Auto merge of #17883 - frewsxcv:frewsxcxv-lowercase, r=SimonSapin

Audit usages of unicode case-changing methods.

Part of https://github.com/servo/servo/issues/17777.

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/17883)
<!-- Reviewable:end -->

components/net/fetch/methods.rs

@@ -21,6 +21,7 @@ use net_traits::request::{Referrer, Request, RequestMode, ResponseTainting};
 use net_traits::request::{Type, Origin, Window};
 use net_traits::response::{Response, ResponseBody, ResponseType};
 use servo_url::ServoUrl;
+use std::ascii::AsciiExt;
 use std::borrow::Cow;
 use std::fmt;
 use std::fs::File;
@@ -514,9 +515,10 @@ pub fn should_be_blocked_due_to_nosniff(request_type: Type, response_headers: &H
         fn parse_header(raw: &[Vec<u8>]) -> HyperResult<Self> {
             raw.first()
                 .and_then(|v| str::from_utf8(v).ok())
-                .and_then(|s| match s.trim().to_lowercase().as_str() {
-                    "nosniff" => Some(XContentTypeOptions),
-                    _ => None
+                .and_then(|s| if s.trim().eq_ignore_ascii_case("nosniff") {
+                    Some(XContentTypeOptions)
+                } else {
+                    None
                 })
                 .ok_or(Error::Header)
         }

components/script/dom/blob.rs

@@ -16,6 +16,7 @@ use ipc_channel::ipc;
 use net_traits::{CoreResourceMsg, IpcSend};
 use net_traits::blob_url_store::{BlobBuf, get_blob_origin};
 use net_traits::filemanager_thread::{FileManagerThreadMsg, ReadFileProgress, RelativePos};
+use std::ascii::AsciiExt;
 use std::mem;
 use std::ops::Index;
 use std::path::PathBuf;
@@ -381,7 +382,7 @@ impl BlobMethods for Blob {
 /// see https://github.com/w3c/FileAPI/issues/43
 fn normalize_type_string(s: &str) -> String {
     if is_ascii_printable(s) {
-        let s_lower = s.to_lowercase();
+        let s_lower = s.to_ascii_lowercase();
         // match s_lower.parse() as Result<Mime, ()> {
             // Ok(_) => s_lower,
             // Err(_) => "".to_string()

components/script/dom/document.rs

@@ -3875,8 +3875,7 @@ fn update_with_current_time_ms(marker: &Cell<u64>) {
 
 /// https://w3c.github.io/webappsec-referrer-policy/#determine-policy-for-token
 pub fn determine_policy_for_token(token: &str) -> Option<ReferrerPolicy> {
-    let lower = token.to_lowercase();
-    return match lower.as_ref() {
+    match_ignore_ascii_case! { token,
         "never" | "no-referrer" => Some(ReferrerPolicy::NoReferrer),
         "default" | "no-referrer-when-downgrade" => Some(ReferrerPolicy::NoReferrerWhenDowngrade),
         "origin" => Some(ReferrerPolicy::Origin),

components/script/dom/htmlareaelement.rs

@@ -240,7 +240,7 @@ impl HTMLAreaElement {
     pub fn get_shape_from_coords(&self) -> Option<Area> {
        let elem = self.upcast::<Element>();
        let shape = elem.get_string_attribute(&"shape".into());
-       let shp: Shape = match shape.to_lowercase().as_ref() {
+       let shp: Shape = match_ignore_ascii_case! { &shape,
            "circle" => Shape::Circle,
            "circ" => Shape::Circle,
            "rectangle" => Shape::Rectangle,

components/script/dom/htmlelement.rs

@@ -32,7 +32,6 @@ use dom::virtualmethods::VirtualMethods;
 use dom_struct::dom_struct;
 use html5ever::{LocalName, Prefix};
 use std::ascii::AsciiExt;
-use std::borrow::ToOwned;
 use std::default::Default;
 use std::rc::Rc;
 use style::attr::AttrValue;
@@ -374,12 +373,16 @@ impl HTMLElementMethods for HTMLElement {
 
 // https://html.spec.whatwg.org/multipage/#attr-data-*
 
+static DATA_PREFIX: &str = "data-";
+static DATA_HYPHEN_SEPARATOR: char = '\x2d';
+
 fn to_snake_case(name: DOMString) -> DOMString {
-    let mut attr_name = "data-".to_owned();
+    let mut attr_name = String::with_capacity(name.len() + DATA_PREFIX.len());
+    attr_name.push_str(DATA_PREFIX);
     for ch in name.chars() {
-        if ch.is_uppercase() {
-            attr_name.push('\x2d');
-            attr_name.extend(ch.to_lowercase());
+        if ch.is_ascii_uppercase() {
+            attr_name.push(DATA_HYPHEN_SEPARATOR);
+            attr_name.push(ch.to_ascii_lowercase());
         } else {
             attr_name.push(ch);
         }
@@ -394,23 +397,21 @@ fn to_snake_case(name: DOMString) -> DOMString {
 // without the data prefix.
 
 fn to_camel_case(name: &str) -> Option<DOMString> {
-    if !name.starts_with("data-") {
+    if !name.starts_with(DATA_PREFIX) {
         return None;
     }
     let name = &name[5..];
-    let has_uppercase = name.chars().any(|curr_char| {
-        curr_char.is_ascii() && curr_char.is_uppercase()
-    });
+    let has_uppercase = name.chars().any(|curr_char| curr_char.is_ascii_uppercase());
     if has_uppercase {
         return None;
     }
-    let mut result = "".to_owned();
+    let mut result = String::with_capacity(name.len().saturating_sub(DATA_PREFIX.len()));
     let mut name_chars = name.chars();
     while let Some(curr_char) = name_chars.next() {
         //check for hyphen followed by character
-        if curr_char == '\x2d' {
+        if curr_char == DATA_HYPHEN_SEPARATOR {
             if let Some(next_char) = name_chars.next() {
-                if next_char.is_ascii() && next_char.is_lowercase() {
+                if next_char.is_ascii_lowercase() {
                     result.push(next_char.to_ascii_uppercase());
                 } else {
                     result.push(curr_char);

components/script/dom/request.rs

@@ -38,7 +38,6 @@ use net_traits::request::Request as NetTraitsRequest;
 use net_traits::request::RequestMode as NetTraitsRequestMode;
 use net_traits::request::Type as NetTraitsRequestType;
 use servo_url::ServoUrl;
-use std::ascii::AsciiExt;
 use std::cell::{Cell, Ref};
 use std::rc::Rc;
 
@@ -453,15 +452,16 @@ fn net_request_from_global(global: &GlobalScope,
 
 // https://fetch.spec.whatwg.org/#concept-method-normalize
 fn normalize_method(m: &str) -> HttpMethod {
-    match m {
-        m if m.eq_ignore_ascii_case("DELETE") => HttpMethod::Delete,
-        m if m.eq_ignore_ascii_case("GET") => HttpMethod::Get,
-        m if m.eq_ignore_ascii_case("HEAD") => HttpMethod::Head,
-        m if m.eq_ignore_ascii_case("OPTIONS") => HttpMethod::Options,
-        m if m.eq_ignore_ascii_case("POST") => HttpMethod::Post,
-        m if m.eq_ignore_ascii_case("PUT") => HttpMethod::Put,
-        m => HttpMethod::Extension(m.to_string()),
+    match_ignore_ascii_case! { m,
+        "delete" => return HttpMethod::Delete,
+        "get" => return HttpMethod::Get,
+        "head" => return HttpMethod::Head,
+        "options" => return HttpMethod::Options,
+        "post" => return HttpMethod::Post,
+        "put" => return HttpMethod::Put,
+        _ => (),
     }
+    HttpMethod::Extension(m.to_string())
 }
 
 // https://fetch.spec.whatwg.org/#concept-method

components/script/lib.rs

@@ -2,6 +2,7 @@
  * 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/. */
 
+#![feature(ascii_ctype)]
 #![feature(box_syntax)]
 #![feature(conservative_impl_trait)]
 #![feature(const_fn)]

components/selectors/parser.rs

@@ -1586,10 +1586,10 @@ where Impl: SelectorImpl, F: FnOnce(i32, i32) -> Component<Impl> {
 /// double-colon syntax, which can be used for all pseudo-elements).
 pub fn is_css2_pseudo_element<'i>(name: &CowRcStr<'i>) -> bool {
     // ** Do not add to this list! **
-    return name.eq_ignore_ascii_case("before") ||
-           name.eq_ignore_ascii_case("after") ||
-           name.eq_ignore_ascii_case("first-line") ||
-           name.eq_ignore_ascii_case("first-letter");
+    match_ignore_ascii_case! { name,
+        "before" | "after" | "first-line" | "first-letter" => true,
+        _ => false,
+    }
 }
 
 /// Parse a simple selector other than a type selector.

components/style/media_queries.rs

@@ -12,7 +12,6 @@ use cssparser::{Delimiter, Parser, Token, ParserInput};
 use parser::ParserContext;
 use selectors::parser::SelectorParseError;
 use serialize_comma_separated_list;
-use std::ascii::AsciiExt;
 use std::fmt;
 use style_traits::{ToCss, ParseError, StyleParseError};
 
@@ -146,20 +145,15 @@ pub enum MediaQueryType {
 
 impl MediaQueryType {
     fn parse(ident: &str) -> Result<Self, ()> {
-        if ident.eq_ignore_ascii_case("all") {
-            return Ok(MediaQueryType::All);
-        }
-
-        // From https://drafts.csswg.org/mediaqueries/#mq-syntax:
-        //
-        //   The <media-type> production does not include the keywords only,
-        //   not, and, and or.
-        if ident.eq_ignore_ascii_case("not") ||
-           ident.eq_ignore_ascii_case("or") ||
-           ident.eq_ignore_ascii_case("and") ||
-           ident.eq_ignore_ascii_case("only") {
-            return Err(())
-        }
+        match_ignore_ascii_case! { ident,
+            "all" => return Ok(MediaQueryType::All),
+            // From https://drafts.csswg.org/mediaqueries/#mq-syntax:
+            //
+            //   The <media-type> production does not include the keywords only,
+            //   not, and, and or.
+            "not" | "or" | "and" | "only" => return Err(()),
+            _ => (),
+        };
 
         Ok(match MediaType::parse(ident) {
             Some(media_type) => MediaQueryType::Known(media_type),

components/style_derive/to_css.rs

@@ -151,7 +151,7 @@ fn where_predicate(ty: syn::Ty) -> syn::WherePredicate {
 
 /// Transforms "FooBar" to "foo-bar".
 ///
-/// If the first Camel segment is "Moz"" or "Webkit", the result string
+/// If the first Camel segment is "Moz" or "Webkit", the result string
 /// is prepended with "-".
 fn to_css_identifier(mut camel_case: &str) -> String {
     camel_case = camel_case.trim_right_matches('_');