1 files changed, 133 insertions, 0 deletions
diff --git a/components/script_plugins/webidl_must_inherit.rs b/components/script_plugins/webidl_must_inherit.rs
new file mode 100644
index 00000000000..96ef9e75db2
--- /dev/null
+++ b/components/script_plugins/webidl_must_inherit.rs
@@ -0,0 +1,133 @@
+/* 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::env;
+
+use std::io;
+use std::path;
+use syntax::ast;
+declare_lint!(
+    WEBIDL_INHERIT_CORRECT,
+    Deny,
+    "Warn and report usage of incorrect webidl inheritance"
+);
+
+pub struct WebIdlPass;
+
+impl WebIdlPass {
+    pub fn new() -> WebIdlPass {
+        WebIdlPass
+    }
+}
+
+fn get_typ_name(typ: String) -> Option<String> {
+    if let Some(i) = typ.rfind(':') {
+        return Some(typ[i + 1..].to_string());
+    }
+    None
+}
+
+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));
+
+    return Ok(dir);
+}
+
+/// Checks if a type is unrooted or contains any owned unrooted types
+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_webidl(name: &str, parent_name: Option<String>) -> io::Result<()> {
+    let path = get_webidl_path(&name)?;
+    println!("struct_webidl_path: {:?}", &path);
+
+    if let Some(parent) = parent_name {
+        let parent_path = get_webidl_path(&parent)?;
+        println!("parent_path: {:?}", &parent_path);
+    }
+
+    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 struct_name = n.to_string();
+        println!("struct_name: {:?}", struct_name);
+
+        let mut parent_typ_name: Option<String> = None;
+        for ref field in def.fields() {
+            let def_id = cx.tcx.hir().local_def_id_from_hir_id(field.hir_id);
+            let ty = cx.tcx.type_of(def_id);
+            let typ = ty.to_string();
+            if let Some(typ_name) = get_typ_name(ty.to_string()) {
+                parent_typ_name = Some(typ_name);
+                break;
+            } else {
+                cx.span_lint(WEBIDL_INHERIT_CORRECT, field.span, "Cannot get type name");
+            }
+
+            // Only first field is relevant.
+            break;
+        }
+
+        // TODO Open and parse corresponding webidl file.
+        cx.span_lint(WEBIDL_INHERIT_CORRECT, item.ident.span, "WEBIDL present.");
+
+        match check_webidl(&struct_name, parent_typ_name) {
+            Ok(()) => {},
+            Err(e) => println!("ERRORRR: {:?}", e),
+        };
+    }
+}