refactor: Update head, tail, skip filter plugins to use new API

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

src/filter_plugin/head.rs

@@ -1,5 +1,5 @@
 use super::FilterPlugin;
-use std::io::Result;
+use std::io::{Result, Read, Write, BufRead};
 
 pub struct HeadBytesFilter {
     remaining: usize,
@@ -14,73 +14,49 @@ impl HeadBytesFilter {
 }
 
 impl FilterPlugin for HeadBytesFilter {
-    fn process(&mut self, data: &[u8]) -> Result<Vec<u8>> {
+    fn filter<R: Read, W: Write>(&mut self, reader: &mut R, writer: &mut W) -> Result<()> {
         if self.remaining == 0 {
-            return Ok(Vec::new());
+            return Ok(());
         }
         
-        let bytes_to_take = std::cmp::min(data.len(), self.remaining);
-        self.remaining -= bytes_to_take;
-        Ok(data[..bytes_to_take].to_vec())
-    }
-
-    fn finish(&mut self) -> Result<Vec<u8>> {
-        Ok(Vec::new())
+        // Read only up to remaining bytes
+        let mut buffer = vec![0; self.remaining];
+        let bytes_read = reader.read(&mut buffer)?;
+        if bytes_read > 0 {
+            writer.write_all(&buffer[..bytes_read])?;
+            self.remaining -= bytes_read;
+        }
+        Ok(())
     }
 }
 
 pub struct HeadLinesFilter {
     remaining: usize,
-    buffer: Vec<u8>,
 }
 
 impl HeadLinesFilter {
     pub fn new(count: usize) -> Self {
         Self {
             remaining: count,
-            buffer: Vec::new(),
         }
     }
 }
 
 impl FilterPlugin for HeadLinesFilter {
-    fn process(&mut self, data: &[u8]) -> Result<Vec<u8>> {
+    fn filter<R: Read, W: Write>(&mut self, reader: &mut R, writer: &mut W) -> Result<()> {
         if self.remaining == 0 {
-            return Ok(Vec::new());
+            return Ok(());
         }
         
-        let mut result = Vec::new();
-        let mut start = 0;
-        
-        for (i, &byte) in data.iter().enumerate() {
-            if byte == b'\n' {
-                self.buffer.extend_from_slice(&data[start..=i]);
-                result.extend_from_slice(&self.buffer);
-                self.buffer.clear();
-                start = i + 1;
-                
-                self.remaining -= 1;
-                if self.remaining == 0 {
-                    break;
-                }
+        let buf_reader = std::io::BufReader::new(reader);
+        for line in buf_reader.lines() {
+            let line = line?;
+            writeln!(writer, "{}", line)?;
+            self.remaining -= 1;
+            if self.remaining == 0 {
+                break;
             }
         }
-        
-        // Add remaining data to buffer
-        if start < data.len() {
-            self.buffer.extend_from_slice(&data[start..]);
-        }
-        
-        Ok(result)
-    }
-
-    fn finish(&mut self) -> Result<Vec<u8>> {
-        if self.remaining > 0 && !self.buffer.is_empty() {
-            let result = self.buffer.clone();
-            self.buffer.clear();
-            Ok(result)
-        } else {
-            Ok(Vec::new())
-        }
+        Ok(())
     }
 }

src/filter_plugin/skip.rs

@@ -1,5 +1,5 @@
 use super::FilterPlugin;
-use std::io::Result;
+use std::io::{Result, Read, Write, BufRead};
 
 pub struct SkipBytesFilter {
     remaining: usize,
@@ -14,85 +14,43 @@ impl SkipBytesFilter {
 }
 
 impl FilterPlugin for SkipBytesFilter {
-    fn process(&mut self, data: &[u8]) -> Result<Vec<u8>> {
-        if self.remaining == 0 {
-            return Ok(data.to_vec());
+    fn filter<R: Read, W: Write>(&mut self, reader: &mut R, writer: &mut W) -> Result<()> {
+        // Skip the specified number of bytes
+        if self.remaining > 0 {
+            let mut buffer = vec![0; self.remaining];
+            let bytes_read = reader.read(&mut buffer)?;
+            self.remaining -= bytes_read;
         }
         
-        if data.len() <= self.remaining {
-            self.remaining -= data.len();
-            Ok(Vec::new())
-        } else {
-            let result = data[self.remaining..].to_vec();
-            self.remaining = 0;
-            Ok(result)
-        }
-    }
-
-    fn finish(&mut self) -> Result<Vec<u8>> {
-        Ok(Vec::new())
+        // Copy the remaining data
+        std::io::copy(reader, writer)?;
+        Ok(())
     }
 }
 
 pub struct SkipLinesFilter {
     remaining: usize,
-    buffer: Vec<u8>,
 }
 
 impl SkipLinesFilter {
     pub fn new(count: usize) -> Self {
         Self {
             remaining: count,
-            buffer: Vec::new(),
         }
     }
 }
 
 impl FilterPlugin for SkipLinesFilter {
-    fn process(&mut self, data: &[u8]) -> Result<Vec<u8>> {
-        if self.remaining == 0 {
-            let mut result = self.buffer.clone();
-            result.extend_from_slice(data);
-            self.buffer.clear();
-            return Ok(result);
-        }
-        
-        let mut result = Vec::new();
-        let mut start = 0;
-        
-        for (i, &byte) in data.iter().enumerate() {
-            if byte == b'\n' {
-                if self.remaining > 0 {
-                    self.remaining -= 1;
-                    start = i + 1;
-                } else {
-                    self.buffer.extend_from_slice(&data[start..=i]);
-                    result.extend_from_slice(&self.buffer);
-                    self.buffer.clear();
-                    start = i + 1;
-                }
-            }
-        }
-        
-        // Add remaining data to buffer
-        if start < data.len() {
-            if self.remaining == 0 {
-                result.extend_from_slice(&data[start..]);
+    fn filter<R: Read, W: Write>(&mut self, reader: &mut R, writer: &mut W) -> Result<()> {
+        let buf_reader = std::io::BufReader::new(reader);
+        for line in buf_reader.lines() {
+            let line = line?;
+            if self.remaining > 0 {
+                self.remaining -= 1;
             } else {
-                self.buffer.extend_from_slice(&data[start..]);
+                writeln!(writer, "{}", line)?;
             }
         }
-        
-        Ok(result)
-    }
-
-    fn finish(&mut self) -> Result<Vec<u8>> {
-        if self.remaining == 0 {
-            let result = self.buffer.clone();
-            self.buffer.clear();
-            Ok(result)
-        } else {
-            Ok(Vec::new())
-        }
+        Ok(())
     }
 }

src/filter_plugin/tail.rs

@@ -1,95 +1,75 @@
 use super::FilterPlugin;
-use std::io::Result;
-use ringbuf::{HeapRb, Rb};
+use std::io::{Result, Read, Write, BufRead};
+use std::collections::VecDeque;
 
 pub struct TailBytesFilter {
-    ring_buffer: HeapRb<u8>,
-    _count: usize,
+    buffer: VecDeque<u8>,
+    count: usize,
 }
 
 impl TailBytesFilter {
     pub fn new(count: usize) -> Self {
         Self {
-            ring_buffer: HeapRb::new(count),
-            _count: count,
+            buffer: VecDeque::with_capacity(count),
+            count,
         }
     }
 }
 
 impl FilterPlugin for TailBytesFilter {
-    fn process(&mut self, data: &[u8]) -> Result<Vec<u8>> {
-        for &byte in data {
-            let _ = self.ring_buffer.push(byte);
+    fn filter<R: Read, W: Write>(&mut self, reader: &mut R, writer: &mut W) -> Result<()> {
+        let mut temp_buffer = vec![0; 8192];
+        loop {
+            let bytes_read = reader.read(&mut temp_buffer)?;
+            if bytes_read == 0 {
+                break;
+            }
+            
+            // Add new data to the buffer
+            for &byte in &temp_buffer[..bytes_read] {
+                if self.buffer.len() == self.count {
+                    self.buffer.pop_front();
+                }
+                self.buffer.push_back(byte);
+            }
         }
-        Ok(Vec::new())
-    }
-
-    fn finish(&mut self) -> Result<Vec<u8>> {
-        // Collect all bytes from the ring buffer
-        let mut result = Vec::with_capacity(self.ring_buffer.len());
-        for byte in self.ring_buffer.iter() {
-            result.push(*byte);
-        }
-        Ok(result)
+        
+        // Write the buffered data at the end
+        let result: Vec<u8> = self.buffer.iter().cloned().collect();
+        writer.write_all(&result)?;
+        Ok(())
     }
 }
 
 pub struct TailLinesFilter {
-    ring_buffer: HeapRb<u8>,
+    lines: VecDeque<String>,
     count: usize,
-    lines_found: usize,
 }
 
 impl TailLinesFilter {
     pub fn new(count: usize) -> Self {
         Self {
-            ring_buffer: HeapRb::new(count * 256), // Estimate 256 bytes per line
+            lines: VecDeque::with_capacity(count),
             count,
-            lines_found: 0,
         }
     }
 }
 
 impl FilterPlugin for TailLinesFilter {
-    fn process(&mut self, data: &[u8]) -> Result<Vec<u8>> {
-        for &byte in data {
-            let _ = self.ring_buffer.push(byte);
-            if byte == b'\n' {
-                self.lines_found += 1;
+    fn filter<R: Read, W: Write>(&mut self, reader: &mut R, writer: &mut W) -> Result<()> {
+        let buf_reader = std::io::BufReader::new(reader);
+        for line in buf_reader.lines() {
+            let line = line?;
+            if self.lines.len() == self.count {
+                self.lines.pop_front();
             }
-        }
-        Ok(Vec::new())
-    }
-
-    fn finish(&mut self) -> Result<Vec<u8>> {
-        // For ring buffer, we can use the iter() method to get all elements
-        // Since it's a circular buffer, we need to handle the wrap-around
-        let mut result = Vec::with_capacity(self.ring_buffer.len());
-        
-        // The ring buffer maintains elements in insertion order
-        for byte in self.ring_buffer.iter() {
-            result.push(*byte);
+            self.lines.push_back(line);
         }
         
-        // Now, we need to find the last 'count' lines
-        if self.count == 0 {
-            return Ok(Vec::new());
+        // Write the buffered lines
+        for line in &self.lines {
+            writeln!(writer, "{}", line)?;
         }
-        
-        // Split into lines and take the last 'count' lines
-        let text = String::from_utf8_lossy(&result);
-        let lines: Vec<&str> = text.split('\n').collect();
-        
-        // Take the last 'count' lines
-        let start_index = if lines.len() > self.count {
-            lines.len() - self.count
-        } else {
-            0
-        };
-        
-        let selected_lines = &lines[start_index..];
-        let result_text = selected_lines.join("\n");
-        
-        Ok(result_text.into_bytes())
+        Ok(())
     }
 }

src/filter_plugin/utils.rs

@@ -1,27 +1,4 @@
 use std::io::Result;
-use super::FilterPlugin;
-
-/// Helper trait for common filter operations
-pub trait FilterUtils {
-    /// Process data through a filter, handling empty results
-    fn process_data(&mut self, data: &[u8]) -> Result<Vec<u8>>;
-
-    /// Process data and check if we should continue processing
-    fn process_and_check_continue(&mut self, data: &[u8]) -> Result<(Vec<u8>, bool)>;
-}
-
-impl<T: FilterPlugin> FilterUtils for T {
-    fn process_data(&mut self, data: &[u8]) -> Result<Vec<u8>> {
-        let result = self.process(data)?;
-        Ok(result)
-    }
-
-    fn process_and_check_continue(&mut self, data: &[u8]) -> Result<(Vec<u8>, bool)> {
-        let result = self.process(data)?;
-        let should_continue = !result.is_empty();
-        Ok((result, should_continue))
-    }
-}
 
 /// Helper function to create a filter chain from a string
 pub fn create_filter_chain(filter_str: &str) -> Result<Option<super::FilterChain>> {