From 6219085ad9f10d034e009edd0531523a55689f7e Mon Sep 17 00:00:00 2001
From: Christian <c@ethdev.com>
Date: Fri, 6 Feb 2015 19:57:08 +0100
Subject: [PATCH] Accessors for structs.

---
 libsolidity/ExpressionCompiler.cpp | 47 +++++++++++++++++++++++-------
 libsolidity/Types.cpp              | 27 +++++++++++------
 test/SolidityEndToEndTest.cpp      | 18 ++++++++++++
 3 files changed, 72 insertions(+), 20 deletions(-)

diff --git a/libsolidity/ExpressionCompiler.cpp b/libsolidity/ExpressionCompiler.cpp
index 875e00bc2..f0c3af226 100644
--- a/libsolidity/ExpressionCompiler.cpp
+++ b/libsolidity/ExpressionCompiler.cpp
@@ -867,19 +867,17 @@ unsigned ExpressionCompiler::appendExpressionCopyToMemory(Type const& _expectedT
 
 void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const& _varDecl)
 {
-	FunctionType thisType(_varDecl);
-	solAssert(thisType.getReturnParameterTypes().size() == 1, "");
-	TypePointer const& resultType = thisType.getReturnParameterTypes().front();
-	unsigned sizeOnStack;
+	FunctionType accessorType(_varDecl);
 
 	unsigned length = 0;
-	TypePointers const& params = thisType.getParameterTypes();
+	TypePointers const& params = accessorType.getParameterTypes();
 	// move arguments to memory
 	for (TypePointer const& param: boost::adaptors::reverse(params))
 		length += appendTypeConversionAndMoveToMemory(*param, *param, Location(), length);
 
-	// retrieve the position of the mapping
+	// retrieve the position of the variable
 	m_context << m_context.getStorageLocationOfVariable(_varDecl);
+	TypePointer returnType = _varDecl.getType();
 
 	for (TypePointer const& param: params)
 	{
@@ -888,13 +886,40 @@ void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const&
 		unsigned argLen = CompilerUtils::getPaddedSize(param->getCalldataEncodedSize());
 		length -= argLen;
 		m_context << u256(argLen + 32) << u256(length) << eth::Instruction::SHA3;
+
+		returnType = dynamic_cast<MappingType const&>(*returnType).getValueType();
 	}
 
-	m_currentLValue = LValue(m_context, LValue::STORAGE, *resultType);
-	m_currentLValue.retrieveValue(resultType, Location(), true);
-	sizeOnStack = resultType->getSizeOnStack();
-	solAssert(sizeOnStack <= 15, "Stack too deep.");
-	m_context << eth::dupInstruction(sizeOnStack + 1) << eth::Instruction::JUMP;
+	unsigned retSizeOnStack = 0;
+	solAssert(accessorType.getReturnParameterTypes().size() >= 1, "");
+	if (StructType const* structType = dynamic_cast<StructType const*>(returnType.get()))
+	{
+		auto const& names = accessorType.getReturnParameterNames();
+		auto const& types = accessorType.getReturnParameterTypes();
+		// struct
+		for (size_t i = 0; i < names.size(); ++i)
+		{
+			m_context << eth::Instruction::DUP1
+					  << structType->getStorageOffsetOfMember(names[i])
+					  << eth::Instruction::ADD;
+			m_currentLValue = LValue(m_context, LValue::STORAGE, *types[i]);
+			m_currentLValue.retrieveValue(types[i], Location(), true);
+			solAssert(types[i]->getSizeOnStack() == 1, "Returning struct elements with stack size != 1 not yet implemented.");
+			m_context << eth::Instruction::SWAP1;
+			retSizeOnStack += types[i]->getSizeOnStack();
+		}
+		m_context << eth::Instruction::POP;
+	}
+	else
+	{
+		// simple value
+		solAssert(accessorType.getReturnParameterTypes().size() == 1, "");
+		m_currentLValue = LValue(m_context, LValue::STORAGE, *returnType);
+		m_currentLValue.retrieveValue(returnType, Location(), true);
+		retSizeOnStack = returnType->getSizeOnStack();
+	}
+	solAssert(retSizeOnStack <= 15, "Stack too deep.");
+	m_context << eth::dupInstruction(retSizeOnStack + 1) << eth::Instruction::JUMP;
 }
 
 ExpressionCompiler::LValue::LValue(CompilerContext& _compilerContext, LValueType _type, Type const& _dataType,
diff --git a/libsolidity/Types.cpp b/libsolidity/Types.cpp
index 385495947..e6f1e8e1c 100644
--- a/libsolidity/Types.cpp
+++ b/libsolidity/Types.cpp
@@ -643,22 +643,31 @@ FunctionType::FunctionType(VariableDeclaration const& _varDecl):
 {
 	TypePointers params;
 	vector<string> paramNames;
-	TypePointers retParams;
-	vector<string> retParamNames;
-	TypePointer varDeclType = _varDecl.getType();
-	auto mappingType = dynamic_cast<MappingType const*>(varDeclType.get());
-	auto returnType = varDeclType;
+	auto returnType = _varDecl.getType();
 
-	while (mappingType != nullptr)
+	while (auto mappingType = dynamic_cast<MappingType const*>(returnType.get()))
 	{
 		params.push_back(mappingType->getKeyType());
 		paramNames.push_back("");
 		returnType = mappingType->getValueType();
-		mappingType = dynamic_cast<MappingType const*>(mappingType->getValueType().get());
 	}
 
-	retParams.push_back(returnType);
-	retParamNames.push_back("");
+	TypePointers retParams;
+	vector<string> retParamNames;
+	if (auto structType = dynamic_cast<StructType const*>(returnType.get()))
+	{
+		for (pair<string, TypePointer> const& member: structType->getMembers())
+			if (member.second->canLiveOutsideStorage())
+			{
+				retParamNames.push_back(member.first);
+				retParams.push_back(member.second);
+			}
+	}
+	else
+	{
+		retParams.push_back(returnType);
+		retParamNames.push_back("");
+	}
 
 	swap(params, m_parameterTypes);
 	swap(paramNames, m_parameterNames);
diff --git a/test/SolidityEndToEndTest.cpp b/test/SolidityEndToEndTest.cpp
index f248a5a07..301cc06ef 100644
--- a/test/SolidityEndToEndTest.cpp
+++ b/test/SolidityEndToEndTest.cpp
@@ -959,6 +959,24 @@ BOOST_AUTO_TEST_CASE(complex_accessors)
 	BOOST_CHECK(callContractFunction("to_multiple_map(uint256,uint256)", 42, 23) == encodeArgs(31));
 }
 
+BOOST_AUTO_TEST_CASE(struct_accessor)
+{
+	char const* sourceCode = R"(
+		contract test {
+			struct Data { uint a; uint8 b; mapping(uint => uint) c; bool d; }
+			mapping(uint => Data) public data;
+			function test() {
+				data[7].a = 1;
+				data[7].b = 2;
+				data[7].c[0] = 3;
+				data[7].d = true;
+			}
+		}
+	)";
+	compileAndRun(sourceCode);
+	BOOST_CHECK(callContractFunction("data(uint256)", 7) == encodeArgs(1, 2, true));
+}
+
 BOOST_AUTO_TEST_CASE(balance)
 {
 	char const* sourceCode = "contract test {\n"