mirror of https://github.com/python/cpython
95 lines
3.7 KiB
Python
95 lines
3.7 KiB
Python
import io
|
|
import sys
|
|
|
|
|
|
# The maximum length of a log message in bytes, including the level marker and
|
|
# tag, is defined as LOGGER_ENTRY_MAX_PAYLOAD in
|
|
# platform/system/logging/liblog/include/log/log.h. As of API level 30, messages
|
|
# longer than this will be be truncated by logcat. This limit has already been
|
|
# reduced at least once in the history of Android (from 4076 to 4068 between API
|
|
# level 23 and 26), so leave some headroom.
|
|
MAX_BYTES_PER_WRITE = 4000
|
|
|
|
# UTF-8 uses a maximum of 4 bytes per character, so limiting text writes to this
|
|
# size ensures that TextIOWrapper can always avoid exceeding MAX_BYTES_PER_WRITE.
|
|
# However, if the actual number of bytes per character is smaller than that,
|
|
# then TextIOWrapper may still join multiple consecutive text writes into binary
|
|
# writes containing a larger number of characters.
|
|
MAX_CHARS_PER_WRITE = MAX_BYTES_PER_WRITE // 4
|
|
|
|
|
|
# When embedded in an app on current versions of Android, there's no easy way to
|
|
# monitor the C-level stdout and stderr. The testbed comes with a .c file to
|
|
# redirect them to the system log using a pipe, but that wouldn't be convenient
|
|
# or appropriate for all apps. So we redirect at the Python level instead.
|
|
def init_streams(android_log_write, stdout_prio, stderr_prio):
|
|
if sys.executable:
|
|
return # Not embedded in an app.
|
|
|
|
sys.stdout = TextLogStream(
|
|
android_log_write, stdout_prio, "python.stdout", errors=sys.stdout.errors)
|
|
sys.stderr = TextLogStream(
|
|
android_log_write, stderr_prio, "python.stderr", errors=sys.stderr.errors)
|
|
|
|
|
|
class TextLogStream(io.TextIOWrapper):
|
|
def __init__(self, android_log_write, prio, tag, **kwargs):
|
|
kwargs.setdefault("encoding", "UTF-8")
|
|
kwargs.setdefault("line_buffering", True)
|
|
super().__init__(BinaryLogStream(android_log_write, prio, tag), **kwargs)
|
|
self._CHUNK_SIZE = MAX_BYTES_PER_WRITE
|
|
|
|
def __repr__(self):
|
|
return f"<TextLogStream {self.buffer.tag!r}>"
|
|
|
|
def write(self, s):
|
|
if not isinstance(s, str):
|
|
raise TypeError(
|
|
f"write() argument must be str, not {type(s).__name__}")
|
|
|
|
# In case `s` is a str subclass that writes itself to stdout or stderr
|
|
# when we call its methods, convert it to an actual str.
|
|
s = str.__str__(s)
|
|
|
|
# We want to emit one log message per line wherever possible, so split
|
|
# the string before sending it to the superclass. Note that
|
|
# "".splitlines() == [], so nothing will be logged for an empty string.
|
|
for line in s.splitlines(keepends=True):
|
|
while line:
|
|
super().write(line[:MAX_CHARS_PER_WRITE])
|
|
line = line[MAX_CHARS_PER_WRITE:]
|
|
|
|
return len(s)
|
|
|
|
|
|
class BinaryLogStream(io.RawIOBase):
|
|
def __init__(self, android_log_write, prio, tag):
|
|
self.android_log_write = android_log_write
|
|
self.prio = prio
|
|
self.tag = tag
|
|
|
|
def __repr__(self):
|
|
return f"<BinaryLogStream {self.tag!r}>"
|
|
|
|
def writable(self):
|
|
return True
|
|
|
|
def write(self, b):
|
|
if type(b) is not bytes:
|
|
try:
|
|
b = bytes(memoryview(b))
|
|
except TypeError:
|
|
raise TypeError(
|
|
f"write() argument must be bytes-like, not {type(b).__name__}"
|
|
) from None
|
|
|
|
# Writing an empty string to the stream should have no effect.
|
|
if b:
|
|
# Encode null bytes using "modified UTF-8" to avoid truncating the
|
|
# message. This should not affect the return value, as the caller
|
|
# may be expecting it to match the length of the input.
|
|
self.android_log_write(self.prio, self.tag,
|
|
b.replace(b"\x00", b"\xc0\x80"))
|
|
|
|
return len(b)
|