
m_currentBestMutability = StateMutability::Pure;
return true;
}
void ViewPureChecker::endVisit(ModifierDefinition const& _modifierDef)
{
solAssert(m_currentFunction == nullptr, "");
m_inferredMutability[&_modifierDef] = m_currentBestMutability;
}
void ViewPureChecker::endVisit(Identifier const& _identifier)
{
Declaration const* declaration = _identifier.annotation().referencedDeclaration;
solAssert(declaration, "");
StateMutability mutability = StateMutability::Pure;
bool writes = _identifier.annotation().lValueRequested;
if (VariableDeclaration const* varDecl = dynamic_cast<VariableDeclaration const*>(declaration))
{
if (varDecl->isStateVariable())
mutability = writes ? StateMutability::NonPayable : StateMutability::View;
}
else if (MagicVariableDeclaration const* magicVar = dynamic_cast<MagicVariableDeclaration const*>(declaration))
{
switch (magicVar->type()->category())
{
case Type::Category::Contract:
solAssert(_identifier.name() == "this" || _identifier.name() == "super", "");
if (!dynamic_cast<ContractType const&>(*magicVar->type()).isSuper())
// reads the address
mutability = StateMutability::View;
break;
case Type::Category::Integer:
solAssert(_identifier.name() == "now", "");
mutability = StateMutability::View;
break;
default:
break;
}
}
reportMutability(mutability, _identifier);
}
void ViewPureChecker::endVisit(InlineAssembly const& _inlineAssembly)
{
// @TOOD we can and should analyze it further.
reportMutability(StateMutability::NonPayable, _inlineAssembly);
}
void ViewPureChecker::reportMutability(StateMutability _mutability, const ASTNode& _node)
{
if (m_currentFunction && m_currentFunction->stateMutability() < _mutability)
{
m_errors = true;
if (_mutability == StateMutability::View)
m_errorReporter.typeError(
_node.location(),
"Function declared as pure, but this expression reads from the environment or state and thus "
"requires \"view\"."
);
else if (_mutability == StateMutability::NonPayable)
m_errorReporter.typeError(
_node.location(),
"Function declared as " +
stateMutabilityToString(m_currentFunction->stateMutability()) +
", but this expression modifies the state and thus "
"requires non-payable (the default) or payable."
);
else
solAssert(false, "");
}
if (_mutability >= m_currentBestMutability)
m_currentBestMutability = _mutability;
}
void ViewPureChecker::endVisit(FunctionCall const& _functionCall)
{
if (_functionCall.annotation().kind != FunctionCallKind::FunctionCall)
return;
StateMutability mut = dynamic_cast<FunctionType const&>(*_functionCall.expression().annotation().type).stateMutability();
// We only require "nonpayable" to call a payble function.
if (mut == StateMutability::Payable)
mut = StateMutability::NonPayable;
reportMutability(mut, _functionCall);
}
void ViewPureChecker::endVisit(MemberAccess const& _memberAccess)
{
StateMutability mutability = StateMutability::Pure;
bool writes = _memberAccess.annotation().lValueRequested;
ASTString const& member = _memberAccess.memberName();
switch (_memberAccess.expression().annotation().type->category())
{
case Type::Category::Contract:
case Type::Category::Integer:
if (member == "balance" && !_memberAccess.annotation().referencedDeclaration)
mutability = StateMutability::View;
break;
case Type::Category::Magic:
// we can ignore the kind of magic and only look at the name of the member
if (member != "data" && member != "sig" && member != "blockhash")
mutability = StateMutability::View;
break;
case Type::Category::Struct:
{
if (_memberAccess.expression().annotation().type->dataStoredIn(DataLocation::Storage))
mutability = writes ? StateMutability::NonPayable : StateMutability::View;
break;
}
case Type::Category::Array:
{
auto const& type = dynamic_cast<ArrayType const&>(*_memberAccess.expression().annotation().type);
if (member == "length" && type.isDynamicallySized() && type.dataStoredIn(DataLocation::Storage))
mutability = writes ? StateMutability::NonPayable : StateMutability::View;
break;
}
default:
break;
}
reportMutability(mutability, _memberAccess);
}
void ViewPureChecker::endVisit(IndexAccess const& _indexAccess)
{
solAssert(_indexAccess.indexExpression(), "");
bool writes = _indexAccess.annotation().lValueRequested;
if (_indexAccess.baseExpression().annotation().type->dataStoredIn(DataLocation::Storage))
reportMutability(writes ? StateMutability::NonPayable : StateMutability::View, _indexAccess);
}
void ViewPureChecker::endVisit(ModifierInvocation const& _modifier)
{
solAssert(_modifier.name(), "");
ModifierDefinition const* mod = dynamic_cast<decltype(mod)>(_modifier.name()->annotation().referencedDeclaration);
solAssert(mod, "");
solAssert(m_inferredMutability.count(mod), "");
reportMutability(m_inferredMutability.at(mod), _modifier);
}
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