[Lldb-commits] [lldb] [lldb-dap] Implement `runInTerminal` for Windows (PR #121269)

[Hu Jialun via lldb-commits]

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@@ -158,13 +156,25 @@ std::string RunInTerminalDebugAdapterCommChannel::GetLauncherError() {
 }
 
 Expected<std::shared_ptr<FifoFile>> CreateRunInTerminalCommFile() {
+  int comm_fd;
   SmallString<256> comm_file;
-  if (std::error_code EC = sys::fs::getPotentiallyUniqueTempFileName(
-          "lldb-dap-run-in-terminal-comm", "", comm_file))
+  if (std::error_code EC = createUniqueNamedPipe(
+          "lldb-dap-run-in-terminal-comm", "", comm_fd, comm_file))
     return createStringError(EC, "Error making unique file name for "
                                  "runInTerminal communication files");
-
-  return CreateFifoFile(comm_file.str());
+  FILE *cf = fdopen(comm_fd, "r+");
+  if (setvbuf(cf, NULL, _IONBF, 0))
+    return createStringError(std::error_code(errno, std::generic_category()),
+                             "Error setting unbuffered mode on C FILE");
+  // There is no portable way to conjure an ofstream from HANDLE, so use FILE *
+  // llvm::raw_fd_stream does not support getline() and there is no
+  // llvm::buffer_istream
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SuibianP wrote:

On the client (launcher) side it should be possible, but on the server end I suppose not. Windows has the distinction of "server" (from `CreateNamedPipe`) and "client" (from `CreateFile`) ends of FIFOs and unlike on POSIX where FIFOs can read from any previous write, clients can only communicate with server but not fellow clients.

Opening a `std::ofstream` (which underlyingly is `CreateFile`) would open a client of the pipe in the same process that connects to the server. The server side must use `CreateNamedPipe` which gives out a `HANDLE`, thus the issue of turning that into some platform independent file object.

https://github.com/llvm/llvm-project/pull/121269