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refactor: decode errors
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@avilagaston9
avilagaston9 committed Apr 19, 2024
1 parent 7675979 commit 0392dc6
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Showing 2 changed files with 105 additions and 76 deletions.
179 changes: 104 additions & 75 deletions lib/ssz_ex/decode.ex
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@ defmodule SszEx.Decode do
@offset_bits 32

@spec decode(binary(), SszEx.schema()) ::
{:ok, any()} | Error.t()
{:ok, any()} | {:error, Error.t()}
def decode(binary, :bool), do: decode_bool(binary)
def decode(binary, {:int, size}), do: decode_uint(binary, size)
def decode(value, {:byte_list, _}), do: {:ok, value}
Expand Down Expand Up @@ -51,35 +51,43 @@ defmodule SszEx.Decode do
end

defp decode_uint(binary, size) when bit_size(binary) != size,
do: %Error{
message:
"Invalid binary length while decoding uint.\nExpected size: #{size}.\nFound:#{bit_size(binary)}\n"
}
do:
{:error,
%Error{
message:
"Invalid binary length while decoding uint.\nExpected size: #{size}.\nFound:#{bit_size(binary)}\n"
}}

defp decode_uint(binary, size) do
<<element::integer-size(size)-little, _rest::bitstring>> = binary
{:ok, element}
end

defp decode_bool(binary) when byte_size(binary) != 1,
do: %Error{
message:
"Invalid binary length while decoding bool.\nExpected size: 1.\nFound:#{byte_size(binary)}\n"
}
do:
{:error,
%Error{
message:
"Invalid binary length while decoding bool.\nExpected size: 1.\nFound:#{byte_size(binary)}\n"
}}

defp decode_bool("\x01"), do: {:ok, true}
defp decode_bool("\x00"), do: {:ok, false}

defp decode_bool(binary),
do: %Error{
message:
"Invalid binary value while decoding bool.\nExpected value: x01/x00.\nFound: x#{Base.encode16(binary)}."
}
do:
{:error,
%Error{
message:
"Invalid binary value while decoding bool.\nExpected value: x01/x00.\nFound: x#{Base.encode16(binary)}."
}}

defp decode_bitlist("", _max_size),
do: %Error{
message: "Invalid binary value while decoding BitList.\nEmpty binary found.\n"
}
do:
{:error,
%Error{
message: "Invalid binary value while decoding BitList.\nEmpty binary found.\n"
}}

defp decode_bitlist(bit_list, max_size) do
num_bytes = byte_size(bit_list)
Expand All @@ -88,15 +96,17 @@ defmodule SszEx.Decode do

cond do
match?(<<_::binary-size(num_bytes - 1), 0>>, bit_list) ->
%Error{
message: "Invalid binary value while decoding BitList.\nMissing sentinel bit.\n"
}
{:error,
%Error{
message: "Invalid binary value while decoding BitList.\nMissing sentinel bit.\n"
}}

len > max_size ->
%Error{
message:
"Invalid binary length while decoding BitList. \nExpected max_size: #{max_size}. Found: #{len}.\n"
}
{:error,
%Error{
message:
"Invalid binary length while decoding BitList. \nExpected max_size: #{max_size}. Found: #{len}.\n"
}}

true ->
{:ok, decoded}
Expand All @@ -113,9 +123,10 @@ defmodule SszEx.Decode do
{:ok, BitVector.new(bit_vector, size)}

_ ->
%Error{
message: "Invalid binary length while decoding BitVector. \nExpected size: #{size}.\n"
}
{:error,
%Error{
message: "Invalid binary length while decoding BitVector. \nExpected size: #{size}.\n"
}}
end
end

Expand Down Expand Up @@ -147,20 +158,24 @@ defmodule SszEx.Decode do

defp check_valid_fixed_list_size(byte_length, inner_type, inner_type_size, max_size)
when byte_length > inner_type_size * max_size,
do: %Error{
message:
"Invalid binary length while decoding list of #{inspect(inner_type)}.\nExpected max_size: #{max_size}.\nFound: #{byte_length}\n"
}
do:
{:error,
%Error{
message:
"Invalid binary length while decoding list of #{inspect(inner_type)}.\nExpected max_size: #{max_size}.\nFound: #{byte_length}\n"
}}

defp check_valid_fixed_list_size(_byte_length, _inner_type, _inner_type_size, _max_size),
do: :ok

defp check_valid_vector_size(byte_length, inner_type, inner_type_size, size)
when byte_length != inner_type_size * size,
do: %Error{
message:
"Invalid binary length while decoding vector of #{inspect(inner_type)}.\nExpected size #{inner_type_size * size} bytes.\nFound: #{byte_length}.\n"
}
do:
{:error,
%Error{
message:
"Invalid binary length while decoding vector of #{inspect(inner_type)}.\nExpected size #{inner_type_size * size} bytes.\nFound: #{byte_length}.\n"
}}

defp check_valid_vector_size(_byte_length, _inner_type, _inner_type_size, _size),
do: :ok
Expand All @@ -170,10 +185,12 @@ defmodule SszEx.Decode do
do: :ok

defp check_valid_vector_size_after_decode(size, decoded_size),
do: %Error{
message:
"Invalid vector decoded size.\nExpected size: #{size}. Decoded vector size: #{decoded_size} "
}
do:
{:error,
%Error{
message:
"Invalid vector decoded size.\nExpected size: #{size}. Decoded vector size: #{decoded_size} "
}}

defp decode_variable_list("", _, _) do
{:ok, []}
Expand All @@ -185,21 +202,24 @@ defmodule SszEx.Decode do
size
)
when div(first_offset, @bytes_per_length_offset) > size,
do: %Error{
message:
"Invalid binary while decoding list of #{inspect(inner_type)}.\nExpected max_size: #{size}.\n First offset points to: #{first_offset}."
}
do:
{:error,
%Error{
message:
"Invalid binary while decoding list of #{inspect(inner_type)}.\nExpected max_size: #{size}.\n First offset points to: #{first_offset}."
}}

defp decode_variable_list(binary, inner_type, _size) do
<<first_offset::integer-32-little, rest_bytes::bitstring>> = binary
num_elements = div(first_offset, @bytes_per_length_offset)

if Integer.mod(first_offset, @bytes_per_length_offset) != 0 ||
first_offset < @bytes_per_length_offset do
%Error{
message:
"Invalid binary while decoding list of #{inspect(inner_type)}.\nFirst offset points to: #{first_offset}."
}
{:error,
%Error{
message:
"Invalid binary while decoding list of #{inspect(inner_type)}.\nFirst offset points to: #{first_offset}."
}}
else
with :ok <-
sanitize_offset(first_offset, nil, byte_size(binary), first_offset) do
Expand Down Expand Up @@ -286,20 +306,24 @@ defmodule SszEx.Decode do

defp check_fixed_container_size(module, expected_length, size)
when expected_length != size,
do: %Error{
message:
"Invalid binary length while decoding #{module}. \nExpected #{expected_length}. \nFound #{size}.\n"
}
do:
{:error,
%Error{
message:
"Invalid binary length while decoding #{module}. \nExpected #{expected_length}. \nFound #{size}.\n"
}}

defp check_fixed_container_size(_module, _expected_length, _size),
do: :ok

defp check_first_offset([{offset, _} | _rest], items_index, _binary_size)
when offset != items_index,
do: %Error{
message:
"First offset does not point to the first variable byte.\nExpected index: #{items_index}.\nOffset: #{offset}. "
}
do:
{:error,
%Error{
message:
"First offset does not point to the first variable byte.\nExpected index: #{items_index}.\nOffset: #{offset}. "
}}

defp check_first_offset(_offsets, _items_index, _binary_size),
do: :ok
Expand Down Expand Up @@ -364,16 +388,18 @@ defmodule SszEx.Decode do
defp sanitize_offset(offset, previous_offset, num_bytes, nil) do
cond do
offset > num_bytes ->
%Error{
message:
"Offset points outside the binary. \nBinary length: #{num_bytes}.\nOffset: #{offset}"
}
{:error,
%Error{
message:
"Offset points outside the binary. \nBinary length: #{num_bytes}.\nOffset: #{offset}"
}}

previous_offset != nil && previous_offset > offset ->
%Error{
message:
"Offset points to bytes prior to the previous offset.\nPrevious offset: #{previous_offset}.\nOffset: #{offset}"
}
{:error,
%Error{
message:
"Offset points to bytes prior to the previous offset.\nPrevious offset: #{previous_offset}.\nOffset: #{offset}"
}}

true ->
:ok
Expand All @@ -383,16 +409,18 @@ defmodule SszEx.Decode do
defp sanitize_offset(offset, previous_offset, _num_bytes, num_fixed_bytes) do
cond do
offset < num_fixed_bytes ->
%Error{
message:
"Offset points “backwards” into the fixed-bytes portion. \nFirst variable byte index: #{num_fixed_bytes}.\nOffset: #{offset}."
}
{:error,
%Error{
message:
"Offset points “backwards” into the fixed-bytes portion. \nFirst variable byte index: #{num_fixed_bytes}.\nOffset: #{offset}."
}}

previous_offset == nil && offset != num_fixed_bytes ->
%Error{
message:
"Offset does not point to the first variable byte.\nExpected index: #{num_fixed_bytes}.\nOffset: #{offset}."
}
{:error,
%Error{
message:
"Offset does not point to the first variable byte.\nExpected index: #{num_fixed_bytes}.\nOffset: #{offset}."
}}

true ->
:ok
Expand All @@ -410,10 +438,11 @@ defmodule SszEx.Decode do
defp decode_fixed_collection(binary, chunk_size, _inner_type, results)
when byte_size(binary) < chunk_size,
do: [
%Error{
message:
"Invalid binary length while decoding collection. \nInner type size: #{chunk_size} bytes. Binary length: #{byte_size(binary)} bytes.\n"
}
{:error,
%Error{
message:
"Invalid binary length while decoding collection. \nInner type size: #{chunk_size} bytes. Binary length: #{byte_size(binary)} bytes.\n"
}}
| results
]

Expand All @@ -426,7 +455,7 @@ defmodule SszEx.Decode do
case Enum.group_by(results, fn {_, {type, _}} -> type end, fn {key, {_, result}} ->
{key, result}
end) do
%Error{} = error -> error
%{error: errors} -> {:error, errors}
summary -> {:ok, Map.get(summary, :ok, [])}
end
end
Expand Down
2 changes: 1 addition & 1 deletion lib/ssz_ex/utils.ex
View file
Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,7 @@ defmodule SszEx.Utils do

def flatten_results_by(results, fun) do
case Enum.group_by(results, fn {type, _} -> type end, fn {_, result} -> result end) do
%Error{} = error -> error
%{error: errors} -> {:error, errors}
summary -> {:ok, fun.(Map.get(summary, :ok, []))}
end
end
Expand Down

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