Erasure encoding availability (paritytech#345)

* Erasure encoding availability initial commit

 * Modifications to availability store to keep chunks as well as
   reconstructed blocks and extrinsics.
 * Gossip messages containig signed erasure chunks.
 * Requesting eraure chunks with polkadot-specific messages.
 * Validation of erasure chunk messages.

* Apply suggestions from code review

Co-Authored-By: Luke Schoen <ltfschoen@users.noreply.github.com>

* Fix build after a merge

* Gossip erasure chunk messages under their own topic

* erasure_chunks should use the appropriate topic

* Updates Cargo.lock

* Fixes after merge

* Removes a couple of leftover pieces of code

* Fixes simple stuff from review

* Updates erasure and storage for more flexible logic

* Changes validation and candidate receipt production.

* Adds add_erasure_chunks method

* Fixes most of the nits

* Better validate_collation and validate_receipt functions

* Fixes the tests

* Apply suggestions from code review

Co-Authored-By: Robert Habermeier <rphmeier@gmail.com>

* Removes unwrap() calls

* Removes ErasureChunks primitive

* Removes redundant fields from ErasureChunk struct

* AvailabilityStore should store CandidateReceipt

* Changes the way chunk messages are imported and validated.

 * Availability store now stores a validator_index and n_validators for
 each relay_parent.
 * Availability store now also stores candidate receipts.
 * Removes importing chunks in the table and moves it into network
 gossip validation.
 * Validation of erasure messages id done against receipts that are
 stored in the availability store.

* Correctly compute topics for erasure messages

* Removes an unused parameter

* Refactors availability db querying into a helper

* Adds the apis described in the writeup

* Adds a runtime api to extract erasure roots form raw extrinsics.

* Adds a barebone BlockImport impl for avalability store

* Adds the implementation of the availability worker

* Fix build after the merge with master.

* Make availability store API async

* Bring back the default wasmtime feature

* Lines width

* Bump runtime version

* Formatting and dead code elimination

* some style nits (#1)

* More nits and api cleanup

* Disable wasm CI for availability-store

* Another nit

* Formatting

.gitlab-ci.yml

@@ -144,7 +144,6 @@ check-web-wasm:                    &test
   script:
     # WASM support is in progress. As more and more crates support WASM, we
     # should add entries here. See https://github.com/paritytech/polkadot/issues/625
-    - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path availability-store/Cargo.toml
     - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path executor/Cargo.toml
     - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path erasure-coding/Cargo.toml
     - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path parachain/Cargo.toml

availability-store/Cargo.toml

@@ -7,9 +7,24 @@ edition = "2018"
 
 [dependencies]
 polkadot-primitives = { path = "../primitives" }
+polkadot-erasure-coding = { path = "../erasure-coding" }
+polkadot-runtime = { path = "../runtime" }
 parking_lot = "0.9.0"
+derive_more = "0.99"
 log = "0.4.8"
+futures01 = "0.1.17"
+futures = { package = "futures", version = "0.3.1", features = ["compat"] }
+tokio = "0.1.7"
+exit-future = "0.1"
 codec = { package = "parity-scale-codec", version = "1.1.0", default-features = false, features = ["derive"] }
+sc-network = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
+consensus_common = { package = "sp-consensus", git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
+client = { package = "sc-client-api", git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
+sc-client = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
+sp-runtime = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-master" }
+sp-blockchain = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
+sp-api = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
+keystore = { package = "sc-keystore", git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
 kvdb = "0.1.1"
 kvdb-memorydb = "0.1.2"