Patch for reviving LSP TCP listener.

solc-lsp-tcp-listener.patch

commit 6cccca59014f49c52faaf19f8f2e9f102f519884
Author: Christian Parpart <christian@parpart.family>
Date:   Mon Nov 29 12:46:52 2021 +0100

    Revert "Drop LSP TCP listener."
    
    This reverts commit 5b61209d11fe046dfc57e4c74762c3da9dfc0e3d.

diff --git a/solc/CMakeLists.txt b/solc/CMakeLists.txt
index 3e3594766..51b77d29b 100644
--- a/solc/CMakeLists.txt
+++ b/solc/CMakeLists.txt
@@ -5,6 +5,19 @@ set(libsolcli_sources
 
 set(libsolcli_libs solidity Boost::boost Boost::program_options)
 
+if(${CMAKE_BUILD_TYPE} STREQUAL "Debug")
+	# Since we do not want to depend on networking code on production binaries,
+	# this feature is only available when creating a debug build.
+	# the LSP's TCP listener is exclusively used more convenient debugging.
+	option(SOLC_LSP_TCP "Solidity LSP: Enables TCP listener support (should only be eanbled for debugging purposes)." OFF)
+	if(SOLC_LSP_TCP)
+		set(libsolcli_defines SOLC_LSP_TCP=1)
+		list(APPEND libsolcli_sources LSPTCPTransport.cpp LSPTCPTransport.h)
+		find_package(Threads REQUIRED)
+		list(APPEND libsolcli_libs Threads::Threads)
+	endif()
+endif()
+
 add_library(solcli ${libsolcli_sources})
 target_compile_definitions(solcli PUBLIC ${libsolcli_defines})
 target_link_libraries(solcli PUBLIC ${libsolcli_libs})
diff --git a/solc/CommandLineInterface.cpp b/solc/CommandLineInterface.cpp
index ba1140f98..1bfa60f95 100644
--- a/solc/CommandLineInterface.cpp
+++ b/solc/CommandLineInterface.cpp
@@ -25,6 +25,10 @@
 
 #include "license.h"
 
+#if defined(SOLC_LSP_TCP)
+#include <solc/LSPTCPTransport.h>
+#endif
+
 #include "solidity/BuildInfo.h"
 
 #include <libsolidity/interface/Version.h>
@@ -902,6 +906,15 @@ void CommandLineInterface::handleAst()
 
 void CommandLineInterface::serveLSP()
 {
+#if defined(SOLC_LSP_TCP)
+	if (m_options.lsp.port.has_value())
+	{
+		lsp::LSPTCPTransport transport(m_options.lsp.port.value());
+		lsp::LanguageServer{transport}.run();
+		return;
+	}
+#endif
+
 	lsp::JSONTransport transport;
 	lsp::LanguageServer{transport}.run();
 }
diff --git a/solc/CommandLineParser.cpp b/solc/CommandLineParser.cpp
index 73f6a1e3a..caa1fdfbd 100644
--- a/solc/CommandLineParser.cpp
+++ b/solc/CommandLineParser.cpp
@@ -1261,6 +1261,19 @@ bool CommandLineParser::processArgs()
 		}
 	}
 
+#if defined(SOLC_LSP_TCP)
+	if (m_args.count("lsp-port"))
+	{
+		unsigned const port = m_args.at("lsp-port").as<unsigned>();
+		if (port > 0xFFFF)
+		{
+			serr() << "LSP port number not in valid port range " << port << '.' << endl;
+			return false;
+		}
+		m_options.lsp.port = port;
+	}
+#endif
+
 	if (m_args.count(g_strModelCheckerContracts))
 	{
 		string contractsStr = m_args[g_strModelCheckerContracts].as<string>();
diff --git a/solc/CommandLineParser.h b/solc/CommandLineParser.h
index d4909a109..4bf0be764 100644
--- a/solc/CommandLineParser.h
+++ b/solc/CommandLineParser.h
@@ -227,6 +227,13 @@ struct CommandLineOptions
 		std::optional<std::string> yulSteps;
 	} optimizer;
 
+#if defined(SOLC_LSP_TCP)
+	struct
+	{
+		std::optional<unsigned short> port;
+	} lsp;
+#endif
+
 	struct
 	{
 		bool initialize = false;
diff --git a/solc/LSPTCPTransport.cpp b/solc/LSPTCPTransport.cpp
new file mode 100644
index 000000000..9c765fa0c
--- /dev/null
+++ b/solc/LSPTCPTransport.cpp
@@ -0,0 +1,96 @@
+/*
+	This file is part of solidity.
+
+	solidity 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.
+
+	solidity 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 solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+// SPDX-License-Identifier: GPL-3.0
+#include <solc/LSPTCPTransport.h>
+
+#include <libsolutil/JSON.h>
+#include <fmt/format.h>
+
+#include <optional>
+#include <string>
+#include <iostream>
+
+namespace solidity::lsp
+{
+
+using std::nullopt;
+using std::optional;
+using std::string_view;
+
+using namespace std::string_literals;
+
+LSPTCPTransport::LSPTCPTransport(unsigned short _port, std::string const& _address):
+	m_io_service(),
+	m_endpoint(boost::asio::ip::make_address(_address), _port),
+	m_acceptor(m_io_service),
+	m_stream(),
+	m_jsonTransport()
+{
+	m_acceptor.open(m_endpoint.protocol());
+	m_acceptor.set_option(boost::asio::ip::tcp::acceptor::reuse_address(true));
+	m_acceptor.bind(m_endpoint);
+	m_acceptor.listen();
+}
+
+bool LSPTCPTransport::closed() const noexcept
+{
+	return !m_acceptor.is_open();
+}
+
+optional<Json::Value> LSPTCPTransport::receive()
+{
+	auto const clientClosed = [&]() { return !m_stream || !m_stream.value().good() || m_stream.value().eof(); };
+
+	if (clientClosed())
+	{
+		m_stream.emplace(m_acceptor.accept());
+		if (clientClosed())
+			return nullopt;
+
+		m_jsonTransport.emplace(m_stream.value(), m_stream.value());
+	}
+
+	if (auto value = m_jsonTransport.value().receive(); value.has_value())
+		return value;
+
+	if (clientClosed())
+	{
+		m_jsonTransport.reset();
+		m_stream.reset();
+	}
+	return nullopt;
+}
+
+void LSPTCPTransport::notify(std::string _method, Json::Value _params)
+{
+	if (m_jsonTransport.has_value())
+		m_jsonTransport.value().notify(move(_method), _params);
+}
+
+void LSPTCPTransport::reply(MessageID _id, Json::Value _result)
+{
+	if (m_jsonTransport.has_value())
+		m_jsonTransport.value().reply(_id, _result);
+}
+
+void LSPTCPTransport::error(MessageID _id, ErrorCode _code, std::string _message)
+{
+	if (m_jsonTransport.has_value())
+		m_jsonTransport.value().error(_id, _code, move(_message));
+}
+
+}
diff --git a/solc/LSPTCPTransport.h b/solc/LSPTCPTransport.h
new file mode 100644
index 000000000..485849906
--- /dev/null
+++ b/solc/LSPTCPTransport.h
@@ -0,0 +1,46 @@
+/*
+	This file is part of solidity.
+
+	solidity 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.
+
+	solidity 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 solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+// SPDX-License-Identifier: GPL-3.0
+#pragma once
+
+#include <libsolidity/lsp/Transport.h>
+
+#include <boost/asio.hpp>
+#include <optional>
+
+namespace solidity::lsp
+{
+
+class LSPTCPTransport: public lsp::Transport {
+public:
+	explicit LSPTCPTransport(unsigned short _port, std::string const& _address = "127.0.0.1");
+
+	bool closed() const noexcept override;
+	std::optional<Json::Value> receive() override;
+	void notify(std::string _method, Json::Value _params) override;
+	void reply(lsp::MessageID _id, Json::Value _result) override;
+	void error(lsp::MessageID _id, lsp::ErrorCode _code, std::string _message) override;
+
+private:
+	boost::asio::io_service m_io_service;
+	boost::asio::ip::tcp::endpoint m_endpoint;
+	boost::asio::ip::tcp::acceptor m_acceptor;
+	std::optional<boost::asio::ip::tcp::iostream> m_stream;
+	std::optional<lsp::JSONTransport> m_jsonTransport;
+};
+
+} // end namespace