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/588493002/)

Reason for revert:
Linux Tests mojo_python_bindings_tests failure
http://build.chromium.org/p/chromium.linux/builders/Linux%20Tests/builds/13712

======================================================================
ERROR: testDefaultsTestSerializationDeserialization (bindings_serialization_deserialization_unittest.SerializationDeserializationTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/mnt/data/b/build/slave/Linux_Tests/build/src/mojo/python/tests/bindings_serialization_deserialization_unittest.py", line 125, in testDefaultsTestSerializationDeserialization
    v2 = sample_service_mojom.DefaultsTest.Deserialize(data, handles)
  File "/mnt/data/b/build/slave/Linux_Tests/build/src/out/Release/python/mojo/bindings/reflection.py", line 113, in Deserialize
    serialization_object.Deserialize(fields, data, handles)
  File "/mnt/data/b/build/slave/Linux_Tests/build/src/out/Release/python/mojo/bindings/serialization.py", line 82, in Deserialize
    (_, version) = HEADER_STRUCT.unpack_from(data)
TypeError: unpack_from() argument 1 must be string or read-only buffer, not bytearray

Original issue's description:
> mojo: Add deserialization to python structs.
>
> This is a reland of https://codereview.chromium.org/578263003 using
> buffer instead of memoryview, because on some early version of python
> 2.7, memoryview cannot be used with struct.unpack_from.
>
> BUG=415491
> R=sdefresne@chromium.org,cmasone@chromium.org
>
> Committed: https://crrev.com/37dd5f484593b1c8b92b825a9648edf7fb6944e6
> Cr-Commit-Position: refs/heads/master@{#295684}

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

Review URL: https://codereview.chromium.org/584003002

Cr-Commit-Position: refs/heads/master@{#295689}

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,
+      self.version: main_struct,
     }
 
   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, buffer(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()
@@ -89,42 +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(data, handles))
-
-  def testFooSerializationDeserialization(self):
-    foo1 = _NewFoo()
-    (data, handles) = foo1.Serialize()
-    foo2 = sample_service_mojom.Foo.Deserialize(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(data, handles)
-    self.assertTrue(_TestEquality(v1, v2))
-
-  def testFooDeserializationError(self):
-    with self.assertRaises(Exception):
-      sample_service_mojom.Foo.Deserialize("", [])