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433892021e
Contributed by Blake Winton, but considerably edited.
227 lines
6.3 KiB
Python
227 lines
6.3 KiB
Python
"""Class based built-in exception hierarchy.
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New with Python 1.5, all standard built-in exceptions are now class objects by
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default. This gives Python's exception handling mechanism a more
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object-oriented feel. Traditionally they were string objects. Python will
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fallback to string based exceptions if the interpreter is invoked with the -X
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option, or if some failure occurs during class exception initialization (in
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this case a warning will be printed).
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Most existing code should continue to work with class based exceptions. Some
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tricky uses of IOError may break, but the most common uses should work.
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Here is a rundown of the class hierarchy. You can change this by editing this
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file, but it isn't recommended. The class names described here are expected
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to be found by the bltinmodule.c file. If you add classes here, you must
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modify bltinmodule.c or the exceptions won't be available in the __builtin__
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module, nor will they be accessible from C.
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The classes with a `*' are new since Python 1.5. They are defined as tuples
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containing the derived exceptions when string-based exceptions are used. If
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you define your own class based exceptions, they should be derived from
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Exception.
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Exception(*)
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+-- StandardError(*)
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+-- SystemExit
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+-- KeyboardInterrupt
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+-- ImportError
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+-- EnvironmentError(*)
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| |
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| +-- IOError
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| +-- OSError(*)
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+-- EOFError
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+-- RuntimeError
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| +-- NotImplementedError(*)
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+-- NameError
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+-- AttributeError
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+-- SyntaxError
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+-- TypeError
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+-- AssertionError
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+-- LookupError(*)
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| +-- IndexError
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| +-- KeyError
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+-- ArithmeticError(*)
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| +-- OverflowError
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| +-- ZeroDivisionError
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| +-- FloatingPointError
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+-- ValueError
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+-- SystemError
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+-- MemoryError
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"""
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class Exception:
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"""Proposed base class for all exceptions."""
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def __init__(self, *args):
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self.args = args
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def __str__(self):
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if not self.args:
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return ''
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elif len(self.args) == 1:
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return str(self.args[0])
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else:
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return str(self.args)
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def __getitem__(self, i):
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return self.args[i]
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class StandardError(Exception):
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"""Base class for all standard Python exceptions."""
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pass
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class SyntaxError(StandardError):
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"""Invalid syntax."""
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filename = lineno = offset = text = None
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msg = ""
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def __init__(self, *args):
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self.args = args
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if len(self.args) >= 1:
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self.msg = self.args[0]
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if len(self.args) == 2:
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info = self.args[1]
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try:
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self.filename, self.lineno, self.offset, self.text = info
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except:
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pass
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def __str__(self):
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return str(self.msg)
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class EnvironmentError(StandardError):
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"""Base class for I/O related errors."""
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def __init__(self, *args):
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self.args = args
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self.errno = None
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self.strerror = None
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self.filename = None
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if len(args) == 3:
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# open() errors give third argument which is the filename. BUT,
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# so common in-place unpacking doesn't break, e.g.:
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#
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# except IOError, (errno, strerror):
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#
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# we hack args so that it only contains two items. This also
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# means we need our own __str__() which prints out the filename
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# when it was supplied.
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self.errno, self.strerror, self.filename = args
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self.args = args[0:2]
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if len(args) == 2:
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# common case: PyErr_SetFromErrno()
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self.errno, self.strerror = args
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def __str__(self):
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if self.filename is not None:
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return '[Errno %s] %s: %s' % (self.errno, self.strerror,
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repr(self.filename))
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elif self.errno and self.strerror:
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return '[Errno %s] %s' % (self.errno, self.strerror)
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else:
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return StandardError.__str__(self)
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class IOError(EnvironmentError):
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"""I/O operation failed."""
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pass
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class OSError(EnvironmentError):
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"""OS system call failed."""
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pass
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class RuntimeError(StandardError):
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"""Unspecified run-time error."""
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pass
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class NotImplementedError(RuntimeError):
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"""Method or function hasn't been implemented yet."""
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pass
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class SystemError(StandardError):
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"""Internal error in the Python interpreter.
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Please report this to the Python maintainer, along with the traceback,
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the Python version, and the hardware/OS platform and version."""
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pass
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class EOFError(StandardError):
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"""Read beyond end of file."""
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pass
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class ImportError(StandardError):
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"""Import can't find module, or can't find name in module."""
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pass
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class TypeError(StandardError):
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"""Inappropriate argument type."""
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pass
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class ValueError(StandardError):
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"""Inappropriate argument value (of correct type)."""
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pass
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class KeyboardInterrupt(StandardError):
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"""Program interrupted by user."""
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pass
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class AssertionError(StandardError):
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"""Assertion failed."""
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pass
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class ArithmeticError(StandardError):
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"""Base class for arithmetic errors."""
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pass
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class OverflowError(ArithmeticError):
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"""Result too large to be represented."""
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pass
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class FloatingPointError(ArithmeticError):
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"""Floating point operation failed."""
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pass
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class ZeroDivisionError(ArithmeticError):
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"""Second argument to a division or modulo operation was zero."""
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pass
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class LookupError(StandardError):
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"""Base class for lookup errors."""
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pass
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class IndexError(LookupError):
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"""Sequence index out of range."""
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pass
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class KeyError(LookupError):
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"""Mapping key not found."""
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pass
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class AttributeError(StandardError):
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"""Attribute not found."""
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pass
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class NameError(StandardError):
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"""Name not found locally or globally."""
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pass
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class MemoryError(StandardError):
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"""Out of memory."""
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pass
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class SystemExit(Exception):
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"""Request to exit from the interpreter."""
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def __init__(self, *args):
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self.args = args
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if len(args) == 0:
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self.code = None
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elif len(args) == 1:
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self.code = args[0]
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else:
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self.code = args
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