Convenience class for type members.

4 files changed, 70 insertions, 41 deletions

diff --git a/AST.cpp b/AST.cpp
index 2972cb5c..9aecbded 100644
--- a/AST.cpp
+++ b/AST.cpp
@@ -462,14 +462,10 @@ void MemberAccess::checkTypeRequirements()
 {
 	m_expression->checkTypeRequirements();
 	m_expression->requireLValue();
-	if (m_expression->getType()->getCategory() != Type::Category::STRUCT)
-		BOOST_THROW_EXCEPTION(createTypeError("Member access to a non-struct (is " +
-													  m_expression->getType()->toString() + ")"));
-	StructType const& type = dynamic_cast<StructType const&>(*m_expression->getType());
-	unsigned memberIndex = type.memberNameToIndex(*m_memberName);
-	if (memberIndex >= type.getMemberCount())
+	Type const& type = *m_expression->getType();
+	m_type = type.getMemberType(*m_memberName);
+	if (!m_type)
 		BOOST_THROW_EXCEPTION(createTypeError("Member \"" + *m_memberName + "\" not found in " + type.toString()));
-	m_type = type.getMemberByIndex(memberIndex);
 	m_isLvalue = true;
 }
 
diff --git a/ExpressionCompiler.cpp b/ExpressionCompiler.cpp
index f37ce39c..89eeb31f 100644
--- a/ExpressionCompiler.cpp
+++ b/ExpressionCompiler.cpp
@@ -208,10 +208,7 @@ void ExpressionCompiler::endVisit(MemberAccess& _memberAccess)
 	if (asserts(m_currentLValue.isInStorage()))
 		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Member access to a non-storage value."));
 	StructType const& type = dynamic_cast<StructType const&>(*_memberAccess.getExpression().getType());
-	unsigned memberIndex = type.memberNameToIndex(_memberAccess.getMemberName());
-	if (asserts(memberIndex <= type.getMemberCount()))
-		BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Member not found in struct during compilation."));
-	m_context << type.getStorageOffsetOfMember(memberIndex) << eth::Instruction::ADD;
+	m_context << type.getStorageOffsetOfMember(_memberAccess.getMemberName()) << eth::Instruction::ADD;
 	m_currentLValue.retrieveValueIfLValueNotRequested(_memberAccess);
 }
 
diff --git a/Types.cpp b/Types.cpp
index 79d4a1c1..897ca221 100644
--- a/Types.cpp
+++ b/Types.cpp
@@ -86,6 +86,8 @@ shared_ptr<Type> Type::forLiteral(Literal const& _literal)
 	}
 }
 
+const MemberList Type::EmptyMemberList = MemberList();
+
 shared_ptr<IntegerType> IntegerType::smallestTypeForLiteral(string const& _literal)
 {
 	bigint value(_literal);
@@ -226,15 +228,15 @@ bool StructType::operator==(Type const& _other) const
 u256 StructType::getStorageSize() const
 {
 	u256 size = 0;
-	for (ASTPointer<VariableDeclaration> const& variable: m_struct.getMembers())
-		size += variable->getType()->getStorageSize();
+	for (pair<string, shared_ptr<Type const>> const& member: getMembers())
+		size += member.second->getStorageSize();
 	return max<u256>(1, size);
 }
 
 bool StructType::canLiveOutsideStorage() const
 {
-	for (unsigned i = 0; i < getMemberCount(); ++i)
-		if (!getMemberByIndex(i)->canLiveOutsideStorage())
+	for (pair<string, shared_ptr<Type const>> const& member: getMembers())
+		if (!member.second->canLiveOutsideStorage())
 			return false;
 	return true;
 }
@@ -244,33 +246,30 @@ string StructType::toString() const
 	return string("struct ") + m_struct.getName();
 }
 
-unsigned StructType::getMemberCount() const
-{
-	return m_struct.getMembers().size();
-}
-
-unsigned StructType::memberNameToIndex(string const& _name) const
-{
-	vector<ASTPointer<VariableDeclaration>> const& members = m_struct.getMembers();
-	for (unsigned index = 0; index < members.size(); ++index)
-		if (members[index]->getName() == _name)
-			return index;
-	return unsigned(-1);
-}
-
-shared_ptr<Type const> const& StructType::getMemberByIndex(unsigned _index) const
+MemberList const& StructType::getMembers() const
 {
-	return m_struct.getMembers()[_index].getType();
+	// We need to lazy-initialize it because of recursive references.
+	if (!m_members)
+	{
+		map<string, shared_ptr<Type const>> members;
+		for (ASTPointer<VariableDeclaration> const& variable: m_struct.getMembers())
+			members[variable->getName()] = variable->getType();
+		m_members.reset(new MemberList(members));
+	}
+	return *m_members;
 }
 
-u256 StructType::getStorageOffsetOfMember(unsigned _index) const
+u256 StructType::getStorageOffsetOfMember(string const& _name) const
 {
 	//@todo cache member offset?
 	u256 offset;
-//	vector<ASTPointer<VariableDeclaration>> const& members = m_struct.getMembers();
-	for (unsigned index = 0; index < _index; ++index)
-		offset += getMemberByIndex(index)->getStorageSize();
-	return offset;
+	for (ASTPointer<VariableDeclaration> variable: m_struct.getMembers())
+	{
+		offset += variable->getType()->getStorageSize();
+		if (variable->getName() == _name)
+			return offset;
+	}
+	BOOST_THROW_EXCEPTION(InternalCompilerError() << errinfo_comment("Storage offset of non-existing member requested."));
 }
 
 bool FunctionType::operator==(Type const& _other) const
diff --git a/Types.h b/Types.h
index b0d95d29..2208a880 100644
--- a/Types.h
+++ b/Types.h
@@ -24,6 +24,7 @@
 
 #include <memory>
 #include <string>
+#include <map>
 #include <boost/noncopyable.hpp>
 #include <libdevcore/Common.h>
 #include <libsolidity/Exceptions.h>
@@ -37,6 +38,33 @@ namespace solidity
 
 // @todo realMxN, string<N>
 
+class Type; // forward
+
+/**
+ * List of members of a type.
+ */
+class MemberList
+{
+public:
+	using TypePointer = std::shared_ptr<Type const>;
+	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 : std::shared_ptr<Type const>();
+	}
+
+	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.
  */
@@ -81,12 +109,21 @@ public:
 	/// Returns false if the type cannot live outside the storage, i.e. if it includes some mapping.
 	virtual bool canLiveOutsideStorage() const { return true; }
 
+	/// 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.
+	std::shared_ptr<Type const> 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;
 };
 
 /**
@@ -187,14 +224,14 @@ public:
 	virtual bool canLiveOutsideStorage() const;
 	virtual std::string toString() const override;
 
-	unsigned getMemberCount() const;
-	/// Returns the index of the member with name @a _name or unsigned(-1) if it does not exist.
-	unsigned memberNameToIndex(std::string const& _name) const;
-	std::shared_ptr<Type const> const& getMemberByIndex(unsigned _index) const;
-	u256 getStorageOffsetOfMember(unsigned _index) const;
+	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;
 };
 
 /**