Current File : //opt/alt/python37/lib/python3.7/site-packages/paste/util/threadedprint.py
# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
"""
threadedprint.py
================
:author: Ian Bicking
:date: 12 Jul 2004
Multi-threaded printing; allows the output produced via print to be
separated according to the thread.
To use this, you must install the catcher, like::
threadedprint.install()
The installation optionally takes one of three parameters:
default
The default destination for print statements (e.g., ``sys.stdout``).
factory
A function that will produce the stream for a thread, given the
thread's name.
paramwriter
Instead of writing to a file-like stream, this function will be
called like ``paramwriter(thread_name, text)`` for every write.
The thread name is the value returned by
``threading.currentThread().getName()``, a string (typically something
like Thread-N).
You can also submit file-like objects for specific threads, which will
override any of these parameters. To do this, call ``register(stream,
[threadName])``. ``threadName`` is optional, and if not provided the
stream will be registered for the current thread.
If no specific stream is registered for a thread, and no default has
been provided, then an error will occur when anything is written to
``sys.stdout`` (or printed).
Note: the stream's ``write`` method will be called in the thread the
text came from, so you should consider thread safety, especially if
multiple threads share the same writer.
Note: if you want access to the original standard out, use
``sys.__stdout__``.
You may also uninstall this, via::
threadedprint.uninstall()
TODO
----
* Something with ``sys.stderr``.
* Some default handlers. Maybe something that hooks into `logging`.
* Possibly cache the results of ``factory`` calls. This would be a
semantic change.
"""
import threading
import sys
from paste.util import filemixin
class PrintCatcher(filemixin.FileMixin):
def __init__(self, default=None, factory=None, paramwriter=None,
leave_stdout=False):
assert len(filter(lambda x: x is not None,
[default, factory, paramwriter])) <= 1, (
"You can only provide one of default, factory, or paramwriter")
if leave_stdout:
assert not default, (
"You cannot pass in both default (%r) and "
"leave_stdout=True" % default)
default = sys.stdout
if default:
self._defaultfunc = self._writedefault
elif factory:
self._defaultfunc = self._writefactory
elif paramwriter:
self._defaultfunc = self._writeparam
else:
self._defaultfunc = self._writeerror
self._default = default
self._factory = factory
self._paramwriter = paramwriter
self._catchers = {}
def write(self, v, currentThread=threading.currentThread):
name = currentThread().getName()
catchers = self._catchers
if not catchers.has_key(name):
self._defaultfunc(name, v)
else:
catcher = catchers[name]
catcher.write(v)
def seek(self, *args):
# Weird, but Google App Engine is seeking on stdout
name = threading.currentThread().getName()
catchers = self._catchers
if not name in catchers:
self._default.seek(*args)
else:
catchers[name].seek(*args)
def read(self, *args):
name = threading.currentThread().getName()
catchers = self._catchers
if not name in catchers:
self._default.read(*args)
else:
catchers[name].read(*args)
def _writedefault(self, name, v):
self._default.write(v)
def _writefactory(self, name, v):
self._factory(name).write(v)
def _writeparam(self, name, v):
self._paramwriter(name, v)
def _writeerror(self, name, v):
assert False, (
"There is no PrintCatcher output stream for the thread %r"
% name)
def register(self, catcher, name=None,
currentThread=threading.currentThread):
if name is None:
name = currentThread().getName()
self._catchers[name] = catcher
def deregister(self, name=None,
currentThread=threading.currentThread):
if name is None:
name = currentThread().getName()
assert self._catchers.has_key(name), (
"There is no PrintCatcher catcher for the thread %r" % name)
del self._catchers[name]
_printcatcher = None
_oldstdout = None
def install(**kw):
global _printcatcher, _oldstdout, register, deregister
if (not _printcatcher or sys.stdout is not _printcatcher):
_oldstdout = sys.stdout
_printcatcher = sys.stdout = PrintCatcher(**kw)
register = _printcatcher.register
deregister = _printcatcher.deregister
def uninstall():
global _printcatcher, _oldstdout, register, deregister
if _printcatcher:
sys.stdout = _oldstdout
_printcatcher = _oldstdout = None
register = not_installed_error
deregister = not_installed_error
def not_installed_error(*args, **kw):
assert False, (
"threadedprint has not yet been installed (call "
"threadedprint.install())")
register = deregister = not_installed_error
class StdinCatcher(filemixin.FileMixin):
def __init__(self, default=None, factory=None, paramwriter=None):
assert len(filter(lambda x: x is not None,
[default, factory, paramwriter])) <= 1, (
"You can only provide one of default, factory, or paramwriter")
if default:
self._defaultfunc = self._readdefault
elif factory:
self._defaultfunc = self._readfactory
elif paramwriter:
self._defaultfunc = self._readparam
else:
self._defaultfunc = self._readerror
self._default = default
self._factory = factory
self._paramwriter = paramwriter
self._catchers = {}
def read(self, size=None, currentThread=threading.currentThread):
name = currentThread().getName()
catchers = self._catchers
if not catchers.has_key(name):
return self._defaultfunc(name, size)
else:
catcher = catchers[name]
return catcher.read(size)
def _readdefault(self, name, size):
self._default.read(size)
def _readfactory(self, name, size):
self._factory(name).read(size)
def _readparam(self, name, size):
self._paramreader(name, size)
def _readerror(self, name, size):
assert False, (
"There is no StdinCatcher output stream for the thread %r"
% name)
def register(self, catcher, name=None,
currentThread=threading.currentThread):
if name is None:
name = currentThread().getName()
self._catchers[name] = catcher
def deregister(self, catcher, name=None,
currentThread=threading.currentThread):
if name is None:
name = currentThread().getName()
assert self._catchers.has_key(name), (
"There is no StdinCatcher catcher for the thread %r" % name)
del self._catchers[name]
_stdincatcher = None
_oldstdin = None
def install_stdin(**kw):
global _stdincatcher, _oldstdin, register_stdin, deregister_stdin
if not _stdincatcher:
_oldstdin = sys.stdin
_stdincatcher = sys.stdin = StdinCatcher(**kw)
register_stdin = _stdincatcher.register
deregister_stdin = _stdincatcher.deregister
def uninstall():
global _stdincatcher, _oldstin, register_stdin, deregister_stdin
if _stdincatcher:
sys.stdin = _oldstdin
_stdincatcher = _oldstdin = None
register_stdin = deregister_stdin = not_installed_error_stdin
def not_installed_error_stdin(*args, **kw):
assert False, (
"threadedprint has not yet been installed for stdin (call "
"threadedprint.install_stdin())")
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