Introduce first groundwork for Wasm executor (#27)

* Introduce first groundwork for Wasm executor.

* Remove old Rust-runtime code.

* Avoid commiting compled files.

* Add runtime precompile.

* Rename so module makes more sense.

* Further renaming.

* Ensure tests work.

* Allow bringing in of externalities.

- Add util functions/macros.
- Add uncompacted runtime.
- Add some external crates from pwasm-std for managing allocs/memory
stuff.

* Nice macros for imports.

* Allow passing in of data through allocators.

Make memcpy and malloc work.
Basic allocator.

* Can now pass in bytes to WasmExecutor.

* Additional cleanup.

* Switch usages of `OutData` to `u64`

No need to be able to return bytes anymore.

* convert to safe but extremely verbose type conversion.

@rphmeier any more concise way of doing this?

* Remove StaticExternalities distinction.

* Remove another unused use.

* Refactor wasm utils out

* Remove extraneous copies that weren't really testing anything.

* Try to use wasm 0.15

* Make it work!

* Call-time externalities working.

* Add basic externalities.

* Fix grumbles and note unwraps to be sorted.

* Test storage externality.

Unforunately had to change signatures of externalities to avoid
immutable function returning a reference. Not sure what to do about
this...

* Fix nits.

* Compile collation logic.

* Move back to refs. Yey.

* Remove "object" id for storage access.

* Fix test.

* Fix up rest of tests.

* remove unwrap.

* Expose set/get code in externalities

Also improve tests and add nice wrappers in rust-wasm.

* Add validator set.

* Introduce validator set into externalities and test.

* Add another external function.

* Remove code and validators; use storage for everything.

* Introduce validators function.

* Tests (and a fix) for the validators getter.

* Allow calls into runtime to return data.

* Remove unneeded trace.

* Make runtime printing a bit nicer.

* Create separate runtimes for testing and polkadot.

* Remove commented code.

* Use new path.

* Refactor into shared support module.

* Fix warning.

* Remove unwraps.

* Make macro a little less unhygenic.

* Add wasm files.

substrate/executor/src/lib.rs

@@ -0,0 +1,52 @@
+// Copyright 2017 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Temporary crate for contracts implementations.
+//!
+//! This will be replaced with WASM contracts stored on-chain.
+//! ** NOTE ***
+//! This is entirely deprecated with the idea of a single-module Wasm module for state transition.
+//! The dispatch table should be replaced with the specific functions needed:
+//! - execute_block(bytes)
+//! - init_block(PrevBlock?) -> InProgressBlock
+//! - add_transaction(InProgressBlock) -> InProgressBlock
+//! I leave it as is for now as it might be removed before this is ever done.
+
+#![warn(missing_docs)]
+
+extern crate polkadot_primitives as primitives;
+extern crate polkadot_serializer as serializer;
+extern crate polkadot_state_machine as state_machine;
+extern crate serde;
+extern crate parity_wasm;
+extern crate byteorder;
+
+#[macro_use]
+extern crate error_chain;
+
+#[cfg(test)]
+extern crate assert_matches;
+
+#[macro_use]
+mod wasm_utils;
+mod wasm_executor;
+
+pub mod error;
+
+/// Creates new RustExecutor for contracts.
+pub fn executor() -> wasm_executor::WasmExecutor {
+	wasm_executor::WasmExecutor::default()
+}