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Diffstat (limited to 'bindings/python/notmuch/errors.py')
| -rw-r--r-- | bindings/python/notmuch/errors.py | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/bindings/python/notmuch/errors.py b/bindings/python/notmuch/errors.py new file mode 100644 index 0000000..f153a9c --- /dev/null +++ b/bindings/python/notmuch/errors.py @@ -0,0 +1,183 @@ +""" +This file is part of notmuch. + +Notmuch is free software: you can redistribute it and/or modify it +under the terms of the GNU General Public License as published by the +Free Software Foundation, either version 3 of the License, or (at your +option) any later version. + +Notmuch is distributed in the hope that it will be useful, but WITHOUT +ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +You should have received a copy of the GNU General Public License +along with notmuch. If not, see <http://www.gnu.org/licenses/>. + +Copyright 2010 Sebastian Spaeth <Sebastian@SSpaeth.de> +""" + +from ctypes import c_char_p, c_int + +from .globals import ( + nmlib, + Enum, + Python3StringMixIn, +) + +class Status(Enum): + """Enum with a string representation of a notmuch_status_t value.""" + _status2str = nmlib.notmuch_status_to_string + _status2str.restype = c_char_p + _status2str.argtypes = [c_int] + + def __init__(self, statuslist): + """It is initialized with a list of strings that are available as + Status().string1 - Status().stringn attributes. + """ + super(Status, self).__init__(statuslist) + + @classmethod + def status2str(self, status): + """Get a (unicode) string representation of a notmuch_status_t value.""" + # define strings for custom error messages + if status == STATUS.NOT_INITIALIZED: + return "Operation on uninitialized object impossible." + return unicode(Status._status2str(status)) + +STATUS = Status(['SUCCESS', + 'OUT_OF_MEMORY', + 'READ_ONLY_DATABASE', + 'XAPIAN_EXCEPTION', + 'FILE_ERROR', + 'FILE_NOT_EMAIL', + 'DUPLICATE_MESSAGE_ID', + 'NULL_POINTER', + 'TAG_TOO_LONG', + 'UNBALANCED_FREEZE_THAW', + 'UNBALANCED_ATOMIC', + 'NOT_INITIALIZED']) +"""STATUS is a class, whose attributes provide constants that serve as return +indicators for notmuch functions. Currently the following ones are defined. For +possible return values and specific meaning for each method, see the method +description. + + * SUCCESS + * OUT_OF_MEMORY + * READ_ONLY_DATABASE + * XAPIAN_EXCEPTION + * FILE_ERROR + * FILE_NOT_EMAIL + * DUPLICATE_MESSAGE_ID + * NULL_POINTER + * TAG_TOO_LONG + * UNBALANCED_FREEZE_THAW + * UNBALANCED_ATOMIC + * NOT_INITIALIZED + +Invoke the class method `notmuch.STATUS.status2str` with a status value as +argument to receive a human readable string""" +STATUS.__name__ = 'STATUS' + + +class NotmuchError(Exception, Python3StringMixIn): + """Is initiated with a (notmuch.STATUS[, message=None]). It will not + return an instance of the class NotmuchError, but a derived instance + of a more specific Error Message, e.g. OutOfMemoryError. Each status + but SUCCESS has a corresponding subclassed Exception.""" + + @classmethod + def get_exc_subclass(cls, status): + """Returns a fine grained Exception() type, + detailing the error status""" + subclasses = { + STATUS.OUT_OF_MEMORY: OutOfMemoryError, + STATUS.READ_ONLY_DATABASE: ReadOnlyDatabaseError, + STATUS.XAPIAN_EXCEPTION: XapianError, + STATUS.FILE_ERROR: FileError, + STATUS.FILE_NOT_EMAIL: FileNotEmailError, + STATUS.DUPLICATE_MESSAGE_ID: DuplicateMessageIdError, + STATUS.NULL_POINTER: NullPointerError, + STATUS.TAG_TOO_LONG: TagTooLongError, + STATUS.UNBALANCED_FREEZE_THAW: UnbalancedFreezeThawError, + STATUS.UNBALANCED_ATOMIC: UnbalancedAtomicError, + STATUS.NOT_INITIALIZED: NotInitializedError, + } + assert 0 < status <= len(subclasses) + return subclasses[status] + + def __new__(cls, *args, **kwargs): + """Return a correct subclass of NotmuchError if needed + + We return a NotmuchError instance if status is None (or 0) and a + subclass that inherits from NotmuchError depending on the + 'status' parameter otherwise.""" + # get 'status'. Passed in as arg or kwarg? + status = args[0] if len(args) else kwargs.get('status', None) + # no 'status' or cls is subclass already, return 'cls' instance + if not status or cls != NotmuchError: + return super(NotmuchError, cls).__new__(cls) + subclass = cls.get_exc_subclass(status) # which class to use? + return subclass.__new__(subclass, *args, **kwargs) + + def __init__(self, status=None, message=None): + self.status = status + self.message = message + + def __unicode__(self): + if self.message is not None: + return self.message + elif self.status is not None: + return STATUS.status2str(self.status) + else: + return 'Unknown error' + + +# List of Subclassed exceptions that correspond to STATUS values and are +# subclasses of NotmuchError. +class OutOfMemoryError(NotmuchError): + status = STATUS.OUT_OF_MEMORY + + +class ReadOnlyDatabaseError(NotmuchError): + status = STATUS.READ_ONLY_DATABASE + + +class XapianError(NotmuchError): + status = STATUS.XAPIAN_EXCEPTION + + +class FileError(NotmuchError): + status = STATUS.FILE_ERROR + + +class FileNotEmailError(NotmuchError): + status = STATUS.FILE_NOT_EMAIL + + +class DuplicateMessageIdError(NotmuchError): + status = STATUS.DUPLICATE_MESSAGE_ID + + +class NullPointerError(NotmuchError): + status = STATUS.NULL_POINTER + + +class TagTooLongError(NotmuchError): + status = STATUS.TAG_TOO_LONG + + +class UnbalancedFreezeThawError(NotmuchError): + status = STATUS.UNBALANCED_FREEZE_THAW + + +class UnbalancedAtomicError(NotmuchError): + status = STATUS.UNBALANCED_ATOMIC + + +class NotInitializedError(NotmuchError): + """Derived from NotmuchError, this occurs if the underlying data + structure (e.g. database is not initialized (yet) or an iterator has + been exhausted. You can test for NotmuchError with .status = + STATUS.NOT_INITIALIZED""" + status = STATUS.NOT_INITIALIZED |