start improving packet macros

3 files changed, 573 insertions, 0 deletions

diff --git a/azalea-protocol/src/mc_buf/mod.rs b/azalea-protocol/src/mc_buf/mod.rs
new file mode 100644
index 00000000..a924431e
--- /dev/null
+++ b/azalea-protocol/src/mc_buf/mod.rs
@@ -0,0 +1,163 @@
+//! Utilities for reading and writing for the Minecraft protocol
+
+mod read;
+mod write;
+
+pub use read::{McBufReadable, McBufVarintReadable, Readable};
+pub use write::{McBufVarintWritable, McBufWritable, Writable};
+
+// const DEFAULT_NBT_QUOTA: u32 = 2097152;
+const MAX_STRING_LENGTH: u16 = 32767;
+// const MAX_COMPONENT_STRING_LENGTH: u32 = 262144;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use azalea_core::resource_location::ResourceLocation;
+    use std::{collections::HashMap, io::Cursor};
+    use tokio::io::BufReader;
+
+    #[test]
+    fn test_write_varint() {
+        let mut buf = Vec::new();
+        buf.write_varint(123456).unwrap();
+        assert_eq!(buf, vec![192, 196, 7]);
+
+        let mut buf = Vec::new();
+        buf.write_varint(0).unwrap();
+        assert_eq!(buf, vec![0]);
+    }
+
+    #[tokio::test]
+    async fn test_read_varint() {
+        let mut buf = BufReader::new(Cursor::new(vec![192, 196, 7]));
+        assert_eq!(buf.read_varint().await.unwrap(), 123456);
+        assert_eq!(buf.get_varint_size(123456), 3);
+
+        let mut buf = BufReader::new(Cursor::new(vec![0]));
+        assert_eq!(buf.read_varint().await.unwrap(), 0);
+        assert_eq!(buf.get_varint_size(0), 1);
+
+        let mut buf = BufReader::new(Cursor::new(vec![1]));
+        assert_eq!(buf.read_varint().await.unwrap(), 1);
+        assert_eq!(buf.get_varint_size(1), 1);
+    }
+
+    #[tokio::test]
+    async fn test_read_varint_longer() {
+        let mut buf = BufReader::new(Cursor::new(vec![138, 56, 0, 135, 56, 123]));
+        assert_eq!(buf.read_varint().await.unwrap(), 7178);
+    }
+
+    #[tokio::test]
+    async fn test_list() {
+        let mut buf = Vec::new();
+        buf.write_list(&vec!["a", "bc", "def"], |buf, s| buf.write_utf(s))
+            .unwrap();
+
+        // there's no read_list because idk how to do it in rust
+        let mut buf = BufReader::new(Cursor::new(buf));
+
+        let mut result = Vec::new();
+        let length = buf.read_varint().await.unwrap();
+        for _ in 0..length {
+            result.push(buf.read_utf().await.unwrap());
+        }
+
+        assert_eq!(result, vec!["a", "bc", "def"]);
+    }
+
+    #[tokio::test]
+    async fn test_int_id_list() {
+        let mut buf = Vec::new();
+        buf.write_list(&vec![1, 2, 3], |buf, i| buf.write_varint(*i))
+            .unwrap();
+
+        let mut buf = BufReader::new(Cursor::new(buf));
+
+        let result = buf.read_int_id_list().await.unwrap();
+        assert_eq!(result, vec![1, 2, 3]);
+    }
+
+    #[tokio::test]
+    async fn test_map() {
+        let mut buf = Vec::new();
+        buf.write_map(
+            vec![("a", 1), ("bc", 23), ("def", 456)],
+            Vec::write_utf,
+            Vec::write_varint,
+        )
+        .unwrap();
+
+        let mut buf = BufReader::new(Cursor::new(buf));
+
+        let mut result = Vec::new();
+        let length = buf.read_varint().await.unwrap();
+        for _ in 0..length {
+            result.push((
+                buf.read_utf().await.unwrap(),
+                buf.read_varint().await.unwrap(),
+            ));
+        }
+
+        assert_eq!(
+            result,
+            vec![
+                ("a".to_string(), 1),
+                ("bc".to_string(), 23),
+                ("def".to_string(), 456)
+            ]
+        );
+    }
+
+    #[tokio::test]
+    async fn test_nbt() {
+        let mut buf = Vec::new();
+        buf.write_nbt(&azalea_nbt::Tag::Compound(HashMap::from_iter(vec![(
+            "hello world".to_string(),
+            azalea_nbt::Tag::Compound(HashMap::from_iter(vec![(
+                "name".to_string(),
+                azalea_nbt::Tag::String("Bananrama".to_string()),
+            )])),
+        )])))
+        .unwrap();
+
+        let mut buf = BufReader::new(Cursor::new(buf));
+
+        let result = buf.read_nbt().await.unwrap();
+        assert_eq!(
+            result,
+            azalea_nbt::Tag::Compound(HashMap::from_iter(vec![(
+                "hello world".to_string(),
+                azalea_nbt::Tag::Compound(HashMap::from_iter(vec![(
+                    "name".to_string(),
+                    azalea_nbt::Tag::String("Bananrama".to_string()),
+                )])),
+            )]))
+        );
+    }
+
+    #[tokio::test]
+    async fn test_long() {
+        let mut buf = Vec::new();
+        buf.write_long(123456).unwrap();
+
+        let mut buf = BufReader::new(Cursor::new(buf));
+
+        assert_eq!(buf.read_long().await.unwrap(), 123456);
+    }
+
+    #[tokio::test]
+    async fn test_resource_location() {
+        let mut buf = Vec::new();
+        buf.write_resource_location(&ResourceLocation::new("minecraft:dirt").unwrap())
+            .unwrap();
+
+        let mut buf = BufReader::new(Cursor::new(buf));
+
+        assert_eq!(
+            buf.read_resource_location().await.unwrap(),
+            ResourceLocation::new("minecraft:dirt").unwrap()
+        );
+    }
+}
diff --git a/azalea-protocol/src/mc_buf/read.rs b/azalea-protocol/src/mc_buf/read.rs
new file mode 100644
index 00000000..c429eb7f
--- /dev/null
+++ b/azalea-protocol/src/mc_buf/read.rs
@@ -0,0 +1,230 @@
+use async_trait::async_trait;
+use azalea_core::resource_location::ResourceLocation;
+use tokio::io::{AsyncRead, AsyncReadExt};
+
+use super::MAX_STRING_LENGTH;
+
+#[async_trait]
+pub trait Readable {
+    async fn read_int_id_list(&mut self) -> Result<Vec<i32>, String>;
+    async fn read_varint(&mut self) -> Result<i32, String>;
+    fn get_varint_size(&mut self, value: i32) -> u8;
+    fn get_varlong_size(&mut self, value: i32) -> u8;
+    async fn read_byte_array(&mut self) -> Result<Vec<u8>, String>;
+    async fn read_bytes_with_len(&mut self, n: usize) -> Result<Vec<u8>, String>;
+    async fn read_bytes(&mut self) -> Result<Vec<u8>, String>;
+    async fn read_utf(&mut self) -> Result<String, String>;
+    async fn read_utf_with_len(&mut self, max_length: u32) -> Result<String, String>;
+    async fn read_byte(&mut self) -> Result<u8, String>;
+    async fn read_int(&mut self) -> Result<i32, String>;
+    async fn read_boolean(&mut self) -> Result<bool, String>;
+    async fn read_nbt(&mut self) -> Result<azalea_nbt::Tag, String>;
+    async fn read_long(&mut self) -> Result<i64, String>;
+    async fn read_resource_location(&mut self) -> Result<ResourceLocation, String>;
+    async fn read_short(&mut self) -> Result<i16, String>;
+}
+
+#[async_trait]
+impl<R> Readable for R
+where
+    R: AsyncRead + std::marker::Unpin + std::marker::Send,
+{
+    async fn read_int_id_list(&mut self) -> Result<Vec<i32>, String> {
+        let len = self.read_varint().await?;
+        let mut list = Vec::with_capacity(len as usize);
+        for _ in 0..len {
+            list.push(self.read_varint().await?);
+        }
+        Ok(list)
+    }
+
+    // fast varints stolen from https://github.com/luojia65/mc-varint/blob/master/src/lib.rs#L67
+    /// Read a single varint from the reader and return the value, along with the number of bytes read
+    async fn read_varint(&mut self) -> Result<i32, String> {
+        let mut buffer = [0];
+        let mut ans = 0;
+        for i in 0..4 {
+            self.read_exact(&mut buffer)
+                .await
+                .map_err(|_| "Invalid VarInt".to_string())?;
+            ans |= ((buffer[0] & 0b0111_1111) as i32) << (7 * i);
+            if buffer[0] & 0b1000_0000 == 0 {
+                return Ok(ans);
+            }
+        }
+        Ok(ans)
+    }
+
+    fn get_varint_size(&mut self, value: i32) -> u8 {
+        for i in 1..5 {
+            if (value & -1 << (i * 7)) != 0 {
+                continue;
+            }
+            return i;
+        }
+        5
+    }
+
+    fn get_varlong_size(&mut self, value: i32) -> u8 {
+        for i in 1..10 {
+            if (value & -1 << (i * 7)) != 0 {
+                continue;
+            }
+            return i;
+        }
+        10
+    }
+
+    async fn read_byte_array(&mut self) -> Result<Vec<u8>, String> {
+        let length = self.read_varint().await? as usize;
+        Ok(self.read_bytes_with_len(length).await?)
+    }
+
+    async fn read_bytes_with_len(&mut self, n: usize) -> Result<Vec<u8>, String> {
+        let mut bytes = vec![0; n];
+        match AsyncReadExt::read_exact(self, &mut bytes).await {
+            Ok(_) => Ok(bytes),
+            Err(_) => Err("Error reading bytes".to_string()),
+        }
+    }
+
+    async fn read_bytes(&mut self) -> Result<Vec<u8>, String> {
+        // read to end of the buffer
+        let mut bytes = vec![];
+        AsyncReadExt::read_to_end(self, &mut bytes)
+            .await
+            .map_err(|_| "Error reading bytes".to_string())?;
+        Ok(bytes)
+    }
+
+    async fn read_utf(&mut self) -> Result<String, String> {
+        self.read_utf_with_len(MAX_STRING_LENGTH.into()).await
+    }
+
+    async fn read_utf_with_len(&mut self, max_length: u32) -> Result<String, String> {
+        let length = self.read_varint().await?;
+        // i don't know why it's multiplied by 4 but it's like that in mojang's code so
+        if length < 0 {
+            return Err(
+                "The received encoded string buffer length is less than zero! Weird string!"
+                    .to_string(),
+            );
+        }
+        if length as u32 > max_length * 4 {
+            return Err(format!(
+                "The received encoded string buffer length is longer than maximum allowed ({} > {})",
+                length,
+                max_length * 4
+            ));
+        }
+
+        // this is probably quite inefficient, idk how to do it better
+        let mut string = String::new();
+        let mut buffer = vec![0; length as usize];
+        self.read_exact(&mut buffer)
+            .await
+            .map_err(|_| "Invalid UTF-8".to_string())?;
+
+        string.push_str(std::str::from_utf8(&buffer).unwrap());
+        if string.len() > length as usize {
+            return Err(format!(
+                "The received string length is longer than maximum allowed ({} > {})",
+                length, max_length
+            ));
+        }
+
+        Ok(string)
+    }
+
+    /// Read a single byte from the reader
+    async fn read_byte(&mut self) -> Result<u8, String> {
+        match AsyncReadExt::read_u8(self).await {
+            Ok(r) => Ok(r),
+            Err(_) => Err("Error reading byte".to_string()),
+        }
+    }
+
+    async fn read_int(&mut self) -> Result<i32, String> {
+        match AsyncReadExt::read_i32(self).await {
+            Ok(r) => Ok(r),
+            Err(_) => Err("Error reading int".to_string()),
+        }
+    }
+
+    async fn read_boolean(&mut self) -> Result<bool, String> {
+        match self.read_byte().await {
+            Ok(0) => Ok(false),
+            Ok(1) => Ok(true),
+            _ => Err("Error reading boolean".to_string()),
+        }
+    }
+
+    async fn read_nbt(&mut self) -> Result<azalea_nbt::Tag, String> {
+        match azalea_nbt::Tag::read(self).await {
+            Ok(r) => Ok(r),
+            // Err(e) => Err(e.to_string()),
+            Err(e) => Err(e.to_string()).unwrap(),
+        }
+    }
+
+    async fn read_long(&mut self) -> Result<i64, String> {
+        match AsyncReadExt::read_i64(self).await {
+            Ok(r) => Ok(r),
+            Err(_) => Err("Error reading long".to_string()),
+        }
+    }
+
+    async fn read_resource_location(&mut self) -> Result<ResourceLocation, String> {
+        // get the resource location from the string
+        let location_string = self.read_utf().await?;
+        let location = ResourceLocation::new(&location_string)?;
+        Ok(location)
+    }
+
+    async fn read_short(&mut self) -> Result<i16, String> {
+        match AsyncReadExt::read_i16(self).await {
+            Ok(r) => Ok(r),
+            Err(_) => Err("Error reading short".to_string()),
+        }
+    }
+}
+
+#[async_trait]
+pub trait McBufReadable
+where
+    Self: Sized,
+{
+    async fn read_into<R>(buf: &mut R) -> Result<Self, String>
+    where
+        R: AsyncRead + std::marker::Unpin + std::marker::Send;
+}
+
+#[async_trait]
+pub trait McBufVarintReadable
+where
+    Self: Sized,
+{
+    async fn varint_read_into<R>(buf: &mut R) -> Result<Self, String>
+    where
+        R: AsyncRead + std::marker::Unpin + std::marker::Send;
+}
+
+#[async_trait]
+impl McBufReadable for i32 {
+    async fn read_into<R>(buf: &mut R) -> Result<Self, String>
+    where
+        R: AsyncRead + std::marker::Unpin + std::marker::Send,
+    {
+        buf.read_int().await
+    }
+}
+
+#[async_trait]
+impl McBufVarintReadable for i32 {
+    async fn varint_read_into<R>(buf: &mut R) -> Result<Self, String>
+    where
+        R: AsyncRead + std::marker::Unpin + std::marker::Send,
+    {
+        buf.read_varint().await
+    }
+}
diff --git a/azalea-protocol/src/mc_buf/write.rs b/azalea-protocol/src/mc_buf/write.rs
new file mode 100644
index 00000000..3c3375b9
--- /dev/null
+++ b/azalea-protocol/src/mc_buf/write.rs
@@ -0,0 +1,180 @@
+use async_trait::async_trait;
+use azalea_core::resource_location::ResourceLocation;
+use byteorder::{BigEndian, WriteBytesExt};
+use std::io::Write;
+
+use super::MAX_STRING_LENGTH;
+
+#[async_trait]
+pub trait Writable {
+    fn write_list<F, T>(&mut self, list: &[T], writer: F) -> Result<(), std::io::Error>
+    where
+        F: FnOnce(&mut Self, &T) -> Result<(), std::io::Error> + Copy,
+        T: Sized,
+        Self: Sized;
+    fn write_int_id_list(&mut self, list: Vec<i32>) -> Result<(), std::io::Error>;
+    fn write_map<KF, VF, KT, VT>(
+        &mut self,
+        map: Vec<(KT, VT)>,
+        key_writer: KF,
+        value_writer: VF,
+    ) -> Result<(), std::io::Error>
+    where
+        KF: Fn(&mut Self, KT) -> Result<(), std::io::Error> + Copy,
+        VF: Fn(&mut Self, VT) -> Result<(), std::io::Error> + Copy,
+        Self: Sized;
+
+    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: i16) -> Result<(), std::io::Error>;
+    fn write_byte_array(&mut self, bytes: &[u8]) -> Result<(), std::io::Error>;
+    fn write_int(&mut self, n: i32) -> Result<(), std::io::Error>;
+    fn write_boolean(&mut self, b: bool) -> Result<(), std::io::Error>;
+    fn write_nbt(&mut self, nbt: &azalea_nbt::Tag) -> Result<(), std::io::Error>;
+    fn write_long(&mut self, n: i64) -> Result<(), std::io::Error>;
+    fn write_resource_location(
+        &mut self,
+        location: &ResourceLocation,
+    ) -> Result<(), std::io::Error>;
+}
+
+#[async_trait]
+impl Writable for Vec<u8> {
+    fn write_list<F, T>(&mut self, list: &[T], writer: F) -> Result<(), std::io::Error>
+    where
+        F: FnOnce(&mut Self, &T) -> Result<(), std::io::Error> + Copy,
+        Self: Sized,
+    {
+        self.write_varint(list.len() as i32)?;
+        for item in list {
+            writer(self, item)?;
+        }
+        Ok(())
+    }
+
+    fn write_int_id_list(&mut self, list: Vec<i32>) -> Result<(), std::io::Error> {
+        self.write_list(&list, |buf, n| buf.write_varint(*n))
+    }
+
+    fn write_map<KF, VF, KT, VT>(
+        &mut self,
+        map: Vec<(KT, VT)>,
+        key_writer: KF,
+        value_writer: VF,
+    ) -> Result<(), std::io::Error>
+    where
+        KF: Fn(&mut Self, KT) -> Result<(), std::io::Error> + Copy,
+        VF: Fn(&mut Self, VT) -> Result<(), std::io::Error> + Copy,
+        Self: Sized,
+    {
+        self.write_varint(map.len() as i32)?;
+        for (key, value) in map {
+            key_writer(self, key)?;
+            value_writer(self, value)?;
+        }
+        Ok(())
+    }
+
+    fn write_byte(&mut self, n: u8) -> Result<(), std::io::Error> {
+        WriteBytesExt::write_u8(self, n)
+    }
+
+    fn write_bytes(&mut self, bytes: &[u8]) -> Result<(), std::io::Error> {
+        self.extend_from_slice(bytes);
+        Ok(())
+    }
+
+    fn write_varint(&mut self, mut value: i32) -> Result<(), std::io::Error> {
+        let mut buffer = [0];
+        if value == 0 {
+            self.write_all(&buffer).unwrap();
+        }
+        while value != 0 {
+            buffer[0] = (value & 0b0111_1111) as u8;
+            value = (value >> 7) & (i32::max_value() >> 6);
+            if value != 0 {
+                buffer[0] |= 0b1000_0000;
+            }
+            self.write_all(&buffer)?;
+        }
+        Ok(())
+    }
+
+    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 {})",
+                string.len(),
+                len
+            );
+        }
+        self.write_varint(string.len() as i32)?;
+        self.write_bytes(string.as_bytes())
+    }
+
+    fn write_utf(&mut self, string: &str) -> Result<(), std::io::Error> {
+        self.write_utf_with_len(string, MAX_STRING_LENGTH.into())
+    }
+
+    fn write_short(&mut self, n: i16) -> Result<(), std::io::Error> {
+        WriteBytesExt::write_i16::<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)
+    }
+
+    fn write_int(&mut self, n: i32) -> Result<(), std::io::Error> {
+        WriteBytesExt::write_i32::<BigEndian>(self, n)
+    }
+
+    fn write_boolean(&mut self, b: bool) -> Result<(), std::io::Error> {
+        self.write_byte(if b { 1 } else { 0 })
+    }
+
+    fn write_nbt(&mut self, nbt: &azalea_nbt::Tag) -> Result<(), std::io::Error> {
+        nbt.write(self)
+            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e.to_string()))
+    }
+
+    fn write_long(&mut self, n: i64) -> Result<(), std::io::Error> {
+        WriteBytesExt::write_i64::<BigEndian>(self, n)
+    }
+
+    fn write_resource_location(
+        &mut self,
+        location: &ResourceLocation,
+    ) -> Result<(), std::io::Error> {
+        self.write_utf(&location.to_string())
+    }
+}
+
+pub trait McBufWritable
+where
+    Self: Sized,
+{
+    fn write_into(&self, buf: &mut Vec<u8>) -> Result<(), std::io::Error>;
+}
+
+pub trait McBufVarintWritable
+where
+    Self: Sized,
+{
+    fn varint_write_into(&self, buf: &mut Vec<u8>) -> Result<(), std::io::Error>;
+}
+
+impl McBufWritable for i32 {
+    fn write_into(&self, buf: &mut Vec<u8>) -> Result<(), std::io::Error> {
+        Writable::write_int(buf, *self)
+    }
+}
+
+impl McBufVarintWritable for i32 {
+    fn varint_write_into(&self, buf: &mut Vec<u8>) -> Result<(), std::io::Error> {
+        buf.write_varint(*self)
+    }
+}