Merge pull request #235 from kono-dada/fix/inplace-model-load

- Avoid removing and re-inserting model entries during load
- Preserve metadata (bytes, style_vectors) when evicting
- Ensure eviction targets a different loaded model, not always the first
- Reduce unnecessary memory allocations and keep list order stable

crates/sbv2_core/src/tts.rs

@@ -240,39 +240,43 @@ impl TTSModelHolder {
     }
     fn find_and_load_model<I: Into<TTSIdent>>(&mut self, ident: I) -> Result<bool> {
         let ident = ident.into();
-        let (bytes, style_vectors) = {
+        // Locate target model entry
-            let model = self
+        let target_index = self
-                .models
-                .iter()
-                .find(|m| m.ident == ident)
-                .ok_or(Error::ModelNotFoundError(ident.to_string()))?;
-            if model.vits2.is_some() {
-                return Ok(true);
-            }
-            (model.bytes.clone().unwrap(), model.style_vectors.clone())
-        };
-        self.unload(ident.clone());
-        let s = model::load_model(&bytes, false)?;
-        if let Some(max) = self.max_loaded_models {
-            if self.models.iter().filter(|x| x.vits2.is_some()).count() >= max {
-                self.unload(self.models.first().unwrap().ident.clone());
-            }
-        }
-        self.models.push(TTSModel {
-            bytes: Some(bytes.to_vec()),
-            vits2: Some(s),
-            style_vectors,
-            ident: ident.clone(),
-        });
-        let model = self
             .models
             .iter()
-            .find(|m| m.ident == ident)
+            .position(|m| m.ident == ident)
             .ok_or(Error::ModelNotFoundError(ident.to_string()))?;
-        if model.vits2.is_some() {
+
+        // Already loaded
+        if self.models[target_index].vits2.is_some() {
             return Ok(true);
         }
-        Err(Error::ModelNotFoundError(ident.to_string()))
+
+        // Get bytes to build a Session
+        let bytes = self.models[target_index]
+            .bytes
+            .clone()
+            .ok_or(Error::ModelNotFoundError(ident.to_string()))?;
+
+        // Enforce max loaded models by evicting a different loaded model's session, not removing the entry
+        if let Some(max) = self.max_loaded_models {
+            let loaded_count = self.models.iter().filter(|m| m.vits2.is_some()).count();
+            if loaded_count >= max {
+                if let Some(evict_index) = self
+                    .models
+                    .iter()
+                    .position(|m| m.vits2.is_some() && m.ident != ident)
+                {
+                    // Drop only the session to free memory; keep bytes/style for future reload
+                    self.models[evict_index].vits2 = None;
+                }
+            }
+        }
+
+        // Build and set session in-place for the target model
+        let s = model::load_model(&bytes, false)?;
+        self.models[target_index].vits2 = Some(s);
+        Ok(true)
     }
 
     /// Get style vector by style id and weight