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//! A set of builders to generate Rust source for PHF data structures at
//! compile time.
//!
//! The provided builders are intended to be used in a Cargo build script to
//! generate a Rust source file that will be included in a library at build
//! time.
//!
//! For more information about `rust-phf` crates, see [the `phf` crate's documentation][phf].
//!
//!
//! ## Examples
//!
//! To use `phf_codegen` on build.rs, you have to add dependencies under `[build-dependencies]`:
//!
//! ```toml
//! [build-dependencies]
//! phf = { version = "0.11.1", default-features = false }
//! phf_codegen = "0.11.1"
//! ```
//!
//! Then put code on build.rs:
//!
//! ```ignore
//! use std::env;
//! use std::fs::File;
//! use std::io::{BufWriter, Write};
//! use std::path::Path;
//!
//! fn main() {
//! let path = Path::new(&env::var("OUT_DIR").unwrap()).join("codegen.rs");
//! let mut file = BufWriter::new(File::create(&path).unwrap());
//!
//! write!(
//! &mut file,
//! "static KEYWORDS: phf::Map<&'static str, Keyword> = {}",
//! phf_codegen::Map::new()
//! .entry("loop", "Keyword::Loop")
//! .entry("continue", "Keyword::Continue")
//! .entry("break", "Keyword::Break")
//! .entry("fn", "Keyword::Fn")
//! .entry("extern", "Keyword::Extern")
//! .build()
//! )
//! .unwrap();
//! write!(&mut file, ";\n").unwrap();
//! }
//! ```
//!
//! and lib.rs:
//!
//! ```ignore
//! #[derive(Clone)]
//! enum Keyword {
//! Loop,
//! Continue,
//! Break,
//! Fn,
//! Extern,
//! }
//!
//! include!(concat!(env!("OUT_DIR"), "/codegen.rs"));
//!
//! pub fn parse_keyword(keyword: &str) -> Option<Keyword> {
//! KEYWORDS.get(keyword).cloned()
//! }
//! ```
//!
//! ### Byte-String Keys
//! Byte strings by default produce references to fixed-size arrays; the compiler needs a hint
//! to coerce them to slices:
//!
//! build.rs:
//!
//! ```no_run
//! use std::env;
//! use std::fs::File;
//! use std::io::{BufWriter, Write};
//! use std::path::Path;
//!
//! fn main() {
//! let path = Path::new(&env::var("OUT_DIR").unwrap()).join("codegen.rs");
//! let mut file = BufWriter::new(File::create(&path).unwrap());
//!
//! writeln!(
//! &mut file,
//! "static KEYWORDS: phf::Map<&'static [u8], Keyword> = \n{};\n",
//! phf_codegen::Map::<&[u8]>::new()
//! .entry(b"loop", "Keyword::Loop")
//! .entry(b"continue", "Keyword::Continue")
//! .entry(b"break", "Keyword::Break")
//! .entry(b"fn", "Keyword::Fn")
//! .entry(b"extern", "Keyword::Extern")
//! .build()
//! ).unwrap();
//! }
//! ```
//!
//! lib.rs:
//!
//! ```ignore
//! #[derive(Clone)]
//! enum Keyword {
//! Loop,
//! Continue,
//! Break,
//! Fn,
//! Extern,
//! }
//!
//! include!(concat!(env!("OUT_DIR"), "/codegen.rs"));
//!
//! pub fn parse_keyword(keyword: &[u8]) -> Option<Keyword> {
//! KEYWORDS.get(keyword).cloned()
//! }
//! ```
//!
//! ## Note
//!
//! The compiler's stack will overflow when processing extremely long method
//! chains (500+ calls). When generating large PHF data structures, consider
//! looping over the entries or making each call a separate statement:
//!
//! ```rust
//! let entries = [("hello", "1"), ("world", "2")];
//!
//! let mut builder = phf_codegen::Map::new();
//! for &(key, value) in &entries {
//! builder.entry(key, value);
//! }
//! // ...
//! ```
//!
//! ```rust
//! let mut builder = phf_codegen::Map::new();
//! builder.entry("hello", "1");
//! builder.entry("world", "2");
//! // ...
//! ```
#![allow(clippy::new_without_default)]
use phf_shared::{FmtConst, PhfHash};
use std::collections::HashSet;
use std::fmt;
use std::hash::Hash;
use phf_generator::HashState;
struct Delegate<T>(T);
impl<T: FmtConst> fmt::Display for Delegate<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.0.fmt_const(f)
}
}
/// A builder for the `phf::Map` type.
pub struct Map<K> {
keys: Vec<K>,
values: Vec<String>,
path: String,
}
impl<K: Hash + PhfHash + Eq + FmtConst> Map<K> {
/// Creates a new `phf::Map` builder.
pub fn new() -> Map<K> {
// FIXME rust#27438
//
// On Windows/MSVC there are major problems with the handling of dllimport.
// Here, because downstream build scripts only invoke generics from phf_codegen,
// the linker ends up throwing a way a bunch of static symbols we actually need.
// This works around the problem, assuming that all clients call `Map::new` by
// calling a non-generic function.
fn noop_fix_for_27438() {}
noop_fix_for_27438();
Map {
keys: vec![],
values: vec![],
path: String::from("::phf"),
}
}
/// Set the path to the `phf` crate from the global namespace
pub fn phf_path(&mut self, path: &str) -> &mut Map<K> {
self.path = path.to_owned();
self
}
/// Adds an entry to the builder.
///
/// `value` will be written exactly as provided in the constructed source.
pub fn entry(&mut self, key: K, value: &str) -> &mut Map<K> {
self.keys.push(key);
self.values.push(value.to_owned());
self
}
/// Calculate the hash parameters and return a struct implementing
/// [`Display`](::std::fmt::Display) which will print the constructed `phf::Map`.
///
/// # Panics
///
/// Panics if there are any duplicate keys.
pub fn build(&self) -> DisplayMap<'_, K> {
let mut set = HashSet::new();
for key in &self.keys {
if !set.insert(key) {
panic!("duplicate key `{}`", Delegate(key));
}
}
let state = phf_generator::generate_hash(&self.keys);
DisplayMap {
path: &self.path,
keys: &self.keys,
values: &self.values,
state,
}
}
}
/// An adapter for printing a [`Map`](Map).
pub struct DisplayMap<'a, K> {
path: &'a str,
state: HashState,
keys: &'a [K],
values: &'a [String],
}
impl<'a, K: FmtConst + 'a> fmt::Display for DisplayMap<'a, K> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// funky formatting here for nice output
write!(
f,
"{}::Map {{
key: {:?},
disps: &[",
self.path, self.state.key
)?;
// write map displacements
for &(d1, d2) in &self.state.disps {
write!(
f,
"
({}, {}),",
d1, d2
)?;
}
write!(
f,
"
],
entries: &[",
)?;
// write map entries
for &idx in &self.state.map {
write!(
f,
"
({}, {}),",
Delegate(&self.keys[idx]),
&self.values[idx]
)?;
}
write!(
f,
"
],
}}"
)
}
}
/// A builder for the `phf::Set` type.
pub struct Set<T> {
map: Map<T>,
}
impl<T: Hash + PhfHash + Eq + FmtConst> Set<T> {
/// Constructs a new `phf::Set` builder.
pub fn new() -> Set<T> {
Set { map: Map::new() }
}
/// Set the path to the `phf` crate from the global namespace
pub fn phf_path(&mut self, path: &str) -> &mut Set<T> {
self.map.phf_path(path);
self
}
/// Adds an entry to the builder.
pub fn entry(&mut self, entry: T) -> &mut Set<T> {
self.map.entry(entry, "()");
self
}
/// Calculate the hash parameters and return a struct implementing
/// [`Display`](::std::fmt::Display) which will print the constructed `phf::Set`.
///
/// # Panics
///
/// Panics if there are any duplicate keys.
pub fn build(&self) -> DisplaySet<'_, T> {
DisplaySet {
inner: self.map.build(),
}
}
}
/// An adapter for printing a [`Set`](Set).
pub struct DisplaySet<'a, T> {
inner: DisplayMap<'a, T>,
}
impl<'a, T: FmtConst + 'a> fmt::Display for DisplaySet<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}::Set {{ map: {} }}", self.inner.path, self.inner)
}
}
/// A builder for the `phf::OrderedMap` type.
pub struct OrderedMap<K> {
keys: Vec<K>,
values: Vec<String>,
path: String,
}
impl<K: Hash + PhfHash + Eq + FmtConst> OrderedMap<K> {
/// Constructs a enw `phf::OrderedMap` builder.
pub fn new() -> OrderedMap<K> {
OrderedMap {
keys: vec![],
values: vec![],
path: String::from("::phf"),
}
}
/// Set the path to the `phf` crate from the global namespace
pub fn phf_path(&mut self, path: &str) -> &mut OrderedMap<K> {
self.path = path.to_owned();
self
}
/// Adds an entry to the builder.
///
/// `value` will be written exactly as provided in the constructed source.
pub fn entry(&mut self, key: K, value: &str) -> &mut OrderedMap<K> {
self.keys.push(key);
self.values.push(value.to_owned());
self
}
/// Calculate the hash parameters and return a struct implementing
/// [`Display`](::std::fmt::Display) which will print the constructed
/// `phf::OrderedMap`.
///
/// # Panics
///
/// Panics if there are any duplicate keys.
pub fn build(&self) -> DisplayOrderedMap<'_, K> {
let mut set = HashSet::new();
for key in &self.keys {
if !set.insert(key) {
panic!("duplicate key `{}`", Delegate(key));
}
}
let state = phf_generator::generate_hash(&self.keys);
DisplayOrderedMap {
path: &self.path,
state,
keys: &self.keys,
values: &self.values,
}
}
}
/// An adapter for printing a [`OrderedMap`](OrderedMap).
pub struct DisplayOrderedMap<'a, K> {
path: &'a str,
state: HashState,
keys: &'a [K],
values: &'a [String],
}
impl<'a, K: FmtConst + 'a> fmt::Display for DisplayOrderedMap<'a, K> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"{}::OrderedMap {{
key: {:?},
disps: &[",
self.path, self.state.key
)?;
for &(d1, d2) in &self.state.disps {
write!(
f,
"
({}, {}),",
d1, d2
)?;
}
write!(
f,
"
],
idxs: &[",
)?;
for &idx in &self.state.map {
write!(
f,
"
{},",
idx
)?;
}
write!(
f,
"
],
entries: &[",
)?;
for (key, value) in self.keys.iter().zip(self.values.iter()) {
write!(
f,
"
({}, {}),",
Delegate(key),
value
)?;
}
write!(
f,
"
],
}}"
)
}
}
/// A builder for the `phf::OrderedSet` type.
pub struct OrderedSet<T> {
map: OrderedMap<T>,
}
impl<T: Hash + PhfHash + Eq + FmtConst> OrderedSet<T> {
/// Constructs a new `phf::OrderedSet` builder.
pub fn new() -> OrderedSet<T> {
OrderedSet {
map: OrderedMap::new(),
}
}
/// Set the path to the `phf` crate from the global namespace
pub fn phf_path(&mut self, path: &str) -> &mut OrderedSet<T> {
self.map.phf_path(path);
self
}
/// Adds an entry to the builder.
pub fn entry(&mut self, entry: T) -> &mut OrderedSet<T> {
self.map.entry(entry, "()");
self
}
/// Calculate the hash parameters and return a struct implementing
/// [`Display`](::std::fmt::Display) which will print the constructed
/// `phf::OrderedSet`.
///
/// # Panics
///
/// Panics if there are any duplicate keys.
pub fn build(&self) -> DisplayOrderedSet<'_, T> {
DisplayOrderedSet {
inner: self.map.build(),
}
}
}
/// An adapter for printing a [`OrderedSet`](OrderedSet).
pub struct DisplayOrderedSet<'a, T> {
inner: DisplayOrderedMap<'a, T>,
}
impl<'a, T: FmtConst + 'a> fmt::Display for DisplayOrderedSet<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"{}::OrderedSet {{ map: {} }}",
self.inner.path, self.inner
)
}
}