Bastian Köcher authored Jan 19, 2020 and Shawn Tabrizi committed Jan 19, 2020

By using `cfg(doc)`, we can generate docs for modules which are only
available from `no_std`. This drastically improves the documentation for
the developers.

* Add rules and unfounding to society.

* Docs and event

* Extra bit of docs.

* Cunningly reduce complexity

* Remove candidates when unfounding.

* Remove suspended candidates when unfounding, too.

Adds a table to the rustdoc that shows how each individual type is
passed between the wasm and the host side.

* Ensure all votes are removed after tally

* Fix comment

* client/finality-grandpa: Reintegrate gossip validator report stream

The `finality-grandpa` `GossipValidator` is called by the `GossipEngine`
in a synchronous fashion on each gossip message. Its main task is to
decide whether to gossip the given message on, or whether to drop it.

In addition it also updates the reputation of a node's peers based on
the incoming gossip messages. To do so it needs to be able to report the
reputation change which it does through an unbounded channel (in order
to stay synchronous).

Previously the receiving side of this channel would be handled by a new
task, polling the channel and forwarding the changes to a clone of the
`GossipEngine` that it would own.

Instead the receiver of the above mentioned channel is now being polled
by the `NetworkBridge` within its `Future::poll` implementation.
Reputation changes are reported through the already existing
`GossipEngine` instance within `NetworkBridge`.

For details on the overall goal, see d4fbb897.

* client/finality-grandpa: Remove exit future from test NetworkBridges

* Drive by fix of doc of `Value`.

* Apply suggestions from code review

Co-Authored-By: André Silva <[email protected]>

Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: André Silva <[email protected]>

* Expose proof generation and verifying api.

* tabs to spaces

* bring back license comment

* Revert "tabs to spaces"

This reverts commit 4c3f72f9.

* Formatting and docs nits

* Bump deps versions

* Upadte Cargo.lock

* into -> in

* Add `max_members` to `found`, add society genesis for Substrate node

* Update test

* Use `Option<bool>` rather than `Option<()>`

* Update from feedback

The `NeighborPacketWorker` within `client/finality-grandpa` does two
things:

1. It receives neighbor packets from components within
`client/finality-grandpa`, sends them down to the `GossipEngine` in
order for neighboring nodes to receive.

2. It periodically sends out the most recent neighbor packet to the
`GossipEngine`.

In order to send out packets it had a clone to a `GossipEgine` within
an atomic reference counter and a mutex. The `NeighborPacketWorker` was
then spawned onto its own asynchronous task.

Instead of running in its own task, this patch reintegrates the
`NeighborPacketWorker` into the main `client/finality-grandpa` task not
requiring the `NeighborPacketWorker` to own a clone of the
`GossipEngine`.

The greater picture

This is a tiny change within a greater refactoring. The overall goal is
to **simplify** how finality-grandpa interacts with the network and to
**reduce** the amount of **unbounded channels** within the logic.

Why no unbounded channels: Bounding channels is needed for backpressure
and proper scheduling. With unbounded channels there is no way of
telling the producer side to slow down for the consumer side to catch
up.  Rephrased, there is no way for the scheduler to know when to favour
the consumer task over the producer task on a crowded channel and the
other way round for an empty channel.

Reducing the amount of shared ownership simplifies the logic and enables
one to use async-await syntax-suggar, given that one does not need to
hold a lock across poll invocations. Using async-await enables one to
use bounded channels without complex logic.

* Add typedefs for storage types

* Fix after merge

* DigestItem::ChangesTrieSignal

* introduce changes_trie::State

* introduce config activation block

* ChangesTrieSignal::as_new_configuration

* moved well_known_cache_keys to client

* extracted DbChangesTrieStorage to separate file

* change meaning of none in blockchain cache

* changes trie config (FULL) cache draft

* eliminating const ChangesTrieConfiguration

* delay pruning

* continue elimination

* do not prune CT config from cache

* removed redundant code

* fix some TODOs

* introduce ConfigurationRange

* use Configuration range in build

* build skewed digest

* remove debug print

* extracted surface iterator

* key_changes works with skewed digests

* fix client build

* add test for NeverPrune

* fix TODO

* fixed some TODOs

* more tests

* fixing TODOs

* fixed compilation

* update runtime version

* git rid of large tuple

* too long lines

* config_activation_block -> zero

* obsolete TODO

* removed unjustified expect

* update TODOs with issue number

* new CT pruning algorithm

fixed cache + multiple blocks finalization

track CT configuraiton on light clients

support CT configuration change revert

revert CT config test

new CT pruning algorithm

fixed cache + multiple blocks finalization

track CT configuraiton on light clients

support CT configuration change revert

revert CT config test

* BlockIdOrHeader isn't really required

* removed debug leftovers + some docs

* more docs

* more post-merge fixes

* more post-merge fixes

* revertes some unnecessary changes

* reverted unnecessary changes

* fix compilation + unnecessary changes

* (restart CI)

* fix cache update when finalizing multiple blocks

* fixed tests

* collect_extrinsics -> set_collect_extrinsics

* restore lost test

* do not calculate block number twice

* Update primitives/blockchain/src/error.rs

Co-Authored-By: cheme <[email protected]>

* map_err -> unwrap_or

* document get_at Result

* delete abandoned file

* added weight for set_changes_trie_config

* prefer_configs -> fail_if_disabled

* Update client/api/src/backend.rs

Co-Authored-By: cheme <[email protected]>

* Update client/db/src/changes_tries_storage.rs

Co-Authored-By: cheme <[email protected]>

* CommitOperation+merge -> CommitOperations

* fixed test compilation

* merged two different CTRange structs

* lost file

* uggrade db from v0 to v1 (init CT cache + add column)

* fix after merge

Co-authored-by: cheme <[email protected]>
Co-authored-by: Gavin Wood <[email protected]>