[lldb-dap] Finish refactoring the request handlers (NFC) (#128553)

Completes the work started in #128262. This PR removes the
old way of register request handlers with callbacks and makes
the operator const.

Author: JDevlieghere

lldb/tools/lldb-dap/DAP.cpp

@@ -755,20 +755,12 @@ bool DAP::HandleObject(const llvm::json::Object &object) {
   if (packet_type == "request") {
     const auto command = GetString(object, "command");
 
-    // Try the new request handler first.
-    auto new_handler_pos = new_request_handlers.find(command);
-    if (new_handler_pos != new_request_handlers.end()) {
+    auto new_handler_pos = request_handlers.find(command);
+    if (new_handler_pos != request_handlers.end()) {
       (*new_handler_pos->second)(object);
       return true; // Success
     }
 
-    // FIXME: Remove request_handlers once everything has been migrated.
-    auto handler_pos = request_handlers.find(command);
-    if (handler_pos != request_handlers.end()) {
-      handler_pos->second(*this, object);
-      return true; // Success
-    }
-
     if (log)
       *log << "error: unhandled command \"" << command.data() << "\""
            << std::endl;
@@ -901,11 +893,6 @@ void DAP::SendReverseRequest(llvm::StringRef command,
   });
 }
 
-void DAP::RegisterRequestCallback(std::string request,
-                                  RequestCallback callback) {
-  request_handlers[request] = callback;
-}
-
 lldb::SBError DAP::WaitForProcessToStop(uint32_t seconds) {
   lldb::SBError error;
   lldb::SBProcess process = target.GetProcess();

lldb/tools/lldb-dap/DAP.h

@@ -68,7 +68,6 @@ enum DAPBroadcasterBits {
   eBroadcastBitStopProgressThread = 1u << 1
 };
 
-typedef void (*RequestCallback)(DAP &dap, const llvm::json::Object &command);
 typedef void (*ResponseCallback)(llvm::Expected<llvm::json::Value> value);
 
 enum class PacketStatus {
@@ -190,8 +189,7 @@ struct DAP {
   // the old process here so we can detect this case and keep running.
   lldb::pid_t restarting_process_id;
   bool configuration_done_sent;
-  std::map<std::string, RequestCallback, std::less<>> request_handlers;
-  llvm::StringMap<std::unique_ptr<RequestHandler>> new_request_handlers;
+  llvm::StringMap<std::unique_ptr<RequestHandler>> request_handlers;
   bool waiting_for_run_in_terminal;
   ProgressEventReporter progress_event_reporter;
   // Keep track of the last stop thread index IDs as threads won't go away
@@ -309,8 +307,6 @@ struct DAP {
   /// listeing for its breakpoint events.
   void SetTarget(const lldb::SBTarget target);
 
-  const std::map<std::string, RequestCallback> &GetRequestHandlers();
-
   PacketStatus GetNextObject(llvm::json::Object &object);
   bool HandleObject(const llvm::json::Object &object);
 
@@ -338,21 +334,9 @@ struct DAP {
   void SendReverseRequest(llvm::StringRef command, llvm::json::Value arguments,
                           ResponseCallback callback);
 
-  /// Registers a callback handler for a Debug Adapter Protocol request
-  ///
-  /// \param[in] request
-  ///     The name of the request following the Debug Adapter Protocol
-  ///     specification.
-  ///
-  /// \param[in] callback
-  ///     The callback to execute when the given request is triggered by the
-  ///     IDE.
-  void RegisterRequestCallback(std::string request, RequestCallback callback);
-
   /// Registers a request handler.
   template <typename Handler> void RegisterRequest() {
-    new_request_handlers[Handler::getCommand()] =
-        std::make_unique<Handler>(*this);
+    request_handlers[Handler::getCommand()] = std::make_unique<Handler>(*this);
   }
 
   /// Debuggee will continue from stopped state.

lldb/tools/lldb-dap/Handler/AttachRequestHandler.cpp

@@ -44,7 +44,7 @@ namespace lldb_dap {
 //   }]
 // }
 
-void AttachRequestHandler::operator()(const llvm::json::Object &request) {
+void AttachRequestHandler::operator()(const llvm::json::Object &request) const {
   dap.is_attach = true;
   dap.last_launch_or_attach_request = request;
   llvm::json::Object response;

lldb/tools/lldb-dap/Handler/BreakpointLocationsHandler.cpp

@@ -125,7 +125,7 @@ namespace lldb_dap {
 //   "required": [ "line" ]
 // },
 void BreakpointLocationsRequestHandler::operator()(
-    const llvm::json::Object &request) {
+    const llvm::json::Object &request) const {
   llvm::json::Object response;
   FillResponse(request, response);
   auto *arguments = request.getObject("arguments");

lldb/tools/lldb-dap/Handler/CompileUnitsRequestHandler.cpp

@@ -53,7 +53,8 @@ namespace lldb_dap {
 //     }
 //   }]
 // }
-void CompileUnitsRequestHandler::operator()(const llvm::json::Object &request) {
+void CompileUnitsRequestHandler::operator()(
+    const llvm::json::Object &request) const {
   llvm::json::Object response;
   FillResponse(request, response);
   llvm::json::Object body;

lldb/tools/lldb-dap/Handler/CompletionsHandler.cpp

@@ -128,7 +128,8 @@ namespace lldb_dap {
 //   "interface", "module", "property", "unit", "value", "enum", "keyword",
 //   "snippet", "text", "color", "file", "reference", "customcolor" ]
 // }
-void CompletionsRequestHandler::operator()(const llvm::json::Object &request) {
+void CompletionsRequestHandler::operator()(
+    const llvm::json::Object &request) const {
   llvm::json::Object response;
   FillResponse(request, response);
   llvm::json::Object body;

lldb/tools/lldb-dap/Handler/ConfigurationDoneRequestHandler.cpp

@@ -45,7 +45,7 @@ namespace lldb_dap {
 //             }]
 // },
 void ConfigurationDoneRequestHandler::operator()(
-    const llvm::json::Object &request) {
+    const llvm::json::Object &request) const {
   llvm::json::Object response;
   FillResponse(request, response);
   dap.SendJSON(llvm::json::Value(std::move(response)));

lldb/tools/lldb-dap/Handler/ContinueRequestHandler.cpp

@@ -66,7 +66,8 @@ namespace lldb_dap {
 //     "required": [ "body" ]
 //   }]
 // }
-void ContinueRequestHandler::operator()(const llvm::json::Object &request) {
+void ContinueRequestHandler::operator()(
+    const llvm::json::Object &request) const {
   llvm::json::Object response;
   FillResponse(request, response);
   lldb::SBProcess process = dap.target.GetProcess();

lldb/tools/lldb-dap/Handler/DataBreakpointInfoRequestHandler.cpp

@@ -108,7 +108,7 @@ namespace lldb_dap {
 //   }]
 // }
 void DataBreakpointInfoRequestHandler::operator()(
-    const llvm::json::Object &request) {
+    const llvm::json::Object &request) const {
   llvm::json::Object response;
   FillResponse(request, response);
   llvm::json::Object body;

lldb/tools/lldb-dap/Handler/DisassembleRequestHandler.cpp

@@ -87,7 +87,8 @@ namespace lldb_dap {
 //     }
 //   }]
 // }
-void DisassembleRequestHandler::operator()(const llvm::json::Object &request) {
+void DisassembleRequestHandler::operator()(
+    const llvm::json::Object &request) const {
   llvm::json::Object response;
   FillResponse(request, response);
   auto *arguments = request.getObject("arguments");