[lldb] Move the generic MCP server code into Protocol/MCP (NFC) #152396
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This is a continuation of llvm#152188, which started splitting up the MCP implementation into a generic implementation in Protocol/MCP that will be shared between LLDB and lldb-mcp. For now I kept all the networking code in the MCP server plugin. Once the changes to JSONTransport land, we might be able to move more of it into the Protocol library.
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@llvm/pr-subscribers-lldb Author: Jonas Devlieghere (JDevlieghere) ChangesThis is a continuation of #152188, which started splitting up the MCP implementation into a generic implementation in Protocol/MCP that will be shared between LLDB and lldb-mcp. For now I kept all the networking code in the MCP server plugin. Once the changes to JSONTransport land, we might be able to move more of it into the Protocol library. Patch is 25.11 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/152396.diff 6 Files Affected:
diff --git a/lldb/include/lldb/Protocol/MCP/Protocol.h b/lldb/include/lldb/Protocol/MCP/Protocol.h
index c43b06809bd3f..6448416eee08f 100644
--- a/lldb/include/lldb/Protocol/MCP/Protocol.h
+++ b/lldb/include/lldb/Protocol/MCP/Protocol.h
@@ -21,7 +21,7 @@
namespace lldb_protocol::mcp {
-static llvm::StringLiteral kVersion = "2024-11-05";
+static llvm::StringLiteral kProtocolVersion = "2024-11-05";
/// A request that expects a response.
struct Request {
diff --git a/lldb/include/lldb/Protocol/MCP/Server.h b/lldb/include/lldb/Protocol/MCP/Server.h
new file mode 100644
index 0000000000000..e8c32d713a2b3
--- /dev/null
+++ b/lldb/include/lldb/Protocol/MCP/Server.h
@@ -0,0 +1,69 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_PROTOCOL_MCP_SERVER_H
+#define LLDB_PROTOCOL_MCP_SERVER_H
+
+#include "lldb/Protocol/MCP/Protocol.h"
+#include "lldb/Protocol/MCP/Resource.h"
+#include "lldb/Protocol/MCP/Tool.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/Support/Error.h"
+
+namespace lldb_protocol::mcp {
+
+class Server {
+public:
+ Server(std::string name, std::string version);
+ virtual ~Server() = default;
+
+ void AddTool(std::unique_ptr<Tool> tool);
+ void AddResourceProvider(std::unique_ptr<ResourceProvider> resource_provider);
+
+protected:
+ virtual Capabilities GetCapabilities() = 0;
+
+ using RequestHandler =
+ std::function<llvm::Expected<Response>(const Request &)>;
+ using NotificationHandler = std::function<void(const Notification &)>;
+
+ void AddRequestHandlers();
+
+ void AddRequestHandler(llvm::StringRef method, RequestHandler handler);
+ void AddNotificationHandler(llvm::StringRef method,
+ NotificationHandler handler);
+
+ llvm::Expected<std::optional<Message>> HandleData(llvm::StringRef data);
+
+ llvm::Expected<Response> Handle(Request request);
+ void Handle(Notification notification);
+
+ llvm::Expected<Response> InitializeHandler(const Request &);
+
+ llvm::Expected<Response> ToolsListHandler(const Request &);
+ llvm::Expected<Response> ToolsCallHandler(const Request &);
+
+ llvm::Expected<Response> ResourcesListHandler(const Request &);
+ llvm::Expected<Response> ResourcesReadHandler(const Request &);
+
+ std::mutex m_mutex;
+
+private:
+ const std::string m_name;
+ const std::string m_version;
+
+ llvm::StringMap<std::unique_ptr<Tool>> m_tools;
+ std::vector<std::unique_ptr<ResourceProvider>> m_resource_providers;
+
+ llvm::StringMap<RequestHandler> m_request_handlers;
+ llvm::StringMap<NotificationHandler> m_notification_handlers;
+};
+
+} // namespace lldb_protocol::mcp
+
+#endif
diff --git a/lldb/source/Plugins/Protocol/MCP/ProtocolServerMCP.cpp b/lldb/source/Plugins/Protocol/MCP/ProtocolServerMCP.cpp
index c9fe474d45c49..c359663239dcc 100644
--- a/lldb/source/Plugins/Protocol/MCP/ProtocolServerMCP.cpp
+++ b/lldb/source/Plugins/Protocol/MCP/ProtocolServerMCP.cpp
@@ -27,25 +27,12 @@ using namespace llvm;
LLDB_PLUGIN_DEFINE(ProtocolServerMCP)
static constexpr size_t kChunkSize = 1024;
+static constexpr llvm::StringLiteral kName = "lldb-mcp";
+static constexpr llvm::StringLiteral kVersion = "0.1.0";
-ProtocolServerMCP::ProtocolServerMCP() : ProtocolServer() {
- AddRequestHandler("initialize",
- std::bind(&ProtocolServerMCP::InitializeHandler, this,
- std::placeholders::_1));
-
- AddRequestHandler("tools/list",
- std::bind(&ProtocolServerMCP::ToolsListHandler, this,
- std::placeholders::_1));
- AddRequestHandler("tools/call",
- std::bind(&ProtocolServerMCP::ToolsCallHandler, this,
- std::placeholders::_1));
-
- AddRequestHandler("resources/list",
- std::bind(&ProtocolServerMCP::ResourcesListHandler, this,
- std::placeholders::_1));
- AddRequestHandler("resources/read",
- std::bind(&ProtocolServerMCP::ResourcesReadHandler, this,
- std::placeholders::_1));
+ProtocolServerMCP::ProtocolServerMCP()
+ : ProtocolServer(),
+ lldb_protocol::mcp::Server(std::string(kName), std::string(kVersion)) {
AddNotificationHandler("notifications/initialized",
[](const lldb_protocol::mcp::Notification &) {
LLDB_LOG(GetLog(LLDBLog::Host),
@@ -77,32 +64,6 @@ llvm::StringRef ProtocolServerMCP::GetPluginDescriptionStatic() {
return "MCP Server.";
}
-llvm::Expected<lldb_protocol::mcp::Response>
-ProtocolServerMCP::Handle(lldb_protocol::mcp::Request request) {
- auto it = m_request_handlers.find(request.method);
- if (it != m_request_handlers.end()) {
- llvm::Expected<lldb_protocol::mcp::Response> response = it->second(request);
- if (!response)
- return response;
- response->id = request.id;
- return *response;
- }
-
- return make_error<MCPError>(
- llvm::formatv("no handler for request: {0}", request.method).str());
-}
-
-void ProtocolServerMCP::Handle(lldb_protocol::mcp::Notification notification) {
- auto it = m_notification_handlers.find(notification.method);
- if (it != m_notification_handlers.end()) {
- it->second(notification);
- return;
- }
-
- LLDB_LOG(GetLog(LLDBLog::Host), "MPC notification: {0} ({1})",
- notification.method, notification.params);
-}
-
void ProtocolServerMCP::AcceptCallback(std::unique_ptr<Socket> socket) {
LLDB_LOG(GetLog(LLDBLog::Host), "New MCP client ({0}) connected",
m_clients.size() + 1);
@@ -157,7 +118,7 @@ llvm::Error ProtocolServerMCP::ReadCallback(Client &client) {
}
llvm::Error ProtocolServerMCP::Start(ProtocolServer::Connection connection) {
- std::lock_guard<std::mutex> guard(m_server_mutex);
+ std::lock_guard<std::mutex> guard(m_mutex);
if (m_running)
return llvm::createStringError("the MCP server is already running");
@@ -189,7 +150,7 @@ llvm::Error ProtocolServerMCP::Start(ProtocolServer::Connection connection) {
llvm::Error ProtocolServerMCP::Stop() {
{
- std::lock_guard<std::mutex> guard(m_server_mutex);
+ std::lock_guard<std::mutex> guard(m_mutex);
if (!m_running)
return createStringError("the MCP sever is not running");
m_running = false;
@@ -204,7 +165,7 @@ llvm::Error ProtocolServerMCP::Stop() {
m_loop_thread.join();
{
- std::lock_guard<std::mutex> guard(m_server_mutex);
+ std::lock_guard<std::mutex> guard(m_mutex);
m_listener.reset();
m_listen_handlers.clear();
m_clients.clear();
@@ -213,48 +174,6 @@ llvm::Error ProtocolServerMCP::Stop() {
return llvm::Error::success();
}
-llvm::Expected<std::optional<lldb_protocol::mcp::Message>>
-ProtocolServerMCP::HandleData(llvm::StringRef data) {
- auto message = llvm::json::parse<lldb_protocol::mcp::Message>(/*JSON=*/data);
- if (!message)
- return message.takeError();
-
- if (const lldb_protocol::mcp::Request *request =
- std::get_if<lldb_protocol::mcp::Request>(&(*message))) {
- llvm::Expected<lldb_protocol::mcp::Response> response = Handle(*request);
-
- // Handle failures by converting them into an Error message.
- if (!response) {
- lldb_protocol::mcp::Error protocol_error;
- llvm::handleAllErrors(
- response.takeError(),
- [&](const MCPError &err) { protocol_error = err.toProtcolError(); },
- [&](const llvm::ErrorInfoBase &err) {
- protocol_error.error.code = MCPError::kInternalError;
- protocol_error.error.message = err.message();
- });
- protocol_error.id = request->id;
- return protocol_error;
- }
-
- return *response;
- }
-
- if (const lldb_protocol::mcp::Notification *notification =
- std::get_if<lldb_protocol::mcp::Notification>(&(*message))) {
- Handle(*notification);
- return std::nullopt;
- }
-
- if (std::get_if<lldb_protocol::mcp::Error>(&(*message)))
- return llvm::createStringError("unexpected MCP message: error");
-
- if (std::get_if<lldb_protocol::mcp::Response>(&(*message)))
- return llvm::createStringError("unexpected MCP message: response");
-
- llvm_unreachable("all message types handled");
-}
-
lldb_protocol::mcp::Capabilities ProtocolServerMCP::GetCapabilities() {
lldb_protocol::mcp::Capabilities capabilities;
capabilities.tools.listChanged = true;
@@ -263,158 +182,3 @@ lldb_protocol::mcp::Capabilities ProtocolServerMCP::GetCapabilities() {
capabilities.resources.listChanged = false;
return capabilities;
}
-
-void ProtocolServerMCP::AddTool(std::unique_ptr<Tool> tool) {
- std::lock_guard<std::mutex> guard(m_server_mutex);
-
- if (!tool)
- return;
- m_tools[tool->GetName()] = std::move(tool);
-}
-
-void ProtocolServerMCP::AddResourceProvider(
- std::unique_ptr<ResourceProvider> resource_provider) {
- std::lock_guard<std::mutex> guard(m_server_mutex);
-
- if (!resource_provider)
- return;
- m_resource_providers.push_back(std::move(resource_provider));
-}
-
-void ProtocolServerMCP::AddRequestHandler(llvm::StringRef method,
- RequestHandler handler) {
- std::lock_guard<std::mutex> guard(m_server_mutex);
- m_request_handlers[method] = std::move(handler);
-}
-
-void ProtocolServerMCP::AddNotificationHandler(llvm::StringRef method,
- NotificationHandler handler) {
- std::lock_guard<std::mutex> guard(m_server_mutex);
- m_notification_handlers[method] = std::move(handler);
-}
-
-llvm::Expected<lldb_protocol::mcp::Response>
-ProtocolServerMCP::InitializeHandler(
- const lldb_protocol::mcp::Request &request) {
- lldb_protocol::mcp::Response response;
- response.result.emplace(llvm::json::Object{
- {"protocolVersion", lldb_protocol::mcp::kVersion},
- {"capabilities", GetCapabilities()},
- {"serverInfo",
- llvm::json::Object{{"name", kName}, {"version", kVersion}}}});
- return response;
-}
-
-llvm::Expected<lldb_protocol::mcp::Response>
-ProtocolServerMCP::ToolsListHandler(
- const lldb_protocol::mcp::Request &request) {
- lldb_protocol::mcp::Response response;
-
- llvm::json::Array tools;
- for (const auto &tool : m_tools)
- tools.emplace_back(toJSON(tool.second->GetDefinition()));
-
- response.result.emplace(llvm::json::Object{{"tools", std::move(tools)}});
-
- return response;
-}
-
-llvm::Expected<lldb_protocol::mcp::Response>
-ProtocolServerMCP::ToolsCallHandler(
- const lldb_protocol::mcp::Request &request) {
- lldb_protocol::mcp::Response response;
-
- if (!request.params)
- return llvm::createStringError("no tool parameters");
-
- const json::Object *param_obj = request.params->getAsObject();
- if (!param_obj)
- return llvm::createStringError("no tool parameters");
-
- const json::Value *name = param_obj->get("name");
- if (!name)
- return llvm::createStringError("no tool name");
-
- llvm::StringRef tool_name = name->getAsString().value_or("");
- if (tool_name.empty())
- return llvm::createStringError("no tool name");
-
- auto it = m_tools.find(tool_name);
- if (it == m_tools.end())
- return llvm::createStringError(llvm::formatv("no tool \"{0}\"", tool_name));
-
- lldb_protocol::mcp::ToolArguments tool_args;
- if (const json::Value *args = param_obj->get("arguments"))
- tool_args = *args;
-
- llvm::Expected<lldb_protocol::mcp::TextResult> text_result =
- it->second->Call(tool_args);
- if (!text_result)
- return text_result.takeError();
-
- response.result.emplace(toJSON(*text_result));
-
- return response;
-}
-
-llvm::Expected<lldb_protocol::mcp::Response>
-ProtocolServerMCP::ResourcesListHandler(
- const lldb_protocol::mcp::Request &request) {
- lldb_protocol::mcp::Response response;
-
- llvm::json::Array resources;
-
- std::lock_guard<std::mutex> guard(m_server_mutex);
- for (std::unique_ptr<ResourceProvider> &resource_provider_up :
- m_resource_providers) {
- for (const lldb_protocol::mcp::Resource &resource :
- resource_provider_up->GetResources())
- resources.push_back(resource);
- }
- response.result.emplace(
- llvm::json::Object{{"resources", std::move(resources)}});
-
- return response;
-}
-
-llvm::Expected<lldb_protocol::mcp::Response>
-ProtocolServerMCP::ResourcesReadHandler(
- const lldb_protocol::mcp::Request &request) {
- lldb_protocol::mcp::Response response;
-
- if (!request.params)
- return llvm::createStringError("no resource parameters");
-
- const json::Object *param_obj = request.params->getAsObject();
- if (!param_obj)
- return llvm::createStringError("no resource parameters");
-
- const json::Value *uri = param_obj->get("uri");
- if (!uri)
- return llvm::createStringError("no resource uri");
-
- llvm::StringRef uri_str = uri->getAsString().value_or("");
- if (uri_str.empty())
- return llvm::createStringError("no resource uri");
-
- std::lock_guard<std::mutex> guard(m_server_mutex);
- for (std::unique_ptr<ResourceProvider> &resource_provider_up :
- m_resource_providers) {
- llvm::Expected<lldb_protocol::mcp::ResourceResult> result =
- resource_provider_up->ReadResource(uri_str);
- if (result.errorIsA<UnsupportedURI>()) {
- llvm::consumeError(result.takeError());
- continue;
- }
- if (!result)
- return result.takeError();
-
- lldb_protocol::mcp::Response response;
- response.result.emplace(std::move(*result));
- return response;
- }
-
- return make_error<MCPError>(
- llvm::formatv("no resource handler for uri: {0}", uri_str).str(),
- MCPError::kResourceNotFound);
-}
diff --git a/lldb/source/Plugins/Protocol/MCP/ProtocolServerMCP.h b/lldb/source/Plugins/Protocol/MCP/ProtocolServerMCP.h
index 2ea9585a2334b..7fe909a728b85 100644
--- a/lldb/source/Plugins/Protocol/MCP/ProtocolServerMCP.h
+++ b/lldb/source/Plugins/Protocol/MCP/ProtocolServerMCP.h
@@ -13,14 +13,13 @@
#include "lldb/Host/MainLoop.h"
#include "lldb/Host/Socket.h"
#include "lldb/Protocol/MCP/Protocol.h"
-#include "lldb/Protocol/MCP/Resource.h"
-#include "lldb/Protocol/MCP/Tool.h"
-#include "llvm/ADT/StringMap.h"
+#include "lldb/Protocol/MCP/Server.h"
#include <thread>
namespace lldb_private::mcp {
-class ProtocolServerMCP : public ProtocolServer {
+class ProtocolServerMCP : public ProtocolServer,
+ public lldb_protocol::mcp::Server {
public:
ProtocolServerMCP();
virtual ~ProtocolServerMCP() override;
@@ -40,48 +39,10 @@ class ProtocolServerMCP : public ProtocolServer {
Socket *GetSocket() const override { return m_listener.get(); }
-protected:
- using RequestHandler =
- std::function<llvm::Expected<lldb_protocol::mcp::Response>(
- const lldb_protocol::mcp::Request &)>;
- using NotificationHandler =
- std::function<void(const lldb_protocol::mcp::Notification &)>;
-
- void AddTool(std::unique_ptr<lldb_protocol::mcp::Tool> tool);
- void AddResourceProvider(
- std::unique_ptr<lldb_protocol::mcp::ResourceProvider> resource_provider);
-
- void AddRequestHandler(llvm::StringRef method, RequestHandler handler);
- void AddNotificationHandler(llvm::StringRef method,
- NotificationHandler handler);
-
private:
void AcceptCallback(std::unique_ptr<Socket> socket);
- llvm::Expected<std::optional<lldb_protocol::mcp::Message>>
- HandleData(llvm::StringRef data);
-
- llvm::Expected<lldb_protocol::mcp::Response>
- Handle(lldb_protocol::mcp::Request request);
- void Handle(lldb_protocol::mcp::Notification notification);
-
- llvm::Expected<lldb_protocol::mcp::Response>
- InitializeHandler(const lldb_protocol::mcp::Request &);
-
- llvm::Expected<lldb_protocol::mcp::Response>
- ToolsListHandler(const lldb_protocol::mcp::Request &);
- llvm::Expected<lldb_protocol::mcp::Response>
- ToolsCallHandler(const lldb_protocol::mcp::Request &);
-
- llvm::Expected<lldb_protocol::mcp::Response>
- ResourcesListHandler(const lldb_protocol::mcp::Request &);
- llvm::Expected<lldb_protocol::mcp::Response>
- ResourcesReadHandler(const lldb_protocol::mcp::Request &);
-
- lldb_protocol::mcp::Capabilities GetCapabilities();
-
- llvm::StringLiteral kName = "lldb-mcp";
- llvm::StringLiteral kVersion = "0.1.0";
+ lldb_protocol::mcp::Capabilities GetCapabilities() override;
bool m_running = false;
@@ -98,14 +59,6 @@ class ProtocolServerMCP : public ProtocolServer {
};
llvm::Error ReadCallback(Client &client);
std::vector<std::unique_ptr<Client>> m_clients;
-
- std::mutex m_server_mutex;
- llvm::StringMap<std::unique_ptr<lldb_protocol::mcp::Tool>> m_tools;
- std::vector<std::unique_ptr<lldb_protocol::mcp::ResourceProvider>>
- m_resource_providers;
-
- llvm::StringMap<RequestHandler> m_request_handlers;
- llvm::StringMap<NotificationHandler> m_notification_handlers;
};
} // namespace lldb_private::mcp
diff --git a/lldb/source/Protocol/MCP/CMakeLists.txt b/lldb/source/Protocol/MCP/CMakeLists.txt
index f1b1098e064a5..a73e7e6a7cab1 100644
--- a/lldb/source/Protocol/MCP/CMakeLists.txt
+++ b/lldb/source/Protocol/MCP/CMakeLists.txt
@@ -1,6 +1,7 @@
add_lldb_library(lldbProtocolMCP NO_PLUGIN_DEPENDENCIES
MCPError.cpp
Protocol.cpp
+ Server.cpp
Tool.cpp
LINK_COMPONENTS
diff --git a/lldb/source/Protocol/MCP/Server.cpp b/lldb/source/Protocol/MCP/Server.cpp
new file mode 100644
index 0000000000000..4ec127fe75bdd
--- /dev/null
+++ b/lldb/source/Protocol/MCP/Server.cpp
@@ -0,0 +1,236 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Protocol/MCP/Server.h"
+#include "lldb/Protocol/MCP/MCPError.h"
+
+using namespace lldb_protocol::mcp;
+using namespace llvm;
+
+Server::Server(std::string name, std::string version)
+ : m_name(std::move(name)), m_version(std::move(version)) {
+ AddRequestHandlers();
+}
+
+void Server::AddRequestHandlers() {
+ AddRequestHandler("initialize", std::bind(&Server::InitializeHandler, this,
+ std::placeholders::_1));
+ AddRequestHandler("tools/list", std::bind(&Server::ToolsListHandler, this,
+ std::placeholders::_1));
+ AddRequestHandler("tools/call", std::bind(&Server::ToolsCallHandler, this,
+ std::placeholders::_1));
+ AddRequestHandler("resources/list", std::bind(&Server::ResourcesListHandler,
+ this, std::placeholders::_1));
+ AddRequestHandler("resources/read", std::bind(&Server::ResourcesReadHandler,
+ this, std::placeholders::_1));
+}
+
+llvm::Expected<Response> Server::Handle(Request request) {
+ auto it = m_request_handlers.find(request.method);
+ if (it != m_request_handlers.end()) {
+ llvm::Expected<Response> response = it->second(request);
+ if (!response)
+ return response;
+ response->id = request.id;
+ return *response;
+ }
+
+ return llvm::make_error<MCPError>(
+ llvm::formatv("no handler for request: {0}", request.method).str());
+}
+
+void Server::Handle(Notification notification) {
+ auto it = m_notification_handlers.find(notification.method);
+ if (it != m_notification_handlers.end()) {
+ it->second(notification);
+ return;
+ }
+}
+
+llvm::Expected<std::optional<Message>>
+Server::HandleData(llvm::StringRef data) {
+ auto message = llvm::json::parse<Message>(/*JSON=*/data);
+ if (!message)
+ return message.takeError();
+
+ if (const Request *request = std::get_if<Request>(&(*message))) {
+ llvm::Expected<Response> response = Handle(*request);
+
+ // Handle failures by converting them into an Error message.
+ if (!response) {
+ Error protocol_error;
+ llvm::handleAllErrors(
+ response.takeError(),
+ ...
[truncated]
|
ashgti
approved these changes
Aug 7, 2025
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This is a continuation of #152188, which started splitting up the MCP implementation into a generic implementation in Protocol/MCP that will be shared between LLDB and lldb-mcp.
For now I kept all the networking code in the MCP server plugin. Once the changes to JSONTransport land, we might be able to move more of it into the Protocol library.