treewide: update to bincode 2

Consistently use bincode's Encode/Decode to avoid issues with
incompatible serde features. Support for storing some temporary files as
JSON is removed.

The size of the "processed" directory is reduced by ~8% with the new
default encoding of bincode 2. Performance is more or less unaffected.

src/io/storage.rs

@@ -10,28 +10,16 @@ use std::{
 };
 
 use anyhow::{Context, Result};
-use serde::{de::DeserializeOwned, Serialize};
+use bincode::{Decode, Encode};
 
 use super::fs;
 
-/// Storage format
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub enum Format {
-	/// Encode as Bincode
-	///
-	/// Bincode is more efficient than JSON, but cannot handle many of
-	/// serde's features like flatten, conditional skipping, ...
-	Bincode,
-	/// Encode as JSON
-	Json,
-}
+/// Bincode configuration
+const BINCODE_CONFIG: bincode::config::Configuration = bincode::config::standard();
 
 /// Serializes data and writes it to a writer
-pub fn write<W: Write, T: Serialize>(writer: &mut W, value: &T, format: Format) -> Result<()> {
-	let data = match format {
-		Format::Bincode => bincode::serialize(value)?,
-		Format::Json => serde_json::to_vec(value)?,
-	};
+pub fn write<W: Write, T: Encode>(writer: &mut W, value: &T) -> Result<()> {
+	let data = bincode::encode_to_vec(value, BINCODE_CONFIG)?;
 	let len = u32::try_from(data.len())?;
 	let compressed = zstd::bulk::compress(&data, 1)?;
 	drop(data);
@@ -45,18 +33,21 @@ pub fn write<W: Write, T: Serialize>(writer: &mut W, value: &T, format: Format)
 /// Serializes data and stores it in a file
 ///
 /// A timestamp is stored in an assiciated metadata file.
-pub fn write_file<T: Serialize>(
+pub fn write_file<T: Encode>(
 	path: &Path,
 	value: &T,
-	format: Format,
 	version: fs::FileMetaVersion,
 	timestamp: SystemTime,
 ) -> Result<()> {
-	fs::create_with_timestamp(path, version, timestamp, |file| write(file, value, format))
+	fs::create_with_timestamp(path, version, timestamp, |file| write(file, value))
 }
 
 /// Reads data from a reader and deserializes it
-pub fn read<R: Read, T: DeserializeOwned>(reader: &mut R, format: Format) -> Result<T> {
+pub fn read<R, T>(reader: &mut R) -> Result<T>
+where
+	R: Read,
+	T: Decode<()>,
+{
 	let mut len_buf = [0u8; 4];
 	reader.read_exact(&mut len_buf)?;
 	let len = usize::try_from(u32::from_be_bytes(len_buf))?;
@@ -66,18 +57,17 @@ pub fn read<R: Read, T: DeserializeOwned>(reader: &mut R, format: Format) -> Res
 	let data = zstd::bulk::decompress(&compressed, len)?;
 	drop(compressed);
 
-	let value = match format {
-		Format::Bincode => bincode::deserialize(&data)?,
-		Format::Json => serde_json::from_slice(&data)?,
-	};
-	Ok(value)
+	Ok(bincode::decode_from_slice(&data, BINCODE_CONFIG)?.0)
 }
 
 /// Reads data from a file and deserializes it
-pub fn read_file<T: DeserializeOwned>(path: &Path, format: Format) -> Result<T> {
+pub fn read_file<T>(path: &Path) -> Result<T>
+where
+	T: Decode<()>,
+{
 	(|| -> Result<T> {
 		let mut file = File::open(path)?;
-		read(&mut file, format)
+		read(&mut file)
 	})()
 	.with_context(|| format!("Failed to read file {}", path.display()))
 }