[Lldb-commits] [lldb] [lldb-dap] Updating RequestHandler to encode/decode arguments and response. (PR #130090)

[Adrian Vogelsgesang via lldb-commits]

================
@@ -57,235 +68,288 @@ class RequestHandler {
   DAP &dap;
 };
 
-class AttachRequestHandler : public RequestHandler {
-public:
-  using RequestHandler::RequestHandler;
+/// Base class for handling DAP requests. Handlers should declare their
+/// arguments and response body types like:
+///
+/// class MyRequestHandler : public RequestHandler<Arguments, ResponseBody> {
+///   ....
+/// };
+template <typename Args, typename Body>
+class RequestHandler : public BaseRequestHandler {
+  using BaseRequestHandler::BaseRequestHandler;
+
+  void operator()(const llvm::json::Object &request) const override {
+    /* no-op, the other overload handles json coding. */
+  }
+
+  void operator()(const protocol::Request &request) const override {
+    protocol::Response response;
+    response.request_seq = request.seq;
+    response.command = request.command;
+    Args arguments;
+    llvm::json::Path::Root root;
+    if (request.rawArguments &&
+        !fromJSON(request.rawArguments, arguments, root)) {
----------------
vogelsgesang wrote:

I think we should handle the case of missing arguments here...
Something like

```
   if constexpr (!std::is_same_v< Args, std::monostate>) {
      if (!request.rawArguments) {
          // Send error...
          return;
      }
      if (!fromJSON(request.rawArguments, arguments, root)) {
          // Send error...
          return;
      }
   }
```

https://github.com/llvm/llvm-project/pull/130090