Make the fuchsia mojo/public repo the source of truth.

mojo/public/tools/bindings/pylib/mojom/generate/pack.py

-# Copyright 2013 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import module as mojom
-
-# This module provides a mechanism for determining the packed order and offsets
-# of a mojom.Struct.
-#
-# ps = pack.PackedStruct(struct)
-# ps.packed_fields will access a list of PackedField objects, each of which
-# will have an offset, a size and a bit (for mojom.BOOLs).
-
-# Size of struct header in bytes: num_bytes [4B] + version [4B].
-HEADER_SIZE = 8
-
-class PackedField(object):
-  kind_to_size = {
-    mojom.BOOL:                  1,
-    mojom.INT8:                  1,
-    mojom.UINT8:                 1,
-    mojom.INT16:                 2,
-    mojom.UINT16:                2,
-    mojom.INT32:                 4,
-    mojom.UINT32:                4,
-    mojom.FLOAT:                 4,
-    mojom.HANDLE:                4,
-    mojom.MSGPIPE:               4,
-    mojom.SHAREDBUFFER:          4,
-    mojom.DCPIPE:                4,
-    mojom.DPPIPE:                4,
-    mojom.NULLABLE_HANDLE:       4,
-    mojom.NULLABLE_MSGPIPE:      4,
-    mojom.NULLABLE_SHAREDBUFFER: 4,
-    mojom.NULLABLE_DCPIPE:       4,
-    mojom.NULLABLE_DPPIPE:       4,
-    mojom.INT64:                 8,
-    mojom.UINT64:                8,
-    mojom.DOUBLE:                8,
-    mojom.STRING:                8,
-    mojom.NULLABLE_STRING:       8
-  }
-
-  @classmethod
-  def GetSizeForKind(cls, kind):
-    if isinstance(kind, (mojom.Array, mojom.Map, mojom.Struct,
-                         mojom.Interface)):
-      return 8
-    if isinstance(kind, mojom.Union):
-      return 16
-    if isinstance(kind, mojom.InterfaceRequest):
-      kind = mojom.MSGPIPE
-    if isinstance(kind, mojom.Enum):
-      # TODO(mpcomplete): what about big enums?
-      return cls.kind_to_size[mojom.INT32]
-    if not kind in cls.kind_to_size:
-      raise Exception("Invalid kind: %s" % kind.spec)
-    return cls.kind_to_size[kind]
-
-  def __init__(self, field):
-    """
-    Args:
-      field: the original field.
-    """
-    self.field = field
-    self.index = field.declaration_order
-    self.ordinal = field.computed_ordinal
-    self.size = self.GetSizeForKind(field.kind)
-    self.offset = field.computed_offset
-    self.bit = field.computed_bit
-    self.min_version = field.computed_min_version
-
-
-def GetPad(offset, alignment):
-  """Returns the pad necessary to reserve space so that |offset + pad| equals to
-  some multiple of |alignment|."""
-  return (alignment - (offset % alignment)) % alignment
-
-
-class PackedStruct(object):
-  def __init__(self, struct):
-    self.struct = struct
-
-    # |packed_fields_in_ordinal_order| contains all the fields,
-    # in ordinal order.
-    self.packed_fields_in_ordinal_order = [PackedField(field)
-        for field in struct.fields_in_ordinal_order]
-
-    # |packed_fields| refers to the same fields as
-    # |packed_fields_in_ordinal_order|, but in increasing offset order.
-    self.packed_fields = [field for field in
-        self.packed_fields_in_ordinal_order]
-    self.packed_fields.sort(key=lambda f: (f.offset, f.bit))
-
-class ByteInfo(object):
-  def __init__(self):
-    self.is_padding = False
-    self.packed_fields = []
-
-
-def GetByteLayout(packed_struct):
-  total_payload_size = packed_struct.struct.versions[-1].num_bytes - HEADER_SIZE
-  bytes = [ByteInfo() for i in xrange(total_payload_size)]
-
-  limit_of_previous_field = 0
-  for packed_field in packed_struct.packed_fields:
-    for i in xrange(limit_of_previous_field, packed_field.offset):
-      bytes[i].is_padding = True
-    bytes[packed_field.offset].packed_fields.append(packed_field)
-    limit_of_previous_field = packed_field.offset + packed_field.size
-
-  for i in xrange(limit_of_previous_field, len(bytes)):
-    bytes[i].is_padding = True
-
-  for byte in bytes:
-    # A given byte cannot both be padding and have a fields packed into it.
-    assert not (byte.is_padding and byte.packed_fields)
-
-  return bytes
-
-
-class VersionInfo(object):
-  def __init__(self, version, num_fields, num_bytes):
-    self.version = version
-    self.num_fields = num_fields
-    self.num_bytes = num_bytes
-