rdf-ex/lib/rdf/serialization/reader.ex

106 lines
3.5 KiB
Elixir

defmodule RDF.Serialization.Reader do
@moduledoc !"""
General functions for reading a `RDF.Graph` or `RDF.Dataset` from a serialization file, stream or encoded-string.
These functions are not intended for direct use, but instead via the automatically
generated functions with the same name on a `RDF.Serialization.Format`, which
implicitly use the proper `RDF.Serialization.Decoder` module.
"""
alias RDF.{Serialization, Dataset, Graph}
@default_file_mode ~w[read utf8]a
@io_read_mode if Version.match?(System.version(), "~> 1.13.0"), do: :eof, else: :all
@spec read_string(module, String.t(), keyword) :: {:ok, Graph.t() | Dataset.t()} | {:error, any}
def read_string(decoder, content, opts \\ []) do
decoder.decode(content, opts)
end
@spec read_string!(module, String.t(), keyword) :: Graph.t() | Dataset.t()
def read_string!(decoder, content, opts \\ []) do
decoder.decode!(content, opts)
end
@spec read_stream(module, Enumerable.t(), keyword) ::
{:ok, Graph.t() | Dataset.t()} | {:error, any}
def read_stream(decoder, stream, opts \\ []) do
if decoder.stream_support?() do
decoder.decode_from_stream(stream, opts)
else
raise "#{inspect(decoder)} does not support streaming"
end
end
@spec read_stream!(module, Enumerable.t(), keyword) :: Graph.t() | Dataset.t()
def read_stream!(decoder, stream, opts \\ []) do
if decoder.stream_support?() do
decoder.decode_from_stream!(stream, opts)
else
raise "#{inspect(decoder)} does not support streaming"
end
end
@spec read_file(module, Path.t(), keyword) :: {:ok, Graph.t() | Dataset.t()} | {:error, any}
def read_file(decoder, file, opts \\ []) do
decoder
|> Serialization.use_file_streaming!(opts)
|> do_read_file(decoder, file, opts)
end
defp do_read_file(false, decoder, file, opts) do
file
|> File.open(file_mode(decoder, opts), &IO.read(&1, @io_read_mode))
|> case do
{:ok, {:error, error}} -> {:error, error}
{:ok, :eof} -> decoder.decode("", opts)
{:ok, content} -> decoder.decode(content, opts)
{:error, error} -> {:error, error}
end
end
defp do_read_file(true, decoder, file, opts) do
file
|> File.stream!(file_mode(decoder, opts))
|> decoder.decode_from_stream(opts)
rescue
error in FunctionClauseError -> reraise error, __STACKTRACE__
error in RuntimeError -> {:error, error.message}
error -> {:error, error}
end
@spec read_file!(module, Path.t(), keyword) :: Graph.t() | Dataset.t()
def read_file!(decoder, file, opts \\ []) do
decoder
|> Serialization.use_file_streaming!(opts)
|> do_read_file!(decoder, file, opts)
end
defp do_read_file!(false, decoder, file, opts) do
file
|> File.open!(file_mode(decoder, opts), &IO.read(&1, @io_read_mode))
|> case do
{:error, error} when is_tuple(error) -> error |> inspect() |> raise()
{:error, error} -> raise(error)
:eof -> decoder.decode!("", opts)
content -> decoder.decode!(content, opts)
end
end
defp do_read_file!(_stream_mode, decoder, file, opts) do
file
|> File.stream!(file_mode(decoder, opts))
|> decoder.decode_from_stream!(opts)
end
@doc false
def file_mode(_decoder, opts) do
opts
|> Keyword.get(:file_mode, @default_file_mode)
|> List.wrap()
|> set_gzip(Keyword.get(opts, :gzip))
end
defp set_gzip(file_mode, true), do: [:compressed | file_mode]
defp set_gzip(file_mode, _), do: file_mode
end