Exporting Natspec documentation to a JSON interface

- Adding a getDocumentation() function to solidity compiler stack
  so that we can obtain the natspec interface for a contract

- Adding libjsoncpp as a dependency of libsolidity. This is done
  in a dirty way, using libjsonrpc-cpp s an intermediate dependency
  for the moment. Will fix soon.

- Start of a test file for Natspec exporting to JSON

AST.h

@@ -199,7 +199,7 @@ public:
 	Block& getBody() { return *m_body; }
 	/// @return A shared pointer of an ASTString.
 	/// Can contain a nullptr in which case indicates absence of documentation
-	ASTPointer<ASTString> const& getDocumentation() { return m_documentation; }
+	ASTPointer<ASTString> const& getDocumentation() const { return m_documentation; }
 
 	void addLocalVariable(VariableDeclaration const& _localVariable) { m_localVariables.push_back(&_localVariable); }
 	std::vector<VariableDeclaration const*> const& getLocalVariables() const { return m_localVariables; }

CMakeLists.txt

@@ -16,6 +16,10 @@ endif()
 include_directories(..)
 
 target_link_libraries(${EXECUTABLE} evmcore devcore)
+# TODO: Temporary until PR 532 https://github.com/ethereum/cpp-ethereum/pull/532
+# gets accepted. Then we can simply add jsoncpp as a dependency and not the
+# whole of JSONRPC as we are doing right here
+target_link_libraries(${EXECUTABLE} ${JSONRPC_LS})
 
 install( TARGETS ${EXECUTABLE} ARCHIVE DESTINATION lib LIBRARY DESTINATION lib )
 install( FILES ${HEADERS} DESTINATION include/${EXECUTABLE} )

CompilerStack.cpp

@@ -28,6 +28,8 @@
 #include <libsolidity/Compiler.h>
 #include <libsolidity/CompilerStack.h>
 
+#include <jsonrpc/json/json.h>
+
 using namespace std;
 
 namespace dev
@@ -125,6 +127,30 @@ string const& CompilerStack::getInterface()
 	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;
+		Json::Value methods;
+
+		vector<FunctionDefinition const*> exportedFunctions = m_contractASTNode->getInterfaceFunctions();
+		for (FunctionDefinition const* f: exportedFunctions)
+		{
+			Json::Value user;
+			user["user"] = Json::Value(*f->getDocumentation());
+			methods[f->getName()] = user;
+		}
+		doc["methods"] = methods;
+		m_documentation = writer.write(doc);
+	}
+	return m_documentation;
+}
+
 bytes CompilerStack::staticCompile(std::string const& _sourceCode, bool _optimize)
 {
 	CompilerStack stack;

CompilerStack.h

@@ -62,6 +62,9 @@ public:
 	/// Returns a string representing the contract interface in JSON.
 	/// Prerequisite: Successful call to parse or compile.
 	std::string const& getInterface();
+	/// Returns a string representing the contract documentation in JSON.
+	/// Prerequisite: Successful call to parse or compile.
+	std::string const& getDocumentation();
 
 	/// Returns the previously used scanner, useful for counting lines during error reporting.
 	Scanner const& getScanner() const { return *m_scanner; }
@@ -77,6 +80,7 @@ private:
 	std::shared_ptr<ContractDefinition> m_contractASTNode;
 	bool m_parseSuccessful;
 	std::string m_interface;
+	std::string m_documentation;
 	std::shared_ptr<Compiler> m_compiler;
 	bytes m_bytecode;
 };