Merge pull request #139 from cowlicks/type-erase

Remove generic parameters from `Hypercore` and `Storage`

Author: ttiurani

benches/disk.rs

@@ -4,7 +4,6 @@ use std::time::{Duration, Instant};
 use criterion::async_executor::AsyncStdExecutor;
 use criterion::{black_box, criterion_group, criterion_main, Criterion};
 use hypercore::{Hypercore, HypercoreBuilder, HypercoreError, Storage};
-use random_access_disk::RandomAccessDisk;
 use tempfile::Builder as TempfileBuilder;
 
 fn bench_create_disk(c: &mut Criterion) {
@@ -24,7 +23,7 @@ fn bench_create_disk(c: &mut Criterion) {
 }
 
 #[cfg(feature = "cache")]
-async fn create_hypercore(name: &str) -> Result<Hypercore<RandomAccessDisk>, HypercoreError> {
+async fn create_hypercore(name: &str) -> Result<Hypercore, HypercoreError> {
     let dir = TempfileBuilder::new()
         .prefix(name)
         .tempdir()
@@ -38,7 +37,7 @@ async fn create_hypercore(name: &str) -> Result<Hypercore<RandomAccessDisk>, Hyp
 }
 
 #[cfg(not(feature = "cache"))]
-async fn create_hypercore(name: &str) -> Result<Hypercore<RandomAccessDisk>, HypercoreError> {
+async fn create_hypercore(name: &str) -> Result<Hypercore, HypercoreError> {
     let dir = TempfileBuilder::new()
         .prefix(name)
         .tempdir()

benches/memory.rs

@@ -19,11 +19,15 @@ fn bench_create_memory(c: &mut Criterion) {
 }
 
 #[cfg(feature = "cache")]
-async fn create_hypercore(
-    page_size: usize,
-) -> Result<Hypercore<RandomAccessMemory>, HypercoreError> {
+async fn create_hypercore(page_size: usize) -> Result<Hypercore, HypercoreError> {
+    use hypercore::StorageTraits;
+
     let storage = Storage::open(
-        |_| Box::pin(async move { Ok(RandomAccessMemory::new(page_size)) }),
+        |_| {
+            Box::pin(async move {
+                Ok(Box::new(RandomAccessMemory::new(page_size)) as Box<dyn StorageTraits>)
+            })
+        },
         false,
     )
     .await?;
@@ -34,11 +38,15 @@ async fn create_hypercore(
 }
 
 #[cfg(not(feature = "cache"))]
-async fn create_hypercore(
-    page_size: usize,
-) -> Result<Hypercore<RandomAccessMemory>, HypercoreError> {
+async fn create_hypercore(page_size: usize) -> Result<Hypercore, HypercoreError> {
+    use hypercore::StorageTraits;
+
     let storage = Storage::open(
-        |_| Box::pin(async move { Ok(RandomAccessMemory::new(page_size)) }),
+        |_| {
+            Box::pin(async move {
+                Ok(Box::new(RandomAccessMemory::new(page_size)) as Box<dyn StorageTraits>)
+            })
+        },
         false,
     )
     .await?;

examples/replication.rs

@@ -4,8 +4,6 @@ use hypercore::{
     Hypercore, HypercoreBuilder, HypercoreError, PartialKeypair, RequestBlock, RequestUpgrade,
     Storage,
 };
-use random_access_disk::RandomAccessDisk;
-use random_access_memory::RandomAccessMemory;
 use tempfile::Builder;
 #[cfg(feature = "tokio")]
 use tokio::main as async_main;
@@ -73,8 +71,8 @@ async fn main() {
 }
 
 async fn replicate_index(
-    origin_hypercore: &mut Hypercore<RandomAccessDisk>,
-    replicated_hypercore: &mut Hypercore<RandomAccessMemory>,
+    origin_hypercore: &mut Hypercore,
+    replicated_hypercore: &mut Hypercore,
     request_index: u64,
 ) {
     let missing_nodes = origin_hypercore

src/builder.rs

@@ -1,4 +1,3 @@
-use random_access_storage::RandomAccess;
 use std::fmt::Debug;
 #[cfg(feature = "cache")]
 use std::time::Duration;
@@ -53,20 +52,14 @@ impl CacheOptionsBuilder {
 
 /// Build a Hypercore instance with options.
 #[derive(Debug)]
-pub struct HypercoreBuilder<T>
-where
-    T: RandomAccess + Debug + Send,
-{
-    storage: Storage<T>,
+pub struct HypercoreBuilder {
+    storage: Storage,
     options: HypercoreOptions,
 }
 
-impl<T> HypercoreBuilder<T>
-where
-    T: RandomAccess + Debug + Send,
-{
+impl HypercoreBuilder {
     /// Create a hypercore builder with a given storage
-    pub fn new(storage: Storage<T>) -> Self {
+    pub fn new(storage: Storage) -> Self {
         Self {
             storage,
             options: HypercoreOptions::new(),
@@ -94,7 +87,7 @@ where
 
     /// Build a new Hypercore.
     #[instrument(err, skip_all)]
-    pub async fn build(self) -> Result<Hypercore<T>, HypercoreError> {
+    pub async fn build(self) -> Result<Hypercore, HypercoreError> {
         Hypercore::new(self.storage, self.options).await
     }
 }

src/core.rs

@@ -1,7 +1,6 @@
 //! Hypercore's main abstraction. Exposes an append-only, secure log structure.
 use ed25519_dalek::Signature;
 use futures::future::Either;
-use random_access_storage::RandomAccess;
 use std::convert::TryFrom;
 use std::fmt::Debug;
 use tracing::instrument;
@@ -40,12 +39,9 @@ impl HypercoreOptions {
 
 /// Hypercore is an append-only log structure.
 #[derive(Debug)]
-pub struct Hypercore<T>
-where
-    T: RandomAccess + Debug,
-{
+pub struct Hypercore {
     pub(crate) key_pair: PartialKeypair,
-    pub(crate) storage: Storage<T>,
+    pub(crate) storage: Storage,
     pub(crate) oplog: Oplog,
     pub(crate) tree: MerkleTree,
     pub(crate) block_store: BlockStore,
@@ -79,15 +75,12 @@ pub struct Info {
     pub writeable: bool,
 }
 
-impl<T> Hypercore<T>
-where
-    T: RandomAccess + Debug + Send,
-{
+impl Hypercore {
     /// Creates/opens new hypercore using given storage and options
     pub(crate) async fn new(
-        mut storage: Storage<T>,
+        mut storage: Storage,
         mut options: HypercoreOptions,
-    ) -> Result<Hypercore<T>, HypercoreError> {
+    ) -> Result<Hypercore, HypercoreError> {
         let key_pair: Option<PartialKeypair> = if options.open {
             if options.key_pair.is_some() {
                 return Err(HypercoreError::BadArgument {
@@ -734,7 +727,6 @@ fn update_contiguous_length(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use random_access_memory::RandomAccessMemory;
 
     #[async_std::test]
     async fn core_create_proof_block_only() -> Result<(), HypercoreError> {
@@ -1099,9 +1091,7 @@ mod tests {
         Ok(())
     }
 
-    async fn create_hypercore_with_data(
-        length: u64,
-    ) -> Result<Hypercore<RandomAccessMemory>, HypercoreError> {
+    async fn create_hypercore_with_data(length: u64) -> Result<Hypercore, HypercoreError> {
         let signing_key = generate_signing_key();
         create_hypercore_with_data_and_key_pair(
             length,
@@ -1116,7 +1106,7 @@ mod tests {
     async fn create_hypercore_with_data_and_key_pair(
         length: u64,
         key_pair: PartialKeypair,
-    ) -> Result<Hypercore<RandomAccessMemory>, HypercoreError> {
+    ) -> Result<Hypercore, HypercoreError> {
         let storage = Storage::new_memory().await?;
         let mut hypercore = Hypercore::new(
             storage,

src/lib.rs

@@ -94,7 +94,7 @@ pub use crate::common::{
 };
 pub use crate::core::{AppendOutcome, Hypercore, Info};
 pub use crate::crypto::{generate_signing_key, sign, verify, PartialKeypair};
-pub use crate::storage::Storage;
+pub use crate::storage::{Storage, StorageTraits};
 pub use ed25519_dalek::{
     SecretKey, Signature, SigningKey, VerifyingKey, KEYPAIR_LENGTH, PUBLIC_KEY_LENGTH,
     SECRET_KEY_LENGTH,

src/storage/mod.rs

@@ -15,16 +15,17 @@ use crate::{
     HypercoreError,
 };
 
+/// Supertrait for Storage
+pub trait StorageTraits: RandomAccess + Debug {}
+impl<T: RandomAccess + Debug> StorageTraits for T {}
+
 /// Save data to a desired storage backend.
 #[derive(Debug)]
-pub struct Storage<T>
-where
-    T: RandomAccess + Debug,
-{
-    tree: T,
-    data: T,
-    bitfield: T,
-    oplog: T,
+pub struct Storage {
+    tree: Box<dyn StorageTraits + Send>,
+    data: Box<dyn StorageTraits + Send>,
+    bitfield: Box<dyn StorageTraits + Send>,
+    oplog: Box<dyn StorageTraits + Send>,
 }
 
 pub(crate) fn map_random_access_err(err: RandomAccessError) -> HypercoreError {
@@ -51,17 +52,18 @@ pub(crate) fn map_random_access_err(err: RandomAccessError) -> HypercoreError {
     }
 }
 
-impl<T> Storage<T>
-where
-    T: RandomAccess + Debug + Send,
-{
+impl Storage {
     /// Create a new instance. Takes a callback to create new storage instances and overwrite flag.
     pub async fn open<Cb>(create: Cb, overwrite: bool) -> Result<Self, HypercoreError>
     where
         Cb: Fn(
             Store,
         ) -> std::pin::Pin<
-            Box<dyn std::future::Future<Output = Result<T, RandomAccessError>> + Send>,
+            Box<
+                dyn std::future::Future<
+                        Output = Result<Box<dyn StorageTraits + Send>, RandomAccessError>,
+                    > + Send,
+            >,
         >,
     {
         let mut tree = create(Store::Tree).await.map_err(map_random_access_err)?;
@@ -235,39 +237,45 @@ where
         Ok(())
     }
 
-    fn get_random_access(&mut self, store: &Store) -> &mut T {
+    fn get_random_access(&mut self, store: &Store) -> &mut Box<dyn StorageTraits + Send> {
         match store {
             Store::Tree => &mut self.tree,
             Store::Data => &mut self.data,
             Store::Bitfield => &mut self.bitfield,
             Store::Oplog => &mut self.oplog,
         }
     }
-}
 
-impl Storage<RandomAccessMemory> {
     /// New storage backed by a `RandomAccessMemory` instance.
     #[instrument(err)]
     pub async fn new_memory() -> Result<Self, HypercoreError> {
-        let create = |_| async { Ok(RandomAccessMemory::default()) }.boxed();
+        let create = |_| {
+            async { Ok(Box::new(RandomAccessMemory::default()) as Box<dyn StorageTraits + Send>) }
+                .boxed()
+        };
         // No reason to overwrite, as this is a new memory segment
         Self::open(create, false).await
     }
-}
 
-#[cfg(not(target_arch = "wasm32"))]
-impl Storage<RandomAccessDisk> {
     /// New storage backed by a `RandomAccessDisk` instance.
+    #[cfg(not(target_arch = "wasm32"))]
     #[instrument(err)]
     pub async fn new_disk(dir: &PathBuf, overwrite: bool) -> Result<Self, HypercoreError> {
         let storage = |store: Store| {
-            let name = match store {
-                Store::Tree => "tree",
-                Store::Data => "data",
-                Store::Bitfield => "bitfield",
-                Store::Oplog => "oplog",
-            };
-            RandomAccessDisk::open(dir.as_path().join(name)).boxed()
+            let dir = dir.clone();
+            async move {
+                let name = match store {
+                    Store::Tree => "tree",
+                    Store::Data => "data",
+                    Store::Bitfield => "bitfield",
+                    Store::Oplog => "oplog",
+                };
+                Ok(
+                    Box::new(RandomAccessDisk::open(dir.as_path().join(name)).await?)
+                        as Box<dyn StorageTraits + Send>,
+                )
+            }
+            .boxed()
         };
         Self::open(storage, overwrite).await
     }

tests/common/mod.rs

@@ -1,6 +1,5 @@
 use anyhow::Result;
 use ed25519_dalek::{SigningKey, VerifyingKey, PUBLIC_KEY_LENGTH, SECRET_KEY_LENGTH};
-use random_access_disk::RandomAccessDisk;
 use sha2::{Digest, Sha256};
 use std::io::prelude::*;
 use std::path::Path;
@@ -35,7 +34,7 @@ pub fn get_test_key_pair() -> PartialKeypair {
     PartialKeypair { public, secret }
 }
 
-pub async fn create_hypercore(work_dir: &str) -> Result<Hypercore<RandomAccessDisk>> {
+pub async fn create_hypercore(work_dir: &str) -> Result<Hypercore> {
     let path = Path::new(work_dir).to_owned();
     let key_pair = get_test_key_pair();
     let storage = Storage::new_disk(&path, true).await?;
@@ -45,7 +44,7 @@ pub async fn create_hypercore(work_dir: &str) -> Result<Hypercore<RandomAccessDi
         .await?)
 }
 
-pub async fn open_hypercore(work_dir: &str) -> Result<Hypercore<RandomAccessDisk>> {
+pub async fn open_hypercore(work_dir: &str) -> Result<Hypercore> {
     let path = Path::new(work_dir).to_owned();
     let storage = Storage::new_disk(&path, false).await?;
     Ok(HypercoreBuilder::new(storage).open(true).build().await?)