[lldb-dap] Stop the process for the threads request

Author: JDevlieghere

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

@@ -10,6 +10,7 @@
 #include "EventHelper.h"
 #include "JSONUtils.h"
 #include "RequestHandler.h"
+#include "lldb/API/SBError.h"
 
 namespace lldb_dap {
 
@@ -54,15 +55,34 @@ void ThreadsRequestHandler::operator()(
   llvm::json::Object response;
   FillResponse(request, response);
 
+  const auto state = process.GetState();
+  const bool stop_and_resume =
+      state != lldb::eStateCrashed && state != lldb::eStateStopped;
+
+  if (stop_and_resume) {
+    lldb::SBError error = dap.WaitForProcessToStop(1);
+    if (error.Fail()) {
+      SetError(response, error);
+      dap.SendJSON(llvm::json::Value(std::move(response)));
+    }
+  }
+
   const uint32_t num_threads = process.GetNumThreads();
   llvm::json::Array threads;
   for (uint32_t thread_idx = 0; thread_idx < num_threads; ++thread_idx) {
     lldb::SBThread thread = process.GetThreadAtIndex(thread_idx);
     threads.emplace_back(CreateThread(thread, dap.thread_format));
   }
-  if (threads.size() == 0) {
-    response["success"] = llvm::json::Value(false);
+
+  if (stop_and_resume) {
+    lldb::SBError error = process.Continue();
+    if (error.Fail()) {
+      SetError(response, error);
+      dap.SendJSON(llvm::json::Value(std::move(response)));
+    }
   }
+
+  response["success"] = llvm::json::Value(threads.size() != 0);
   llvm::json::Object body;
   body.try_emplace("threads", std::move(threads));
   response.try_emplace("body", std::move(body));

lldb/tools/lldb-dap/JSONUtils.cpp

@@ -268,6 +268,15 @@ void FillResponse(const llvm::json::Object &request,
   response.try_emplace("success", true);
 }
 
+void SetError(llvm::json::Object &response, lldb::SBError error) {
+  assert(error.Fail());
+
+  response["success"] = llvm::json::Value(error.Success());
+  const char *error_cstr = error.GetCString();
+  if (error_cstr && error_cstr[0])
+    EmplaceSafeString(response, "message", std::string(error_cstr));
+}
+
 // "Scope": {
 //   "type": "object",
 //   "description": "A Scope is a named container for variables. Optionally

lldb/tools/lldb-dap/JSONUtils.h

@@ -12,6 +12,7 @@
 #include "DAPForward.h"
 #include "Protocol/ProtocolTypes.h"
 #include "lldb/API/SBCompileUnit.h"
+#include "lldb/API/SBError.h"
 #include "lldb/API/SBFileSpec.h"
 #include "lldb/API/SBFormat.h"
 #include "lldb/API/SBLineEntry.h"
@@ -197,6 +198,15 @@ GetStringMap(const llvm::json::Object &obj, llvm::StringRef key);
 void FillResponse(const llvm::json::Object &request,
                   llvm::json::Object &response);
 
+/// Set the response to failed and populate the message if there is one.
+///
+/// \param[in,out] response
+///     An llvm::json::Object object that will be populated.
+///
+/// \param[in] error
+///     A LLDB error in the failed state.
+void SetError(llvm::json::Object &response, lldb::SBError error);
+
 /// Converts \a bp to a JSON value and appends the first valid location to the
 /// \a breakpoints array.
 ///