ethminer/libjsconsole/JSConsole.h

/*
	This file is part of cpp-ethereum.

	cpp-ethereum is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	cpp-ethereum is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
/** @file JSConsole.h
 * @author Marek Kotewicz <marek@ethdev.com>
 * @date 2015
 * Ethereum client.
 */

#pragma once

#include <libdevcore/Log.h>

#if ETH_READLINE
#include <readline/readline.h>
#include <readline/history.h>
#endif

namespace dev
{
namespace eth
{

template<typename Engine, typename Printer>
class JSConsole
{
public:
	JSConsole(): m_engine(Engine()), m_printer(Printer(m_engine)) {}
	~JSConsole() {}

	void readExpression() const
	{
		std::string cmd = "";
		g_logPost = [](std::string const& a, char const*)
		{
			std::cout << "\r           \r" << a << std::endl << std::flush;
#if ETH_READLINE
			rl_forced_update_display();
#endif
		};

		bool isEmpty = true;
		int openBrackets = 0;
		do {
			std::string rl;
#if ETH_READLINE
			char* buff = readline(promptForIndentionLevel(openBrackets).c_str());
			if (buff)
			{
				rl = std::string(buff);
				free(buff);
			}
#else
			std::cout << promptForIndentionLevel(openBrackets) << std::flush;
			std::getline(std::cin, rl);
#endif
			isEmpty = rl.empty();
			//@todo this should eventually check the structure of the input, since unmatched
			// brackets in strings will fail to execute the input now.
			if (!isEmpty)
			{
				cmd += rl;
				int open = 0;
				for (char c: {'{', '[', '('})
					open += std::count(cmd.begin(), cmd.end(), c);
				int closed = 0;
				for (char c: {'}', ']', ')'})
					closed += std::count(cmd.begin(), cmd.end(), c);
				openBrackets = open - closed;
			}
		} while (openBrackets > 0);

		if (!isEmpty)
		{
#if ETH_READLINE
			add_history(cmd.c_str());
#endif
			auto value = m_engine.eval(cmd.c_str());
			std::string result = m_printer.prettyPrint(value).cstr();
			std::cout << result << std::endl;
		}
	}

	void eval(std::string const& _expression) { m_engine.eval(_expression.c_str()); }

protected:
	Engine m_engine;
	Printer m_printer;

	virtual std::string promptForIndentionLevel(int _i) const
	{
		if (_i == 0)
			return "> ";

		return std::string((_i + 1) * 2, ' ');
	}
};

}
}