Method: FSDB::Database#replace

Defined in:
lib/fsdb/database.rb

#replace(path) ⇒ Object

Replace the yielded object (or nil) with the return value of the block. Returns the object that was replaced. No object need exist at path.

Use replace instead of edit when accessing db over a drb connection. Use replace instead of insert if the path needs to be protected while the object is prepared for insertion.

Note that (unlike #edit) destructive methods on the object do not persistently change the state of the object, unless the object is the return value of the block.



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# File 'lib/fsdb/database.rb', line 585

def replace(path)
  abs_path = absolute(path)
  file_id = make_file_id(abs_path)
  object_exclusive file_id do |cache_entry|
    open_write_lock(path) do |f|
      old_object = f.stat.zero? ? nil : cache_object(f, cache_entry)
      object = yield old_object if block_given?
      dump(object, f)
      cache_entry.update(f.mtime, inc_version_of(f, cache_entry), object)
      old_object
    end
  end
rescue DirIsImmutableError
  raise DirIsImmutableError, "Cannot replace dir #{path} in #{inspect}"
rescue NotDirError
  raise NotDirError, "Not a directory - #{path} in #{inspect}"
rescue AbortedTransaction
  clear_entry(file_id) # The cached object may have edits which are not valid.
  nil
rescue FormatError
  clear_entry(file_id)
  File.delete(abs_path)
  raise
rescue PathComponentError
  raise PathComponentError, "Some component of #{path} in #{inspect} " +
      "already exists and is not a directory"
rescue CreateFileError
  raise CreateFileError, "Cannot create file at #{path} in #{inspect}"
rescue MissingFileError
  if PLATFORM_IS_WINDOWS_ME and File.directory?(abs_path)
    raise DirIsImmutableError
  else
    raise NotDirError
  end
rescue Exception
  clear_entry(file_id)
  raise
end