use BincodeVecWriter in async_db

for reusing current item buf

lib/src/async_db.rs

@@ -24,12 +24,14 @@ type LSize = u32;
 const LEN_SIZE: usize = std::mem::size_of::<LSize>();
 const BINCODE_CFG: bincode::config::Configuration = bincode::config::standard();
 
+use crate::util::BincodeVecWriter;
 use crate::util::ErrorToString;
 
 pub struct WriterOpts {
     pub compress_lvl: Level,
     pub data_buf_size: usize,
     pub out_buf_size: usize,
+    pub current_buf_size: usize,
 }
 
 impl Default for WriterOpts {
@@ -38,6 +40,7 @@ impl Default for WriterOpts {
             compress_lvl: Level::Default,
             data_buf_size: 500 * 1024 * 1024,
             out_buf_size: 200 * 1024 * 1024,
+            current_buf_size: 100 * 1024,
         }
     }
 }
@@ -48,6 +51,7 @@ where
 {
     out: io::BufWriter<fs::File>,
     data_buf: Vec<u8>,
+    cur_buf_item: BincodeVecWriter,
     table: Vec<LSize>,
     compress_lvl: Level,
     _t: PhantomData<Arc<T>>,
@@ -61,6 +65,8 @@ where
         let out = fs::File::create(path).await.str_err()?;
         let out = io::BufWriter::with_capacity(opts.out_buf_size, out);
         let data_buf: Vec<u8> = Vec::with_capacity(opts.data_buf_size);
+        let cur_buf_item: Vec<u8> = Vec::with_capacity(opts.current_buf_size);
+        let cur_buf_item = BincodeVecWriter::new(cur_buf_item);
 
         let compress_lvl = opts.compress_lvl;
 
@@ -69,6 +75,7 @@ where
         Ok(Self {
             out,
             data_buf,
+            cur_buf_item,
             table,
             compress_lvl,
             _t: PhantomData,
@@ -78,12 +85,13 @@ where
     pub async fn push(&mut self, item: T) -> Result<(), String> {
         let pos: LSize = self.data_buf.len() as LSize;
 
-        let item_data = bincode::encode_to_vec(item, BINCODE_CFG).str_err()?;
+        bincode::encode_into_writer(item, &mut self.cur_buf_item, BINCODE_CFG).str_err()?;
 
-        let mut zencoder = ZstdEncoder::with_quality(&item_data[..], self.compress_lvl);
+        let mut zencoder = ZstdEncoder::with_quality(&self.cur_buf_item[..], self.compress_lvl);
         io::copy(&mut zencoder, &mut self.data_buf)
             .await
             .str_err()?;
+        self.cur_buf_item.clear();
 
         self.table.push(pos);
 
@@ -387,9 +395,9 @@ mod test {
         let dir = tempdir().expect("tempdir");
         let tmpfile = dir.path().join("test.tmp");
         let opts = WriterOpts {
-            compress_lvl: Level::Default,
             data_buf_size: 10 * 1024 * 1024,
             out_buf_size: 10 * 1024 * 1024,
+            ..Default::default()
         };
         let mut writer: Writer<TestData> = Writer::new(&tmpfile, opts).await.expect("new writer");
 
@@ -407,9 +415,9 @@ mod test {
         let dir = tempdir().expect("tempdir");
         let tmpfile = dir.path().join("test.tmp");
         let opts = WriterOpts {
-            compress_lvl: Level::Default,
             data_buf_size: 10 * 1024 * 1024,
             out_buf_size: 10 * 1024 * 1024,
+            ..Default::default()
         };
         let mut writer: Writer<TestData> = Writer::new(&tmpfile, opts).await.expect("new writer");
 
@@ -435,9 +443,9 @@ mod test {
         let dir = tempdir().expect("tempdir");
         let tmpfile = dir.path().join("test.tmp");
         let opts = WriterOpts {
-            compress_lvl: Level::Default,
             data_buf_size: 10 * 1024 * 1024,
             out_buf_size: 10 * 1024 * 1024,
+            ..Default::default()
         };
         let mut writer: Writer<TestData> = Writer::new(&tmpfile, opts).await.expect("new writer");
 
@@ -472,9 +480,9 @@ mod test {
         let dir = tempdir().expect("tempdir");
         let tmpfile = dir.path().join("test.tmp");
         let opts = WriterOpts {
-            compress_lvl: Level::Default,
             data_buf_size: 10 * 1024 * 1024,
             out_buf_size: 10 * 1024 * 1024,
+            ..Default::default()
         };
         let mut writer: Writer<TestData> = Writer::new(&tmpfile, opts).await.expect("new writer");