Revert of mojo: Add deserialization to python structs. (patchset #3 id:40001...

Revert of mojo: Add deserialization to python structs. (patchset #3 id:40001 of https://codereview.chromium.org/578263003/)

Reason for revert:
New unit tests fail.

https://build.chromium.org/p/chromium.linux/builders/Linux%20Tests/builds/13695

Original issue's description:
> mojo: Add deserialization to python structs.
>
> BUG=415491
> R=sdefresne@chromium.org,cmasone@chromium.org
>
> Committed: https://crrev.com/ea8a6ef576c314506c4b3ee25544f6bcaa895fe1
> Cr-Commit-Position: refs/heads/master@{#295478}

TBR=cmasone@chromium.org,sdefresne@chromium.org,qsr@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=415491

Review URL: https://codereview.chromium.org/579383002

Cr-Commit-Position: refs/heads/master@{#295522}

mojo/public/python/mojo/bindings/descriptor.py

@@ -7,7 +7,6 @@ The descriptors used to define generated elements of the mojo python bindings.
 """
 
 import array
-import itertools
 import struct
 
 # pylint: disable=F0401
@@ -56,7 +55,7 @@ class SerializableType(Type):
 
   def Serialize(self, value, data_offset, data, handle_offset):
     """
-    Serialize a value of this type.
+    Serialize an value of this type.
 
     Args:
       value: the value to serialize.
@@ -70,21 +69,6 @@ class SerializableType(Type):
     """
     raise NotImplementedError()
 
-  def Deserialize(self, value, data, handles):
-    """
-    Deserialize a value of this type.
-
-    Args:
-      value: the base value for this type. This is always a numeric type, and
-             corresponds to the first element in the tuple returned by
-             Serialize.
-      data: the bytearray to retrieve additional data from.
-      handles: the array of handles contained in the message to deserialize.
-
-    Returns the deserialized value.
-    """
-    raise NotImplementedError()
-
 
 class BooleanType(Type):
   """Type object for booleans"""
@@ -104,9 +88,6 @@ class NumericType(SerializableType):
   def Serialize(self, value, data_offset, data, handle_offset):
     return (value, [])
 
-  def Deserialize(self, value, data, handles):
-    return value
-
 
 class IntegerType(NumericType):
   """Type object for integer types."""
@@ -154,28 +135,15 @@ class PointerType(SerializableType):
   def Serialize(self, value, data_offset, data, handle_offset):
     if value is None and not self.nullable:
       raise serialization.SerializationException(
-          'Trying to serialize null for non nullable type.')
+          "Trying to serialize null for non nullable type.")
     if value is None:
       return (0, [])
     return self.SerializePointer(value, data_offset, data, handle_offset)
 
-  def Deserialize(self, value, data, handles):
-    if value == 0:
-      if not self.nullable:
-        raise serialization.DeserializationException(
-            'Trying to deserialize null for non nullable type.')
-      return None
-    pointed_data = data[value:]
-    (size, nb_elements) = serialization.HEADER_STRUCT.unpack_from(pointed_data)
-    return self.DeserializePointer(size, nb_elements, pointed_data, handles)
-
   def SerializePointer(self, value, data_offset, data, handle_offset):
     """Serialize the not null value."""
     raise NotImplementedError()
 
-  def DeserializePointer(self, size, nb_elements, data, handles):
-    raise NotImplementedError()
-
 
 class StringType(PointerType):
   """
@@ -202,11 +170,6 @@ class StringType(PointerType):
     return self._array_type.SerializeArray(
         string_array, data_offset, data, handle_offset)
 
-  def DeserializePointer(self, size, nb_elements, data, handles):
-    string_array = self._array_type.DeserializeArray(
-        size, nb_elements, data, handles)
-    return unicode(string_array.tostring(), 'utf8')
-
 
 class HandleType(SerializableType):
   """Type object for handles."""
@@ -225,20 +188,11 @@ class HandleType(SerializableType):
   def Serialize(self, value, data_offset, data, handle_offset):
     if not value.IsValid() and not self.nullable:
       raise serialization.SerializationException(
-          'Trying to serialize null for non nullable type.')
+          "Trying to serialize null for non nullable type.")
     if not value.IsValid():
       return (-1, [])
     return (handle_offset, [value])
 
-  def Deserialize(self, value, data, handles):
-    if value == -1:
-      if not self.nullable:
-        raise serialization.DeserializationException(
-            'Trying to deserialize null for non nullable type.')
-      return mojo.system.Handle()
-    # TODO(qsr) validate handle order
-    return handles[value]
-
 
 class BaseArrayType(PointerType):
   """Abstract Type object for arrays."""
@@ -249,22 +203,13 @@ class BaseArrayType(PointerType):
 
   def SerializePointer(self, value, data_offset, data, handle_offset):
     if self.length != 0 and len(value) != self.length:
-      raise serialization.SerializationException('Incorrect array size')
+      raise serialization.SerializationException("Incorrect array size")
     return self.SerializeArray(value, data_offset, data, handle_offset)
 
   def SerializeArray(self, value, data_offset, data, handle_offset):
     """Serialize the not null array."""
     raise NotImplementedError()
 
-  def DeserializePointer(self, size, nb_elements, data, handles):
-    if self.length != 0 and size != self.length:
-      raise serialization.DeserializationException('Incorrect array size')
-    return self.DeserializeArray(size, nb_elements, data, handles)
-
-  def DeserializeArray(self, size, nb_elements, data, handles):
-    raise NotImplementedError()
-
-
 class BooleanArrayType(BaseArrayType):
 
   def __init__(self, nullable=False, length=0):
@@ -279,17 +224,8 @@ class BooleanArrayType(BaseArrayType):
   def SerializeArray(self, value, data_offset, data, handle_offset):
     groups = [value[i:i+8] for i in range(0, len(value), 8)]
     converted = array.array('B', [_ConvertBooleansToByte(x) for x in groups])
-    return _SerializeNativeArray(converted, data_offset, data, len(value))
-
-  def DeserializeArray(self, size, nb_elements, data, handles):
-    converted = self._array_type.DeserializeArray(
-        size, nb_elements, data, handles)
-    elements = list(itertools.islice(
-        itertools.chain.from_iterable(
-            [_ConvertByteToBooleans(x, 8) for x in converted]),
-        0,
-        nb_elements))
-    return elements
+    return self._array_type.SerializeArray(
+        converted, data_offset, data, handle_offset)
 
 
 class GenericArrayType(BaseArrayType):
@@ -309,11 +245,12 @@ class GenericArrayType(BaseArrayType):
     size = (serialization.HEADER_STRUCT.size +
             self.sub_type.GetByteSize() * len(value))
     data_end = len(data)
-    position = len(data) + serialization.HEADER_STRUCT.size
+    position = len(data) - data_offset
     data.extend(bytearray(size +
                           serialization.NeededPaddingForAlignment(size)))
     returned_handles = []
     to_pack = []
+    position = position + 2
     for item in value:
       (new_data, new_handles) = self.sub_type.Serialize(
           item,
@@ -324,23 +261,12 @@ class GenericArrayType(BaseArrayType):
       returned_handles.extend(new_handles)
       position = position + self.sub_type.GetByteSize()
     serialization.HEADER_STRUCT.pack_into(data, data_end, size, len(value))
-    struct.pack_into('%d%s' % (len(value), self.sub_type.GetTypeCode()),
+    struct.pack_into("%d%s" % (len(value), self.sub_type.GetTypeCode()),
                      data,
                      data_end + serialization.HEADER_STRUCT.size,
                      *to_pack)
     return (data_offset, returned_handles)
 
-  def DeserializeArray(self, size, nb_elements, data, handles):
-    values = struct.unpack_from(
-        '%d%s' % (nb_elements, self.sub_type.GetTypeCode()),
-        data[serialization.HEADER_STRUCT.size:])
-    result = []
-    position = serialization.HEADER_STRUCT.size
-    for value in values:
-      result.append(self.sub_type.Deserialize(value, data[position:], handles))
-      position += self.sub_type.GetByteSize()
-    return result
-
 
 class NativeArrayType(BaseArrayType):
   """Type object for arrays of native types."""
@@ -358,12 +284,15 @@ class NativeArrayType(BaseArrayType):
     return array.array(self.array_typecode, value)
 
   def SerializeArray(self, value, data_offset, data, handle_offset):
-    return _SerializeNativeArray(value, data_offset, data, len(value))
-
-  def DeserializeArray(self, size, nb_elements, data, handles):
-    result = array.array(self.array_typecode)
-    result.fromstring(data[serialization.HEADER_STRUCT.size:size].tobytes())
-    return result
+    data_size = len(data)
+    data.extend(bytearray(serialization.HEADER_STRUCT.size))
+    data.extend(value.tostring())
+    data_length = len(data) - data_size
+    data.extend(bytearray(
+        serialization.NeededPaddingForAlignment(data_length)))
+    serialization.HEADER_STRUCT.pack_into(
+        data, data_size, data_length, len(value))
+    return (data_offset, [])
 
 
 class StructType(PointerType):
@@ -389,9 +318,6 @@ class StructType(PointerType):
     data.extend(new_data)
     return (data_offset, new_handles)
 
-  def DeserializePointer(self, size, nb_elements, data, handles):
-    return self.struct_type.Deserialize(data, handles)
-
 
 class NoneType(SerializableType):
   """Placeholder type, used temporarily until all mojo types are handled."""
@@ -405,9 +331,6 @@ class NoneType(SerializableType):
   def Serialize(self, value, data_offset, data, handle_offset):
     return (0, [])
 
-  def Deserialize(self, value, data, handles):
-    return None
-
 
 TYPE_NONE = NoneType()
 
@@ -469,9 +392,6 @@ class FieldGroup(object):
   def Serialize(self, obj, data_offset, data, handle_offset):
     raise NotImplementedError()
 
-  def Deserialize(self, value, data, handles):
-    raise NotImplementedError()
-
 
 class SingleFieldGroup(FieldGroup, FieldDescriptor):
   """A FieldGroup that contains a single FieldDescriptor."""
@@ -494,10 +414,6 @@ class SingleFieldGroup(FieldGroup, FieldDescriptor):
     value = getattr(obj, self.name)
     return self.field_type.Serialize(value, data_offset, data, handle_offset)
 
-  def Deserialize(self, value, data, handles):
-    entity = self.field_type.Deserialize(value, data, handles)
-    return { self.name: entity }
-
 
 class BooleanGroup(FieldGroup):
   """A FieldGroup to pack booleans."""
@@ -506,7 +422,7 @@ class BooleanGroup(FieldGroup):
     self.version = min([descriptor.field_number  for descriptor in descriptors])
 
   def GetTypeCode(self):
-    return 'B'
+    return "B"
 
   def GetByteSize(self):
     return 1
@@ -519,33 +435,7 @@ class BooleanGroup(FieldGroup):
         [getattr(obj, field.name) for field in self.GetDescriptors()])
     return (value, [])
 
-  def Deserialize(self, value, data, handles):
-    values =  itertools.izip_longest([x.name for x in self.descriptors],
-                                      _ConvertByteToBooleans(value),
-                                     fillvalue=False)
-    return dict(values)
-
-
-def _SerializeNativeArray(value, data_offset, data, length):
-  data_size = len(data)
-  data.extend(bytearray(serialization.HEADER_STRUCT.size))
-  data.extend(value.tostring())
-  data_length = len(data) - data_size
-  data.extend(bytearray(serialization.NeededPaddingForAlignment(data_length)))
-  serialization.HEADER_STRUCT.pack_into(data, data_size, data_length, length)
-  return (data_offset, [])
-
 
 def _ConvertBooleansToByte(booleans):
   """Pack a list of booleans into an integer."""
   return reduce(lambda x, y: x * 2 + y, reversed(booleans), 0)
-
-
-def _ConvertByteToBooleans(value, min_size=0):
-  "Unpack an integer into a list of booleans."""
-  res = []
-  while value:
-    res.append(bool(value&1))
-    value = value / 2
-  res.extend([False] * (min_size - len(res)))
-  return res

mojo/public/python/mojo/bindings/reflection.py

@@ -107,14 +107,6 @@ class MojoStructType(type):
       return serialization_object.Serialize(self, handle_offset)
     dictionary['Serialize'] = Serialize
 
-    def Deserialize(cls, data, handles):
-      result = cls.__new__(cls)
-      fields = {}
-      serialization_object.Deserialize(fields, data, handles)
-      result._fields = fields
-      return result
-    dictionary['Deserialize'] = classmethod(Deserialize)
-
     return type.__new__(mcs, name, bases, dictionary)
 
   # Prevent adding new attributes, or mutating constants.

mojo/public/python/mojo/bindings/serialization.py

@@ -16,42 +16,28 @@ class SerializationException(Exception):
   pass
 
 
-class DeserializationException(Exception):
-  """Error when strying to deserialize a struct."""
-  pass
-
-
 class Serialization(object):
   """
   Helper class to serialize/deserialize a struct.
   """
   def __init__(self, groups):
-    self.version = _GetVersion(groups)
     self._groups = groups
+    self.version = _GetVersion(groups)
     main_struct = _GetStruct(groups)
     self.size = HEADER_STRUCT.size + main_struct.size
     self._struct_per_version = {
       self.version: main_struct,
     }
-    self._groups_per_version = {
-        self.version: groups,
-    }
 
   def _GetMainStruct(self):
     return self._GetStruct(self.version)
 
-  def _GetGroups(self, version):
-    # If asking for a version greater than the last known.
-    version = min(version, self.version)
-    if version not in self._groups_per_version:
-      self._groups_per_version[version] = _FilterGroups(self._groups, version)
-    return self._groups_per_version[version]
-
   def _GetStruct(self, version):
-    # If asking for a version greater than the last known.
+    # If asking for a greater ver
     version = min(version, self.version)
     if version not in self._struct_per_version:
-      self._struct_per_version[version] = _GetStruct(self._GetGroups(version))
+      self._struct_per_version[version] = _GetStruct(_FilterGroups(self._groups,
+                                                                   version))
     return self._struct_per_version[version]
 
   def Serialize(self, obj, handle_offset):
@@ -78,18 +64,6 @@ class Serialization(object):
     self._GetMainStruct().pack_into(data, HEADER_STRUCT.size, *to_pack)
     return (data, handles)
 
-  def Deserialize(self, fields, data, handles):
-    (_, version) = HEADER_STRUCT.unpack_from(data)
-    version_struct = self._GetStruct(version)
-    entitities = version_struct.unpack_from(data, HEADER_STRUCT.size)
-    filtered_groups = self._GetGroups(version)
-    position = HEADER_STRUCT.size
-    for (group, value) in zip(filtered_groups, entitities):
-      position = position + NeededPaddingForAlignment(position,
-                                                      group.GetByteSize())
-      fields.update(group.Deserialize(value, data[position:], handles))
-      position += group.GetByteSize()
-
 
 def NeededPaddingForAlignment(value, alignment=8):
   """Returns the padding necessary to align value with the given alignment."""
@@ -103,7 +77,7 @@ def _GetVersion(groups):
 
 
 def _FilterGroups(groups, version):
-  return [group for group in groups if group.GetVersion() < version]
+  return [group for group in groups if group.version < version]
 
 
 def _GetStruct(groups):

mojo/python/tests/bindings_serialization_deserialization_unittest.py

@@ -2,67 +2,19 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import math
 import unittest
 
 # pylint: disable=F0401
-import mojo.bindings.reflection as reflection
 import mojo.system
 
 # Generated files
 # pylint: disable=F0401
-import sample_import_mojom
-import sample_import2_mojom
 import sample_service_mojom
 
 
 def _NewHandle():
   return mojo.system.MessagePipe().handle0
 
-
-def _TestEquality(x, y):
-  if x == y:
-    return True
-
-  if type(x) != type(y):
-    print '\n%r != %r. Element are not of the same type.' % (x, y)
-    return False
-
-  if isinstance(x, float) and math.isnan(x) and math.isnan(y):
-    return True
-
-  if hasattr(x, '__len__'):
-    if len(x) != len(y):
-      print '\n%r != %r. Iterables are not of the same size.' % (x, y)
-      return False
-    for (x1, y1) in zip(x, y):
-      if not _TestEquality(x1, y1):
-        return False
-    return True
-
-  if (hasattr(x, '__metaclass__') and
-      x.__metaclass__ == reflection.MojoStructType):
-    properties = [p for p in dir(x) if not p.startswith('_')]
-    for p in properties:
-      p1 = getattr(x, p)
-      p2 = getattr(y, p)
-      if not hasattr(p1, '__call__') and not _TestEquality(p1, p2):
-        print '\n%r != %r. Not equal for property %r.' % (x, y, p)
-        return False
-    return True
-
-  return False
-
-
-def _NewBar():
-  bar_instance = sample_service_mojom.Bar()
-  bar_instance.alpha = 22
-  bar_instance.beta = 87
-  bar_instance.gamma = 122
-  bar_instance.type = sample_service_mojom.Bar.Type.BOTH
-  return bar_instance
-
-
 def _NewFoo():
   foo_instance = sample_service_mojom.Foo()
   foo_instance.name = "Foo.name"
@@ -71,10 +23,10 @@ def _NewFoo():
   foo_instance.a = False
   foo_instance.b = True
   foo_instance.c = True
-  foo_instance.bar = _NewBar()
+  foo_instance.bar = sample_service_mojom.Bar()
   foo_instance.extra_bars = [
-      _NewBar(),
-      _NewBar(),
+      sample_service_mojom.Bar(),
+      sample_service_mojom.Bar()
   ]
   foo_instance.data = 'Hello world'
   foo_instance.source = _NewHandle()
@@ -89,43 +41,12 @@ def _NewFoo():
       ],
       [],
   ]
-  foo_instance.array_of_bools = [ True, 0, 1, 2, 0, 0, 0, 0, 0, True ]
+  foo_instance.array_of_bools = [ True, 0, 1, 2, 0 ]
   return foo_instance
 
-
 class SerializationDeserializationTest(unittest.TestCase):
 
-  def testTestEquality(self):
-    self.assertFalse(_TestEquality(1, 2))
-
   def testFooSerialization(self):
     (data, _) = _NewFoo().Serialize()
     self.assertTrue(len(data))
     self.assertEquals(len(data) % 8, 0)
-
-  def testFooDeserialization(self):
-    (data, handles) = _NewFoo().Serialize()
-    self.assertTrue(
-        sample_service_mojom.Foo.Deserialize(memoryview(data), handles))
-
-  def testFooSerializationDeserialization(self):
-    foo1 = _NewFoo()
-    (data, handles) = foo1.Serialize()
-    foo2 = sample_service_mojom.Foo.Deserialize(memoryview(data), handles)
-    self.assertTrue(_TestEquality(foo1, foo2))
-
-  def testDefaultsTestSerializationDeserialization(self):
-    v1 = sample_service_mojom.DefaultsTest()
-    v1.a18 = []
-    v1.a19 = ""
-    v1.a21 = sample_import_mojom.Point()
-    v1.a22.location = sample_import_mojom.Point()
-    v1.a22.size = sample_import2_mojom.Size()
-    (data, handles) = v1.Serialize()
-    v2 = sample_service_mojom.DefaultsTest.Deserialize(memoryview(data),
-                                                       handles)
-    self.assertTrue(_TestEquality(v1, v2))
-
-  def testFooDeserializationError(self):
-    with self.assertRaises(Exception):
-      sample_service_mojom.Foo.Deserialize("", [])