Update commit log, use mapped file queue

src/commit_log.rs

@@ -1,37 +1,28 @@
-use std::path::PathBuf;
 use snafu::{location, Location};
 use crate::error::Error::InvalidInput;
-
 use crate::msg_index::MessageIndexUnit;
-use crate::mmap_file::MemoryMappedFile;
 use crate::error::Result;
+use crate::mapped_file_queue::MappedFileQueue;
 
 pub struct CommitLog {
-    current_file: MemoryMappedFile,
+    mapped_file_queue: MappedFileQueue,
 }
 
 impl CommitLog {
-    pub fn open(base_path: &str, max_file_size: u64) -> Result<Self> {
-        let base_dir = PathBuf::from(base_path);
-        let msg_log_path = base_dir.join("test.log");
-        // Create or open the initial MemoryMappedFile
-        let current_file = MemoryMappedFile::open(
-            msg_log_path.to_str().unwrap(), 0, max_file_size)?;
-
-        Ok(CommitLog {
-            current_file
-        })
+    pub fn open(store_path: &str, max_file_size: u64) -> Result<Self> {
+        let mapped_file_queue = MappedFileQueue::open(store_path, max_file_size)?;
+        Ok(CommitLog { mapped_file_queue })
     }
 
     pub fn write_records(&mut self, data: &Vec<u8>) -> Result<usize> {
         // Write the record to the current file
-        self.current_file.append(data)
+        self.mapped_file_queue.append(data)
     }
 
     pub fn read_records(&self, msg_index_unit: &MessageIndexUnit) -> Result<Vec<u8>> {
         if msg_index_unit.size > 0 {
             // Read and return records
-            self.current_file.read(
+            self.mapped_file_queue.read(
                 msg_index_unit.offset as usize, msg_index_unit.size as usize)
         } else {
             Err(InvalidInput {

src/mapped_file_queue.rs

@@ -13,14 +13,15 @@ pub struct MappedFileQueue {
 impl MappedFileQueue {
     // Constructor: Open or create a memory-mapped file.
     pub fn open(store_path: &str, max_file_size: u64) -> Result<Self> {
+        // TODO load exist mapped files
         Ok(MappedFileQueue { store_path: store_path.to_string(), max_file_size, mapped_files: Vec::new() })
     }
 
     pub fn get_mapped_files(&self) -> &Vec<MemoryMappedFile> {
         &self.mapped_files
     }
 
-    fn create_mapped_file(&mut self, start_offset: usize) -> &mut MemoryMappedFile {
+    pub fn create_mapped_file(&mut self, start_offset: usize) -> &mut MemoryMappedFile {
         let store_path_clone = self.store_path.clone();
         let base_dir = PathBuf::from(store_path_clone);
         let file_name = format!("{:020}", start_offset);