blob: ea4c6336d44b9f7ae305c63d610a4973f5bbfd6d [file] [log] [blame]
# Copyright 2019 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
from typing import Sequence, TypeVar, Generic, List, Tuple, Callable, Dict
from import Declaration
from difl.changes import Change, DeclAdded, DeclRemoved
from difl.comparator import Comparator
D = TypeVar('D', bound=Declaration)
def intersect_changes(
before: Sequence[D],
after: Sequence[D],
compare: Callable[[D, D, Comparator], List[Change]],
comparator: Comparator,
include_decl_added_and_decl_removed=True) -> List[Change]:
# dictionaries of declarations by name
before_by_name = { d for d in before}
after_by_name = { d for d in after}
# immutable sets of declaration names
before_names = frozenset(before_by_name.keys())
after_names = frozenset(after_by_name.keys())
changes: List[Change] = []
if include_decl_added_and_decl_removed:
for decl in [after_by_name[n] for n in after_names - before_names]:
changes.append(DeclAdded(before=None, after=decl))
for decl in [before_by_name[n] for n in before_names - after_names]:
changes.append(DeclRemoved(before=decl, after=None))
for before_decl, after_decl in [
(before_by_name[n], after_by_name[n])
for n in before_names.intersection(after_names)
changes.extend(compare(before_decl, after_decl, comparator))
return changes