Publish ssz_types (and deps) to crates.io (#468)

* Rename `hashing` crate to `eth2_hashing`

* Add license, desc to eth2_hashing Cargo.toml

* Remove merkle root from eth2 hashing

* Remove old benches folder (zombied from old branch)

* Add docs to eth2_hashing

* Prepare tree_hash for publishing on crates.io

* Update deps to use crates.io instead of paths

* Update all crates to pull ssz from crates.io

* Remove cached_tree_hash, add patches to manifest

* Fix compile error in benches

* Remove unused code

* Fix fake_crypto compile error

eth2/utils/eth2_hashing/.cargo/config

@@ -0,0 +1,2 @@
+[target.wasm32-unknown-unknown]
+runner = 'wasm-bindgen-test-runner'

eth2/utils/eth2_hashing/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "eth2_hashing"
+version = "0.1.0"
+authors = ["Paul Hauner <paul@paulhauner.com>"]
+edition = "2018"
+license = "Apache-2.0"
+description = "Hashing primitives used in Ethereum 2.0"
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+ring = "0.14.6"
+
+[dev-dependencies]
+rustc-hex = "2.0.1"
+
+[target.'cfg(target_arch = "wasm32")'.dev-dependencies]
+wasm-bindgen-test = "0.2.47"

eth2/utils/eth2_hashing/fuzz/.gitignore

@@ -0,0 +1,4 @@
+
+target
+corpus
+artifacts

eth2/utils/eth2_hashing/fuzz/Cargo.toml

@@ -0,0 +1,22 @@
+
+[package]
+name = "hashing-fuzz"
+version = "0.0.1"
+authors = ["Automatically generated"]
+publish = false
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies.hashing]
+path = ".."
+[dependencies.libfuzzer-sys]
+git = "https://github.com/rust-fuzz/libfuzzer-sys.git"
+
+# Prevent this from interfering with workspaces
+[workspace]
+members = ["."]
+
+[[bin]]
+name = "fuzz_target_hash"
+path = "fuzz_targets/fuzz_target_hash.rs"

eth2/utils/eth2_hashing/fuzz/fuzz_targets/fuzz_target_hash.rs

@@ -0,0 +1,9 @@
+#![no_main]
+#[macro_use] extern crate libfuzzer_sys;
+extern crate hashing;
+
+use hashing::hash;
+
+fuzz_target!(|data: &[u8]| {
+    let _result = hash(data);
+});

eth2/utils/eth2_hashing/src/lib.rs

@@ -0,0 +1,44 @@
+//! Provides a simple hash function utilizing `ring::digest::SHA256`.
+//!
+//! The purpose of this crate is to provide an abstraction to whatever hash function Ethereum
+//! 2.0 is using. The hash function has been subject to change during the specification process, so
+//! defining it once in this crate makes it easy to replace.
+
+#[cfg(not(target_arch = "wasm32"))]
+use ring::digest::{digest, SHA256};
+
+#[cfg(target_arch = "wasm32")]
+use sha2::{Digest, Sha256};
+
+/// Returns the digest of `input`.
+///
+/// Uses `ring::digest::SHA256`.
+pub fn hash(input: &[u8]) -> Vec<u8> {
+    #[cfg(not(target_arch = "wasm32"))]
+    let h = digest(&SHA256, input).as_ref().into();
+
+    #[cfg(target_arch = "wasm32")]
+    let h = Sha256::digest(input).as_ref().into();
+
+    h
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use rustc_hex::FromHex;
+
+    #[cfg(target_arch = "wasm32")]
+    use wasm_bindgen_test::*;
+
+    #[cfg_attr(not(target_arch = "wasm32"), test)]
+    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+    fn test_hashing() {
+        let input: Vec<u8> = b"hello world".as_ref().into();
+
+        let output = hash(input.as_ref());
+        let expected_hex = "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9";
+        let expected: Vec<u8> = expected_hex.from_hex().unwrap();
+        assert_eq!(expected, output);
+    }
+}