Check if a directory exists within a google-nativeclient file system?

Question

I'm trying to check if a directory exists in a Native Client file system but can't find any functions to do it. I tried creating a PPB_FileRef for the directory and then opening that using PPB_FileIO::Open and then calling PPB_FileIO::Query but PPB_FileIO::Open returns PP_ERROR_NOTAFILE and then the second call fails.

This is the code I have been trying, some of the initialisation is left out for brevity.

PP_Instance instance; // initialised elsewhere
PPB_FileRef *fileRefInterface; // initialised elsewhere
PPB_FileIO *fileIOInterface; // initialised elsewhere
PP_Resource fileSystemResource; // initialised elsewhere

PP_Resource fileRefResource = fileRefInterface->Create(
  fileSystemResource,
  "/directory");

PP_Resource fileIOResource = fileIOInterface->Create(instance);

// This call is returning PP_ERROR_NOTAFILE
//
int32_t result = fileIOInterface->Open(
  fileIOResource,
  fileRefResource,
  PP_FILEOPENFLAG_READ,
  PP_BlockUntilComplete()); // this is being called from a background thread.
if (result != PP_OK)
{
  return false;
}

PP_FileInfo info;
result = fileIOInterface->Query(fileIOResource, &info, PP_BlockUntilComplete());
if (result != PP_OK)
{
  return info.type == PP_FILETYPE_DIRECTORY;
}

return false;

Is a return value of PP_ERROR_NOTAFILE from PPB_FileIO::Open for a valid PPB_FileRef enough for me to tell it's a directory or is there another better method I should be using?

Thanks, James

Answer 1

Yes, currently the way to determine if a PPB_FileRef refers to a directory is to try to open it and look for a PP_ERROR_NOTAFILE return value.

For background PP_ERROR_NOTAFILE was added after the branch for pepper_25 was made, so until pepper_26 becomes available in the SDK, one should develop with pepper_canary to get its definition in pp_errors.h . For more details, see the relevant Chrome change list , which specifically mentions that this return value is used when trying to open a directory.

The current behavior is arguably a bit opaque. There is a "dev" (experimental/unfinished) interface PPB_DirectoryReader that when released will provide a more direct way to work with directories.