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https://github.com/servo/servo.git
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92 lines
4.6 KiB
Rust
92 lines
4.6 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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use syntax::{ast, ast_util};
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use rustc::lint::{Context, LintPass, LintArray, Level};
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use rustc::middle::{ty, def};
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use utils::match_lang_ty;
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declare_lint!(INHERITANCE_INTEGRITY, Deny,
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"Ensures that struct fields are properly laid out for inheritance to work");
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/// Lint for ensuring proper layout of DOM structs
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///
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/// A DOM struct must have one Reflector field or one field
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/// which itself is a DOM struct (in which case it must be the first field).
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pub struct InheritancePass;
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impl LintPass for InheritancePass {
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fn get_lints(&self) -> LintArray {
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lint_array!(INHERITANCE_INTEGRITY)
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}
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fn check_struct_def(&mut self, cx: &Context, def: &ast::StructDef, _i: ast::Ident,
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_gen: &ast::Generics, id: ast::NodeId) {
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// Lints are run post expansion, so it's fine to use
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// #[_dom_struct_marker] here without also checking for #[dom_struct]
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if ty::has_attr(cx.tcx, ast_util::local_def(id), "_dom_struct_marker") {
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// Find the reflector, if any
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let reflector_span = def.fields.iter().enumerate()
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.find(|&(ctr, f)| {
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if match_lang_ty(cx, &*f.node.ty, "reflector") {
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if ctr > 0 {
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cx.span_lint(INHERITANCE_INTEGRITY, f.span,
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"The Reflector should be the first field of the DOM \
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struct");
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}
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return true;
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}
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false
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})
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.map(|(_, f)| f.span);
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// Find all #[dom_struct] fields
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let dom_spans: Vec<_> = def.fields.iter().enumerate().filter_map(|(ctr, f)| {
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if let ast::TyPath(..) = f.node.ty.node {
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if let Some(&def::PathResolution { base_def: def::DefTy(def_id, _), .. }) =
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cx.tcx.def_map.borrow().get(&f.node.ty.id) {
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if ty::has_attr(cx.tcx, def_id, "_dom_struct_marker") {
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// If the field is not the first, it's probably
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// being misused (a)
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if ctr > 0 {
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cx.span_lint(INHERITANCE_INTEGRITY, f.span,
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"Bare DOM structs should only be used as the first field of a \
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DOM struct. Consider using JS<T> instead.");
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}
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return Some(f.span)
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}
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}
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}
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None
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}).collect();
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// We should not have both a reflector and a dom struct field
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if let Some(sp) = reflector_span {
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if dom_spans.len() > 0 {
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cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
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"This DOM struct has both Reflector and bare DOM struct members");
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if cx.current_level(INHERITANCE_INTEGRITY) != Level::Allow {
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let sess = cx.sess();
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sess.span_note(sp, "Reflector found here");
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for span in dom_spans.iter() {
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sess.span_note(*span, "Bare DOM struct found here");
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}
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}
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}
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// Nor should we have more than one dom struct field
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} else if dom_spans.len() > 1 {
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cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
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"This DOM struct has multiple DOM struct members, only one is allowed");
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if cx.current_level(INHERITANCE_INTEGRITY) != Level::Allow {
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for span in dom_spans.iter() {
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cx.sess().span_note(*span, "Bare DOM struct found here");
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}
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}
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} else if dom_spans.len() == 0 {
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cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
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"This DOM struct has no reflector or parent DOM struct");
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}
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}
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}
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}
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