fix: Adapt FilteringReader to use FilterChain for streaming

Co-authored-by: aider (openai/andrew/openrouter/deepseek/deepseek-chat-v3.1) <aider@aider.chat>

src/services/item_service.rs

@@ -50,30 +50,22 @@ impl<R: Read> Read for FilteringReader<R> {
         self.buffer.clear();
         self.buffer_pos = 0;
 
-        // Read from the original reader
+        // Read from the original reader into a temporary buffer
         let mut temp_buf = vec![0; buf.len()];
         let bytes_read = self.reader.read(&mut temp_buf)?;
 
         if bytes_read == 0 {
-            // If we're at EOF, process any remaining data in the filter chain
-            if let Some(chain) = &mut self.filter_chain {
-                let finished_data = chain.finish()?;
-                if !finished_data.is_empty() {
-                    self.buffer = finished_data;
-                    let bytes_to_copy = std::cmp::min(buf.len(), self.buffer.len());
-                    buf[..bytes_to_copy].copy_from_slice(&self.buffer[..bytes_to_copy]);
-                    self.buffer_pos = bytes_to_copy;
-                    return Ok(bytes_to_copy);
-                }
-            }
             return Ok(0);
         }
 
         // Process through the filter chain if it exists
         if let Some(chain) = &mut self.filter_chain {
-            let processed_data = chain.process(&temp_buf[..bytes_read])?;
+            // Use a cursor to read the input data
-            if !processed_data.is_empty() {
+            let mut input_cursor = std::io::Cursor::new(&temp_buf[..bytes_read]);
-                self.buffer = processed_data;
+            // Write filtered output to our buffer
+            chain.filter(&mut input_cursor, &mut self.buffer)?;
+            
+            if !self.buffer.is_empty() {
                 let bytes_to_copy = std::cmp::min(buf.len(), self.buffer.len());
                 buf[..bytes_to_copy].copy_from_slice(&self.buffer[..bytes_to_copy]);
                 self.buffer_pos = bytes_to_copy;