From 57e90188b813617dfd9e114698b810663bd648eb Mon Sep 17 00:00:00 2001
From: "kexuan.yang" <kexuan.yang@gmail.com>
Date: Thu, 25 Jul 2024 01:14:29 +0800
Subject: [PATCH] Adjust mmap flash call to improve performance

Signed-off-by: kexuan.yang <kexuan.yang@gmail.com>
---
 src/core/iter.rs       |  4 ++--
 src/core/memory_map.rs | 20 ++++++++++++--------
 src/core/writer.rs     | 14 ++++++--------
 3 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/src/core/iter.rs b/src/core/iter.rs
index 18bd580..014a8e0 100644
--- a/src/core/iter.rs
+++ b/src/core/iter.rs
@@ -130,6 +130,7 @@ mod tests {
         let _ = fs::remove_file(file_name);
         let file = OpenOptions::new()
             .create(true)
+            .truncate(true)
             .write(true)
             .read(true)
             .open(file_name)
@@ -140,8 +141,7 @@ mod tests {
         let test_encoder = &TestEncoderDecoder;
         for i in 0..10 {
             let buffer = Buffer::from_i32(&i.to_string(), i);
-            mm.append(test_encoder.encode_to_bytes(&buffer, i as u32).unwrap())
-                .unwrap();
+            mm.append(test_encoder.encode_to_bytes(&buffer, i as u32).unwrap());
             buffers.push(buffer);
         }
         let decoder = &TestEncoderDecoder;
diff --git a/src/core/memory_map.rs b/src/core/memory_map.rs
index 8a2ec40..f779514 100644
--- a/src/core/memory_map.rs
+++ b/src/core/memory_map.rs
@@ -82,13 +82,19 @@ unsafe impl Sync for RawMmap {}
 #[repr(transparent)]
 pub struct MemoryMap(RawMmap);
 
+impl Drop for MemoryMap {
+    fn drop(&mut self) {
+        self.0.flush(self.write_offset()).unwrap();
+    }
+}
+
 impl MemoryMap {
     pub fn new(file: &File, len: usize) -> Self {
         let raw_mmap = RawMmap::new(file.as_raw_fd(), len).unwrap();
         MemoryMap(raw_mmap)
     }
 
-    pub fn append(&mut self, value: Vec<u8>) -> io::Result<()> {
+    pub fn append(&mut self, value: Vec<u8>) {
         let data_len = value.len();
         let start = self.write_offset();
         let content_len = start - LEN_OFFSET;
@@ -96,13 +102,11 @@ impl MemoryMap {
         let new_content_len = data_len + content_len;
         self.0[0..LEN_OFFSET].copy_from_slice(new_content_len.to_be_bytes().as_slice());
         self.0[start..end].copy_from_slice(value.as_slice());
-        self.0.flush(end)
     }
 
-    pub fn reset(&mut self) -> io::Result<()> {
+    pub fn reset(&mut self) {
         let len = 0usize;
         self.0[0..LEN_OFFSET].copy_from_slice(len.to_be_bytes().as_slice());
-        self.0.flush(LEN_OFFSET)
     }
 
     pub fn content_start_offset(&self) -> usize {
@@ -144,8 +148,8 @@ mod tests {
         file.set_len(1024).unwrap();
         let mut mm = MemoryMap::new(&file, 1024);
         assert_eq!(mm.write_offset(), LEN_OFFSET);
-        mm.append(vec![1, 2, 3]).unwrap();
-        mm.append(vec![4]).unwrap();
+        mm.append(vec![1, 2, 3]);
+        mm.append(vec![4]);
         assert_eq!(mm.write_offset(), 12);
 
         let read = mm.read(8..10);
@@ -155,8 +159,8 @@ mod tests {
         let read = mm.read(mm.write_offset() - 1..mm.write_offset());
         assert_eq!(read[0], 4);
 
-        mm.reset().unwrap();
-        mm.append(vec![5, 4, 3, 2, 1]).unwrap();
+        mm.reset();
+        mm.append(vec![5, 4, 3, 2, 1]);
         assert_eq!(mm.write_offset(), 13);
         let read = mm.read(8..9);
         assert_eq!(read[0], 5);
diff --git a/src/core/writer.rs b/src/core/writer.rs
index ff8310a..7267dd1 100644
--- a/src/core/writer.rs
+++ b/src/core/writer.rs
@@ -2,7 +2,6 @@ use crate::core::buffer::{Buffer, Decoder, Encoder};
 use crate::core::config::Config;
 use crate::core::io_looper::Callback;
 use crate::core::memory_map::MemoryMap;
-use crate::Error::EncodeFailed;
 use std::time::Instant;
 
 const LOG_TAG: &str = "MMKV:IO";
@@ -48,7 +47,7 @@ impl IOWriter {
             self.need_trim = true;
         }
         if target_end <= max_len {
-            self.mm.append(data).unwrap();
+            self.mm.append(data);
             self.position += 1;
             return;
         }
@@ -60,6 +59,7 @@ impl IOWriter {
                 "start trim, current len {}",
                 self.mm.write_offset()
             );
+            info!(LOG_TAG,"start take snapshot");
             let (mut snapshot, _) = self
                 .mm
                 .iter(|bytes, position| self.decoder.decode_bytes(bytes, position))
@@ -69,17 +69,15 @@ impl IOWriter {
             } else {
                 snapshot.insert(buffer.key().to_string(), buffer);
             }
-            self.mm
-                .reset()
-                .map_err(|e| EncodeFailed(e.to_string()))
-                .unwrap();
+            info!(LOG_TAG,"snapshot finished in {:?}", time_start.elapsed());
+            self.mm.reset();
             self.position = 0;
             for buffer in snapshot.values() {
                 let bytes = self.encoder.encode_to_bytes(buffer, self.position).unwrap();
                 if self.mm.write_offset() + bytes.len() > max_len {
                     self.expand();
                 }
-                self.mm.append(bytes).unwrap();
+                self.mm.append(bytes);
                 self.position += 1;
             }
             self.need_trim = false;
@@ -93,7 +91,7 @@ impl IOWriter {
         } else {
             // expand and write
             self.expand();
-            self.mm.append(data).unwrap();
+            self.mm.append(data);
             self.position += 1;
         }
     }