zf

formatter.ex (8189B)

---

 defmodule Jason.Formatter do
   @moduledoc ~S"""
   Pretty-printing and minimizing functions for JSON-encoded data.
 
   Input is required to be in an 8-bit-wide encoding such as UTF-8 or Latin-1
   in `t:iodata/0` format. Input must have valid JSON, invalid JSON may produce
   unexpected results or errors.
   """
 
   @type opts :: [
           {:indent, iodata}
           | {:line_separator, iodata}
           | {:record_separator, iodata}
           | {:after_colon, iodata}
         ]
 
   import Record
   defrecordp :opts, [:indent, :line, :record, :colon]
 
   @dialyzer :no_improper_lists
 
   @doc ~S"""
   Pretty-prints JSON-encoded `input`.
 
   `input` may contain multiple JSON objects or arrays, optionally separated
   by whitespace (e.g., one object per line). Objects in output will be
   separated by newlines. No trailing newline is emitted.
 
   ## Options
 
     * `:indent` - used for nested objects and arrays (default: two spaces - `"  "`);
     * `:line_separator` - used in nested objects (default: `"\n"`);
     * `:record_separator` - separates root-level objects and arrays
       (default is the value for `:line_separator` option);
     * `:after_colon` - printed after a colon inside objects (default: one space - `" "`).
 
   ## Examples
 
       iex> Jason.Formatter.pretty_print(~s|{"a":{"b": [1, 2]}}|)
       ~s|{
         "a": {
           "b": [
             1,
             2
           ]
         }
       }|
 
   """
   @spec pretty_print(iodata, opts) :: binary
   def pretty_print(input, opts \\ []) do
     input
     |> pretty_print_to_iodata(opts)
     |> IO.iodata_to_binary()
   end
 
   @doc ~S"""
   Pretty-prints JSON-encoded `input` and returns iodata.
 
   This function should be preferred to `pretty_print/2`, if the pretty-printed
   JSON will be handed over to one of the IO functions or sent
   over the socket. The Erlang runtime is able to leverage vectorised
   writes and avoid allocating a continuous buffer for the whole
   resulting string, lowering memory use and increasing performance.
   """
   @spec pretty_print_to_iodata(iodata, opts) :: iodata
   def pretty_print_to_iodata(input, opts \\ []) do
     opts = parse_opts(opts, "  ", "\n", nil, " ")
 
     depth = :first
     empty = false
 
     {output, _state} = pp_iodata(input, [], depth, empty, opts)
 
     output
   end
 
   @doc ~S"""
   Minimizes JSON-encoded `input`.
 
   `input` may contain multiple JSON objects or arrays, optionally
   separated by whitespace (e.g., one object per line). Minimized
   output will contain one object per line. No trailing newline is emitted.
 
   ## Options
 
     * `:record_separator` - controls the string used as newline (default: `"\n"`).
 
   ## Examples
 
       iex> Jason.Formatter.minimize(~s|{ "a" : "b" , "c": \n\n 2}|)
       ~s|{"a":"b","c":2}|
 
   """
   @spec minimize(iodata, opts) :: binary
   def minimize(input, opts \\ []) do
     input
     |> minimize_to_iodata(opts)
     |> IO.iodata_to_binary()
   end
 
   @doc ~S"""
   Minimizes JSON-encoded `input` and returns iodata.
 
   This function should be preferred to `minimize/2`, if the minimized
   JSON will be handed over to one of the IO functions or sent
   over the socket. The Erlang runtime is able to leverage vectorised
   writes and avoid allocating a continuous buffer for the whole
   resulting string, lowering memory use and increasing performance.
   """
   @spec minimize_to_iodata(iodata, opts) :: iodata
   def minimize_to_iodata(input, opts) do
     record = Keyword.get(opts, :record_separator, "\n")
     opts = opts(indent: "", line: "", record: record, colon: "")
 
     depth = :first
     empty = false
 
     {output, _state} = pp_iodata(input, [], depth, empty, opts)
 
     output
   end
 
   defp parse_opts([{option, value} | opts], indent, line, record, colon) do
     value = IO.iodata_to_binary(value)
     case option do
       :indent -> parse_opts(opts, value, line, record, colon)
       :record_separator -> parse_opts(opts, indent, line, value, colon)
       :after_colon -> parse_opts(opts, indent, line, record, value)
       :line_separator -> parse_opts(opts, indent, value, record || value, colon)
     end
   end
 
   defp parse_opts([], indent, line, record, colon) do
     opts(indent: indent, line: line, record: record || line, colon: colon)
   end
 
   for depth <- 1..16 do
     defp tab("  ", unquote(depth)), do: unquote(String.duplicate("  ", depth))
   end
 
   defp tab("", _), do: ""
   defp tab(indent, depth), do: List.duplicate(indent, depth)
 
   defp pp_iodata(<<>>, output_acc, depth, empty, opts) do
     {output_acc, &pp_iodata(&1, &2, depth, empty, opts)}
   end
 
   defp pp_iodata(<<byte, rest::binary>>, output_acc, depth, empty, opts) do
     pp_byte(byte, rest, output_acc, depth, empty, opts)
   end
 
   defp pp_iodata([], output_acc, depth, empty, opts) do
     {output_acc, &pp_iodata(&1, &2, depth, empty, opts)}
   end
 
   defp pp_iodata([byte | rest], output_acc, depth, empty, opts) when is_integer(byte) do
     pp_byte(byte, rest, output_acc, depth, empty, opts)
   end
 
   defp pp_iodata([head | tail], output_acc, depth, empty, opts) do
     {output_acc, cont} = pp_iodata(head, output_acc, depth, empty, opts)
     cont.(tail, output_acc)
   end
 
   defp pp_byte(byte, rest, output, depth, empty, opts) when byte in ' \n\r\t' do
     pp_iodata(rest, output, depth, empty, opts)
   end
 
   defp pp_byte(byte, rest, output, depth, empty, opts) when byte in '{[' do
     {out, depth} =
       cond do
         depth == :first -> {byte, 1}
         depth == 0 -> {[opts(opts, :record), byte], 1}
         empty -> {[opts(opts, :line), tab(opts(opts, :indent), depth), byte], depth + 1}
         true -> {byte, depth + 1}
       end
 
     empty = true
     pp_iodata(rest, [output, out], depth, empty, opts)
   end
 
   defp pp_byte(byte, rest, output, depth, true = _empty, opts) when byte in '}]' do
     empty = false
     depth = depth - 1
     pp_iodata(rest, [output, byte], depth, empty, opts)
   end
 
   defp pp_byte(byte, rest, output, depth, false = empty, opts) when byte in '}]' do
     depth = depth - 1
     out = [opts(opts, :line), tab(opts(opts, :indent), depth), byte]
     pp_iodata(rest, [output, out], depth, empty, opts)
   end
 
   defp pp_byte(byte, rest, output, depth, _empty, opts) when byte in ',' do
     empty = false
     out = [byte, opts(opts, :line), tab(opts(opts, :indent), depth)]
     pp_iodata(rest, [output, out], depth, empty, opts)
   end
 
   defp pp_byte(byte, rest, output, depth, empty, opts) when byte in ':' do
     out = [byte, opts(opts, :colon)]
     pp_iodata(rest, [output, out], depth, empty, opts)
   end
 
   defp pp_byte(byte, rest, output, depth, empty, opts) do
     out = if empty, do: [opts(opts, :line), tab(opts(opts, :indent), depth), byte], else: byte
     empty = false
 
     if byte == ?" do
       pp_string(rest, [output, out], _in_bs = false, &pp_iodata(&1, &2, depth, empty, opts))
     else
       pp_iodata(rest, [output, out], depth, empty, opts)
     end
   end
 
   defp pp_string(<<>>, output_acc, in_bs, cont) do
     {output_acc, &pp_string(&1, &2, in_bs, cont)}
   end
 
   defp pp_string(binary, output_acc, true = _in_bs, cont) when is_binary(binary) do
     <<byte, rest::binary>> = binary
     pp_string(rest, [output_acc, byte], false, cont)
   end
 
   defp pp_string(binary, output_acc, false = _in_bs, cont) when is_binary(binary) do
     case :binary.match(binary, ["\"", "\\"]) do
       :nomatch ->
         {[output_acc | binary], &pp_string(&1, &2, false, cont)}
       {pos, 1} ->
         {head, tail} = :erlang.split_binary(binary, pos + 1)
         case :binary.at(binary, pos) do
           ?\\ -> pp_string(tail, [output_acc | head], true, cont)
           ?" -> cont.(tail, [output_acc | head])
         end
     end
   end
 
   defp pp_string([], output_acc, in_bs, cont) do
     {output_acc, &pp_string(&1, &2, in_bs, cont)}
   end
 
   defp pp_string([byte | rest], output_acc, in_bs, cont) when is_integer(byte) do
     cond do
       in_bs -> pp_string(rest, [output_acc, byte], false, cont)
       byte == ?" -> cont.(rest, [output_acc, byte])
       true -> pp_string(rest, [output_acc, byte], byte == ?\\, cont)
     end
   end
 
   defp pp_string([head | tail], output_acc, in_bs, cont) do
     {output_acc, cont} = pp_string(head, output_acc, in_bs, cont)
     cont.(tail, output_acc)
   end
 end