feat: bump rayon version, parallel feature flag (#4)

* feat: bump rayon version

* feat: parallel feature flag

* chore: bump pmtree minor version number

Cargo.toml

@@ -1,15 +1,19 @@
 [package]
 name = "vacp2p_pmtree"
-version = "2.0.2"
+version = "2.0.3"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Persistent Merkle Tree in Rust"
 
 [dev-dependencies]
-hex-literal = "=0.3.4"
+hex-literal = "0.3.4"
 tiny-keccak = { version = "=2.0.2", features = ["keccak"] }
 sled = "=0.34.7"
-ark-serialize = "=0.3.0"
+ark-serialize = { version = "0.5.0", default-features = false }
 
 [dependencies]
-rayon = { version = "=1.7.0", optional =  false }
+rayon = { version = "1.10.0", optional = true }
+
+[features]
+default = []
+parallel = ["rayon", "ark-serialize/parallel"]

src/tree.rs

@@ -4,6 +4,9 @@ use std::cmp::{max, min};
 use std::collections::HashMap;
 use std::sync::{Arc, RwLock};
 
+#[cfg(feature = "parallel")]
+use rayon;
+
 // db[DEPTH_KEY] = depth
 const DEPTH_KEY: DBKey = (u64::MAX - 1).to_be_bytes();
 
@@ -240,11 +243,7 @@ where
 
         let subtree = Arc::new(RwLock::new(subtree));
 
-        let root_val = rayon::ThreadPoolBuilder::new()
-            .num_threads(rayon::current_num_threads())
-            .build()
-            .unwrap()
-            .install(|| Self::batch_recalculate(root_key, Arc::clone(&subtree), self.depth));
+        let root_val = Self::batch_recalculate(root_key, Arc::clone(&subtree), self.depth);
 
         let subtree = RwLock::into_inner(Arc::try_unwrap(subtree).unwrap()).unwrap();
 
@@ -320,11 +319,18 @@ where
             return *subtree.read().unwrap().get(&key).unwrap();
         }
 
+        #[cfg(feature = "parallel")]
         let (left, right) = rayon::join(
             || Self::batch_recalculate(left_child, Arc::clone(&subtree), depth),
             || Self::batch_recalculate(right_child, Arc::clone(&subtree), depth),
         );
 
+        #[cfg(not(feature = "parallel"))]
+        let (left, right) = (
+            Self::batch_recalculate(left_child, Arc::clone(&subtree), depth),
+            Self::batch_recalculate(right_child, Arc::clone(&subtree), depth),
+        );
+
         let result = H::hash(&[left, right]);
 
         subtree.write().unwrap().insert(key, result);

tests/memory_keccak.rs

@@ -1,10 +1,10 @@
 use hex_literal::hex;
-use vacp2p_pmtree::*;
 use std::collections::HashMap;
 use tiny_keccak::{Hasher as _, Keccak};
+use vacp2p_pmtree::*;
 
 struct MemoryDB(HashMap<DBKey, Value>);
-struct MyKeccak(Keccak);
+struct MyKeccak;
 
 #[derive(Default)]
 struct MemoryDBConfig;
@@ -33,7 +33,7 @@ impl Database for MemoryDB {
     }
 
     fn put_batch(&mut self, subtree: HashMap<DBKey, Value>) -> PmtreeResult<()> {
-        self.0.extend(subtree.into_iter());
+        self.0.extend(subtree);
 
         Ok(())
     }

tests/sled_keccak.rs

@@ -1,10 +1,10 @@
 use hex_literal::hex;
-use vacp2p_pmtree::*;
 use std::collections::HashMap;
 use std::fs;
 use tiny_keccak::{Hasher as _, Keccak};
+use vacp2p_pmtree::*;
 
-struct MyKeccak(Keccak);
+struct MyKeccak;
 struct MySled(sled::Db);
 
 #[derive(Default)]