256 lines
8.0 KiB
Elixir
256 lines
8.0 KiB
Elixir
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
|