use litrs::StringLit;
use proc_macro::{Delimiter, Group, Literal, Span, TokenStream, TokenTree};
use fallible_iterator::FallibleIterator;
use sqlite3_parser::ast::fmt::ToTokens;
use sqlite3_parser::ast::ParameterInfo;
use sqlite3_parser::lexer::sql::Parser;
#[doc(hidden)]
#[proc_macro]
pub fn __bind(input: TokenStream) -> TokenStream {
try_bind(input).unwrap_or_else(|msg| parse_ts(&format!("compile_error!({msg:?})")))
}
type Result<T> = std::result::Result<T, String>;
fn try_bind(input: TokenStream) -> Result<TokenStream> {
let (stmt, literal) = {
let mut iter = input.clone().into_iter();
let stmt = iter.next().unwrap();
let literal = iter.next().unwrap();
assert!(iter.next().is_none());
(stmt, literal)
};
let literal = match into_literal(&literal) {
Some(it) => it,
None => return Err("expected a plain string literal".to_string()),
};
let call_site = literal.span();
let string_lit = match StringLit::try_from(literal) {
Ok(string_lit) => string_lit,
Err(e) => return Ok(e.to_compile_error()),
};
let sql = string_lit.value();
let mut parser = Parser::new(sql.as_bytes());
let ast = match parser.next() {
Ok(None) => return Err("Invalid input".to_owned()),
Err(err) => {
return Err(err.to_string());
}
Ok(Some(ast)) => ast,
};
let mut info = ParameterInfo::default();
if let Err(err) = ast.to_tokens(&mut info) {
return Err(err.to_string());
}
if info.count == 0 {
return Ok(TokenStream::new());
}
if info.count as usize != info.names.len() {
return Err("Mixing named and numbered parameters is not supported.".to_string());
}
let mut res = TokenStream::new();
for (i, name) in info.names.iter().enumerate() {
res.extend(Some(stmt.clone()));
res.extend(respan(
parse_ts(&format!(
".raw_bind_parameter({}, &{})?;",
i + 1,
&name[1..]
)),
call_site,
));
}
Ok(res)
}
fn into_literal(ts: &TokenTree) -> Option<Literal> {
match ts {
TokenTree::Literal(l) => Some(l.clone()),
TokenTree::Group(g) => match g.delimiter() {
Delimiter::None => match g.stream().into_iter().collect::<Vec<_>>().as_slice() {
[TokenTree::Literal(l)] => Some(l.clone()),
_ => None,
},
Delimiter::Parenthesis | Delimiter::Brace | Delimiter::Bracket => None,
},
_ => None,
}
}
fn respan(ts: TokenStream, span: Span) -> TokenStream {
let mut res = TokenStream::new();
for tt in ts {
let tt = match tt {
TokenTree::Ident(mut ident) => {
ident.set_span(ident.span().resolved_at(span).located_at(span));
TokenTree::Ident(ident)
}
TokenTree::Group(group) => {
TokenTree::Group(Group::new(group.delimiter(), respan(group.stream(), span)))
}
_ => tt,
};
res.extend(Some(tt))
}
res
}
fn parse_ts(s: &str) -> TokenStream {
s.parse().unwrap()
}