class twisted.mail.imap4.MessageSet: (source)
A set of message identifiers usable by both IMAP4Client and IMAP4Server via IMailboxIMAP.store and IMailboxIMAP.fetch.
These identifiers can be either message sequence numbers or unique identifiers. See Section 2.3.1, "Message Numbers", RFC 3501.
This represents the sequence-set described in Section 9, "Formal Syntax" of RFC 3501:
MessageSet can describe a single identifier, e.g. MessageSet(1)MessageSet can describe * via None, e.g. MessageSet(None)MessageSet can describe a range of identifiers, e.g. MessageSet(1, 2). The range is inclusive and unordered (see seq-range in RFC 3501, Section 9), so that Message(2, 1) is equivalent to MessageSet(1, 2), and both describe messages 1 and 2. Ranges can include * by specifying None, e.g. MessageSet(None, 1). In all cases ranges are normalized so that the smallest identifier comes first, and None always comes last; Message(2, 1) becomes MessageSet(1, 2) and MessageSet(None, 1) becomes MessageSet(1, None)MessageSet can describe a sequence of single identifiers and ranges, constructed by addition. MessageSet(1) + MessageSet(5, 10) refers the message identified by 1 and the messages identified by 5 through 10.NB: The meaning of * varies, but it always represents the largest number in use.
For servers: Your IMailboxIMAP provider must set MessageSet.last to the highest-valued identifier (unique or message sequence) before iterating over it.
For clients: * consumes ranges smaller than it, e.g. MessageSet(1, 100) + MessageSet(50, None) is equivalent to 1:*.
| Instance Variable | getnext | A function that returns the next message number, used when iterating through the MessageSet. By default, a function returning the next integer is supplied, but as this can be rather inefficient for sparse UID iterations, it is recommended to supply one when messages are requested by UID. The argument is provided as a hint to the implementation and may be ignored if it makes sense to do so (eg, if an iterator is being used that maintains its own state, it is guaranteed that it will not be called out-of-order). |
| Method | __init__ | Create a new MessageSet() |
| Instance Variable | ranges | Undocumented |
| Property | last | The largest number in use. This is undefined until it has been set by assigning to this property. |
| Method | last.setter | Replaces all occurrences of "*". This should be the largest number in use. Must be set before attempting to use the MessageSet as a container. |
| Method | add | Add another range |
| Method | __add__ | Undocumented |
| Method | extend | Extend our messages with another message or set of messages. |
| Method | clean | Clean ranges list, combining adjacent ranges |
| Method | __contains__ | May raise TypeError if we encounter an open-ended range |
| Method | __iter__ | Undocumented |
| Method | __len__ | Undocumented |
| Method | __str__ | Undocumented |
| Method | __repr__ | Undocumented |
| Method | __eq__ | Undocumented |
| Class Variable | _empty | Undocumented |
| Class Variable | _infinity | Undocumented |
| Instance Variable | _last | Undocumented |
| Method | _noneInRanges | Is there a None in our ranges? |
| Method | _iterator | Undocumented |
MessageSet. By default, a function returning the next integer is supplied, but as this can be rather inefficient for sparse UID iterations, it is recommended to supply one when messages are requested by UID. The argument is provided as a hint to the implementation and may be ignored if it makes sense to do so (eg, if an iterator is being used that maintains its own state, it is guaranteed that it will not be called out-of-order).int returning int)
The largest number in use. This is undefined until it has been set by assigning to this property.
Replaces all occurrences of "*". This should be the largest number in use. Must be set before attempting to use the MessageSet as a container.
| Raises | ValueError | if a largest value has already been set. |
Extend our messages with another message or set of messages.
| Parameters | other | The messages to include. (type: MessageSet, tuple of two ints, or a single int) |
Is there a None in our ranges?
MessageSet.clean merges overlapping or consecutive ranges. None is represents a value larger than any number. There are thus two cases:
(x, *) + (y, z) such that x is smaller than y(z, *) + (x, y) such that z is larger than y(Other cases, such as y < x < z, can be split into these two cases; for example (y - 1, y) + (x, x) + (z, z + 1))
In case 1, * > y and * > z, so (x, *) + (y, z) = (x, *)
In case 2, z > x and z > y, so the intervals do not merge, and the ranges are sorted as [(x, y), (z, *)]. * is represented as (*, *), so this is the same as 2. but with a z that is greater than everything.
The result is that there is a maximum of two Nones, and one of them has to be the high element in the last tuple in self.ranges. That means checking if self.ranges[-1][-1] is None suffices to check if any element is None.
| Returns | True if None is in some range in ranges and False if otherwise. | |