From 056180fb24ced86125a35786633a3e897f51a500 Mon Sep 17 00:00:00 2001
From: chriseth <c@ethdev.com>
Date: Mon, 3 Aug 2015 18:09:39 +0200
Subject: [PATCH] strings as mapping keys.

---
 libsolidity/AST.cpp                       |  3 +-
 libsolidity/ExpressionCompiler.cpp        | 35 +++++++++++++++++------
 libsolidity/Types.cpp                     |  2 ++
 test/libsolidity/SolidityEndToEndTest.cpp | 33 +++++++++++++++++++++
 4 files changed, 63 insertions(+), 10 deletions(-)

diff --git a/libsolidity/AST.cpp b/libsolidity/AST.cpp
index ee6e52250..05e2d52e8 100644
--- a/libsolidity/AST.cpp
+++ b/libsolidity/AST.cpp
@@ -784,8 +784,7 @@ void Expression::expectType(Type const& _expectedType)
 			" is not implicitly convertible to expected type " +
 			_expectedType.toString() +
 			"."
-		)
-		);
+		));
 }
 
 void Expression::requireLValue()
diff --git a/libsolidity/ExpressionCompiler.cpp b/libsolidity/ExpressionCompiler.cpp
index 786d386d9..f27cf5fe5 100644
--- a/libsolidity/ExpressionCompiler.cpp
+++ b/libsolidity/ExpressionCompiler.cpp
@@ -85,6 +85,10 @@ void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const&
 		if (auto mappingType = dynamic_cast<MappingType const*>(returnType.get()))
 		{
 			solAssert(CompilerUtils::freeMemoryPointer >= 0x40, "");
+			solAssert(
+				!paramTypes[i]->isDynamicallySized(),
+				"Accessors for mapping with dynamically-sized keys not yet implemented."
+			);
 			// pop offset
 			m_context << eth::Instruction::POP;
 			// move storage offset to memory.
@@ -803,15 +807,30 @@ bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
 	if (baseType.getCategory() == Type::Category::Mapping)
 	{
 		// stack: storage_base_ref
-		Type const& keyType = *dynamic_cast<MappingType const&>(baseType).getKeyType();
-		m_context << u256(0); // memory position
+		auto const& mapping = dynamic_cast<MappingType const&>(baseType);
+		Type const& keyType = *mapping.getKeyType();
 		solAssert(_indexAccess.getIndexExpression(), "Index expression expected.");
-		solAssert(keyType.getCalldataEncodedSize() <= 0x20, "Dynamic keys not yet implemented.");
-		appendExpressionCopyToMemory(keyType, *_indexAccess.getIndexExpression());
-		m_context << eth::Instruction::SWAP1;
-		solAssert(CompilerUtils::freeMemoryPointer >= 0x40, "");
-		utils().storeInMemoryDynamic(IntegerType(256));
-		m_context << u256(0) << eth::Instruction::SHA3;
+		if (keyType.isDynamicallySized())
+		{
+			_indexAccess.getIndexExpression()->accept(*this);
+			utils().fetchFreeMemoryPointer();
+			// stack: base index mem
+			// note: the following operations must not allocate memory!
+			utils().encodeToMemory(TypePointers{mapping.getKeyType()}, TypePointers(), false, true);
+			m_context << eth::Instruction::SWAP1;
+			utils().storeInMemoryDynamic(IntegerType(256));
+			utils().toSizeAfterFreeMemoryPointer();
+		}
+		else
+		{
+			m_context << u256(0); // memory position
+			appendExpressionCopyToMemory(keyType, *_indexAccess.getIndexExpression());
+			m_context << eth::Instruction::SWAP1;
+			solAssert(CompilerUtils::freeMemoryPointer >= 0x40, "");
+			utils().storeInMemoryDynamic(IntegerType(256));
+			m_context << u256(0);
+		}
+		m_context << eth::Instruction::SHA3;
 		m_context << u256(0);
 		setLValueToStorageItem(_indexAccess);
 	}
diff --git a/libsolidity/Types.cpp b/libsolidity/Types.cpp
index d85c0511f..89ff2134f 100644
--- a/libsolidity/Types.cpp
+++ b/libsolidity/Types.cpp
@@ -179,6 +179,8 @@ TypePointer Type::fromMapping(ElementaryTypeName& _keyType, TypeName& _valueType
 		BOOST_THROW_EXCEPTION(_valueType.createTypeError("Invalid type name."));
 	// Convert value type to storage reference.
 	valueType = ReferenceType::copyForLocationIfReference(DataLocation::Storage, valueType);
+	// Convert key type to memory.
+	keyType = ReferenceType::copyForLocationIfReference(DataLocation::Memory, keyType);
 	return make_shared<MappingType>(keyType, valueType);
 }
 
diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index d44545145..fc1d2eab8 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -5099,6 +5099,39 @@ BOOST_AUTO_TEST_CASE(memory_structs_with_mappings)
 	BOOST_CHECK(callContractFunction("f()") == encodeArgs(u256(0)));
 }
 
+BOOST_AUTO_TEST_CASE(string_as_mapping_key)
+{
+	char const* sourceCode = R"(
+		contract Test {
+			mapping(string => uint) data;
+			function set(string _s, uint _v) { data[_s] = _v; }
+			function get(string _s) returns (uint) { return data[_s]; }
+		}
+	)";
+	compileAndRun(sourceCode, 0, "Test");
+	vector<string> strings{
+		"Hello, World!",
+		"Hello,                            World!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1111",
+		"",
+		"1"
+	};
+	for (unsigned i = 0; i < strings.size(); i++)
+		BOOST_CHECK(callContractFunction(
+			"set(string,uint256)",
+			u256(0x40),
+			u256(7 + i),
+			u256(strings[i].size()),
+			strings[i]
+		) == encodeArgs());
+	for (unsigned i = 0; i < strings.size(); i++)
+		BOOST_CHECK(callContractFunction(
+			"get(string)",
+			u256(0x20),
+			u256(strings[i].size()),
+			strings[i]
+		) == encodeArgs(u256(7 + i)));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }