Move script lints to script_plugins

The plugins crate now just allows to hook into clippy from a single crate.

components/script_plugins/utils.rs

@@ -0,0 +1,73 @@
+/* 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 rustc::hir::def_id::DefId;
+use rustc::lint::{LateContext, LintContext};
+use syntax::ast;
+use syntax::codemap::{ExpnFormat, Span};
+use syntax::ptr::P;
+
+/// Matches a type with a provided string, and returns its type parameters if successful
+pub fn match_ty_unwrap<'a>(ty: &'a ast::Ty, segments: &[&str]) -> Option<&'a [P<ast::Ty>]> {
+    match ty.node {
+        ast::TyKind::Path(_, ast::Path { segments: ref seg, .. }) => {
+            // So hir::Path isn't the full path, just the tokens that were provided.
+            // I could muck around with the maps and find the full path
+            // however the more efficient way is to simply reverse the iterators and zip them
+            // which will compare them in reverse until one of them runs out of segments
+            if seg.iter().rev().zip(segments.iter().rev()).all(|(a, b)| &*a.identifier.name.as_str() == *b) {
+                match seg.last() {
+                    Some(&ast::PathSegment { parameters: Some(ref params), .. }) => {
+                        match **params {
+                            ast::PathParameters::AngleBracketed(ref a) => Some(&a.types),
+
+                            // `Foo(A,B) -> C`
+                            ast::PathParameters::Parenthesized(_) => None,
+                        }
+                    }
+                    Some(&ast::PathSegment { parameters: None, .. }) => Some(&[]),
+                    None => None,
+                }
+            } else {
+                None
+            }
+        },
+        _ => None
+    }
+}
+
+/// check if a DefId's path matches the given absolute type path
+/// usage e.g. with
+/// `match_def_path(cx, id, &["core", "option", "Option"])`
+pub fn match_def_path(cx: &LateContext, def_id: DefId, path: &[&str]) -> bool {
+    let krate = &cx.tcx.crate_name(def_id.krate);
+    if krate != &path[0] {
+        return false;
+    }
+
+    let path = &path[1..];
+    let other = cx.tcx.def_path(def_id).data;
+
+    if other.len() != path.len() {
+        return false;
+    }
+
+    other.into_iter()
+         .map(|e| e.data)
+         .zip(path)
+         .all(|(nm, p)| &*nm.as_interned_str() == *p)
+}
+
+pub fn in_derive_expn(cx: &LateContext, span: Span) -> bool {
+    cx.sess().codemap().with_expn_info(span.expn_id,
+            |info| {
+                if let Some(i) = info {
+                    if let ExpnFormat::MacroAttribute(n) = i.callee.format {
+                        if n.as_str().contains("derive") {
+                            true
+                        } else { false }
+                    } else { false }
+                } else { false }
+            })
+}