Add block state generator

Cargo.toml

@@ -5,9 +5,7 @@ edition = "2021"
 description = "A framework for building Minecraft servers in Rust."
 repository = "https://github.com/rj00a/valence"
 license = "MIT"
-
-[workspace]
-members = ["valence-data"]
+build = "build/main.rs"
 
 [dependencies]
 aes = "0.7"
@@ -48,3 +46,11 @@ features = ["rustls-tls", "json"]
 
 [dev-dependencies]
 env_logger = "0.9"
+
+[build-dependencies]
+anyhow = "1"
+heck = "0.4"
+proc-macro2 = "1"
+quote = "1"
+serde = {version = "1", features = ["derive"]}
+serde_json = "1"

build/block.rs

@@ -0,0 +1,584 @@
+// TODO: can't match on str in const fn.
+
+use std::collections::BTreeSet;
+use std::path::Path;
+use std::process::Command;
+use std::{env, fs};
+
+use anyhow::Context;
+use heck::{ToPascalCase, ToShoutySnakeCase};
+use proc_macro2::TokenStream;
+use quote::quote;
+use serde::Deserialize;
+
+use crate::ident;
+
+pub fn build() -> anyhow::Result<()> {
+    let blocks = parse_blocks_json()?;
+
+    let max_block_state = blocks.iter().map(|b| b.max_state_id).max().unwrap();
+
+    let state_to_type = blocks
+        .iter()
+        .map(|b| {
+            let min = b.min_state_id;
+            let max = b.max_state_id;
+            let name = ident(b.name.to_pascal_case());
+            quote! {
+                #min..=#max => BlockType::#name,
+            }
+        })
+        .collect::<TokenStream>();
+
+    let get_arms = blocks
+        .iter()
+        .filter(|&b| !b.props.is_empty())
+        .map(|b| {
+            let block_type_name = ident(b.name.to_pascal_case());
+
+            let arms = b
+                .props
+                .iter()
+                .map(|p| {
+                    let prop_name = ident(p.name.to_pascal_case());
+                    let min_state_id = b.min_state_id;
+                    let product: u16 = b
+                        .props
+                        .iter()
+                        .take_while(|&other| p.name != other.name)
+                        .map(|p| p.vals.len() as u16)
+                        .product();
+
+                    let num_values = p.vals.len() as u16;
+
+                    let arms = p.vals.iter().enumerate().map(|(i, v)| {
+                        let value_idx = i as u16;
+                        let value_name = ident(v.to_pascal_case());
+                        quote! {
+                            #value_idx => Some(PropValue::#value_name),
+                        }
+                    }).collect::<TokenStream>();
+
+                    quote! {
+                        PropName::#prop_name => match (self.0 - #min_state_id) / #product % #num_values {
+                            #arms
+                            _ => unreachable!(),
+                        },
+                    }
+                })
+                .collect::<TokenStream>();
+
+            quote! {
+                BlockType::#block_type_name => match name {
+                    #arms
+                    _ => None,
+                },
+            }
+        })
+        .collect::<TokenStream>();
+
+    let set_arms = blocks
+        .iter()
+        .filter(|&b| !b.props.is_empty())
+        .map(|b| {
+            let block_type_name = ident(b.name.to_pascal_case());
+
+            let arms = b
+                .props
+                .iter()
+                .map(|p| {
+                    let prop_name = ident(p.name.to_pascal_case());
+                    let min_state_id = b.min_state_id;
+                    let product: u16 = b
+                        .props
+                        .iter()
+                        .take_while(|&other| p.name != other.name)
+                        .map(|p| p.vals.len() as u16)
+                        .product();
+
+                    let num_values = p.vals.len() as u16;
+
+                    let arms = p
+                        .vals
+                        .iter()
+                        .enumerate()
+                        .map(|(i, v)| {
+                            let val_idx = i as u16;
+                            let val_name = ident(v.to_pascal_case());
+                            quote! {
+                                PropValue::#val_name =>
+                                    Self(self.0 - (self.0 - #min_state_id) / #product % #num_values * #product
+                                        + #val_idx * #product),
+                            }
+                        })
+                        .collect::<TokenStream>();
+
+                    quote! {
+                        PropName::#prop_name => match val {
+                            #arms
+                            _ => self,
+                        },
+                    }
+                })
+                .collect::<TokenStream>();
+
+            quote! {
+                BlockType::#block_type_name => match name {
+                    #arms
+                    _ => self,
+                },
+            }
+        })
+        .collect::<TokenStream>();
+
+    let default_block_states = blocks
+        .iter()
+        .map(|b| {
+            let name = ident(b.name.to_shouty_snake_case());
+            let state = b.default_state;
+            let doc = format!("The default block state for `{}`.", b.name);
+            quote! {
+                #[doc = #doc]
+                pub const #name: BlockState = BlockState(#state);
+            }
+        })
+        .collect::<TokenStream>();
+
+    let type_to_state = blocks
+        .iter()
+        .map(|b| {
+            let typ = ident(b.name.to_pascal_case());
+            let state = ident(b.name.to_shouty_snake_case());
+            quote! {
+                BlockType::#typ => BlockState::#state,
+            }
+        })
+        .collect::<TokenStream>();
+
+    let block_type_variants = blocks
+        .iter()
+        .map(|b| ident(b.name.to_pascal_case()))
+        .collect::<Vec<_>>();
+
+    let block_type_from_str_arms = blocks
+        .iter()
+        .map(|b| {
+            let name = &b.name;
+            let name_ident = ident(name.to_pascal_case());
+            quote! {
+                #name => Some(BlockType::#name_ident),
+            }
+        })
+        .collect::<TokenStream>();
+
+    let block_type_to_str_arms = blocks
+        .iter()
+        .map(|b| {
+            let name = &b.name;
+            let name_ident = ident(name.to_pascal_case());
+            quote! {
+                BlockType::#name_ident => #name,
+            }
+        })
+        .collect::<TokenStream>();
+
+    let block_type_props_arms = blocks
+        .iter()
+        .filter(|&b| !b.props.is_empty())
+        .map(|b| {
+            let name = ident(b.name.to_pascal_case());
+            let prop_names = b.props.iter().map(|p| ident(p.name.to_pascal_case()));
+
+            quote! {
+                Self::#name => &[#(PropName::#prop_names,)*],
+            }
+        })
+        .collect::<TokenStream>();
+
+    let num_block_types = blocks.len();
+
+    let prop_names = blocks
+        .iter()
+        .flat_map(|b| b.props.iter().map(|p| &p.name))
+        .collect::<BTreeSet<_>>();
+
+    let prop_name_variants = prop_names
+        .iter()
+        .map(|&name| ident(name.to_pascal_case()))
+        .collect::<Vec<_>>();
+
+    let prop_name_from_str_arms = prop_names
+        .iter()
+        .map(|&name| {
+            let ident = ident(name.to_pascal_case());
+            quote! {
+                #name => Some(PropName::#ident),
+            }
+        })
+        .collect::<TokenStream>();
+
+    let prop_name_to_str_arms = prop_names
+        .iter()
+        .map(|&name| {
+            let ident = ident(name.to_pascal_case());
+            quote! {
+                PropName::#ident => #name,
+            }
+        })
+        .collect::<TokenStream>();
+
+    let num_prop_names = prop_names.len();
+
+    let prop_values = blocks
+        .iter()
+        .flat_map(|b| b.props.iter().flat_map(|p| &p.vals))
+        .collect::<BTreeSet<_>>();
+
+    let prop_value_variants = prop_values
+        .iter()
+        .map(|val| ident(val.to_pascal_case()))
+        .collect::<Vec<_>>();
+
+    let prop_value_from_str_arms = prop_values
+        .iter()
+        .map(|val| {
+            let ident = ident(val.to_pascal_case());
+            quote! {
+                #val => Some(PropValue::#ident),
+            }
+        })
+        .collect::<TokenStream>();
+
+    let prop_value_to_str_arms = prop_values
+        .iter()
+        .map(|val| {
+            let ident = ident(val.to_pascal_case());
+            quote! {
+                PropValue::#ident => #val,
+            }
+        })
+        .collect::<TokenStream>();
+
+    let prop_value_from_u16_arms = prop_values
+        .iter()
+        .filter_map(|v| v.parse::<u16>().ok())
+        .map(|n| {
+            let ident = ident(n.to_string());
+            quote! {
+                #n => Some(PropValue::#ident),
+            }
+        })
+        .collect::<TokenStream>();
+
+    let prop_value_to_u16_arms = prop_values
+        .iter()
+        .filter_map(|v| v.parse::<u16>().ok())
+        .map(|n| {
+            let ident = ident(n.to_string());
+            quote! {
+                PropValue::#ident => Some(#n),
+            }
+        })
+        .collect::<TokenStream>();
+
+    let num_property_names = prop_values.len();
+
+    let finshed = quote! {
+        /// Represents the state of a block, not including block entity data such as
+        /// the text on a sign, the design on a banner, or the content of a spawner.
+        #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Default, Hash, Debug)]
+        pub struct BlockState(u16);
+
+        impl BlockState {
+            /// Returns the default block state for a given block type.
+            pub const fn from_type(typ: BlockType) -> Self {
+                match typ {
+                    #type_to_state
+                }
+            }
+
+            /// Returns the [`BlockType`] of this block state.
+            pub const fn to_type(self) -> BlockType {
+                match self.0 {
+                    #state_to_type
+                    _ => unreachable!(),
+                }
+            }
+
+            /// Constructs a block state from a raw block state ID.
+            ///
+            /// If the given ID is invalid, `None` is returned.
+            pub const fn from_raw(id: u16) -> Option<Self> {
+                if id <= #max_block_state {
+                    Some(Self(id))
+                } else {
+                    None
+                }
+            }
+
+            /// Converts this block state to its underlying raw block state ID.
+            ///
+            /// The original block state can be recovered with [`BlockState::from_raw`].
+            pub const fn to_raw(self) -> u16 {
+                self.0
+            }
+
+            /// Gets the value of the property with the given name from this block.
+            /// 
+            /// If this block does not have the property, then `None` is returned.
+            pub const fn get(self, name: PropName) -> Option<PropValue> {
+                match self.to_type() {
+                    #get_arms
+                    _ => None
+                }
+            }
+
+            /// Sets the value of a propery on this block, returning the modified block.
+            /// 
+            /// If this block does not have the given property or the property value is invalid,
+            /// then the orginal block is returned unchanged.
+            #[must_use]
+            pub const fn set(self, name: PropName, val: PropValue) -> Self {
+                match self.to_type() {
+                    #set_arms
+                    _ => self,
+                }
+            }
+
+            #default_block_states
+        }
+
+        /// An enumeration of all block types.
+        #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+        pub enum BlockType {
+            #(#block_type_variants,)*
+        }
+
+        impl BlockType {
+            /// Construct a block type from its snake_case name.
+            ///
+            /// Returns `None` if the given name is not valid.
+            pub fn from_str(name: &str) -> Option<BlockType> {
+                match name {
+                    #block_type_from_str_arms
+                    _ => None
+                }
+            }
+
+            /// Get the snake_case name of this block type.
+            pub const fn to_str(self) -> &'static str {
+                match self {
+                    #block_type_to_str_arms
+                }
+            }
+
+            /// Returns the default block state for a given block type.
+            pub const fn to_state(self) -> BlockState {
+                BlockState::from_type(self)
+            }
+
+            /// Returns a slice of all properties this block type has.
+            pub const fn props(self) -> &'static [PropName] {
+                match self {
+                    #block_type_props_arms
+                    _ => &[],
+                }
+            }
+
+            /// An array of all block types.
+            pub const ALL: [Self; #num_block_types] = [#(Self::#block_type_variants,)*];
+        }
+
+        /// The default block type is `air`.
+        impl Default for BlockType {
+            fn default() -> Self {
+                Self::Air
+            }
+        }
+
+        /// Contains all possible block state property names.
+        ///
+        /// For example, `waterlogged`, `facing`, and `half` are all property names.
+        #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+        pub enum PropName {
+            #(#prop_name_variants,)*
+        }
+
+        impl PropName {
+            /// Construct a property name from its snake_case name.
+            ///
+            /// Returns `None` if the given name is not valid.
+            pub fn from_str(name: &str) -> Option<Self> {
+                match name {
+                    #prop_name_from_str_arms
+                    _ => None,
+                }
+            }
+
+            /// Get the snake_case name of this property name.
+            pub const fn to_str(self) -> &'static str {
+                match self {
+                    #prop_name_to_str_arms
+                }
+            }
+
+            /// An array of all property names.
+            pub const ALL: [Self; #num_prop_names] = [#(Self::#prop_name_variants,)*];
+        }
+
+        /// Contains all possible values that a block property might have.
+        ///
+        /// For example, `upper`, `true`, and `2` are all property values.
+        #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+        pub enum PropValue {
+            #(#prop_value_variants,)*
+        }
+
+        impl PropValue {
+            /// Construct a property value from its snake_case name.
+            ///
+            /// Returns `None` if the given name is not valid.
+            pub fn from_str(name: &str) -> Option<Self> {
+                match name {
+                    #prop_value_from_str_arms
+                    _ => None,
+                }
+            }
+
+            /// Get the snake_case name of this property value.
+            pub const fn to_str(self) -> &'static str {
+                match self {
+                    #prop_value_to_str_arms
+                }
+            }
+
+            /// Converts a `u16` into a numeric property value.
+            /// Returns `None` if the given number does not have a
+            /// corresponding property value.
+            pub const fn from_u16(n: u16) -> Option<Self> {
+                match n {
+                    #prop_value_from_u16_arms
+                    _ => None,
+                }
+            }
+
+            /// Converts this property value into a `u16` if it is numeric.
+            /// Returns `None` otherwise.
+            pub const fn to_u16(self) -> Option<u16> {
+                match self {
+                    #prop_value_to_u16_arms
+                    _ => None,
+                }
+            }
+
+            pub const fn from_bool(b: bool) -> Self {
+                if b {
+                    Self::True
+                } else {
+                    Self::False
+                }
+            }
+
+            pub const fn to_bool(self) -> Option<bool> {
+                match self {
+                    Self::True => Some(true),
+                    Self::False => Some(false),
+                    _ => None,
+                }
+            }
+
+            /// An array of all property values.
+            pub const ALL: [Self; #num_property_names] = [#(Self::#prop_value_variants,)*];
+        }
+
+        impl From<bool> for PropValue {
+            fn from(b: bool) -> Self {
+                Self::from_bool(b)
+            }
+        }
+    };
+
+    let out_path =
+        Path::new(&env::var_os("OUT_DIR").context("can't get OUT_DIR env var")?).join("block.rs");
+
+    fs::write(&out_path, &finshed.to_string())?;
+
+    // Format the output for debugging purposes.
+    // Doesn't matter if rustfmt is unavailable.
+    let _ = Command::new("rustfmt").arg(out_path).output();
+
+    Ok(())
+}
+
+struct Block {
+    name: String,
+    default_state: u16,
+    min_state_id: u16,
+    max_state_id: u16,
+    /// Order of elements in this vec is significant.
+    props: Vec<Prop>,
+}
+
+struct Prop {
+    name: String,
+    vals: Vec<String>,
+}
+
+fn parse_blocks_json() -> anyhow::Result<Vec<Block>> {
+    #[derive(Clone, PartialEq, Debug, Deserialize)]
+    #[serde(rename_all = "camelCase")]
+    struct JsonBlock {
+        id: u16,
+        name: String,
+        display_name: String,
+        hardness: f64,
+        resistance: f64,
+        stack_size: u32,
+        diggable: bool,
+        material: String,
+        transparent: bool,
+        emit_light: u8,
+        filter_light: u8,
+        default_state: u16,
+        min_state_id: u16,
+        max_state_id: u16,
+        states: Vec<State>,
+        bounding_box: String,
+    }
+
+    #[derive(Clone, PartialEq, Debug, Deserialize)]
+    #[serde(tag = "type", rename_all = "camelCase")]
+    enum State {
+        Enum { name: String, values: Vec<String> },
+        Int { name: String, values: Vec<String> },
+        Bool { name: String },
+    }
+
+    let blocks: Vec<JsonBlock> = serde_json::from_str(include_str!("../data/blocks.json"))?;
+
+    Ok(blocks
+        .into_iter()
+        .map(|b| Block {
+            name: b.name,
+            default_state: b.default_state,
+            min_state_id: b.min_state_id,
+            max_state_id: b.max_state_id,
+            props: b
+                .states
+                .into_iter()
+                .map(|s| Prop {
+                    name: match &s {
+                        State::Enum { name, .. } => name.clone(),
+                        State::Int { name, .. } => name.clone(),
+                        State::Bool { name } => name.clone(),
+                    },
+                    vals: match &s {
+                        State::Enum { values, .. } => values.clone(),
+                        State::Int { values, .. } => values.clone(),
+                        State::Bool { .. } => vec!["false".to_string(), "true".to_string()],
+                    },
+                })
+                .collect(),
+        })
+        .collect())
+}

build/main.rs

@@ -0,0 +1,32 @@
+use std::fs;
+
+use anyhow::Context;
+use proc_macro2::{Ident, Span};
+
+mod block;
+
+pub fn main() -> anyhow::Result<()> {
+    // If any of the files in the data directory are modified, rerun the build
+    // script.
+    for entry in fs::read_dir("data")? {
+        let entry = entry?;
+        if entry.metadata()?.is_file() {
+            let buf = entry.path();
+            let path = buf.to_str().context("bad file name")?;
+            println!("cargo:rerun-if-changed={path}");
+        }
+    }
+
+    block::build()?;
+
+    Ok(())
+}
+
+fn ident(s: impl AsRef<str>) -> Ident {
+    let s = s.as_ref().trim();
+    if s.starts_with(char::is_numeric) {
+        Ident::new(&format!("_{s}"), Span::call_site())
+    } else {
+        Ident::new(s, Span::call_site())
+    }
+}

src/block.rs

@@ -0,0 +1,20 @@
+#![allow(clippy::all)]
+
+include!(concat!(env!("OUT_DIR"), "/block.rs"));
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn get_set_consistency() {
+        for typ in BlockType::ALL {
+            let block = typ.to_state();
+
+            for &prop in typ.props() {
+                let new_block = block.set(prop, block.get(prop).unwrap());
+                assert_eq!(new_block, block);
+            }
+        }
+    }
+}

src/lib.rs

@@ -19,6 +19,7 @@ pub mod util;
 mod var_int;
 mod var_long;
 mod world;
+pub mod block;
 
 pub use aabb::Aabb;
 pub use chunk::{Chunk, ChunkPos};

valence-data/Cargo.toml

@@ -1,9 +0,0 @@
-[package]
-name = "valence-data"
-version = "0.1.0"
-edition = "2021"
-description = "Generated code for the Valence project."
-repository = "https://github.com/rj00a/valence"
-license = "MIT"
-
-[dependencies]

valence-data/src/lib.rs

@@ -1,8 +0,0 @@
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_works() {
-        let result = 2 + 2;
-        assert_eq!(result, 4);
-    }
-}