test3:ramfs-rename try1

Author: LHHL7

arceos/Cargo.toml

@@ -94,6 +94,7 @@ axfs_ramfs = { path = "./axfs_ramfs" }
 
 [patch.crates-io]
 kernel_guard = { path = "../crates/kernel_guard"} 
+axfs_ramfs = { path = "./axfs_ramfs" }
 
 [profile.release]
 lto = true

arceos/api/arceos_api/src/lib.rs

@@ -192,8 +192,8 @@ pub mod fs {
         pub type MyFileSystemIf;
     }
 
-    define_api! {
-        @cfg "fs";
+    define_api! {//定义了api后  用户程序、开启了fs特性的上层crate都可以直接用函数
+        @cfg "fs";//// 条件编译：只有在启用 "fs" 特性时才包含此API
 
         /// Opens a file at the path relative to the current directory with the
         /// options specified by `opts`.

arceos/axfs_ramfs/Cargo.toml

@@ -12,7 +12,7 @@
 [package]
 edition = "2021"
 name = "axfs_ramfs"
-version = "0.1.1"
+version = "0.1.2" #原来0.1.1
 authors = ["Yuekai Jia <equation618@gmail.com>"]
 build = false
 autobins = false

arceos/axfs_ramfs/src/dir.rs

@@ -1,7 +1,7 @@
 use alloc::collections::BTreeMap;
 use alloc::sync::{Arc, Weak};
 use alloc::{string::String, vec::Vec};
-
+use crate::alloc::string::ToString;
 use axfs_vfs::{VfsDirEntry, VfsNodeAttr, VfsNodeOps, VfsNodeRef, VfsNodeType};
 use axfs_vfs::{VfsError, VfsResult};
 use spin::RwLock;
@@ -14,7 +14,9 @@ use crate::file::FileNode;
 pub struct DirNode {
     this: Weak<DirNode>,
     parent: RwLock<Weak<dyn VfsNodeOps>>,
-    children: RwLock<BTreeMap<String, VfsNodeRef>>,
+    children: RwLock<BTreeMap<String, VfsNodeRef>>,//目录项表
+    //                        ↑文件名    ↑文件实体（相当于inode的抽象
+    //BTreeMap数据结构相当于一个map 存键值对 但是将键值对插到平衡二叉树 内部是有序的并且迭代的时候按照键的顺序
 }
 
 impl DirNode {
@@ -67,6 +69,27 @@ impl DirNode {
         children.remove(name);
         Ok(())
     }
+    fn rename_in_same_dir(&self, old_name: &str, new_name: &str) -> VfsResult {
+        log::error!("[dir] call rename_in_same_dir oldname:{},newname:{}",old_name,new_name);
+        let mut children = self.children.write();  // Rwlock是读写锁 通过.write（） 获取写锁
+        //可以有多个读锁（共享） 或者有一个写锁（独占） 但不能同时有读锁和写锁
+        // 现在可以安全地修改 children...
+        log::error!("[dir] getting node");
+        let node=children.get(old_name).ok_or(VfsError::NotFound)?.clone();//找到old_name对应inode
+        //get是通过键查找值 返回option  ok_or(E)将option<T>转化为Result<T,E>
+        // ?操作符可以跟在option或者result后面 成功了就解包 失败了就提前返回
+         // 检查目标是否已存在
+        if children.contains_key(new_name) {
+            return Err(VfsError::AlreadyExists);
+        }
+         // 关键操作：修改名称映射，不复制数据！
+        children.remove(old_name);
+        children.insert(new_name.to_string(),node);// 同一个 node 对象！
+
+        log::error!("[dir] complete rename in same dir!");
+        // VfsResult的定义 等价于：type VfsResult<T> = Result<T, VfsError>;
+        Ok(())
+    }
 }
 
 impl VfsNodeOps for DirNode {
@@ -164,11 +187,22 @@ impl VfsNodeOps for DirNode {
             self.remove_node(name)
         }
     }
-
-    axfs_vfs::impl_vfs_dir_default! {}
+    
+    fn rename(&self,src_path:&str,dst_path:&str)->VfsResult{
+        log::error!("[dir] call rename");
+        //现在先实现只支持在同一目录下重命名
+        let (src_name, src_rest) = split_path(src_path);
+        let (dst_dir,dst_rest)=split_path(dst_path);
+        let dst_rest=dst_rest.unwrap();
+        //
+        
+        self.rename_in_same_dir(src_name, dst_rest)
+    }
+    axfs_vfs::impl_vfs_dir_default! {}//提供了其他方法的默认实现
+    //经过查cargo.lock 发现axfs_vfs是外部依赖
 }
 
-fn split_path(path: &str) -> (&str, Option<&str>) {
+fn split_path(path: &str) -> (&str, Option<&str>) {//去掉开头的/  再以中间的第一个/进行切分
     let trimmed_path = path.trim_start_matches('/');
     trimmed_path.find('/').map_or((trimmed_path, None), |n| {
         (&trimmed_path[..n], Some(&trimmed_path[n + 1..]))

arceos/axfs_ramfs/src/lib.rs

@@ -28,6 +28,7 @@ pub struct RamFileSystem {
 impl RamFileSystem {
     /// Create a new instance.
     pub fn new() -> Self {
+        log::error!("[lib.rs] call ramfs new()");
         Self {
             parent: Once::new(),
             root: DirNode::new(None),
@@ -51,6 +52,7 @@ impl VfsOps for RamFileSystem {
     }
 
     fn root_dir(&self) -> VfsNodeRef {
+        log::error!("[lib] call root_dir");
         self.root.clone()
     }
 }

arceos/exercises/alt_alloc/src/main.rs

@@ -13,6 +13,11 @@ use alloc::vec::Vec;
 fn main() {
     println!("Running bump tests...");
 
+    #[cfg(feature = "axstd")]
+    println!("axstd feature is ENABLED");
+    
+    #[cfg(not(feature = "axstd"))]
+    println!("axstd feature is DISABLED");
     const N: usize = 3_000_000;
     let mut v = Vec::with_capacity(N);
     for i in 0..N {

arceos/exercises/ramfs_rename/src/main.rs

@@ -9,6 +9,9 @@ mod ramfs;
 
 use std::io::{self, prelude::*};
 use std::fs::{self, File};
+//self相当于模块本身 相当于：
+//use std::fs;
+//use std::fs::File;
 
 fn create_file(fname: &str, text: &str) -> io::Result<()> {
     println!("Create '{}' and write [{}] ...", fname, text);
@@ -47,6 +50,13 @@ fn process() -> io::Result<()> {
 
 #[cfg_attr(feature = "axstd", no_mangle)]
 fn main() {
+    //测试axstd是否启用---start---
+    #[cfg(feature = "axstd")]
+    println!("axstd feature is ENABLED");
+    
+    #[cfg(not(feature = "axstd"))]
+    println!("axstd feature is DISABLED");
+    //----end------
     if let Err(e) = process() {
         panic!("Error: {}", e);
     }

arceos/modules/axfs/Cargo.toml

@@ -18,7 +18,8 @@ fatfs = ["dep:fatfs"]
 myfs = ["dep:crate_interface"]
 use-ramdisk = []
 
-default = ["devfs", "ramfs", "fatfs", "procfs", "sysfs"]
+# default = ["devfs", "ramfs", "fatfs", "procfs", "sysfs"]
+default = ["devfs", "ramfs", "procfs", "sysfs"]  # 不使用fatfs
 
 [dependencies]
 log = "0.4.21"

arceos/modules/axfs/src/api/mod.rs

@@ -85,5 +85,5 @@ pub fn remove_file(path: &str) -> io::Result<()> {
 ///
 /// This only works then the new path is in the same mounted fs.
 pub fn rename(old: &str, new: &str) -> io::Result<()> {
-    crate::root::rename(old, new)
+    crate::root::rename(old, new)//crate代表本crate axfs
 }

arceos/modules/axfs/src/lib.rs

@@ -38,9 +38,26 @@ use axdriver::{prelude::*, AxDeviceContainer};
 
 /// Initializes filesystems by block devices.
 pub fn init_filesystems(mut blk_devs: AxDeviceContainer<AxBlockDevice>) {
+    // info!("Initialize filesystems...");
+
+    // let dev = blk_devs.take_one().expect("No block device found!");
+    // info!("  use block device 0: {:?}", dev.device_name());
+    // self::root::init_rootfs(self::dev::Disk::new(dev));
     info!("Initialize filesystems...");
 
-    let dev = blk_devs.take_one().expect("No block device found!");
-    info!("  use block device 0: {:?}", dev.device_name());
-    self::root::init_rootfs(self::dev::Disk::new(dev));
+    #[cfg(feature = "fatfs")]
+    {
+        if let Some(dev) = blk_devs.take_one() {
+            let disk = self::dev::Disk::new(dev);
+            self::root::init_rootfs(Some(disk)); // 传递 Some(disk)
+        } else {
+            warn!("No block device for FATFS, but RAMFS will be used");
+            self::root::init_rootfs(None); // 传递 None
+        }
+    }
+    
+    #[cfg(not(feature = "fatfs"))]
+    {
+        self::root::init_rootfs(None); // 不需要磁盘
+    }
 }