kata-types: Replace StorageHandlerManager with type alias

Removed the `StorageHandlerManager` struct and its associated implementations and
introduced a type alias `StorageHandlerManager` for `HandlerManager` to simplify the code.
The new type alias maintains the same functionality while reducing redundancy.

Signed-off-by: ChengyuZhu6 <chengyu.zhu@intel.com>

src/libs/kata-types/src/handler.rs

@@ -12,13 +12,19 @@ pub struct HandlerManager<H> {
     handlers: HashMap<String, H>,
 }
 
-impl<H> Default for HandlerManager<H> {
+impl<H> Default for HandlerManager<H> 
+where
+    H: Clone,
+{
     fn default() -> Self {
         Self::new()
     }
 }
 
-impl<H> HandlerManager<H> {
+impl<H> HandlerManager<H> 
+where
+    H: Clone,
+{
     /// Create a new instance of `HandlerManager`.
     pub fn new() -> Self {
         Self {
@@ -27,14 +33,18 @@ impl<H> HandlerManager<H> {
     }
 
     /// Register a handler.
-    pub fn add_handler(&mut self, id: &str, handler: H) -> Result<()> {
-        match self.handlers.entry(id.to_string()) {
-            Entry::Occupied(_) => Err(anyhow!("handler for {} already exists", id)),
-            Entry::Vacant(entry) => {
-                entry.insert(handler);
-                Ok(())
+    pub fn add_handler(&mut self, ids: &[&str], handler: H) -> Result<()> {
+        for &id in ids {
+            match self.handlers.entry(id.to_string()) {
+                Entry::Occupied(_) => {
+                    return Err(anyhow!("handler for {} already exists", id));
+                }
+                Entry::Vacant(entry) => {
+                    entry.insert(handler.clone());
+                }
             }
         }
+        Ok(())
     }
 
     /// Get handler with specified `id`.

src/libs/kata-types/src/mount.rs

@@ -5,10 +5,11 @@
 //
 
 use anyhow::{anyhow, Context, Error, Result};
-use std::collections::hash_map::Entry;
 use std::convert::TryFrom;
 use std::{collections::HashMap, fs, path::PathBuf};
 
+use crate::handler::HandlerManager;
+
 /// Prefix to mark a volume as Kata special.
 pub const KATA_VOLUME_TYPE_PREFIX: &str = "kata:";
 
@@ -59,6 +60,9 @@ pub const KATA_VIRTUAL_VOLUME_LAYER_NYDUS_FS: &str = "layer_nydus_fs";
 /// Download and extra container image inside guest vm.
 pub const KATA_VIRTUAL_VOLUME_IMAGE_GUEST_PULL: &str = "image_guest_pull";
 
+/// Manager to manage registered storage device handlers.
+pub type StorageHandlerManager<H> = HandlerManager<H>;
+
 /// Information about a mount.
 #[derive(Debug, Clone, Default, serde::Serialize, serde::Deserialize)]
 pub struct Mount {
@@ -441,57 +445,6 @@ pub trait StorageDevice: Send + Sync {
     fn cleanup(&self) -> Result<()>;
 }
 
-/// Manager to manage registered storage device handlers.
-pub struct StorageHandlerManager<H> {
-    handlers: HashMap<String, H>,
-}
-
-impl<H> Default for StorageHandlerManager<H> 
-where
-    H: Clone,
-{
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<H> StorageHandlerManager<H> 
-where
-    H: Clone,
-{
-    /// Create a new instance of `StorageHandlerManager`.
-    pub fn new() -> Self {
-        Self {
-            handlers: HashMap::new(),
-        }
-    }
-
-    /// Register a storage device handler.
-    pub fn add_handler(&mut self, ids: &[&str], handler: H) -> Result<()> {
-        for &id in ids {
-            match self.handlers.entry(id.to_string()) {
-                Entry::Occupied(_) => {
-                    return Err(anyhow!("storage handler for {} already exists", id));
-                }
-                Entry::Vacant(entry) => {
-                    entry.insert(handler.clone());
-                }
-            }
-        }
-        Ok(())
-    }
-
-    /// Get storage handler with specified `id`.
-    pub fn handler(&self, id: &str) -> Option<&H> {
-        self.handlers.get(id)
-    }
-
-    /// Get names of registered handlers.
-    pub fn get_handlers(&self) -> Vec<String> {
-        self.handlers.keys().map(|v| v.to_string()).collect()
-    }
-}
-
 /// Join user provided volume path with kata direct-volume root path.
 ///
 /// The `volume_path` is base64-url-encoded and then safely joined to the `prefix`