//! A set of macros to generate Rust source for PHF data structures at compile time.
//! See [the `phf` crate's documentation][phf] for details.
//!
//! [phf]:
https://docs.rs/phf
use phf_generator::HashState;
use phf_shared::PhfHash;
use proc_macro::TokenStream;
use quote::quote;
use std::collections::HashSet;
use std::hash::Hasher;
use syn::parse::{self, Parse, ParseStream};
use syn::punctuated::Punctuated;
use syn::{parse_macro_input, Error, Expr, ExprLit, Lit, Token, UnOp};
#[cfg(feature = "unicase")]
use unicase_::UniCase;
#[derive(Hash, PartialEq, Eq, Clone)]
enum ParsedKey {
Str(String),
Binary(Vec<u8>),
Char(char),
I8(i8),
I16(i16),
I32(i32),
I64(i64),
I128(i128),
U8(u8),
U16(u16),
U32(u32),
U64(u64),
U128(u128),
Bool(bool),
#[cfg(feature = "unicase")]
UniCase(UniCase<String>),
}
impl PhfHash for ParsedKey {
fn phf_hash<H>(&self, state: &mut H)
where
H: Hasher,
{
match self {
ParsedKey::Str(s) => s.phf_hash(state),
ParsedKey::Binary(s) => s.phf_hash(state),
ParsedKey::Char(s) => s.phf_hash(state),
ParsedKey::I8(s) => s.phf_hash(state),
ParsedKey::I16(s) => s.phf_hash(state),
ParsedKey::I32(s) => s.phf_hash(state),
ParsedKey::I64(s) => s.phf_hash(state),
ParsedKey::I128(s) => s.phf_hash(state),
ParsedKey::U8(s) => s.phf_hash(state),
ParsedKey::U16(s) => s.phf_hash(state),
ParsedKey::U32(s) => s.phf_hash(state),
ParsedKey::U64(s) => s.phf_hash(state),
ParsedKey::U128(s) => s.phf_hash(state),
ParsedKey::Bool(s) => s.phf_hash(state),
#[cfg(feature = "unicase")]
ParsedKey::UniCase(s) => s.phf_hash(state),
}
}
}
impl ParsedKey {
fn from_expr(expr: &Expr) -> Option<ParsedKey> {
match expr {
Expr::Lit(lit) => match &lit.lit {
Lit::Str(s) => Some(ParsedKey::Str(s.value())),
Lit::ByteStr(s) => Some(ParsedKey::Binary(s.value())),
Lit::Byte(s) => Some(ParsedKey::U8(s.value())),
Lit::Char(s) => Some(ParsedKey::Char(s.value())),
Lit::Int(s) => match s.suffix() {
// we've lost the sign at this point, so `-128i8` looks like `128i8`,
// which doesn't fit in an `i8`; parse it as a `u8` and cast (to `0i8`),
// which is handled below, by `Unary`
"i8" => Some(ParsedKey::I8(s.base10_parse::<u8>().unwrap() as i8)),
"i16" => Some(ParsedKey::I16(s.base10_parse::<u16>().unwrap() as i16)),
"i32" => Some(ParsedKey::I32(s.base10_parse::<u32>().unwrap() as i32)),
"i64" => Some(ParsedKey::I64(s.base10_parse::<u64>().unwrap() as i64)),
"i128" => Some(ParsedKey::I128(s.base10_parse::<u128>().unwrap() as i128)),
"u8" => Some(ParsedKey::U8(s.base10_parse::<u8>().unwrap())),
"u16" => Some(ParsedKey::U16(s.base10_parse::<u16>().unwrap())),
"u32" => Some(ParsedKey::U32(s.base10_parse::<u32>().unwrap())),
"u64" => Some(ParsedKey::U64(s.base10_parse::<u64>().unwrap())),
"u128" => Some(ParsedKey::U128(s.base10_parse::<u128>().unwrap())),
_ => None,
},
Lit::Bool(s) => Some(ParsedKey::Bool(s.value)),
_ => None,
},
Expr::Array(array) => {
let mut buf = vec![];
for expr in &array.elems {
match expr {
Expr::Lit(lit) => match &lit.lit {
Lit::Int(s) => match s.suffix() {
"u8" | "" => buf.push(s.base10_parse::<u8>().unwrap()),
_ => return None,
},
_ => return None,
},
_ => return None,
}
}
Some(ParsedKey::Binary(buf))
}
Expr::Unary(unary) => {
// if we received an integer literal (always unsigned) greater than i__::max_value()
// then casting it to a signed integer type of the same width will negate it to
// the same absolute value so we don't need to negate it here
macro_rules! try_negate (
($val:expr) => {if $val < 0 { $val } else { -$val }}
);
match unary.op {
UnOp::Neg(_) => match ParsedKey::from_expr(&unary.expr)? {
ParsedKey::I8(v) => Some(ParsedKey::I8(try_negate!(v))),
ParsedKey::I16(v) => Some(ParsedKey::I16(try_negate!(v))),
ParsedKey::I32(v) => Some(ParsedKey::I32(try_negate!(v))),
ParsedKey::I64(v) => Some(ParsedKey::I64(try_negate!(v))),
ParsedKey::I128(v) => Some(ParsedKey::I128(try_negate!(v))),
_ => None,
},
UnOp::Deref(_) => {
let mut expr = &*unary.expr;
while let Expr::Group(group) = expr {
expr = &*group.expr;
}
match expr {
Expr::Lit(ExprLit {
lit: Lit::ByteStr(s),
..
}) => Some(ParsedKey::Binary(s.value())),
_ => None,
}
}
_ => None,
}
}
Expr::Group(group) => ParsedKey::from_expr(&group.expr),
#[cfg(feature = "unicase")]
Expr::Call(call) => {
if let Expr::Path(ep) = call.func.as_ref() {
let segments = &mut ep.path.segments.iter().rev();
let last = &segments.next()?.ident;
let last_ahead = &segments.next()?.ident;
let is_unicode = last_ahead == "UniCase" && last == "unicode";
let is_ascii = last_ahead == "UniCase" && last == "ascii";
if call.args.len() == 1 && (is_unicode || is_ascii) {
if let Some(Expr::Lit(ExprLit {
attrs: _,
lit: Lit::Str(s),
})) = call.args.first()
{
let v = if is_unicode {
UniCase::unicode(s.value())
} else {
UniCase::ascii(s.value())
};
Some(ParsedKey::UniCase(v))
} else {
None
}
} else {
None
}
} else {
None
}
}
_ => None,
}
}
}
struct Key {
parsed: ParsedKey,
expr: Expr,
}
impl PhfHash for Key {
fn phf_hash<H>(&self, state: &mut H)
where
H: Hasher,
{
self.parsed.phf_hash(state)
}
}
impl Parse for Key {
fn parse(input: ParseStream<'_>) -> parse::Result<Key> {
let expr = input.parse()?;
let parsed = ParsedKey::from_expr(&expr)
.ok_or_else(|| Error::new_spanned(&expr, "unsupported key expression"))?;
Ok(Key { parsed, expr })
}
}
struct Entry {
key: Key,
value: Expr,
}
impl PhfHash for Entry {
fn phf_hash<H>(&self, state: &mut H)
where
H: Hasher,
{
self.key.phf_hash(state)
}
}
impl Parse for Entry {
fn parse(input: ParseStream<'_>) -> parse::Result<Entry> {
let key = input.parse()?;
input.parse::<Token![=>]>()?;
let value = input.parse()?;
Ok(Entry { key, value })
}
}
struct Map(Vec<Entry>);
impl Parse for Map {
fn parse(input: ParseStream<'_>) -> parse::Result<Map> {
let parsed = Punctuated::<Entry, Token![,]>::parse_terminated(input)?;
let map = parsed.into_iter().collect::<Vec<_>>();
check_duplicates(&map)?;
Ok(Map(map))
}
}
struct Set(Vec<Entry>);
impl Parse for Set {
fn parse(input: ParseStream<'_>) -> parse::Result<Set> {
let parsed = Punctuated::<Key, Token![,]>::parse_terminated(input)?;
let set = parsed
.into_iter()
.map(|key| Entry {
key,
value: syn::parse_str("()").unwrap(),
})
.collect::<Vec<_>>();
check_duplicates(&set)?;
Ok(Set(set))
}
}
fn check_duplicates(entries: &[Entry]) -> parse::Result<()> {
let mut keys = HashSet::new();
for entry in entries {
if !keys.insert(&entry.key.parsed) {
return Err(Error::new_spanned(&entry.key.expr, "duplicate key"));
}
}
Ok(())
}
fn build_map(entries: &[Entry], state: HashState) -> proc_macro2::TokenStream {
let key = state.key;
let disps = state.disps.iter().map(|&(d1, d2)| quote!((#d1, #d2)));
let entries = state.map.iter().map(|&idx| {
let key = &entries[idx].key.expr;
let value = &entries[idx].value;
quote!((#key, #value))
});
quote! {
phf::Map {
key: #key,
disps: &[#(#disps),*],
entries: &[#(#entries),*],
}
}
}
fn build_ordered_map(entries: &[Entry], state: HashState) -> proc_macro2::TokenStream {
let key = state.key;
let disps = state.disps.iter().map(|&(d1, d2)| quote!((#d1, #d2)));
let idxs = state.map.iter().map(|idx| quote!(#idx));
let entries = entries.iter().map(|entry| {
let key = &entry.key.expr;
let value = &entry.value;
quote!((#key, #value))
});
quote! {
phf::OrderedMap {
key: #key,
disps: &[#(#disps),*],
idxs: &[#(#idxs),*],
entries: &[#(#entries),*],
}
}
}
#[proc_macro]
pub fn phf_map(input: TokenStream) -> TokenStream {
let map = parse_macro_input!(input as Map);
let state = phf_generator::generate_hash(&map.0);
build_map(&map.0, state).into()
}
#[proc_macro]
pub fn phf_set(input: TokenStream) -> TokenStream {
let set = parse_macro_input!(input as Set);
let state = phf_generator::generate_hash(&set.0);
let map = build_map(&set.0, state);
quote!(phf::Set { map: #map }).into()
}
#[proc_macro]
pub fn phf_ordered_map(input: TokenStream) -> TokenStream {
let map = parse_macro_input!(input as Map);
let state = phf_generator::generate_hash(&map.0);
build_ordered_map(&map.0, state).into()
}
#[proc_macro]
pub fn phf_ordered_set(input: TokenStream) -> TokenStream {
let set = parse_macro_input!(input as Set);
let state = phf_generator::generate_hash(&set.0);
let map = build_ordered_map(&set.0, state);
quote!(phf::OrderedSet { map: #map }).into()
}
