WIP state resolution

This commit is contained in:
Pim Kunis 2021-07-03 12:30:57 +02:00
parent c7672a1bd9
commit d30e49f5a9

292
lib/matrix_server/event.ex Normal file
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# https://matrix.uhoreg.ca/stateres/reloaded.html
defmodule MatrixServer.Event do
@derive {Inspect, except: [:prev_events, :auth_events]}
defstruct [
:event_id,
:event_type,
:timestamp,
:state_key,
:sender,
:content,
:prev_events,
:auth_events,
:power_levels
]
alias __MODULE__, as: Event
@type t :: %Event{event_id: String.t(), event_type: Atom.t(), timestamp: Integer.t()}
def new_state_event, do: %Event{new() | event_type: :state}
def new_message_event, do: %Event{new() | event_type: :message}
def new do
%Event{
event_id: "",
timestamp: 0,
state_key: "",
sender: "",
content: "",
prev_events: [],
auth_events: [],
power_levels: %{}
}
end
def join(user), do: %Event{membership(user) | content: "join"}
def leave(user), do: %Event{membership(user) | content: "leave"}
def invite(actor, subject), do: %Event{membership(actor, subject) | content: "invite"}
def kick(actor, subject), do: %Event{membership(actor, subject) | content: "leave"}
def ban(actor, subject), do: %Event{membership(actor, subject) | content: "ban"}
def set_power_levels(user, power_levels) do
%Event{new() | event_type: :power_levels, sender: user, power_levels: power_levels}
end
def set_topic(user, topic) do
%Event{new() | event_type: :topic, sender: user, content: topic}
end
def get_state_set_from_event_list(events) do
Enum.reduce(events, %{}, fn
%Event{event_type: event_type, state_key: state_key} = event, acc ->
Map.put(acc, {event_type, state_key}, event)
end)
end
def auth_chain(event), do: auth_chain(event, MapSet.new())
def auth_chain(%Event{auth_events: auth_events}, set) do
Enum.reduce(auth_events, set, fn event, acc ->
event
|> auth_chain()
|> MapSet.union(acc)
|> MapSet.put(event)
end)
end
def in_room(user, state_set) when is_map_key(state_set, {:membership, user}) do
state_set[{:membership, user}].content == "join"
end
def in_room(_, _), do: false
def get_power_levels(state_set) when is_map_key(state_set, {:power_levels, ""}) do
state_set[{:power_levels, ""}].power_levels
end
def get_power_levels(_), do: nil
def has_power_level(_, nil, _), do: true
def has_power_level(user, power_levels, level) do
Map.get(power_levels, user, 0) >= level
end
# TODO: join and power levels events
def is_authorized(%Event{event_type: :create, prev_events: prev_events}, _),
do: prev_events == []
def is_authorized(%Event{sender: sender} = event, state_set) do
in_room(sender, state_set) and
has_power_level(sender, get_power_levels(state_set), get_event_power_level(event))
end
def is_authorized2(%Event{auth_events: auth_events} = event, state_set) do
state_set =
Enum.reduce(auth_events, state_set, fn %Event{event_type: event_type, state_key: state_key} =
event,
acc ->
Map.put_new(acc, {event_type, state_key}, event)
end)
is_authorized(event, state_set)
end
def iterative_auth_checks(events, state_set) do
Enum.reduce(events, state_set, fn event, acc ->
if is_authorized2(event, acc), do: insert_event(event, acc), else: acc
end)
end
def insert_event(%Event{event_type: event_type, state_key: state_key} = event, state_set) do
Map.put(state_set, {event_type, state_key}, event)
end
def is_control_event(%Event{event_type: :power_levels, state_key: state_key})
when state_key != "",
do: true
def is_control_event(%Event{event_type: :join_rules, state_key: state_key})
when state_key != "",
do: true
def is_control_event(%Event{
event_type: :membership,
state_key: state_key,
sender: sender,
content: "ban"
}),
do: sender != state_key
def is_control_event(%Event{
event_type: :membership,
state_key: state_key,
sender: sender,
content: "leave"
}),
do: sender != state_key
def is_control_event(_), do: false
def calculate_conflict(state_sets) do
domain =
state_sets
|> Enum.map(&Map.keys/1)
|> List.flatten()
|> MapSet.new()
full_state_map_list =
Enum.map(domain, fn k ->
events =
Enum.map(state_sets, &Map.get(&1, k))
|> MapSet.new()
{k, events}
end)
{unconflicted, conflicted} =
Enum.split_with(full_state_map_list, fn {_k, events} ->
MapSet.size(events) == 1
end)
unconflicted_state_map =
Enum.map(unconflicted, fn {k, events} ->
event =
events
|> MapSet.to_list()
|> hd()
{k, event}
end)
|> Enum.into(%{})
conflicted_state_map =
Enum.flat_map(conflicted, fn {_, events} ->
events
|> MapSet.delete(nil)
|> MapSet.to_list()
end)
|> MapSet.new()
{unconflicted_state_map, conflicted_state_map}
end
def full_auth_chain(events) do
events
|> Enum.map(&auth_chain/1)
|> Enum.reduce(MapSet.new(), &MapSet.union/2)
end
def auth_difference(state_sets) do
full_auth_chains = Enum.map(state_sets, fn state_set ->
state_set
|> Map.values()
|> full_auth_chain()
end)
auth_chain_union = Enum.reduce(full_auth_chains, MapSet.new(), &MapSet.union/2)
auth_chain_intersection = Enum.reduce(full_auth_chains, MapSet.new(), &MapSet.intersection/2)
MapSet.difference(auth_chain_union, auth_chain_intersection)
end
def example1 do
create = %Event{new() | event_id: "create", event_type: :create, sender: "@alice:example.com"}
alice_joins = %Event{
join("@alice:example.com")
| event_id: "alice joins",
prev_events: [create],
auth_events: [create]
}
pl = %Event{
set_power_levels("@alice:example.com", %{"@alice:example.com" => 100})
| event_id: "power level",
prev_events: [alice_joins],
auth_events: [alice_joins, create]
}
join_rules = %Event{
new()
| event_id: "join rules",
event_type: :join_rules,
sender: "@alice:example.com",
content: "private",
prev_events: [pl],
auth_events: [pl, alice_joins, create]
}
invite_bob = %Event{
invite("@alice:example.com", "@bob:example.com")
| event_id: "invite bob",
prev_events: [join_rules],
auth_events: [pl, alice_joins, create]
}
invite_carol = %Event{
invite("@alice:example.com", "@carol:example.com")
| event_id: "invite carol",
prev_events: [invite_bob],
auth_events: [pl, alice_joins, create]
}
bob_join = %Event{
join("@bob:example.com")
| event_id: "bob joins",
prev_events: [invite_carol],
auth_events: [invite_bob, join_rules, create]
}
[create, alice_joins, pl, join_rules, invite_bob, invite_carol, bob_join]
end
def example2 do
create = %Event{
new_state_event()
| event_id: "create",
event_type: :create,
sender: "@alice:example.com"
}
pl1 = %Event{
set_power_levels("@alice:example.com", %{"@alice:example.com" => 100})
| event_id: "power levels 1"
}
pl2 = %Event{
set_power_levels("@alice:example.com", %{
"@alice:example.com" => 100,
"@bob:example.com" => 50
})
| event_id: "power levels 2"
}
topic = %Event{set_topic("@bob:example.com", "This is a topic") | event_id: "topic"}
state_set1 = get_state_set_from_event_list([create, pl1])
state_set2 = get_state_set_from_event_list([create, pl2, topic])
state_set3 = get_state_set_from_event_list([create, pl2])
[state_set1, state_set2, state_set3]
end
defp membership(user), do: membership(user, user)
defp membership(actor, subject) do
%Event{new() | event_type: :membership, sender: actor, state_key: subject}
end
defp get_event_power_level(%Event{state_key: ""}), do: 0
defp get_event_power_level(_), do: 50
end