8000 Reimplement `.map` logic making `Node` immutable · Powercoder64/ffmpeg-python@497105f · GitHub
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depaudepau
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Reimplement .map logic making Node immutable
1 parent 861980d commit 497105f

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3 files changed

+121
-43
lines changed

3 files changed

+121
-43
lines changed

‎ffmpeg/_ffmpeg.py

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -83,9 +83,7 @@ def map(*streams):
8383
if not tail:
8484
return head
8585

86-
head.node._add_streams(tail)
87-
88-
return head
86+
return OutputNode(head.node, tail).stream()
8987

9088

9189
__all__ = [

‎ffmpeg/nodes.py

Lines changed: 117 additions & 38 deletions
Original file line numberDiff line numberDiff line change
@@ -1,9 +1,12 @@
11
from __future__ import unicode_literals
22

3+
import warnings
4+
35
from .dag import KwargReprNode
46
from ._utils import escape_chars, get_hash_int
57
from builtins import object
6-
import os
8+
import os, sys
9+
import inspect
710

811

912
def _is_of_types(obj, types):
@@ -19,6 +22,13 @@ def _get_types_str(types):
1922
return ', '.join(['{}.{}'.format(x.__module__, x.__name__) for x in types])
2023

2124

25+
def _get_arg_count(callable):
26+
if sys.version_info.major >= 3:
27+
return len(inspect.getfullargspec(callable).args)
28+
else:
29+
return len(inspect.getargspec(callable).args)
30+
31+
2232
class Stream(object):
2333
"""Represents the outgoing edge of an upstream node; may be used to create more downstream nodes."""
2434

@@ -30,6 +40,7 @@ def __init__(self, upstream_node, upstream_label, node_types, upstream_selector=
3040
self.label = upstream_label
3141
self.selector = upstream_selector
3242

43+
3344
def __hash__(self):
3445
return get_hash_int([hash(self.node), hash(self.label)])
3546

@@ -85,6 +96,22 @@ def get_stream_spec_nodes(stream_spec):
8596
class Node(KwargReprNode):
8697
"""Node base"""
8798

99+
@property
100+
def min_inputs(self):
101+
return self.__min_inputs
102+
103+
@property
104+
def max_inputs(self):
105+
return self.__max_inputs
106+
107+
@property
108+
def incoming_stream_types(self):
109+
return self.__incoming_stream_types
110+
111+
@property
112+
def outgoing_stream_type(self):
113+
return self.__outgoing_stream_type
114+
88115
@classmethod
89116
def __check_input_len(cls, stream_map, min_inputs, max_inputs):
90117
if min_inputs is not None and len(stream_map) < min_inputs:
@@ -106,19 +133,85 @@ def __get_incoming_edge_map(cls, stream_map):
106133
incoming_edge_map[downstream_label] = (upstream.node, upstream.label, upstream.selector)
107134
return incoming_edge_map
108135

109-
def __init__(self, stream_spec, name, incoming_stream_types, outgoing_stream_type, min_inputs, max_inputs, args=[],
110-
kwargs={}):
136+
def __init_fromscratch__(self, stream_spec, name, incoming_stream_types, outgoing_stream_type, min_inputs,
137+
max_inputs, args=[],
138+
kwargs={}):
111139
stream_map = get_stream_map(stream_spec)
112140
self.__check_input_len(stream_map, min_inputs, max_inputs)
113141
self.__check_input_types(stream_map, incoming_stream_types)
114142
incoming_edge_map = self.__get_incoming_edge_map(stream_map)
143+
115144
super(Node, self).__init__(incoming_edge_map, name, args, kwargs)
116145
self.__outgoing_stream_type = outgoing_stream_type
146+
self.__incoming_stream_types = incoming_stream_types
147+
self.__min_inputs = min_inputs
148+
self.__max_inputs = max_inputs
149+
150+
def __init_fromnode__(self, old_node, stream_spec):
151+
# Make sure old node and new node are of the same type
152+
if type(self) != type(old_node):
153+
raise ValueError("'old_node' should be of type {}".format(self.__class__.__name__))
154+
155+
# Copy needed data from old node
156+
name = old_node.name
157+
incoming_stream_types = old_node.incoming_stream_types
158+
outgoing_stream_type = old_node.outgoing_stream_type
159+
min_inputs = old_node.min_inputs
160+
max_inputs = old_node.max_inputs
161+
prev_edges = old_node.incoming_edge_map.values()
162+
args = old_node.args
163+
kwargs = old_node.kwargs
164+
165+
# Check new stream spec - the old spec should have already been checked
166+
new_stream_map = get_stream_map(stream_spec)
167+
self.__check_input_types(new_stream_map, incoming_stream_types)
168+
169+
# Generate new edge map
170+
new_inc_edge_map = self.__get_incoming_edge_map(new_stream_map)
171+
new_edges = new_inc_edge_map.values()
172+
173+
# Rename all edges
174+
new_edge_map = dict(enumerate(list(prev_edges) + list(new_edges)))
175+
176+
# Check new length
177+
self.__check_input_len(new_edge_map, min_inputs, max_inputs)
117178

179+
super(Node, self).__init__(new_edge_map, name, args, kwargs)
180+
self.__outgoing_stream_type = outgoing_stream_type
118181
self.__incoming_stream_types = incoming_stream_types
119182
self.__min_inputs = min_inputs
120183
self.__max_inputs = max_inputs
121184

185+
# noinspection PyMissingConstructor
186+
def __init__(self, *args, **kwargs):
187+
"""
188+
If called with the following arguments, the new Node is created from scratch:
189+
- stream_spec, name, incoming_stream_types, outgoing_stream_type, min_inputs, max_inputs, args=[], kwargs={}
190+
191+
If called with the following arguments, the new node is a copy of `old_node` that includes the additional
192+
`stream_spec`:
193+
- old_node, stream_spec
194+
"""
195+
# Python doesn't support constructor overloading. This hacky code detects how we want to construct the object
196+
# based on the number of arguments and the type of the first argument, then calls the appropriate constructor
197+
# helper method
198+
199+
# "1+" is for `self`
200+
argc = 1 + len(args) + len(kwargs)
201+
202+
first_arg = "old_node" in kwargs and kwargs["old_node"] or args[0]
203+
204+
if argc == _get_arg_count(self.__init_fromnode__) and type(first_arg) == type(self):
205+
self.__init_fromnode__(*args, **kwargs)
206+
else:
207+
if isinstance(first_arg, Node):
208+
raise ValueError(
209+
"{}.__init__() received an instance of {} as the first argument. If you want to create a "
210+
"copy of an existing node, the types must match and you must provide an additional stream_spec."
211+
.format(self.__class__.__name__, first_arg.__class__.__name__)
212+
)
213+
self.__init_fromscratch__(*args, **kwargs)
214+
122215
def stream(self, label=None, select=None):
123216
"""Create an outgoing stream originating from this node.
124217
@@ -136,43 +229,19 @@ def __getitem__(self, item):
136229
else:
137230
return self.stream(label=item)
138231

139-
def _add_streams(self, stream_spec):
140-
"""Attach additional streams after the Node is initialized.
141-
"""
142-
# Back up previous edges
143-
prev_edges = self.incoming_edge_map.values()
144-
145-
# Check new edges
146-
new_stream_map = get_stream_map(stream_spec)
147-
self.__check_input_types(new_stream_map, self.__incoming_stream_types)
148-
149-
# Generate new edge map
150-
new_inc_edge_map = self.__get_incoming_edge_map(new_stream_map)
151-
new_edges = new_inc_edge_map.values()
152-
153-
# Rename all edges
154-
new_edge_map = dict(enumerate(list(prev_edges) + list(new_edges)))
155-
156-
# Check new length
157-
self.__check_input_len(new_edge_map, self.__min_inputs, self.__max_inputs)
158-
159-
# Overwrite old map (exploiting the fact that dict is mutable; incoming_edge_map is a read-only property)
160-
if None in self.incoming_edge_map:
161-
self.incoming_edge_map.pop(None)
162-
self.incoming_edge_map.update(new_edge_map)
163-
164232

165233
class FilterableStream(Stream):
166234
def __init__(self, upstream_node, upstream_label, upstream_selector=None):
167235
super(FilterableStream, self).__init__(upstream_node, upstream_label, {InputNode, FilterNode},
168236
upstream_selector)
169237

170238

239+
# noinspection PyMethodOverriding
171240
class InputNode(Node):
172241
"""InputNode type"""
173242

174-
def __init__(self, name, args=[], kwargs={}):
175-
super(InputNode, self).__init__(
243+
def __init_fromscratch__(self, name, args=[], kwargs={}):
244+
super(InputNode, self).__init_fromscratch__(
176245
stream_spec=None,
177246
name=name,
178247
incoming_stream_types={},
@@ -183,14 +252,18 @@ def __init__(self, name, args=[], kwargs={}):
183252
kwargs=kwargs
184253
)
185254

255+
def __init_fromnode__(self, old_node, stream_spec):
256+
raise TypeError("{} can't be constructed from an existing node".format(self.__class__.__name__))
257+
186258
@property
187259
def short_repr(self):
188260
return os.path.basename(self.kwargs['filename'])
189261

190262

263+
# noinspection PyMethodOverriding
191264
class FilterNode(Node):
192-
def __init__(self, stream_spec, name, max_inputs=1, args=[], kwargs={}):
193-
super(FilterNode, self).__init__(
265+
def __init_fromscratch__(self, stream_spec, name, max_inputs=1, args=[], kwargs={}):
266+
super(FilterNode, self).__init_fromscratch__(
194267
stream_spec=stream_spec,
195268
name=name,
196269
incoming_stream_types={FilterableStream},
@@ -227,9 +300,10 @@ def _get_filter(self, outgoing_edges):
227300
return escape_chars(params_text, '\\\'[],;')
228301

229302

303+
# noinspection PyMethodOverriding
230304
class OutputNode(Node):
231-
def __init__(self, stream, name, args=[], kwargs={}):
232-
super(OutputNode, self).__init__(
305+
def __init_fromscratch__(self, stream, name, args=[], kwargs={}):
306+
super(OutputNode, self).__init_fromscratch__(
233307
stream_spec=stream,
234308
name=name,
235309
incoming_stream_types={FilterableStream},
@@ -251,9 +325,10 @@ def __init__(self, upstream_node, upstream_label, upstream_selector=None):
251325
upstream_selector=upstream_selector)
252326

253327

328+
# noinspection PyMethodOverriding
254329
class MergeOutputsNode(Node):
255-
def __init__(self, streams, name):
256-
super(MergeOutputsNode, self).__init__(
330+
def __init_fromscratch__(self, streams, name):
331+
super(MergeOutputsNode, self).__init_fromscratch__(
257332
stream_spec=streams,
258333
name=name,
259334
incoming_stream_types={OutputStream},
@@ -263,9 +338,10 @@ def __init__(self, streams, name):
263338
)
264339

265340

341+
# noinspection PyMethodOverriding
266342
class GlobalNode(Node):
267-
def __init__(self, stream, name, args=[], kwargs={}):
268-
super(GlobalNode, self).__init__(
343+
def __init_fromscratch__(self, stream, name, args=[], kwargs={}):
344+
super(GlobalNode, self).__init_fromscratch__(
269345
stream_spec=stream,
270346
name=name,
271347
incoming_stream_types={OutputStream},
@@ -276,6 +352,9 @@ def __init__(self, stream, name, args=[], kwargs={}):
276352
kwargs=kwargs
277353
)
278354

355+
def __init_fromnode__(self, old_node, stream_spec):
356+
raise TypeError("{} can't be constructed from an existing node".format(self.__class__.__name__))
357+
279358

280359
def stream_operator(stream_classes={Stream}, name=None):
281360
def decorator(func):

‎ffmpeg/tests/test_ffmpeg.py

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -166,11 +166,12 @@ def test_map_same_effect_as_output():
166166
i1 = ffmpeg.input(TEST_INPUT_FILE1)
167167
i2 = ffmpeg.input(TEST_OVERLAY_FILE)
168168

169-
o_map = i1.output(TEST_OUTPUT_FILE1)
170-
o_map.map(i2)
169+
_o_map = i1.output(TEST_OUTPUT_FILE1)
170+
o_map = _o_map.map(i2)
171171

172172
o_nomap = ffmpeg.output(i1, i2, TEST_OUTPUT_FILE1)
173173

174+
assert id(o_map) != id(_o_map) # Checks immutability
174175
assert o_map.node.incoming_edge_map == o_nomap.node.incoming_edge_map
175176
assert o_map.get_args() == o_nomap.get_args() == ['-i', TEST_INPUT_FILE1,
176177
'-i', TEST_OVERLAY_FILE,

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