feat: add revision retrieving

src/storage/mod.rs

@@ -1,12 +1,21 @@
 pub mod fs;
 
-use std::path::PathBuf;
+use std::{io::BufReader, path::PathBuf};
+
+use flate2::read::GzDecoder;
 
 use crate::{Data, error::Result};
 
 pub trait StorageImpl {
-    fn get_revision(&self, app_state: Data) -> Result<usize>;
+    fn get_revision_metadata(&self, app_state: Data) -> Result<usize>;
     fn store_revision(&self, app_state: Data) -> Result<()>;
+    fn retrieve_revision(
+        &self,
+        app_state: Data,
+        revision: usize,
+    ) -> Result<tar::Archive<GzDecoder<BufReader<std::fs::File>>>>;
+    fn unpack_revision(&self, app_state: Data, destination: PathBuf, revision: usize)
+    -> Result<()>;
 }
 
 pub enum Storage {
@@ -16,9 +25,9 @@ pub enum Storage {
 pub const IGNORE_FILES: [&str; 6] = ["assets", "cache", "catpacks", "logs", "meta", "metacache"];
 
 impl StorageImpl for Storage {
-    fn get_revision(&self, app_state: Data) -> Result<usize> {
+    fn get_revision_metadata(&self, app_state: Data) -> Result<usize> {
         match self {
-            Self::FS(storage) => storage.get_revision(app_state),
+            Self::FS(storage) => storage.get_revision_metadata(app_state),
         }
     }
 
@@ -27,6 +36,27 @@ impl StorageImpl for Storage {
             Self::FS(storage) => storage.store_revision(app_state),
         }
     }
+
+    fn retrieve_revision(
+        &self,
+        app_state: Data,
+        revision: usize,
+    ) -> Result<tar::Archive<GzDecoder<BufReader<std::fs::File>>>> {
+        match self {
+            Self::FS(storage) => storage.retrieve_revision(app_state, revision),
+        }
+    }
+
+    fn unpack_revision(
+        &self,
+        app_state: Data,
+        destination: PathBuf,
+        revision: usize,
+    ) -> Result<()> {
+        match self {
+            Self::FS(storage) => storage.unpack_revision(app_state, destination, revision),
+        }
+    }
 }
 
 pub fn get_storage_from_env() -> Storage {