servo/components/script_plugins/webidl_must_inherit.rs
2019-04-20 22:39:38 +02:00

222 lines
5.8 KiB
Rust

/* 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 https://mozilla.org/MPL/2.0/. */
use rustc::hir::{self, HirId};
use rustc::lint::{LateContext, LateLintPass, LintArray, LintContext, LintPass};
use rustc::ty;
use std::boxed;
use std::env;
use std::error::Error;
use std::fmt;
use std::fs;
use std::io;
use std::path;
use syntax::ast;
use webidl::ast::*;
use webidl::visitor::*;
use webidl::*;
declare_lint!(
WEBIDL_INHERIT_CORRECT,
Deny,
"Warn and report usage of incorrect webidl inheritance"
);
pub struct WebIdlPass;
#[derive(Clone, Debug)]
pub struct ParentMismatchError {
name: String,
rust_parent: String,
webidl_parent: String,
}
impl fmt::Display for ParentMismatchError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"webidl-rust inheritance mismatch, rust: {:?}, rust parent: {:?}, webidl parent: {:?}",
self.name, self.rust_parent, self.webidl_parent
)
}
}
impl Error for ParentMismatchError {
fn description(&self) -> &str {
"ParentMismatchError"
}
fn cause(&self) -> Option<&Error> {
None
}
}
impl WebIdlPass {
pub fn new() -> WebIdlPass {
WebIdlPass
}
}
fn get_ty_name(ty: &str) -> &str {
if let Some(i) = ty.rfind(':') {
&ty[i + 1..]
} else {
ty
}
}
fn get_webidl_path(struct_name: &str) -> io::Result<path::PathBuf> {
let mut dir = env::current_dir()?;
dir.push("components/script/dom/webidls/");
dir.push(format!("{}.webidl", struct_name));
Ok(dir)
}
fn is_webidl_ty(cx: &LateContext, ty: &ty::TyS) -> bool {
let mut ret = false;
ty.maybe_walk(|t| {
match t.sty {
ty::Adt(did, _substs) => {
if cx.tcx.has_attr(did.did, "webidl") {
ret = true;
}
false
},
ty::Ref(..) => false, // don't recurse down &ptrs
ty::RawPtr(..) => false, // don't recurse down *ptrs
ty::FnDef(..) | ty::FnPtr(_) => false,
_ => true,
}
});
ret
}
fn check_inherits(code: &str, name: &str, parent_name: &str) -> Result<(), Box<Error>> {
let idl = parse_string(code)?;
let mut visitor = InterfaceVisitor::new(name.to_string());
visitor.visit(&idl);
let inherits = visitor.get_inherits();
if inherits == parent_name {
return Ok(());
}
// If there is no parent, first field must be of type Reflector.
if inherits == "" && parent_name == "Reflector" {
return Ok(());
}
if inherits == "" &&
name == "PaintRenderingContext2D" &&
parent_name == "CanvasRenderingContext2D"
{
// PaintRenderingContext2D embeds a CanvasRenderingContext2D
// instead of a Reflector as an optimization,
// but this is fine since CanvasRenderingContext2D
// also has a reflector
return Ok(());
}
Err(boxed::Box::from(ParentMismatchError {
name: name.to_string(),
rust_parent: parent_name.to_string(),
webidl_parent: inherits.to_string(),
}))
}
fn check_webidl(name: &str, parent_name: &Option<String>) -> Result<(), Box<Error>> {
let path = get_webidl_path(&name)?;
if let Some(parent) = parent_name {
let code = fs::read_to_string(path)?;
return check_inherits(&code, name, &parent);
}
Ok(())
}
impl LintPass for WebIdlPass {
fn name(&self) -> &'static str {
"ServoWebIDLPass"
}
fn get_lints(&self) -> LintArray {
lint_array!(WEBIDL_INHERIT_CORRECT)
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for WebIdlPass {
fn check_struct_def(
&mut self,
cx: &LateContext<'a, 'tcx>,
def: &'tcx hir::VariantData,
n: ast::Name,
_gen: &'tcx hir::Generics,
id: HirId,
) {
let def_id = cx.tcx.hir().local_def_id_from_hir_id(id);
if !is_webidl_ty(cx, cx.tcx.type_of(def_id)) {
return;
}
let item = match cx.tcx.hir().get_by_hir_id(id) {
hir::Node::Item(item) => item,
_ => cx
.tcx
.hir()
.expect_item_by_hir_id(cx.tcx.hir().get_parent_item(id)),
};
let parent_name = def.fields().iter().next().map(|field| {
let def_id = cx.tcx.hir().local_def_id_from_hir_id(field.hir_id);
let ty = cx.tcx.type_of(def_id).to_string();
get_ty_name(&ty).to_string()
});
let struct_name = n.to_string();
match check_webidl(&struct_name, &parent_name) {
Ok(()) => {},
Err(e) => {
let description = format!("{}", e);
cx.span_lint(WEBIDL_INHERIT_CORRECT, item.ident.span, &description)
},
};
}
}
struct InterfaceVisitor {
name: String,
inherits: String,
}
impl InterfaceVisitor {
pub fn new(name: String) -> Self {
InterfaceVisitor {
name: name,
inherits: String::new(),
}
}
pub fn get_inherits(&self) -> &String {
&self.inherits
}
}
impl<'ast> ImmutableVisitor<'ast> for InterfaceVisitor {
fn visit_callback_interface(&mut self, callback_interface: &'ast CallbackInterface) {
if callback_interface.name == self.name {
if let Some(ref inherit) = callback_interface.inherits {
self.inherits = inherit.to_string()
}
}
}
fn visit_non_partial_interface(&mut self, non_partial_interface: &'ast NonPartialInterface) {
if non_partial_interface.name == self.name {
if let Some(ref inherit) = non_partial_interface.inherits {
self.inherits = inherit.to_string()
}
}
}
}