Use file descriptors instead of paths

Cargo.toml

@@ -17,7 +17,7 @@ fixed = "2.0.0-alpha.11"
 futures = "0.3.28"
 futures-concurrency = "7.6.0"
 group = "0.13.0"
-itertools = "0.12"
+itertools = "0.13"
 num-traits = "0.2.16"
 overload = "0.1.1"
 rand = "0.8.5"
@@ -30,6 +30,7 @@ tokio-util = { version = "0.7.9", features = ["io", "net", "io-util", "codec", "
 tracing = "0.1.40"
 
 [dev-dependencies]
+tempfile = "3.10.1"
 tokio-test = "0.4.4"
 curve25519-dalek = { version = "4.1.1", features = ["group", "serde"] }
 sha2 = "0.10.8"

src/schemes/spdz.rs

@@ -377,7 +377,7 @@ fn power<F: std::ops::MulAssign + Clone + std::ops::Mul<Output = F>>(base: F, ex
 #[cfg(test)]
 mod test {
 
-    use std::path::Path;
+    use std::io::Seek;
     use ff::Field;
     use rand::thread_rng;
     use rand::SeedableRng;
@@ -1410,21 +1410,23 @@ mod test {
     fn test_dealer_writing_to_file() {
         // preprosessing by dealer
         type F = Element32;
-        let file_names = vec![
-            Path::new("/tmp/context2.bin"),
-            Path::new("/tmp/context1.bin"),
+        let mut files = [
+            tempfile::tempfile().unwrap(),
+            tempfile::tempfile().unwrap(),
         ];
         let known_to_each = vec![1, 2];
         let number_of_triplets = 2;
         preprocessing::write_preproc_to_file(
-            &file_names,
+            &mut files,
             known_to_each,
             number_of_triplets,
             F::from_u128(0u128),
         )
         .unwrap();
-        let p1_context: SpdzContext<F> = preprocessing::read_preproc_from_file(file_names[0]);
-        let p2_context: SpdzContext<F> = preprocessing::read_preproc_from_file(file_names[1]);
+        files[0].rewind().unwrap();
+        files[1].rewind().unwrap();
+        let p1_context: SpdzContext<F> = preprocessing::read_preproc_from_file(&mut files[0]);
+        let p2_context: SpdzContext<F> = preprocessing::read_preproc_from_file(&mut files[1]);
         // unpacking
         let p1_params = p1_context.params;
         let p2_params = p2_context.params;

src/schemes/spdz/preprocessing.rs

@@ -8,8 +8,7 @@ use std::{
     error::Error,
     fmt,
     fs::File,
-    io::{self, Read, Write},
-    path::Path,
+    io::{self, Write},
 };
 #[derive(Debug, Clone, PartialEq)]
 pub enum MissingPreProcErrorType {
@@ -89,37 +88,31 @@ pub struct SecretValues<F> {
     pub mac_key: F,
 }
 pub fn write_preproc_to_file<F: PrimeField + serde::Serialize + serde::de::DeserializeOwned>(
-    file_names: &[&Path],
+    files: &mut [File],
     known_to_each: Vec<usize>,
     number_of_triplets: usize,
     _: F,
 ) -> Result<(), Box<dyn Error>> {
-    let number_of_parties = file_names.len();
+    let number_of_parties = files.len();
     assert!(number_of_parties == known_to_each.len());
     let rng = rand_chacha::ChaCha20Rng::from_entropy();
     // Notice here that the secret values are not written to the file, No party is allowed to know the value.
     let (contexts, _): (Vec<SpdzContext<F>>, _) =
         dealer_prepross(rng, known_to_each, number_of_triplets, number_of_parties);
-    let names_and_contexts = file_names.iter().zip(contexts);
-    for (name, context) in names_and_contexts {
+    let names_and_contexts = files.iter_mut().zip(contexts);
+    for (file, context) in names_and_contexts {
         let data: Vec<u8> = bincode::serialize(&context)?;
-        let mut file = File::create(name)?;
         file.write_all(&data)?;
-        file.sync_all()?;
     }
     Ok(())
 }
 
 
 pub fn read_preproc_from_file<F: PrimeField + serde::Serialize + serde::de::DeserializeOwned>(
-    file_name: &Path,
+    file: &mut File,
 ) -> SpdzContext<F> {
     // TODO: return Result instead.
-    let mut data = Vec::new();
-    let mut file = File::open(file_name).expect("open file");
-    file.read_to_end(&mut data).expect("read to end");
-    let new_context: SpdzContext<F> = bincode::deserialize(&data).expect("deserialize");
-    new_context
+    bincode::deserialize_from(file).unwrap()
 }
 
 
@@ -259,8 +252,8 @@ impl<F: PrimeField + serde::Serialize + serde::de::DeserializeOwned> SpdzContext
         generate_empty_context(number_of_parties, mac_key_share, who_am_i)
     }
 
-    pub fn from_file(path: &Path) -> Result<Self, io::Error> {
-        Ok(read_preproc_from_file(path))
+    pub fn from_file(mut file: File) -> Result<Self, io::Error> {
+        Ok(read_preproc_from_file(&mut file))
     }
 }
 

wecare/Cargo.toml

@@ -11,3 +11,6 @@ tokio = { version = "1.33.0", features = ["full"] }
 curve25519-dalek = { version = "4.1.1", features = ["group", "serde"] }
 rand = "0.8.5"
 fixed = "2.0.0-alpha.11"
+
+[dev-dependencies]
+tempfile = "3.10.1"