perf: avoid serde_json::from_reader

ethers-etherscan/src/lib.rs

@@ -399,21 +399,14 @@ impl Cache {
 
     fn get<T: DeserializeOwned>(&self, prefix: &str, address: Address) -> Option<T> {
         let path = self.root.join(prefix).join(format!("{address:?}.json"));
-        let reader = std::io::BufReader::new(std::fs::File::open(path).ok()?);
-        if let Ok(inner) = serde_json::from_reader::<_, CacheEnvelope<T>>(reader) {
-            // If this does not return None then we have passed the expiry
-            if SystemTime::now()
-                .duration_since(UNIX_EPOCH)
-                .expect("system time is before unix epoch")
-                .checked_sub(Duration::from_secs(inner.expiry))
-                .is_some()
-            {
-                return None
-            }
-
-            return Some(inner.data)
-        }
-        None
+        let Ok(contents) = std::fs::read_to_string(path) else { return None };
+        let Ok(inner) = serde_json::from_str::<CacheEnvelope<T>>(&contents) else { return None };
+        // If this does not return None then we have passed the expiry
+        SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .expect("system time is before unix epoch")
+            .checked_sub(Duration::from_secs(inner.expiry))
+            .map(|_| inner.data)
     }
 }
 

ethers-solc/src/artifact_output/mod.rs

@@ -21,7 +21,6 @@ use std::{
     ffi::OsString,
     fmt, fs,
     hash::Hash,
-    io,
     ops::Deref,
     path::{Path, PathBuf},
 };
@@ -763,10 +762,7 @@ pub trait ArtifactOutput {
     ///     - The file does not exist
     ///     - The file's content couldn't be deserialized into the `Artifact` type
     fn read_cached_artifact(path: impl AsRef<Path>) -> Result<Self::Artifact> {
-        let path = path.as_ref();
-        let file = fs::File::open(path).map_err(|err| SolcError::io(err, path))?;
-        let file = io::BufReader::new(file);
-        Ok(serde_json::from_reader(file)?)
+        crate::utils::read_json_file(path)
     }
 
     /// Read the cached artifacts that are located the paths the iterator yields

ethers-solc/src/utils.rs

@@ -448,10 +448,8 @@ pub(crate) fn tempdir(name: &str) -> Result<tempfile::TempDir, SolcIoError> {
 /// Reads the json file and deserialize it into the provided type
 pub fn read_json_file<T: DeserializeOwned>(path: impl AsRef<Path>) -> Result<T, SolcError> {
     let path = path.as_ref();
-    let file = std::fs::File::open(path).map_err(|err| SolcError::io(err, path))?;
-    let file = std::io::BufReader::new(file);
-    let val: T = serde_json::from_reader(file)?;
-    Ok(val)
+    let contents = std::fs::read_to_string(path).map_err(|err| SolcError::io(err, path))?;
+    serde_json::from_str(&contents).map_err(Into::into)
 }
 
 /// Creates the parent directory of the `file` and all its ancestors if it does not exist