Make structures Send (#28)

* Upgrade code to rust 2018 edtion to use async await

* Create test case to ensure struct is send

* Replace all references from Rc to Arc

Cargo.toml

@@ -7,6 +7,7 @@ documentation = "https://docs.rs/merkle-tree-stream"
 authors = ["Yoshua Wuyts <[email protected]>"]
 license = "MIT OR Apache-2.0"
 readme = "README.md"
+edition = "2018"
 
 [dependencies]
 flat-tree = "4.0.1"
@@ -15,3 +16,4 @@ flat-tree = "4.0.1"
 hex = "0.4.0"
 quickcheck = "0.9.0"
 crypto-hash = "0.3.1"
+async-std = "1.5.0"

README.md

@@ -25,14 +25,14 @@ extern crate rust_sodium;
 use merkle_tree_stream::{HashMethods, DefaultNode, MerkleTreeStream, Node,
                         PartialNode};
 use rust_sodium::crypto::hash::sha256;
-use std::rc::Rc;
+use std::sync::Arc;
 
 struct H;
 impl HashMethods for H {
   type Node = DefaultNode;
   type Hash = Vec<u8>;
 
-  fn leaf(&self, leaf: &PartialNode, _roots: &[Rc<Self::Node>]) -> Self::Hash {
+  fn leaf(&self, leaf: &PartialNode, _roots: &[Arc<Self::Node>]) -> Self::Hash {
     let data = leaf.as_ref().unwrap();
     sha256::hash(&data).0.to_vec()
   }

examples/async.rs

@@ -0,0 +1,49 @@
+use async_std::task;
+use merkle_tree_stream::{
+  DefaultNode, HashMethods, MerkleTreeStream, Node, NodeKind, PartialNode,
+};
+use std::sync::Arc;
+use std::vec::Vec;
+
+struct XorHashMethods;
+impl HashMethods for XorHashMethods {
+  type Node = DefaultNode;
+  type Hash = Vec<u8>;
+
+  fn leaf(&self, leaf: &PartialNode, _roots: &[Arc<Self::Node>]) -> Self::Hash {
+    // bitwise XOR the data into u8
+    let hash = match leaf.data() {
+      NodeKind::Parent => 0,
+      NodeKind::Leaf(data) => data.iter().fold(0, |acc, x| acc ^ x),
+    };
+    vec![hash]
+  }
+
+  fn parent(&self, a: &Self::Node, b: &Self::Node) -> Self::Hash {
+    let hash = Node::hash(a)
+      .iter()
+      .chain(Node::hash(b).iter())
+      .fold(0, |acc, x| acc ^ x);
+    vec![hash]
+  }
+}
+
+async fn append<H: HashMethods>(
+  mts: &mut MerkleTreeStream<H>,
+  content: &[u8],
+  nodes: &mut Vec<Arc<H::Node>>,
+) {
+  mts.next(content, nodes);
+}
+
+fn main() {
+  task::block_on(task::spawn(async {
+    let mut mts = MerkleTreeStream::new(XorHashMethods, Vec::new());
+    let mut nodes = Vec::new();
+    append(&mut mts, b"hello", &mut nodes).await;
+    append(&mut mts, b"hashed", &mut nodes).await;
+    mts.next(b"world", &mut nodes);
+
+    println!("{:?}", nodes);
+  }));
+}

examples/main.rs

@@ -3,15 +3,15 @@ extern crate merkle_tree_stream;
 use merkle_tree_stream::{
   DefaultNode, HashMethods, MerkleTreeStream, Node, NodeKind, PartialNode,
 };
-use std::rc::Rc;
+use std::sync::Arc;
 use std::vec::Vec;
 
 struct XorHashMethods;
 impl HashMethods for XorHashMethods {
   type Node = DefaultNode;
   type Hash = Vec<u8>;
 
-  fn leaf(&self, leaf: &PartialNode, _roots: &[Rc<Self::Node>]) -> Self::Hash {
+  fn leaf(&self, leaf: &PartialNode, _roots: &[Arc<Self::Node>]) -> Self::Hash {
     // bitwise XOR the data into u8
     let hash = match leaf.data() {
       NodeKind::Parent => 0,

src/lib.rs

@@ -4,15 +4,15 @@
 //! ## Example
 //! ```rust
 //! use merkle_tree_stream::{DefaultNode, HashMethods, MerkleTreeStream, Node, PartialNode, NodeKind};
-//! use std::rc::Rc;
+//! use std::sync::Arc;
 //! use std::vec::Vec;
 //!
 //! struct XorHashMethods;
 //! impl HashMethods for XorHashMethods {
 //!   type Node = DefaultNode;
 //!   type Hash = Vec<u8>;
 //!
-//!   fn leaf(&self, leaf: &PartialNode, _roots: &[Rc<Self::Node>]) -> Self::Hash {
+//!   fn leaf(&self, leaf: &PartialNode, _roots: &[Arc<Self::Node>]) -> Self::Hash {
 //!     // bitwise XOR the data into u8
 //!     let hash = match leaf.data() {
 //!       NodeKind::Parent => 0,
@@ -39,10 +39,10 @@ extern crate flat_tree as flat;
 mod default_node;
 mod partial_node;
 
-pub use default_node::DefaultNode;
-pub use partial_node::{NodeKind, PartialNode};
+pub use crate::default_node::DefaultNode;
+pub use crate::partial_node::{NodeKind, PartialNode};
 
-use std::rc::Rc;
+use std::sync::Arc;
 
 /// The parts that make up a full Node from a PartialNode
 #[derive(Debug)]
@@ -80,7 +80,7 @@ pub trait HashMethods {
   /// The type of hash returned from the hashing functions.
   type Hash;
   /// Pass data through a hash function.
-  fn leaf(&self, leaf: &PartialNode, roots: &[Rc<Self::Node>]) -> Self::Hash;
+  fn leaf(&self, leaf: &PartialNode, roots: &[Arc<Self::Node>]) -> Self::Hash;
   /// Pass hashes through a hash function.
   fn parent(&self, a: &Self::Node, b: &Self::Node) -> Self::Hash;
 }
@@ -105,15 +105,15 @@ pub trait Node {
 /// ## Example
 /// ```rust
 /// use merkle_tree_stream::{DefaultNode, HashMethods, MerkleTreeStream, Node, PartialNode, NodeKind};
-/// use std::rc::Rc;
+/// use std::sync::Arc;
 /// use std::vec::Vec;
 ///
 /// struct XorHashMethods;
 /// impl HashMethods for XorHashMethods {
 ///   type Node = DefaultNode;
 ///   type Hash = Vec<u8>;
 ///
-///   fn leaf(&self, leaf: &PartialNode, _roots: &[Rc<Self::Node>]) -> Self::Hash {
+///   fn leaf(&self, leaf: &PartialNode, _roots: &[Arc<Self::Node>]) -> Self::Hash {
 ///     // bitwise XOR the data into u8
 ///     let hash = match leaf.data() {
 ///       NodeKind::Parent => 0,
@@ -177,13 +177,13 @@ pub trait Node {
 #[derive(Debug)]
 pub struct MerkleTreeStream<T: HashMethods> {
   handler: T,
-  roots: Vec<Rc<T::Node>>,
+  roots: Vec<Arc<T::Node>>,
   blocks: usize,
 }
 
 impl<H: HashMethods> MerkleTreeStream<H> {
   /// Create a new MerkleTreeStream instance.
-  pub fn new(handler: H, roots: Vec<Rc<H::Node>>) -> MerkleTreeStream<H> {
+  pub fn new(handler: H, roots: Vec<Arc<H::Node>>) -> MerkleTreeStream<H> {
     MerkleTreeStream {
       handler,
       roots,
@@ -193,7 +193,7 @@ impl<H: HashMethods> MerkleTreeStream<H> {
 
   /// Pass a string buffer through the flat-tree hash functions, and write the
   /// result back out to "nodes".
-  pub fn next<'a>(&mut self, data: &[u8], nodes: &'a mut Vec<Rc<H::Node>>) {
+  pub fn next<'a>(&mut self, data: &[u8], nodes: &'a mut Vec<Arc<H::Node>>) {
     let index: usize = 2 * self.blocks;
     self.blocks += 1;
 
@@ -206,10 +206,10 @@ impl<H: HashMethods> MerkleTreeStream<H> {
 
     let hash = self.handler.leaf(&leaf, &self.roots);
     let parts = NodeParts { node: leaf, hash };
-    let node = Rc::new(H::Node::from(parts));
+    let node = Arc::new(H::Node::from(parts));
 
-    self.roots.push(Rc::clone(&node));
-    nodes.push(Rc::clone(&node));
+    self.roots.push(Arc::clone(&node));
+    nodes.push(Arc::clone(&node));
 
     while self.roots.len() > 1 {
       let leaf = {
@@ -238,14 +238,14 @@ impl<H: HashMethods> MerkleTreeStream<H> {
         self.roots.pop();
       }
 
-      let leaf = Rc::new(leaf);
-      self.roots.push(Rc::clone(&leaf));
-      nodes.push(Rc::clone(&leaf));
+      let leaf = Arc::new(leaf);
+      self.roots.push(Arc::clone(&leaf));
+      nodes.push(Arc::clone(&leaf));
     }
   }
 
   /// Get the roots vector.
-  pub fn roots(&self) -> &Vec<Rc<H::Node>> {
+  pub fn roots(&self) -> &Vec<Arc<H::Node>> {
     &self.roots
   }
 }

tests/lib.rs

@@ -11,14 +11,14 @@ use merkle_tree_stream::{
 use quickcheck::quickcheck;
 use std::collections::HashSet;
 use std::iter;
-use std::rc::Rc;
+use std::sync::Arc;
 
 struct H;
 impl HashMethods for H {
   type Node = DefaultNode;
   type Hash = Vec<u8>;
 
-  fn leaf(&self, leaf: &PartialNode, _roots: &[Rc<Self::Node>]) -> Self::Hash {
+  fn leaf(&self, leaf: &PartialNode, _roots: &[Arc<Self::Node>]) -> Self::Hash {
     match leaf.data() {
       NodeKind::Leaf(data) => {
         hex_digest(Algorithm::SHA256, &data).as_bytes().to_vec()
@@ -39,7 +39,7 @@ impl HashMethods for H {
 fn mts_one_node() {
   let roots = Vec::new();
   let mut mts = MerkleTreeStream::new(H, roots);
-  let mut nodes: Vec<Rc<DefaultNode>> = Vec::new();
+  let mut nodes: Vec<Arc<DefaultNode>> = Vec::new();
   mts.next(b"hello", &mut nodes);
   assert_eq!(1, nodes.len());
 
@@ -57,7 +57,7 @@ fn mts_one_node() {
 fn mts_more_nodes() {
   let roots = Vec::new();
   let mut mts = MerkleTreeStream::new(H, roots);
-  let mut nodes: Vec<Rc<DefaultNode>> = Vec::new();
+  let mut nodes: Vec<Arc<DefaultNode>> = Vec::new();
   mts.next(b"a", &mut nodes);
   mts.next(b"b", &mut nodes);
 
@@ -115,7 +115,7 @@ fn mts_more_nodes() {
   }
 }
 
-fn build_mts(data: &[Vec<u8>]) -> (MerkleTreeStream<H>, Vec<Rc<DefaultNode>>) {
+fn build_mts(data: &[Vec<u8>]) -> (MerkleTreeStream<H>, Vec<Arc<DefaultNode>>) {
   let roots = vec![];
   let mut mts = MerkleTreeStream::new(H, roots);
   let mut nodes = vec![];
@@ -124,7 +124,7 @@ fn build_mts(data: &[Vec<u8>]) -> (MerkleTreeStream<H>, Vec<Rc<DefaultNode>>) {
   (mts, nodes)
 }
 
-fn all_children(index: usize) -> Box<Iterator<Item = usize>> {
+fn all_children(index: usize) -> Box<dyn Iterator<Item = usize>> {
   let self_ = iter::once(index);
   match flat_tree::children(index) {
     None => Box::new(self_),
@@ -218,7 +218,7 @@ fn all_leaves_contain_data() {
 #[test]
 fn hashes_change_when_data_is_changed() {
   /// Finds the parent indices (in-tree IDs) of the nth data block
-  fn parent_indices(nodes: &[Rc<DefaultNode>], n: usize) -> HashSet<usize> {
+  fn parent_indices(nodes: &[Arc<DefaultNode>], n: usize) -> HashSet<usize> {
     let modified_node_index = nodes
       .iter()
       .filter(|node| node.data.is_some())
@@ -240,9 +240,9 @@ fn hashes_change_when_data_is_changed() {
   }
 
   fn partition(
-    nodes: Vec<Rc<DefaultNode>>,
+    nodes: Vec<Arc<DefaultNode>>,
     indices: &HashSet<usize>,
-  ) -> (Vec<Rc<DefaultNode>>, Vec<Rc<DefaultNode>>) {
+  ) -> (Vec<Arc<DefaultNode>>, Vec<Arc<DefaultNode>>) {
     nodes
       .into_iter()
       .partition(|node| indices.contains(&node.index()))