Using jsoncpp for exporting ABI interface from solidity

- Also changing the interface JSON test to have a shorter name
  plus to provide meaningful error message in case of failure

libsolidity/CompilerStack.cpp

@@ -85,54 +85,52 @@ void CompilerStack::streamAssembly(ostream& _outStream)
 
 string const& CompilerStack::getInterface()
 {
+	Json::StyledWriter writer;
 	if (!m_parseSuccessful)
 		BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Parsing was not successful."));
+
 	if (m_interface.empty())
 	{
-		stringstream interface;
+		Json::Value methods(Json::arrayValue);
-		interface << '[';
+
 		vector<FunctionDefinition const*> exportedFunctions = m_contractASTNode->getInterfaceFunctions();
-		unsigned functionsCount = exportedFunctions.size();
 		for (FunctionDefinition const* f: exportedFunctions)
 		{
-			auto streamVariables = [&](vector<ASTPointer<VariableDeclaration>> const& _vars)
+			Json::Value method;
+			Json::Value inputs(Json::arrayValue);
+			Json::Value outputs(Json::arrayValue);
+
+			auto streamVariables = [&](vector<ASTPointer<VariableDeclaration>> const& _vars,
+									   Json::Value &json)
 			{
-				unsigned varCount = _vars.size();
 				for (ASTPointer<VariableDeclaration> const& var: _vars)
 				{
-					interface << "{"
+					Json::Value input;
-							  << "\"name\":" << escaped(var->getName(), false) << ","
+					input["name"] = var->getName();
-							  << "\"type\":" << escaped(var->getType()->toString(), false)
+					input["type"] = var->getType()->toString();
-							  << "}";
+					json.append(input);
-					if (--varCount > 0)
-						interface << ",";
 				}
 			};
 
-			interface << '{'
+			method["name"] = f->getName();
-					  << "\"name\":" << escaped(f->getName(), false) << ","
+			streamVariables(f->getParameters(), inputs);
-					  << "\"inputs\":[";
+			method["inputs"] = inputs;
-			streamVariables(f->getParameters());
+			streamVariables(f->getReturnParameters(), outputs);
-			interface << "],"
+			method["outputs"] = outputs;
-					  << "\"outputs\":[";
+
-			streamVariables(f->getReturnParameters());
+			methods.append(method);
-			interface << "]"
-					  << "}";
-			if (--functionsCount > 0)
-				interface << ",";
 		}
-		interface << ']';
+		m_interface = writer.write(methods);
-		m_interface = interface.str();
 	}
 	return m_interface;
 }
 
 string const& CompilerStack::getDocumentation()
 {
-
 	Json::StyledWriter writer;
 	if (!m_parseSuccessful)
 		BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Parsing was not successful."));
+
 	if (m_documentation.empty())
 	{
 		Json::Value doc;

test/solidityJSONInterfaceTest.cpp

@@ -34,7 +34,7 @@ namespace test
 class InterfaceChecker
 {
 public:
-	bool checkInterface(std::string const& _code, std::string const& _expectedInterfaceString)
+	void checkInterface(std::string const& _code, std::string const& _expectedInterfaceString)
 	{
 		m_compilerStack.parse(_code);
 		std::string generatedInterfaceString = m_compilerStack.getInterface();
@@ -42,7 +42,9 @@ public:
 		m_reader.parse(generatedInterfaceString, generatedInterface);
 		Json::Value expectedInterface;
 		m_reader.parse(_expectedInterfaceString, expectedInterface);
-		return expectedInterface == generatedInterface;
+		BOOST_CHECK_MESSAGE(expectedInterface == generatedInterface,
+							"Expected " << _expectedInterfaceString <<
+							"\n but got:\n" << generatedInterfaceString);
 	}
 
 private:
@@ -50,7 +52,7 @@ private:
 	Json::Reader m_reader;
 };
 
-BOOST_FIXTURE_TEST_SUITE(SolidityCompilerJSONInterfaceOutput, InterfaceChecker)
+BOOST_FIXTURE_TEST_SUITE(solidityABIJSON, InterfaceChecker)
 
 BOOST_AUTO_TEST_CASE(basic_test)
 {
@@ -76,7 +78,7 @@ BOOST_AUTO_TEST_CASE(basic_test)
 	}
 	])";
 
-	BOOST_CHECK(checkInterface(sourceCode, interface));
+	checkInterface(sourceCode, interface);
 }
 
 BOOST_AUTO_TEST_CASE(empty_contract)
@@ -86,7 +88,7 @@ BOOST_AUTO_TEST_CASE(empty_contract)
 
 	char const* interface = "[]";
 
-	BOOST_CHECK(checkInterface(sourceCode, interface));
+	checkInterface(sourceCode, interface);
 }
 
 BOOST_AUTO_TEST_CASE(multiple_methods)
@@ -129,7 +131,7 @@ BOOST_AUTO_TEST_CASE(multiple_methods)
 	}
 	])";
 
-	BOOST_CHECK(checkInterface(sourceCode, interface));
+	checkInterface(sourceCode, interface);
 }
 
 BOOST_AUTO_TEST_CASE(multiple_params)
@@ -160,7 +162,7 @@ BOOST_AUTO_TEST_CASE(multiple_params)
 	}
 	])";
 
-	BOOST_CHECK(checkInterface(sourceCode, interface));
+	checkInterface(sourceCode, interface);
 }
 
 BOOST_AUTO_TEST_CASE(multiple_methods_order)
@@ -204,7 +206,7 @@ BOOST_AUTO_TEST_CASE(multiple_methods_order)
 	}
 	])";
 
-	BOOST_CHECK(checkInterface(sourceCode, interface));
+	checkInterface(sourceCode, interface);
 }
 
 BOOST_AUTO_TEST_SUITE_END()