20260421 优化内存布局，降低内存峰值需求压低到4.5GB左右，在4c8g 机器上，稳定跑snapshot + delta

src/current_repo_index.rs

@@ -23,7 +23,6 @@ pub struct CurrentRepoObject {
 #[derive(Default, Debug)]
 pub struct CurrentRepoIndex {
     by_uri: HashMap<String, CurrentRepoEntry>,
-    by_scope: HashMap<String, HashSet<String>>,
 }
 
 pub type CurrentRepoIndexHandle = Arc<Mutex<CurrentRepoIndex>>;
@@ -43,10 +42,12 @@ impl CurrentRepoIndex {
 
     pub fn list_scope_uris(&self, repository_source: &str) -> Vec<String> {
         let mut out = self
-            .by_scope
-            .get(repository_source)
-            .map(|set| set.iter().cloned().collect::<Vec<_>>())
-            .unwrap_or_default();
+            .by_uri
+            .iter()
+            .filter_map(|(rsync_uri, entry)| {
+                (entry.repository_source == repository_source).then(|| rsync_uri.clone())
+            })
+            .collect::<Vec<_>>();
         out.sort();
         out
     }
@@ -56,7 +57,11 @@ impl CurrentRepoIndex {
     }
 
     pub fn scope_count(&self) -> usize {
-        self.by_scope.len()
+        self.by_uri
+            .values()
+            .map(|entry| entry.repository_source.as_str())
+            .collect::<HashSet<_>>()
+            .len()
     }
 
     pub fn snapshot_objects(&self) -> Vec<CurrentRepoObject> {
@@ -76,7 +81,6 @@ impl CurrentRepoIndex {
 
     pub fn clear(&mut self) {
         self.by_uri.clear();
-        self.by_scope.clear();
     }
 
     pub fn apply_repository_view_entries(
@@ -92,11 +96,6 @@ impl CurrentRepoIndex {
     fn apply_repository_view_entry(&mut self, entry: &RepositoryViewEntry) -> Result<(), String> {
         entry.validate_internal().map_err(|e| e.to_string())?;
 
-        let old_scope = self
-            .by_uri
-            .get(&entry.rsync_uri)
-            .map(|existing| existing.repository_source.clone());
-
         match entry.state {
             RepositoryViewState::Present | RepositoryViewState::Replaced => {
                 let repository_source = entry.repository_source.clone().ok_or_else(|| {
@@ -112,17 +111,6 @@ impl CurrentRepoIndex {
                     )
                 })?;
                 let current_hash = decode_sha256_hex_32(&current_hash_hex)?;
-
-                if let Some(old_scope) = old_scope.as_ref() {
-                    if old_scope != &repository_source {
-                        self.remove_uri_from_scope(old_scope, &entry.rsync_uri);
-                    }
-                }
-
-                self.by_scope
-                    .entry(repository_source.clone())
-                    .or_default()
-                    .insert(entry.rsync_uri.clone());
                 self.by_uri.insert(
                     entry.rsync_uri.clone(),
                     CurrentRepoEntry {
@@ -135,27 +123,12 @@ impl CurrentRepoIndex {
                 );
             }
             RepositoryViewState::Withdrawn => {
-                if let Some(scope) = entry.repository_source.as_ref().or(old_scope.as_ref()) {
-                    self.remove_uri_from_scope(scope, &entry.rsync_uri);
-                }
                 self.by_uri.remove(&entry.rsync_uri);
             }
         }
 
         Ok(())
     }
-
-    fn remove_uri_from_scope(&mut self, scope: &str, rsync_uri: &str) {
-        let empty = if let Some(entries) = self.by_scope.get_mut(scope) {
-            entries.remove(rsync_uri);
-            entries.is_empty()
-        } else {
-            false
-        };
-        if empty {
-            self.by_scope.remove(scope);
-        }
-    }
 }
 
 fn decode_sha256_hex_32(value: &str) -> Result<[u8; 32], String> {
@@ -281,7 +254,7 @@ mod tests {
             .expect_err("invalid hash should fail");
         assert!(err.contains("invalid"), "{err}");
 
-        let err = index
+        index
             .apply_repository_view_entries(&[RepositoryViewEntry {
                 rsync_uri: "rsync://example.test/repo/b.roa".to_string(),
                 current_hash: Some("22".repeat(32)),