[lldb-dap] Ensure we aquire the SB API lock while handling requests.

Aquiring the lock for the target should help ensure consistency with other background operations, like the thread monitoring events that can trigger run commands from a different thread.

Author: ashgti

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

@@ -14,6 +14,7 @@
 #include "Protocol/ProtocolBase.h"
 #include "RunInTerminal.h"
 #include "llvm/Support/Error.h"
+#include <mutex>
 
 #if !defined(_WIN32)
 #include <unistd.h>
@@ -180,6 +181,9 @@ void BaseRequestHandler::Run(const Request &request) {
     return;
   }
 
+  lldb::SBMutex lock = dap.GetAPIMutex();
+  std::lock_guard<lldb::SBMutex> guard(lock);
+
   // FIXME: After all the requests have migrated from LegacyRequestHandler >
   // RequestHandler<> we should be able to move this into
   // RequestHandler<>::operator().