[ROUTING] Improve 'routing.Table' interface.

[evanlinjin]

Description:

Currently, we are very dependent on (routing.Table).RangeRules() to search the contents of routing.Table. We should have specific search functions for each search (add methods to routing.Table interface).

Motivation:

This allows for a clearer overview of how we interact with the routing table.

Tasks:

• [ ] Document a list of the aforementioned cases.
• [ ] Make a proposal of how we are to change the routing.Table interface.
• [ ] Make relevant changes.
• [ ] Test.

[ivcosla]

Which ability do you think we are lacking now when looking for a rule?. Do you have any specific case in which it will be convenient to have additional search functions?

[Darkren]

@ivcosla I think it's not like lacking it's more of improvement and comfort to use if I get it correctly.

@evanlinjin I looked through all of the RangeRules calls. The most valuable use cases I see there are:

• Search for a specific type of rule
• Search for a rule not yet expired

Based on this, I would propose to add the following funcs to the interface:

• NotExpired() map[RouteID]Rule
• RuleOfType(t RuleType) map[RouteID]Rule Also these could be done in the same manner as RangeRules now (e.g. receive iterating func as an argument)

For further discussion I may also suggest:

• Expired() map[RouteID]Rule

All other funcs that need more complex search should still use the RangeRules

[evanlinjin]

I like this. But I would rename RuleOfType to RulesOfType. Also, let's have both NotExpired() and Expired().