buffer optimizations

Author: andygrove

Cargo.lock

@@ -70,35 +70,8 @@ struct DemoHandler {}
 impl PacketHandler for DemoHandler {
 
     fn handle_request(&self, p: &Packet) -> Action {
-        print_packet_chars(&p.bytes);
-        match p.packet_type() {
-            Ok(PacketType::ComQuery) => {
-
-                // ComQuery packets just contain a SQL string as the payload
-                let slice = &p.bytes[5..];
-
-                // convert the slice to a String object
-                let sql = String::from_utf8(slice.to_vec()).expect("Invalid UTF-8");
-
-                // log the query
-                println!("SQL: {}", sql);
-
-                // dumb example of conditional proxy behavior
-                if sql.contains("avocado") {
-                    // take over processing of this packet and return an error packet
-                    // to the client
-                    Action::Respond(vec![Packet::error_packet(
-                                                1064, // error code
-                                                [0x31,0x32,0x33,0x34,0x35], // sql state
-                                                String::from("Proxy rejecting any avocado-related queries"))])
-                } else {
-                    // pass the packet to MySQL unmodified
-                    Action::Forward
-                }
-            },
-            // pass the packet to MySQL unmodified
-            _ => Action::Forward
-        }
+//
+        Action::Forward
     }
 
     fn handle_response(&self, _: &Packet) -> Action {

examples/proxy.rs

@@ -193,15 +193,17 @@ impl ConnReader {
                 let mut temp : Vec<u8> = Vec::with_capacity(s);
                 temp.extend_from_slice(&self.read_buf[0..s]);
                 let p = Packet { bytes: temp };
-
-                // shift data down
-                let mut j = 0;
-                for i in s .. self.read_pos {
-                    self.read_buf[j] = self.read_buf[i];
-                    j += 1;
+                if self.read_pos == s {
+                    self.read_pos = 0;
+                } else {
+                    // shift data down
+                    let mut j = 0;
+                    for i in s .. self.read_pos {
+                        self.read_buf[j] = self.read_buf[i];
+                        j += 1;
+                    }
+                    self.read_pos -= s;
                 }
-                self.read_pos -= s;
-
                 Some(p)
             } else {
                 None
@@ -236,13 +238,18 @@ impl ConnWriter {
             match self.stream.poll_write() {
                 Async::Ready(_) => {
                     let s = try!((&*self.stream).write(&self.write_buf[0..self.write_pos]));
-
-                    let mut j = 0;
-                    for i in s..self.write_pos {
-                        self.write_buf[j] = self.write_buf[i];
-                        j += 1;
+                    if s == self.write_pos {
+                        self.write_pos = 0;
+                    } else {
+                        // for a partial write, shift data down
+                        let mut j = 0;
+                        for i in s..self.write_pos {
+                            self.write_buf[j] = self.write_buf[i];
+                            j += 1;
+                        }
+                        self.write_pos -= s;
                     }
-                    self.write_pos -= s;
+
                 },
                 _ => return Ok(Async::NotReady)
             }