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Python part of the warnings subsystem.
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"""Python part of the warnings subsystem.""" | ||
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import sys, re, types | ||
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defaultaction = "default" | ||
filters = [] | ||
onceregistry = {} | ||
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def warn(message, category=None, stacklevel=1): | ||
"""Issue a warning, or maybe ignore it or raise an exception.""" | ||
# Check category argument | ||
if category is None: | ||
category = UserWarning | ||
assert issubclass(category, Warning) | ||
# Get context information | ||
try: | ||
caller = sys._getframe(stacklevel) | ||
except ValueError: | ||
globals = sys.__dict__ | ||
lineno = 1 | ||
else: | ||
globals = caller.f_globals | ||
lineno = caller.f_lineno | ||
module = globals['__name__'] | ||
filename = globals.get('__file__') | ||
if filename: | ||
fnl = filename.lower() | ||
if fnl.endswith(".pyc") or fnl.endswith(".pyo"): | ||
filename = filename[:-1] | ||
else: | ||
if module == "__main__": | ||
filename = sys.argv[0] | ||
if not filename: | ||
filename = module | ||
# Quick test for common case | ||
registry = globals.setdefault("__warningregistry__", {}) | ||
key = (message, category, lineno) | ||
if registry.get(key): | ||
return | ||
# Search the filters | ||
for item in filters: | ||
action, msg, cat, mod, ln = item | ||
if (msg.match(message) and | ||
issubclass(category, cat) and | ||
mod.match(module) and | ||
(ln == 0 or lineno == ln)): | ||
break | ||
else: | ||
action = defaultaction | ||
# Early exit actions | ||
if action == "ignore": | ||
registry[key] = 1 | ||
return | ||
if action == "error": | ||
raise category(message) | ||
# Other actions | ||
if action == "once": | ||
registry[key] = 1 | ||
oncekey = (message, category) | ||
if onceregistry.get(oncekey): | ||
return | ||
onceregistry[oncekey] = 1 | ||
elif action == "always": | ||
pass | ||
elif action == "module": | ||
registry[key] = 1 | ||
altkey = (message, category, 0) | ||
if registry.get(altkey): | ||
return | ||
registry[altkey] = 1 | ||
elif action == "default": | ||
registry[key] = 1 | ||
else: | ||
# Unrecognized actions are errors | ||
raise RuntimeError( | ||
"Unrecognized action (%s) in warnings.filters:\n %s" % | ||
(`action`, str(item))) | ||
# Print message and context | ||
showwarning(message, category, filename, lineno) | ||
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def showwarning(message, category, filename, lineno, file=None): | ||
"""Hook to write a warning to a file; replace if you like.""" | ||
if file is None: | ||
file = sys.stderr | ||
file.write(formatwarning(message, category, filename, lineno)) | ||
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def formatwarning(message, category, filename, lineno): | ||
"""Hook to format a warning the standard way.""" | ||
import linecache | ||
s = "%s:%s: %s: %s\n" % (filename, lineno, category.__name__, message) | ||
line = linecache.getline(filename, lineno).strip() | ||
if line: | ||
s = s + " " + line + "\n" | ||
return s | ||
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def filterwarnings(action, message="", category=Warning, module="", lineno=0): | ||
"""Insert an entry into the list of warnings filters (at the front). | ||
Use assertions to check that all arguments have the right type.""" | ||
assert action in ("error", "ignore", "always", "default", "module", | ||
"once"), "invalid action: %s" % `action` | ||
assert isinstance(message, types.StringType), "message must be a string" | ||
assert isinstance(category, types.ClassType), "category must be a class" | ||
assert issubclass(category, Warning), "category must be a Warning subclass" | ||
assert type(module) is types.StringType, "module must be a string" | ||
assert type(lineno) is types.IntType and lineno >= 0, \ | ||
"lineno must be an int >= 0" | ||
filters.insert(0, (action, re.compile(message, re.I), category, | ||
re.compile(module), lineno)) | ||
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def resetwarnings(): | ||
"""Reset the list of warnings filters to its default state.""" | ||
filters[:] = [] | ||
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class _OptionError(Exception): | ||
"""Exception used by option processing helpers.""" | ||
pass | ||
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# Helper to process -W options passed via sys.warnoptions | ||
def _processoptions(args): | ||
for arg in args: | ||
try: | ||
_setoption(arg) | ||
except _OptionError, msg: | ||
print >>sys.stderr, "Invalid -W option ignored:", msg | ||
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# Helper for _processoptions() | ||
def _setoption(arg): | ||
parts = arg.split(':') | ||
if len(parts) > 5: | ||
raise _OptionError("unparsable -W option %s" % `arg`) | ||
while len(parts) < 5: | ||
parts.append('') | ||
action, message, category, module, lineno = [s.strip() | ||
for s in parts] | ||
action = _getaction(action) | ||
message = re.escape(message) | ||
category = _getcategory(category) | ||
module = re.escape(module) | ||
if module: | ||
module = module + '$' | ||
if lineno: | ||
try: | ||
lineno = int(lineno) | ||
if lineno < 0: | ||
raise ValueError | ||
except (ValueError, OverflowError): | ||
raise _OptionError("invalid lineno %s" % `lineno`) | ||
else: | ||
lineno = 0 | ||
filterwarnings(action, message, category, module, lineno) | ||
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# Helper for _setoption() | ||
def _getaction(action): | ||
if not action: | ||
return "default" | ||
if action == "all": return "always" # Alias | ||
for a in ['default', 'always', 'ignore', 'module', 'once', 'error']: | ||
if a.startswith(action): | ||
return a | ||
raise _OptionError("invalid action: %s" % `action`) | ||
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# Helper for _setoption() | ||
def _getcategory(category): | ||
if not category: | ||
return Warning | ||
if re.match("^[a-zA-Z0-9_]+$", category): | ||
try: | ||
cat = eval(category) | ||
except KeyError: | ||
raise _OptionError("invalid warning category: %s" % `category`) | ||
else: | ||
i = category.rfind(".") | ||
module = category[:i] | ||
klass = category[i+1:] | ||
m = __import__(module, None, None, [klass]) | ||
cat = getattr(m, klass) | ||
if (not isinstance(cat, types.ClassType) or | ||
not issubclass(cat, Warning)): | ||
raise _OptionError("invalid warning category: %s" % `category`) | ||
return cat | ||
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# Self-test | ||
def _test(): | ||
import getopt | ||
testoptions = [] | ||
try: | ||
opts, args = getopt.getopt(sys.argv[1:], "W:") | ||
except getopt.error, msg: | ||
print >>sys.stderr, msg | ||
return | ||
for o, a in opts: | ||
testoptions.append(a) | ||
try: | ||
_processoptions(testoptions) | ||
except _OptionError, msg: | ||
print >>sys.stderr, msg | ||
return | ||
for item in filters: print item | ||
hello = "hello world" | ||
warn(hello); warn(hello); warn(hello); warn(hello) | ||
warn(hello, UserWarning) | ||
warn(hello, DeprecationWarning) | ||
for i in range(3): | ||
warn(hello) | ||
filterwarnings("error", "", Warning, "", 0) | ||
try: | ||
warn(hello) | ||
except Exception, msg: | ||
print "Caught", msg.__class__.__name__ + ":", msg | ||
else: | ||
print "No exception" | ||
resetwarnings() | ||
try: | ||
filterwarnings("booh", "", Warning, "", 0) | ||
except Exception, msg: | ||
print "Caught", msg.__class__.__name__ + ":", msg | ||
else: | ||
print "No exception" | ||
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# Module initialization | ||
if __name__ == "__main__": | ||
import __main__ | ||
sys.modules['warnings'] = __main__ | ||
_test() | ||
else: | ||
_processoptions(sys.warnoptions) |