Merge pull request #92 from davesque/fix-dynamic-arrays

Update arrays to use head-tail encoding
ethereum · Aug 22, 2018 · 082819a · 082819a
2 parents d67e89c + 3342b54
commit 082819a
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Showing 9 changed files with 120 additions and 18 deletions.
diff --git a/.circleci/config.yml b/.circleci/config.yml
@@ -19,7 +19,7 @@ common: &common
         when: on_fail
     - restore_cache:
         keys:
-          - v2-cache-{{ .Environment.CIRCLE_JOB }}-{{ checksum "setup.py" }}-{{ checksum "tox.ini" }}
+          - v4-cache-{{ .Environment.CIRCLE_JOB }}-{{ checksum "setup.py" }}-{{ checksum "tox.ini" }}
     - run:
         name: install dependencies
         command: pip install --user tox
@@ -33,7 +33,7 @@ common: &common
           - ~/.cache/pip
           - ~/.local
           - ./eggs
-        key: v3-cache-{{ .Environment.CIRCLE_JOB }}-{{ checksum "setup.py" }}-{{ checksum "tox.ini" }}
+        key: v4-cache-{{ .Environment.CIRCLE_JOB }}-{{ checksum "setup.py" }}-{{ checksum "tox.ini" }}
 
 jobs:
   doctest:

diff --git a/docs/index.rst b/docs/index.rst
@@ -29,6 +29,7 @@ Table of Contents
     encoding
     decoding
     registry
+    nested_dynamic_arrays
     eth_abi
     releases
 

diff --git a/docs/nested_dynamic_arrays.rst b/docs/nested_dynamic_arrays.rst
@@ -0,0 +1,12 @@
+Nested Dynamic Arrays
+=====================
+
+The ``eth-abi`` library supports the Solidity ABIv2 encoding format for nested
+dynamic arrays.  This means that values for data types such as the following
+are legal and encodable/decodable: ``int[][]``, ``string[]``, ``string[2]``,
+etc.
+
+.. warning::
+
+    Though Solidity's ABIv2 has mostly been finalized, the specification is
+    technically still in development and may change.
diff --git a/eth_abi/decoding.py b/eth_abi/decoding.py
@@ -209,6 +209,15 @@ def split_data_and_padding(self, raw_data):
 class BaseArrayDecoder(BaseDecoder):
     item_decoder = None
 
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+
+        # Use a head-tail decoder to decode dynamic elements
+        if self.item_decoder.is_dynamic:
+            self.item_decoder = HeadTailDecoder(
+                tail_decoder=self.item_decoder,
+            )
+
     def validate(self):
         super().validate()
 
@@ -246,13 +255,16 @@ def decode(self, stream):
 
 
 class DynamicArrayDecoder(BaseArrayDecoder):
+    # Dynamic arrays are always dynamic, regardless of their elements
     is_dynamic = True
 
     @to_tuple
     def decode(self, stream):
         array_size = decode_uint_256(stream)
+        stream.push_frame(32)
         for _ in range(array_size):
             yield self.item_decoder(stream)
+        stream.pop_frame()
 
 
 class FixedByteSizeDecoder(SingleDecoder):

diff --git a/eth_abi/encoding.py b/eth_abi/encoding.py
@@ -617,12 +617,20 @@ def validate_value(self, value):
     def encode_elements(self, value):
         self.validate_value(value)
 
-        encoded_elements = b''.join((
-            self.item_encoder(item)
-            for item in value
-        ))
+        item_encoder = self.item_encoder
+        tail_chunks = tuple(item_encoder(i) for i in value)
 
-        return encoded_elements
+        items_are_dynamic = getattr(item_encoder, 'is_dynamic', False)
+        if not items_are_dynamic:
+            return b''.join(tail_chunks)
+
+        head_length = 32 * len(value)
+        tail_offsets = (0,) + tuple(accumulate(map(len, tail_chunks[:-1])))
+        head_chunks = tuple(
+            encode_uint_256(head_length + offset)
+            for offset in tail_offsets
+        )
+        return b''.join(head_chunks + tail_chunks)
 
     @parse_type_str(with_arrlist=True)
     def from_type_str(cls, abi_type, registry):

diff --git a/eth_abi/utils/padding.py b/eth_abi/utils/padding.py
@@ -1,4 +1,4 @@
-from cytoolz import (
+from eth_utils.toolz import (
     curry,
 )
 

diff --git a/setup.py b/setup.py
@@ -48,7 +48,7 @@
     url='https://github.com/ethereum/eth-abi',
     include_package_data=True,
     install_requires=[
-        'eth-utils>=1.0.1,<2.0.0',
+        'eth-utils>=1.2.0,<2.0.0',
         'eth-typing<=2',
         'parsimonious==0.8.0',
     ],

diff --git a/tests/common/unit.py b/tests/common/unit.py
@@ -176,20 +176,89 @@ def words(*descriptions: str) -> bytes:
     ),
     (
         '((int,int[],(int,int)[]),(int,int),int)',
-        ((1, (2, 3), ((4, 5), (6, 7))), (8, 9), 10),
-        words('80', '8', '9', 'a', '1', '60', 'c0', '2', '2', '3', '2', '4', '5', '6', '7'),
+        (
+            (
+                1,
+                (2, 3),
+                ((4, 5), (6, 7)),
+            ),
+            (8, 9),
+            10,
+        ),
+        words(
+            '80',  # offset of dynamic tuple
+            '8',  # outer tuple static tuple
+            '9',
+            'a',  # outer tuple int
+            '1',  # beginning of dynamic tuple (int)
+            '60',  # offset of dynamic tuple list of ints
+            'c0',  # offset of dynamic tuple list of tuples
+            '2',  # size of list of ints
+            '2',
+            '3',
+            '2',  # size of list of tuples
+            '4',  # beginning of first tuple
+            '5',
+            '6',  # beginning of second tuple
+            '7',
+        ),
         words('1', '2', '3', '4', '5', '6', '7', '8', '9', 'a'),
     ),
     (
         '(int,int)[][]',
-        (((1, 2),), ((3, 4), (5, 6)), ((7, 8), (9, 10), (11, 12))),
-        words('3', '1', '1', '2', '2', '3', '4', '5', '6', '3', '7', '8', '9', 'a', 'b', 'c'),
+        (
+            ((1, 2),),
+            ((3, 4), (5, 6)),
+            ((7, 8), (9, 10), (11, 12)),
+        ),
+        words(
+            '3',  # size of outer dynamic list
+            '60',  # offset of first dynamic list
+            'c0',  # offset of second dynamic list
+            '160',  # offset of third dynamic list
+            '1',  # size of first list
+            '1',  # start of first tuple
+            '2',
+            '2',  # size of second list
+            '3',  # start of second tuple
+            '4',
+            '5',  # start of third tuple
+            '6',
+            '3',  # size of third list
+            '7',  # start of fourth tuple
+            '8',
+            '9',  # start of fifth tuple
+            'a',
+            'b',  # start of sixth tuple
+            'c',
+        ),
         words('1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c'),
     ),
     (
         '((int,int)[][2])',
-        ((((1, 2), (3, 4)), ((5, 6), (7, 8), (9, 10))),),
-        words('20', '2', '1', '2', '3', '4', '3', '5', '6', '7', '8', '9', 'a'),
+        (
+            (
+                ((1, 2), (3, 4)),
+                ((5, 6), (7, 8), (9, 10)),
+            ),
+        ),
+        words(
+            '20',  # offset of constant size array
+            '40',  # offset of first dynamic list of tuples
+            'e0',  # offset of second dynamic list of tuples
+            '2',  # size of first list
+            '1',  # start of first tuple
+            '2',
+            '3',  # start of second tuple
+            '4',
+            '3',  # size of second list
+            '5',  # start of third tuple
+            '6',
+            '7',  # start of fourth tuple
+            '8',
+            '9',  # start of fifth tuple
+            'a',
+        ),
         words('1', '2', '3', '4', '5', '6', '7', '8', '9', 'a'),
     ),
 ]

diff --git a/tests/test_decoding/test_decoder_properties.py b/tests/test_decoding/test_decoder_properties.py
@@ -1,14 +1,14 @@
 import sys
 
-from cytoolz import (
-    complement,
-)
 from eth_utils import (
     big_endian_to_int,
     decode_hex,
     int_to_big_endian,
     to_normalized_address,
 )
+from eth_utils.toolz import (
+    complement,
+)
 from hypothesis import (
     example,
     given,