writing packets is now friendlier

minecraft-protocol/src/mc_buf.rs

@@ -10,18 +10,31 @@ use tokio::io::{AsyncRead, AsyncReadExt};
 const MAX_STRING_LENGTH: u16 = 32767;
 // const MAX_COMPONENT_STRING_LENGTH: u32 = 262144;
 
-pub fn write_byte(buf: &mut Vec<u8>, n: u8) {
-    WriteBytesExt::write_u8(buf, n).unwrap();
+#[async_trait]
+pub trait Writable {
+    fn write_byte(&mut self, n: u8) -> Result<(), std::io::Error>;
+    fn write_bytes(&mut self, bytes: &[u8]) -> Result<(), std::io::Error>;
+    fn write_varint(&mut self, value: i32) -> Result<(), std::io::Error>;
+    fn write_utf_with_len(&mut self, string: &str, len: usize) -> Result<(), std::io::Error>;
+    fn write_utf(&mut self, string: &str) -> Result<(), std::io::Error>;
+    fn write_short(&mut self, n: u16) -> Result<(), std::io::Error>;
+    fn write_byte_array(&mut self, bytes: &[u8]) -> Result<(), std::io::Error>;
 }
 
-pub fn write_bytes(buf: &mut Vec<u8>, bytes: &[u8]) {
-    buf.extend_from_slice(bytes);
+#[async_trait]
+impl Writable for Vec<u8> {
+    fn write_byte(&mut self, n: u8) -> Result<(), std::io::Error> {
+        WriteBytesExt::write_u8(self, n)
     }
 
-pub fn write_varint(buf: &mut Vec<u8>, mut value: i32) {
+    fn write_bytes(&mut self, bytes: &[u8]) -> Result<(), std::io::Error> {
+        Ok(self.extend_from_slice(bytes))
+    }
+
+    fn write_varint(&mut self, mut value: i32) -> Result<(), std::io::Error> {
         let mut buffer = [0];
         if value == 0 {
-        buf.write_all(&buffer).unwrap();
+            self.write_all(&buffer).unwrap();
         }
         while value != 0 {
             buffer[0] = (value & 0b0111_1111) as u8;
@@ -29,11 +42,12 @@ pub fn write_varint(buf: &mut Vec<u8>, mut value: i32) {
             if value != 0 {
                 buffer[0] |= 0b1000_0000;
             }
-        buf.write_all(&buffer).unwrap();
+            self.write_all(&buffer)?;
         }
+        Ok(())
     }
 
-pub fn write_utf_with_len(buf: &mut Vec<u8>, string: &str, len: usize) {
+    fn write_utf_with_len(&mut self, string: &str, len: usize) -> Result<(), std::io::Error> {
         if string.len() > len {
             panic!(
                 "String too big (was {} bytes encoded, max {})",
@@ -41,20 +55,22 @@ pub fn write_utf_with_len(buf: &mut Vec<u8>, string: &str, len: usize) {
                 len
             );
         }
-    write_varint(buf, string.len() as i32);
-    write_bytes(buf, string.as_bytes());
-}
-pub fn write_utf(buf: &mut Vec<u8>, string: &str) {
-    write_utf_with_len(buf, string, MAX_STRING_LENGTH.into());
+        self.write_varint(string.len() as i32);
+        self.write_bytes(string.as_bytes())
     }
 
-pub fn write_short(buf: &mut Vec<u8>, n: u16) {
-    WriteBytesExt::write_u16::<BigEndian>(buf, n).unwrap();
+    fn write_utf(&mut self, string: &str) -> Result<(), std::io::Error> {
+        self.write_utf_with_len(string, MAX_STRING_LENGTH.into())
     }
 
-pub fn write_byte_array(buf: &mut Vec<u8>, bytes: &[u8]) {
-    write_varint(buf, bytes.len() as i32);
-    write_bytes(buf, bytes);
+    fn write_short(&mut self, n: u16) -> Result<(), std::io::Error> {
+        WriteBytesExt::write_u16::<BigEndian>(self, n)
+    }
+
+    fn write_byte_array(&mut self, bytes: &[u8]) -> Result<(), std::io::Error> {
+        self.write_varint(bytes.len() as i32);
+        self.write_bytes(bytes)
+    }
 }
 
 #[async_trait]
@@ -159,11 +175,11 @@ mod tests {
     #[test]
     fn test_write_varint() {
         let mut buf = Vec::new();
-        write_varint(&mut buf, 123456);
+        buf.write_varint(123456);
         assert_eq!(buf, vec![192, 196, 7]);
 
         let mut buf = Vec::new();
-        write_varint(&mut buf, 0);
+        buf.write_varint(0);
         assert_eq!(buf, vec![0]);
     }
 

minecraft-protocol/src/packets/handshake/client_intention_packet.rs

@@ -2,7 +2,7 @@ use std::hash::Hash;
 
 use tokio::io::BufReader;
 
-use crate::{mc_buf, packets::ConnectionProtocol};
+use crate::{mc_buf::Writable, packets::ConnectionProtocol};
 
 use super::HandshakePacket;
 
@@ -21,10 +21,10 @@ impl ClientIntentionPacket {
     }
 
     pub fn write(&self, buf: &mut Vec<u8>) {
-        mc_buf::write_varint(buf, self.protocol_version as i32);
-        mc_buf::write_utf(buf, &self.hostname);
-        mc_buf::write_short(buf, self.port);
-        mc_buf::write_varint(buf, self.intention.clone() as i32);
+        buf.write_varint(self.protocol_version as i32).unwrap();
+        buf.write_utf(&self.hostname).unwrap();
+        buf.write_short(self.port).unwrap();
+        buf.write_varint(self.intention.clone() as i32).unwrap();
     }
 
     pub async fn read<T: tokio::io::AsyncRead + std::marker::Unpin + std::marker::Send>(

minecraft-protocol/src/packets/login/serverbound_hello_packet.rs

@@ -1,7 +1,7 @@
 use std::hash::Hash;
 use tokio::io::BufReader;
 
-use crate::mc_buf;
+use crate::mc_buf::Writable;
 
 use super::LoginPacket;
 
@@ -16,7 +16,7 @@ impl ServerboundHelloPacket {
     }
 
     pub fn write(&self, buf: &mut Vec<u8>) {
-        mc_buf::write_utf(buf, &self.username);
+        buf.write_utf(&self.username).unwrap();
     }
 
     pub async fn read<T: tokio::io::AsyncRead + std::marker::Unpin + std::marker::Send>(

minecraft-protocol/src/write.rs

@@ -1,6 +1,6 @@
 use tokio::{io::AsyncWriteExt, net::TcpStream};
 
-use crate::{mc_buf, packets::ProtocolPacket};
+use crate::{mc_buf::Writable, packets::ProtocolPacket};
 
 pub async fn write_packet(packet: impl ProtocolPacket, stream: &mut TcpStream) {
     // TODO: implement compression
@@ -10,7 +10,7 @@ pub async fn write_packet(packet: impl ProtocolPacket, stream: &mut TcpStream) {
 
     // write the packet id
     let mut id_and_data_buf = vec![];
-    mc_buf::write_varint(&mut id_and_data_buf, packet.id() as i32);
+    id_and_data_buf.write_varint(packet.id() as i32);
     packet.write(&mut id_and_data_buf);
 
     // write the packet data
@@ -18,7 +18,7 @@ pub async fn write_packet(packet: impl ProtocolPacket, stream: &mut TcpStream) {
     // make a new buffer that has the length at the beginning
     // and id+data at the end
     let mut complete_buf: Vec<u8> = Vec::new();
-    mc_buf::write_varint(&mut complete_buf, id_and_data_buf.len() as i32);
+    complete_buf.write_varint(id_and_data_buf.len() as i32);
     complete_buf.append(&mut id_and_data_buf);
 
     // finally, write and flush to the stream