1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
"""
This Listener simply prints to stdout / the terminal or a file.
"""
import logging
from typing import Any, Optional, TextIO, Union, cast
from ..message import Message
from ..typechecking import StringPathLike
from .generic import MessageWriter
log = logging.getLogger("can.io.printer")
class Printer(MessageWriter):
"""
The Printer class is a subclass of :class:`~can.Listener` which simply prints
any messages it receives to the terminal (stdout). A message is turned into a
string using :meth:`~can.Message.__str__`.
:attr write_to_file: `True` if this instance prints to a file instead of
standard out
"""
file: Optional[TextIO]
def __init__(
self,
file: Optional[Union[StringPathLike, TextIO]] = None,
append: bool = False,
**kwargs: Any,
) -> None:
"""
:param file: An optional path-like object or a file-like object to "print"
to instead of writing to standard out (stdout).
If this is a file-like object, it has to be opened in text
write mode, not binary write mode.
:param append: If set to `True` messages, are appended to the file,
else the file is truncated
"""
self.write_to_file = file is not None
mode = "a" if append else "w"
super().__init__(file, mode=mode)
def on_message_received(self, msg: Message) -> None:
if self.write_to_file:
cast(TextIO, self.file).write(str(msg) + "\n")
else:
print(msg) # noqa: T201
def file_size(self) -> int:
"""Return an estimate of the current file size in bytes."""
if self.file is not None:
return self.file.tell()
return 0
|
