path: root/Types.h

/*
    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
 * Solidity data types
 */

#pragma once

#include <memory>
#include <string>
#include <map>
#include <boost/noncopyable.hpp>
#include <libdevcore/Common.h>
#include <libsolidity/Exceptions.h>
#include <libsolidity/ASTForward.h>
#include <libsolidity/Token.h>

namespace dev
{
namespace solidity
{

// @todo realMxN, string<N>

class Type; // forward
using TypePointer = std::shared_ptr<Type const>;
using TypePointers = std::vector<TypePointer>;

/**
 * List of members of a type.
 */
class MemberList
{
public:
    using MemberMap = std::map<std::string, TypePointer>;

    MemberList() {}
    explicit MemberList(MemberMap const& _members): m_memberTypes(_members) {}
    TypePointer getMemberType(std::string const& _name) const
    {
        auto it = m_memberTypes.find(_name);
        return it != m_memberTypes.end() ? it->second : TypePointer();
    }

    MemberMap::const_iterator begin() const { return m_memberTypes.begin(); }
    MemberMap::const_iterator end() const { return m_memberTypes.end(); }

private:
    MemberMap m_memberTypes;
};


/**
 * Abstract base class that forms the root of the type hierarchy.
 */
class Type: private boost::noncopyable
{
public:
    enum class Category
    {
        INTEGER, BOOL, REAL, STRING, CONTRACT, STRUCT, FUNCTION, MAPPING, VOID, TYPE, MAGIC
    };

    ///@{
    ///@name Factory functions
    /// Factory functions that convert an AST @ref TypeName to a Type.
    static std::shared_ptr<Type const> fromElementaryTypeName(Token::Value _typeToken);
    static std::shared_ptr<Type const> fromUserDefinedTypeName(UserDefinedTypeName const& _typeName);
    static std::shared_ptr<Type const> fromMapping(Mapping const& _typeName);
    static std::shared_ptr<Type const> fromFunction(FunctionDefinition const& _function);
    /// @}

    /// Auto-detect the proper type for a literal. @returns an empty pointer if the literal does
    /// not fit any type.
    static std::shared_ptr<Type const> forLiteral(Literal const& _literal);

    virtual Category getCategory() const = 0;
    virtual bool isImplicitlyConvertibleTo(Type const& _other) const { return *this == _other; }
    virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const
    {
        return isImplicitlyConvertibleTo(_convertTo);
    }
    virtual bool acceptsBinaryOperator(Token::Value) const { return false; }
    virtual bool acceptsUnaryOperator(Token::Value) const { return false; }

    virtual bool operator==(Type const& _other) const { return getCategory() == _other.getCategory(); }
    virtual bool operator!=(Type const& _other) const { return !this->operator ==(_other); }

    /// @returns number of bytes used by this type when encoded for CALL, or 0 if the encoding
    /// is not a simple big-endian encoding or the type cannot be stored on the stack.
    virtual unsigned getCalldataEncodedSize() const { return 0; }
    /// @returns number of bytes required to hold this value in storage.
    /// For dynamically "allocated" types, it returns the size of the statically allocated head,
    virtual u256 getStorageSize() const { return 1; }
    /// Returns true if the type can be stored in storage.
    virtual bool canBeStored() const { return true; }
    /// Returns false if the type cannot live outside the storage, i.e. if it includes some mapping.
    virtual bool canLiveOutsideStorage() const { return true; }
    /// Returns true if the type can be stored as a value (as opposed to a reference) on the stack,
    /// i.e. it behaves differently in lvalue context and in value context.
    virtual bool isValueType() const { return false; }
    virtual unsigned getSizeOnStack() const { return 1; }

    /// Returns the list of all members of this type. Default implementation: no members.
    virtual MemberList const& getMembers() const { return EmptyMemberList; }
    /// Convenience method, returns the type of the given named member or an empty pointer if no such member exists.
    TypePointer getMemberType(std::string const& _name) const { return getMembers().getMemberType(_name); }

    virtual std::string toString() const = 0;
    virtual u256 literalValue(Literal const&) const
    {
        BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Literal value requested "
                                                                          "for type without literals."));
    }

protected:
    /// Convenience object used when returning an empty member list.
    static const MemberList EmptyMemberList;
};

/**
 * Any kind of integer type including hash and address.
 */
class IntegerType: public Type
{
public:
    enum class Modifier
    {
        UNSIGNED, SIGNED, HASH, ADDRESS
    };
    virtual Category getCategory() const override { return Category::INTEGER; }

    /// @returns the smallest integer type for the given literal or an empty pointer
    /// if no type fits.
    static std::shared_ptr<IntegerType const> smallestTypeForLiteral(std::string const& _literal);

    explicit IntegerType(int _bits, Modifier _modifier = Modifier::UNSIGNED);

    virtual bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;
    virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
    virtual bool acceptsBinaryOperator(Token::Value _operator) const override;
    virtual bool acceptsUnaryOperator(Token::Value _operator) const override;

    virtual bool operator==(Type const& _other) const override;

    virtual unsigned getCalldataEncodedSize() const override { return m_bits / 8; }
    virtual bool isValueType() const override { return true; }

    virtual MemberList const& getMembers() const { return isAddress() ? AddressMemberList : EmptyMemberList; }

    virtual std::string toString() const override;
    virtual u256 literalValue(Literal const& _literal) const override;

    int getNumBits() const { return m_bits; }
    bool isHash() const { return m_modifier == Modifier::HASH || m_modifier == Modifier::ADDRESS; }
    bool isAddress() const { return m_modifier == Modifier::ADDRESS; }
    int isSigned() const { return m_modifier == Modifier::SIGNED; }

private:
    int m_bits;
    Modifier m_modifier;
    static const MemberList AddressMemberList;
};

/**
 * The boolean type.
 */
class BoolType: public Type
{
public:
    virtual Category getCategory() const { return Category::BOOL; }
    virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
    virtual bool acceptsBinaryOperator(Token::Value _operator) const override
    {
        return _operator == Token::AND || _operator == Token::OR;
    }
    virtual bool acceptsUnaryOperator(Token::Value _operator) const override
    {
        return _operator == Token::NOT || _operator == Token::DELETE;
    }

    virtual unsigned getCalldataEncodedSize() const { return 1; }
    virtual bool isValueType() const override { return true; }

    virtual std::string toString() const override { return "bool"; }
    virtual u256 literalValue(Literal const& _literal) const override;
};

/**
 * The type of a contract instance, there is one distinct type for each contract definition.
 */
class ContractType: public Type
{
public:
    virtual Category getCategory() const override { return Category::CONTRACT; }
    ContractType(ContractDefinition const& _contract): m_contract(_contract) {}
    /// Contracts can be converted to themselves and to addresses.
    virtual bool isExplicitlyConvertibleTo(Type const& _convertTo) const override;
    virtual bool operator==(Type const& _other) const override;
    virtual u256 getStorageSize() const override;
    virtual std::string toString() const override;

private:
    ContractDefinition const& m_contract;
};

/**
 * The type of a struct instance, there is one distinct type per struct definition.
 */
class StructType: public Type
{
public:
    virtual Category getCategory() const override { return Category::STRUCT; }
    StructType(StructDefinition const& _struct): m_struct(_struct) {}
    virtual bool acceptsUnaryOperator(Token::Value _operator) const override
    {
        return _operator == Token::DELETE;
    }

    virtual bool operator==(Type const& _other) const override;
    virtual u256 getStorageSize() const override;
    virtual bool canLiveOutsideStorage() const override;
    virtual unsigned getSizeOnStack() const override { return 1; /*@todo*/ }
    virtual std::string toString() const override;

    virtual MemberList const& getMembers() const override;

    u256 getStorageOffsetOfMember(std::string const& _name) const;

private:
    StructDefinition const& m_struct;
    /// List of member types, will be lazy-initialized because of recursive references.
    mutable std::unique_ptr<MemberList> m_members;
};

/**
 * The type of a function, identified by its (return) parameter types.
 * @todo the return parameters should also have names, i.e. return parameters should be a struct
 * type.
 */
class FunctionType: public Type
{
public:
    /// The meaning of the value(s) on the stack referencing the function:
    /// INTERNAL: jump tag, EXTERNAL: contract address + function index,
    /// OTHERS: special virtual function, nothing on the stack
    enum class Location { INTERNAL, EXTERNAL, SEND, SHA3, SUICIDE, ECRECOVER, SHA256, RIPEMD160 };

    virtual Category getCategory() const override { return Category::FUNCTION; }
    explicit FunctionType(FunctionDefinition const& _function);
    FunctionType(TypePointers const& _parameterTypes, TypePointers const& _returnParameterTypes,
                 Location _location = Location::INTERNAL):
        m_parameterTypes(_parameterTypes), m_returnParameterTypes(_returnParameterTypes),
        m_location(_location) {}

    TypePointers const& getParameterTypes() const { return m_parameterTypes; }
    TypePointers const& getReturnParameterTypes() const { return m_returnParameterTypes; }

    virtual bool operator==(Type const& _other) const override;
    virtual std::string toString() const override;
    virtual bool canBeStored() const override { return false; }
    virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable function type requested.")); }
    virtual bool canLiveOutsideStorage() const override { return false; }
    virtual unsigned getSizeOnStack() const override;

    Location getLocation() const { return m_location; }

private:
    TypePointers m_parameterTypes;
    TypePointers m_returnParameterTypes;
    Location m_location;
};

/**
 * The type of a mapping, there is one distinct type per key/value type pair.
 */
class MappingType: public Type
{
public:
    virtual Category getCategory() const override { return Category::MAPPING; }
    MappingType(TypePointer const& _keyType, TypePointer const& _valueType):
        m_keyType(_keyType), m_valueType(_valueType) {}

    virtual bool operator==(Type const& _other) const override;
    virtual std::string toString() const override;
    virtual bool canLiveOutsideStorage() const override { return false; }

    TypePointer getKeyType() const { return m_keyType; }
    TypePointer getValueType() const { return m_valueType; }

private:
    TypePointer m_keyType;
    TypePointer m_valueType;
};

/**
 * The void type, can only be implicitly used as the type that is returned by functions without
 * return parameters.
 */
class VoidType: public Type
{
public:
    virtual Category getCategory() const override { return Category::VOID; }
    VoidType() {}

    virtual std::string toString() const override { return "void"; }
    virtual bool canBeStored() const override { return false; }
    virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable void type requested.")); }
    virtual bool canLiveOutsideStorage() const override { return false; }
    virtual unsigned getSizeOnStack() const override { return 0; }
};

/**
 * The type of a type reference. The type of "uint32" when used in "a = uint32(2)" is an example
 * of a TypeType.
 */
class TypeType: public Type
{
public:
    virtual Category getCategory() const override { return Category::TYPE; }
    TypeType(TypePointer const& _actualType): m_actualType(_actualType) {}

    TypePointer const& getActualType() const { return m_actualType; }

    virtual bool operator==(Type const& _other) const override;
    virtual bool canBeStored() const override { return false; }
    virtual u256 getStorageSize() const override { BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage size of non-storable type type requested.")); }
    virtual bool canLiveOutsideStorage() const override { return false; }
    virtual std::string toString() const override { return "type(" + m_actualType->toString() + ")"; }

private:
    TypePointer m_actualType;
};


/**
 * Special type for magic variables (block, msg, tx), similar to a struct but without any reference
 * (it always references a global singleton by name).
 */
class MagicType: public Type
{
public:
    enum class Kind { BLOCK, MSG, TX };
    virtual Category getCategory() const override { return Category::MAGIC; }

    MagicType(Kind _kind);
    virtual bool operator==(Type const& _other) const;
    virtual bool canBeStored() const override { return false; }
    virtual bool canLiveOutsideStorage() const override { return true; }
    virtual unsigned getSizeOnStack() const override { return 0; }
    virtual MemberList const& getMembers() const override { return m_members; }

    virtual std::string toString() const override;

private:
    Kind m_kind;

    MemberList m_members;
};

}
}