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Add inheritance-checking lint

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This commit is contained in:
Manish Goregaokar 2014-12-01 14:13:50 -05:00
parent 7d65673561
commit d761877ef6
9 changed files with 139 additions and 21 deletions
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18
components/plugins/jstraceable.rs
View file

@ -14,12 +14,20 @@ use syntax::parse::token::InternedString;
pub fn expand_dom_struct(_: &mut ExtCtxt, _: Span, _: &MetaItem, item: P<Item>) -> P<Item> {
let mut item2 = (*item).clone();
item2.attrs.push(attr::mk_attr_outer(attr::mk_attr_id(), attr::mk_word_item(InternedString::new("must_root"))));
item2.attrs.push(attr::mk_attr_outer(attr::mk_attr_id(), attr::mk_word_item(InternedString::new("privatize"))));
item2.attrs.push(attr::mk_attr_outer(attr::mk_attr_id(), attr::mk_word_item(InternedString::new("jstraceable"))));
{
let add_attr = |s| {
item2.attrs.push(attr::mk_attr_outer(attr::mk_attr_id(), attr::mk_word_item(InternedString::new(s))));
};
add_attr("must_root");
add_attr("privatize");
add_attr("jstraceable");
// The following attribute is only for internal usage
item2.attrs.push(attr::mk_attr_outer(attr::mk_attr_id(), attr::mk_word_item(InternedString::new("_generate_reflector"))));
// The following attributes are only for internal usage
add_attr("_generate_reflector");
// #[dom_struct] gets consumed, so this lets us keep around a residue
// Do NOT register a modifier/decorator on this attribute
add_attr("_dom_struct_marker");
}
P(item2)
}

1
components/plugins/lib.rs
View file

@ -47,5 +47,6 @@ 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_lint_pass(box lints::PrivatizePass as LintPassObject);
reg.register_lint_pass(box lints::InheritancePass as LintPassObject);
}

74
components/plugins/lints.rs
View file

@ -5,18 +5,22 @@
use syntax::{ast, ast_map, ast_util, codemap, visit};
use syntax::ast::Public;
use syntax::attr::AttrMetaMethods;
use rustc::lint::{Context, LintPass, LintArray};
use rustc::lint::{Context, LintPass, LintArray, Level};
use rustc::middle::ty::expr_ty;
use rustc::middle::{ty, def};
use rustc::middle::typeck::astconv::AstConv;
use rustc::util::ppaux::Repr;
use utils::match_lang_ty;
declare_lint!(TRANSMUTE_TYPE_LINT, Allow,
"Warn and report types being transmuted")
declare_lint!(UNROOTED_MUST_ROOT, Deny,
"Warn and report usage of unrooted jsmanaged objects")
declare_lint!(PRIVATIZE, Deny,
"Allows to enforce private fields for struct definitions")
declare_lint!(INHERITANCE_INTEGRITY, Deny,
"Ensures that struct fields are properly laid out for inheritance to work")
/// Lint for auditing transmutes
///
@ -41,6 +45,12 @@ pub struct UnrootedPass;
/// This lint (disable with `-A privatize`/`#[allow(privatize)]`) ensures all types marked with `#[privatize]` have no private fields
pub struct PrivatizePass;
/// Lint for ensuring proper layout of DOM structs
///
/// A DOM struct must have one Reflector field or one field
/// which itself is a DOM struct (in which case it must be the first field).
pub struct InheritancePass;
impl LintPass for TransmutePass {
fn get_lints(&self) -> LintArray {
lint_array!(TRANSMUTE_TYPE_LINT)
@ -251,3 +261,65 @@ impl LintPass for PrivatizePass {
}
}
}
impl LintPass for InheritancePass {
fn get_lints(&self) -> LintArray {
lint_array!(INHERITANCE_INTEGRITY)
}
fn check_struct_def(&mut self, cx: &Context, def: &ast::StructDef, _i: ast::Ident, _gen: &ast::Generics, id: ast::NodeId) {
// Lints are run post expansion, so it's fine to use
// #[_dom_struct_marker] here without also checking for #[dom_struct]
if ty::has_attr(cx.tcx, ast_util::local_def(id), "_dom_struct_marker") {
// Find the reflector, if any
let reflector_span = def.fields.iter()
.find(|f| match_lang_ty(cx, &*f.node.ty, "reflector"))
.map(|f| f.span);
// Find all #[dom_struct] fields
let dom_spans: Vec<_> = def.fields.iter().enumerate().filter_map(|(ctr, f)| {
if let ast::TyPath(_, _, ty_id) = f.node.ty.node {
if let Some(def::DefTy(def_id, _)) = cx.tcx.def_map.borrow().find_copy(&ty_id) {
if ty::has_attr(cx.tcx, def_id, "_dom_struct_marker") {
// If the field is not the first, it's probably
// being misused (a)
if ctr > 0 {
cx.span_lint(INHERITANCE_INTEGRITY, f.span,
"Bare DOM structs should only be used as the first field of a \
DOM struct. Consider using JS<T> instead.");
}
return Some(f.span)
}
}
}
None
}).collect();
// We should not have both a reflector and a dom struct field
if let Some(sp) = reflector_span {
if dom_spans.len() > 0 {
cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
"This DOM struct has both Reflector and bare DOM struct members");
if cx.current_level(INHERITANCE_INTEGRITY) != Level::Allow {
let sess = cx.sess();
sess.span_note(sp, "Reflector found here");
for span in dom_spans.iter() {
sess.span_note(*span, "Bare DOM struct found here");
}
}
}
// Nor should we have more than one dom struct field
} else if dom_spans.len() > 1 {
cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
"This DOM struct has multiple DOM struct members, only one is allowed");
if cx.current_level(INHERITANCE_INTEGRITY) != Level::Allow {
for span in dom_spans.iter() {
cx.sess().span_note(*span, "Bare DOM struct found here");
}
}
} else if dom_spans.len() == 0 {
cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
"This DOM struct has no reflector or parent DOM struct");
}
}
}
}

8
components/plugins/reflector.rs
View file

@ -11,9 +11,9 @@ use utils::match_ty_unwrap;
pub fn expand_reflector(cx: &mut ExtCtxt, span: Span, _: &MetaItem, item: &Item, push: |P<Item>|) {
if let ast::ItemStruct(ref def, _) = item.node {
let struct_name = item.ident;
// This path has to be hardcoded, unfortunately, since we can't resolve paths at expansion time
match def.fields.iter().find(|f| match_ty_unwrap(&*f.node.ty, &["dom", "bindings", "utils", "Reflector"]).is_some()) {
// If it has a field that is a Reflector, use that
Some(f) => {
@ -28,10 +28,6 @@ pub fn expand_reflector(cx: &mut ExtCtxt, span: Span, _: &MetaItem, item: &Item,
impl_item.map(|it| push(it))
},
// Or just call it on the first field (supertype).
// TODO: Write a lint to ensure that this first field is indeed a #[dom_struct],
// and the only such field in the struct definition (including reflectors)
// Unfortunately we can't do it here itself because a def_map (from middle) is not available
// at expansion time
None => {
let field_name = def.fields[0].node.ident();
let impl_item = quote_item!(cx,
@ -45,6 +41,6 @@ pub fn expand_reflector(cx: &mut ExtCtxt, span: Span, _: &MetaItem, item: &Item,
}
};
} else {
cx.span_bug(span, "#[dom_struct] seems to have been applied to a non-struct");
cx.span_err(span, "#[dom_struct] seems to have been applied to a non-struct");
}
}

33
components/plugins/utils.rs
View file

@ -2,10 +2,17 @@
* 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 rustc::lint::Context;
use rustc::middle::{ty, def};
use syntax::ptr::P;
use syntax::ast;
use syntax::ast::{TyPath, Path, AngleBracketedParameters, PathSegment, Ty};
use syntax::attr::mark_used;
/// Matches a type with a provided string, and returns its type parameters if successful
///
/// Try not to use this for types defined in crates you own, use match_lang_ty instead (for lint passes)
pub fn match_ty_unwrap<'a>(ty: &'a Ty, segments: &[&str]) -> Option<&'a [P<Ty>]> {
match ty.node {
TyPath(Path {segments: ref seg, ..}, _, _) => {
@ -27,3 +34,29 @@ pub fn match_ty_unwrap<'a>(ty: &'a Ty, segments: &[&str]) -> Option<&'a [P<Ty>]>
_ => None
}
}
/// Checks if a type has a #[servo_lang = "str"] attribute
pub fn match_lang_ty(cx: &Context, ty: &Ty, value: &str) -> bool {
let mut found = false;
if let TyPath(_, _, ty_id) = ty.node {
if let Some(def::DefTy(def_id, _)) = cx.tcx.def_map.borrow().find_copy(&ty_id) {
// Iterating through attributes is hard because of cross-crate defs
ty::each_attr(cx.tcx, def_id, |attr| {
if let ast::MetaNameValue(ref name, ref val) = attr.node.value.node {
if name.get() == "servo_lang" {
if let ast::LitStr(ref v, _) = val.node {
if v.get() == value {
mark_used(attr);
found = true;
// We're done with the loop
return false;
}
}
}
}
true
});
};
}
found
}