From 861980db0bd6d7add7ec6324777238603a4468fe Mon Sep 17 00:00:00 2001 From: Davide Depau Date: Tue, 9 Jan 2018 11:31:51 +0100 Subject: [PATCH] Simplify, expand and explain complicated loops in dag.py --- ffmpeg/dag.py | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/ffmpeg/dag.py b/ffmpeg/dag.py index 0138197..7dc02f6 100644 --- a/ffmpeg/dag.py +++ b/ffmpeg/dag.py @@ -75,8 +75,10 @@ DagEdge = namedtuple('DagEdge', ['downstream_node', 'downstream_label', 'upstrea def get_incoming_edges(downstream_node, incoming_edge_map): edges = [] - for downstream_label, upstream_info in [(i[0], i[1]) for i in incoming_edge_map.items()]: + for downstream_label, upstream_info in incoming_edge_map.items(): + # `upstream_info` may contain the upstream_selector. [:2] trims it away upstream_node, upstream_label = upstream_info[:2] + # Take into account the stream selector if it's present (i.e. len(upstream_info) >= 3) upstream_selector = None if len(upstream_info) < 3 else upstream_info[2] edges += [DagEdge(downstream_node, downstream_label, upstream_node, upstream_label, upstream_selector)] return edges @@ -86,7 +88,9 @@ def get_outgoing_edges(upstream_node, outgoing_edge_map): edges = [] for upstream_label, downstream_infos in list(outgoing_edge_map.items()): for downstream_info in downstream_infos: + # `downstream_info` may contain the downstream_selector. [:2] trims it away downstream_node, downstream_label = downstream_info[:2] + # Take into account the stream selector if it's present downstream_selector = None if len(downstream_info) < 3 else downstream_info[2] edges += [DagEdge(downstream_node, downstream_label, upstream_node, upstream_label, downstream_selector)] return edges @@ -99,8 +103,10 @@ class KwargReprNode(DagNode): @property def __upstream_hashes(self): hashes = [] - # This is needed to allow extra stuff in the incoming_edge_map's value tuples - for downstream_label, (upstream_node, upstream_label) in [(i[0], i[1][:2]) for i in self.incoming_edge_map.items()]: + for downstream_label, upstream_info in self.incoming_edge_map.items(): + # `upstream_info` may contain the upstream_selector. [:2] trims it away + upstream_node, upstream_label = upstream_info[:2] + # The stream selector is discarded when calculating the hash: the stream "as a whole" is still the same hashes += [hash(x) for x in [downstream_label, upstream_node, upstream_label]] return hashes