rdf-ex/lib/rdf/serialization/writer.ex

96 lines
3.2 KiB
Elixir

defmodule RDF.Serialization.Writer do
@moduledoc !"""
General functions for writing the statements of a RDF data structure to a file, string or stream.
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.Encoder` module.
"""
alias RDF.Serialization
@default_file_mode ~w[write exclusive]a
@default_stream_mode :iodata
@spec write_string(module, RDF.Data.t(), keyword) :: {:ok, String.t()} | {:error, any}
def write_string(encoder, data, opts \\ []) do
encoder.encode(data, opts)
end
@spec write_string!(module, RDF.Data.t(), keyword) :: String.t()
def write_string!(encoder, data, opts \\ []) do
encoder.encode!(data, opts)
end
@spec write_stream(module, RDF.Data.t(), keyword) :: Enumerable.t()
def write_stream(encoder, data, opts \\ []) do
if encoder.stream_support?() do
encoder.stream(data, opts)
else
raise "#{inspect(encoder)} does not support streaming"
end
end
@spec write_file(module, RDF.Data.t(), Path.t(), keyword) :: :ok | {:error, any}
def write_file(encoder, data, path, opts \\ []) do
encoder
|> Serialization.use_file_streaming(opts)
|> do_write_file(encoder, data, path, opts)
:ok
rescue
error in FunctionClauseError -> reraise error, __STACKTRACE__
error in RuntimeError -> {:error, error.message}
error -> {:error, error}
end
defp do_write_file(false, encoder, data, path, opts) do
with {:ok, encoded_string} <- encoder.encode(data, opts) do
File.write(path, encoded_string, file_mode(encoder, opts))
end
end
defp do_write_file(stream_mode, encoder, data, path, opts) do
data
|> encoder.stream(set_stream_mode(opts, stream_mode))
|> Enum.into(File.stream!(path, file_mode(encoder, opts)))
end
@spec write_file!(module, RDF.Data.t(), Path.t(), keyword) :: :ok
def write_file!(encoder, data, path, opts \\ []) do
encoder
|> Serialization.use_file_streaming!(opts)
|> do_write_file!(encoder, data, path, opts)
end
defp do_write_file!(false, encoder, data, path, opts) do
encoded_string = encoder.encode!(data, opts)
File.write!(path, encoded_string, file_mode(encoder, opts))
end
defp do_write_file!(stream_mode, encoder, data, path, opts) do
data
|> encoder.stream(set_stream_mode(opts, stream_mode))
|> Enum.into(File.stream!(path, file_mode(encoder, opts)))
:ok
end
defp set_stream_mode(opts, true), do: Keyword.put(opts, :mode, @default_stream_mode)
defp set_stream_mode(opts, stream_mode), do: Keyword.put(opts, :mode, stream_mode)
@doc false
def file_mode(_encoder, opts) do
opts
|> Keyword.get(:file_mode, @default_file_mode)
|> List.wrap()
|> set_force(Keyword.get(opts, :force))
|> set_gzip(Keyword.get(opts, :gzip))
end
defp set_force(file_mode, true), do: List.delete(file_mode, :exclusive)
defp set_force(file_mode, _), do: file_mode
defp set_gzip(file_mode, true), do: [:compressed | file_mode]
defp set_gzip(file_mode, _), do: file_mode
end