Add #[jstraceable] syntax extension

This commit is contained in:
Manish Goregaokar 2014-09-24 01:15:12 +05:30
parent 27f3bcd718
commit 3b7e07699e
2 changed files with 81 additions and 3 deletions

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@ -0,0 +1,76 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use syntax::ext::base::ExtCtxt;
use syntax::codemap::Span;
use syntax::ptr::P;
use syntax::ast::{Item, MetaItem, Expr};
use syntax::ast;
use syntax::ext::build::AstBuilder;
use syntax::ext::deriving::generic::{combine_substructure, EnumMatching, FieldInfo, MethodDef, Struct, Substructure, TraitDef, ty};
pub fn expand_jstraceable(cx: &mut ExtCtxt, span: Span, mitem: &MetaItem, item: &Item, push: |P<Item>|) {
let trait_def = TraitDef {
span: span,
attributes: Vec::new(),
path: ty::Path::new(vec!("dom","bindings","trace","JSTraceable")),
additional_bounds: Vec::new(),
generics: ty::LifetimeBounds::empty(),
methods: vec!(
MethodDef {
name: "trace",
generics: ty::LifetimeBounds::empty(),
explicit_self: ty::borrowed_explicit_self(),
args: vec!(ty::Ptr(box ty::Literal(ty::Path::new(vec!("js","jsapi","JSTracer"))), ty::Raw(ast::MutMutable))),
ret_ty: ty::nil_ty(),
attributes: vec!(),
combine_substructure: combine_substructure(|a, b, c| {
jstraceable_substructure(a, b, c)
})
}
)
};
trait_def.expand(cx, mitem, item, push)
}
// Mostly copied from syntax::ext::deriving::hash
fn jstraceable_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
let state_expr = match substr.nonself_args {
[ref state_expr] => state_expr,
_ => cx.span_bug(trait_span, "incorrect number of arguments in `jstraceable`")
};
let hash_ident = substr.method_ident;
let call_hash = |span, thing_expr| {
let expr = cx.expr_method_call(span, thing_expr, hash_ident, vec!(state_expr.clone()));
cx.stmt_expr(expr)
};
let mut stmts = Vec::new();
let fields = match *substr.fields {
Struct(ref fs) => fs,
EnumMatching(index, variant, ref fs) => {
// Determine the discriminant. We will feed this value to the byte
// iteration function.
let discriminant = match variant.node.disr_expr {
Some(ref d) => d.clone(),
None => cx.expr_uint(trait_span, index)
};
stmts.push(call_hash(trait_span, discriminant));
fs
}
_ => cx.span_bug(trait_span, "impossible substructure in `jstraceable`")
};
for &FieldInfo { ref self_, span, .. } in fields.iter() {
stmts.push(call_hash(span, self_.clone()));
}
if stmts.len() == 0 {
cx.span_bug(trait_span, "#[jstraceable] needs at least one field");
}
cx.expr_block(cx.block(trait_span, stmts, None))
}

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@ -6,8 +6,6 @@
#![deny(unused_imports, unused_variable)]
#[phase(plugin,link)]
extern crate syntax;
#[phase(plugin, link)]
@ -17,14 +15,18 @@ extern crate sync;
use rustc::lint::LintPassObject;
use rustc::plugin::Registry;
use syntax::ext::base::ItemDecorator;
use syntax::parse::token::intern;
mod lints;
mod macros;
mod jstraceable;
#[plugin_registrar]
pub fn plugin_registrar(reg: &mut Registry) {
reg.register_lint_pass(box lints::TransmutePass as LintPassObject);
reg.register_lint_pass(box lints::UnrootedPass as LintPassObject);
reg.register_syntax_extension(intern("jstraceable"), ItemDecorator(box jstraceable::expand_jstraceable))
}