From c744a3aea2cead8c53dc5e33d62ad74855ab128c Mon Sep 17 00:00:00 2001
From: Ben Pig Chu <benpichu@gmail.com>
Date: Sat, 27 Oct 2018 01:16:38 +0800
Subject: [PATCH] get_entry(), as a different design from list()

---
 src/sfs.rs   | 8 ++++++++
 src/tests.rs | 5 ++++-
 src/vfs.rs   | 3 +++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/sfs.rs b/src/sfs.rs
index 4c4d5f2..abb201e 100644
--- a/src/sfs.rs
+++ b/src/sfs.rs
@@ -396,6 +396,14 @@ impl vfs::INode for INode {
             _ => unimplemented!(),
         }
     }
+    fn get_entry(&self,id: usize) -> vfs::Result<String> {
+        assert_eq!(self.disk_inode.type_, FileType::Dir);
+        assert!(id<self.disk_inode.blocks as usize);
+        use vfs::INode;
+        let mut entry: DiskEntry = unsafe { uninitialized() };
+        self._read_at(id as usize * BLKSIZE, entry.as_buf_mut()).unwrap();
+        Ok(String::from(entry.name.as_ref()))
+    }
     fn list(&self) -> vfs::Result<Vec<String>> {
         assert_eq!(self.disk_inode.type_, FileType::Dir);
 
diff --git a/src/tests.rs b/src/tests.rs
index f2ac9f6..f0a6d9b 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -54,7 +54,7 @@ fn create_new_sfs() {
     let root = sfs.root_inode();
 }
 
-//#[test]
+// #[test]
 fn print_root() {
     let sfs = _open_sample_file();
     let root = sfs.root_inode();
@@ -62,6 +62,9 @@ fn print_root() {
 
     let files = root.borrow().list().unwrap();
     println!("{:?}", files);
+    assert_eq!(files[3],root.borrow().get_entry(3).unwrap());
+
+    sfs.sync().unwrap();
 }
 
 #[test]
diff --git a/src/vfs.rs b/src/vfs.rs
index 84e7f9d..eadd870 100644
--- a/src/vfs.rs
+++ b/src/vfs.rs
@@ -29,6 +29,9 @@ pub trait INode: Debug + Any {
     fn link(&mut self, name: &str, other:&mut INode) -> Result<()>;
     fn lookup(&self, path: &str) -> Result<INodePtr>;
     fn list(&self) -> Result<Vec<String>>;
+    /// like list()[id]
+    /// only get one item in list, often faster than list
+    fn get_entry(&self,id: usize) -> Result<String>;
 //    fn io_ctrl(&mut self, op: u32, data: &[u8]) -> Result<()>;
     fn fs(&self) -> Weak<FileSystem>;
     /// this is used to implement dynamics cast