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use crate::syntax::namespace::Namespace;
use crate::syntax::{ForeignName, Pair};
use proc_macro2::{Ident, TokenStream};
use quote::ToTokens;
use std::fmt::{self, Display, Write};
// A mangled symbol consisting of segments separated by '$'.
// For example: cxxbridge1$string$new
pub struct Symbol(String);
impl Display for Symbol {
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
Display::fmt(&self.0, formatter)
}
}
impl ToTokens for Symbol {
fn to_tokens(&self, tokens: &mut TokenStream) {
ToTokens::to_tokens(&self.0, tokens);
}
}
impl Symbol {
fn push(&mut self, segment: &dyn Display) {
let len_before = self.0.len();
if !self.0.is_empty() {
self.0.push('$');
}
self.0.write_fmt(format_args!("{}", segment)).unwrap();
assert!(self.0.len() > len_before);
}
pub fn from_idents<'a>(it: impl Iterator<Item = &'a dyn Segment>) -> Self {
let mut symbol = Symbol(String::new());
for segment in it {
segment.write(&mut symbol);
}
assert!(!symbol.0.is_empty());
symbol
}
/// For example, for taking a symbol and then making a new symbol
/// for a vec of that symbol.
pub fn prefix_with(&self, prefix: &str) -> Symbol {
Symbol(format!("{}{}", prefix, self.to_string()))
}
}
pub trait Segment {
fn write(&self, symbol: &mut Symbol);
}
impl Segment for str {
fn write(&self, symbol: &mut Symbol) {
symbol.push(&self);
}
}
impl Segment for usize {
fn write(&self, symbol: &mut Symbol) {
symbol.push(&self);
}
}
impl Segment for Ident {
fn write(&self, symbol: &mut Symbol) {
symbol.push(&self);
}
}
impl Segment for Symbol {
fn write(&self, symbol: &mut Symbol) {
symbol.push(&self);
}
}
impl Segment for Namespace {
fn write(&self, symbol: &mut Symbol) {
for segment in self {
symbol.push(segment);
}
}
}
impl Segment for Pair {
fn write(&self, symbol: &mut Symbol) {
self.namespace.write(symbol);
self.cxx.write(symbol);
}
}
impl Segment for ForeignName {
fn write(&self, symbol: &mut Symbol) {
// TODO: support C++ names containing whitespace (`unsigned int`) or
// non-alphanumeric characters (`operator++`).
self.to_string().write(symbol);
}
}
impl<T> Segment for &'_ T
where
T: ?Sized + Segment + Display,
{
fn write(&self, symbol: &mut Symbol) {
(**self).write(symbol);
}
}
pub fn join(segments: &[&dyn Segment]) -> Symbol {
let mut symbol = Symbol(String::new());
for segment in segments {
segment.write(&mut symbol);
}
assert!(!symbol.0.is_empty());
symbol
}