Part of #9744
Removes all redundant `# -*- coding: utf-8 -*-` lines from files, as python 3 automatically reads source code as utf-8 now.
`Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>`
The idea is that in future tokens will encode a mapping of instance to position. However, we don't want to include the full instance name in the string representation, so instead we'll have a mapping between instance name and an immutable integer ID in the DB that we can use instead. We'll then do the lookup when we serialize/deserialize the token (we could alternatively pass around an `Instance` type that includes both the name and ID, but that turns out to be a lot more invasive).
This removes `SourcePaginationConfig` and `get_pagination_rows`. The reasoning behind this is that these generic classes/functions erased the types of the IDs it used (i.e. instead of passing around `StreamToken` it'd pass in e.g. `token.room_key`, which don't have uniform types).
It's just a thin wrapper around two ID gens to make `get_current_token`
and `get_next` return tuples. This can easily be replaced by calling the
appropriate methods on the underlying ID gens directly.
Python will return a tuple whether there are parentheses around the returned values or not.
I'm just sick of my editor complaining about this all over the place :)
If no `from` param is specified we calculate and use the "current
token" that inlcuded typing, presence, etc. These are unused during
pagination and are not available on workers, so we simply don't
calculate them.
parse_integer and parse_string can take a request and raise errors
in case we have wrong or missing params.
This PR tries to use them more to deduplicate some code and make it
better readable
If a client didn't specify a from token when paginating backwards
synapse would attempt to query the (global) maximum topological token.
This a) doesn't make much sense since they're room specific and b) there
are no indices that lets postgres do this efficiently.
Jonathan de Jong