Function DirNextEntry

rEFIt_UEFI/refit/lib.cpp:1390–1449

}

EFI_STATUS DirNextEntry(IN EFI_FILE *Directory, IN OUT EFI_FILE_INFO **DirEntry, IN UINTN FilterMode)
{
  EFI_STATUS Status;
  VOID *Buffer;
  UINTN LastBufferSize, BufferSize;
  INTN IterCount;
  
  for (;;) {
    
    // free pointer from last call
    if (*DirEntry != NULL) {
      FreePool(*DirEntry);
      *DirEntry = NULL;
    }
    
    // read next directory entry
    LastBufferSize = BufferSize = 256;
    Buffer = (__typeof__(Buffer))AllocateZeroPool(BufferSize);
    for (IterCount = 0; ; IterCount++) {
      Status = Directory->Read(Directory, &BufferSize, Buffer);
      if (Status != EFI_BUFFER_TOO_SMALL || IterCount >= 4)
        break;
      if (BufferSize <= LastBufferSize) {
		  DBG("FS Driver requests bad buffer size %llu (was %llu), using %llu instead\n", BufferSize, LastBufferSize, LastBufferSize * 2);
        BufferSize = LastBufferSize * 2;
#if REFIT_DEBUG > 0
      } else {
		  DBG("Reallocating buffer from %llu to %llu\n", LastBufferSize, BufferSize);
#endif
      }
      Buffer = (__typeof__(Buffer))EfiReallocatePool(Buffer, LastBufferSize, BufferSize);
      LastBufferSize = BufferSize;
    }
    if (EFI_ERROR(Status)) {
      FreePool(Buffer);
      break;
    }
    
    // check for end of listing
    if (BufferSize == 0) {    // end of directory listing
      FreePool(Buffer);
      break;
    }
    
    // entry is ready to be returned
    *DirEntry = (EFI_FILE_INFO *)Buffer;
    if (*DirEntry) {
      // filter results
      if (FilterMode == 1) {   // only return directories
        if (((*DirEntry)->Attribute & EFI_FILE_DIRECTORY))
          break;
      } else if (FilterMode == 2) {   // only return files
        if (((*DirEntry)->Attribute & EFI_FILE_DIRECTORY) == 0)
          break;
      } else                   // no filter or unknown filter -> return everything
        break;
    }
  }