perf: use btree entry

Author: Stranger6667

css-inline/src/html/attributes.rs

@@ -1,5 +1,5 @@
 use html5ever::{local_name, namespace_url, ns, tendril::StrTendril, QualName};
-use std::collections::BTreeMap;
+use std::collections::{btree_map::Entry, BTreeMap};
 
 /// A collection of HTML attributes.
 #[derive(Debug)]
@@ -39,15 +39,8 @@ impl Attributes {
             .map(|value| &**value)
     }
 
-    pub(crate) fn get_style_mut(&mut self) -> Option<&mut StrTendril> {
+    pub(crate) fn get_style_entry(&mut self) -> Entry<'_, QualName, StrTendril> {
         self.map
-            .get_mut(&QualName::new(None, ns!(), local_name!("style")))
-    }
-
-    pub(crate) fn set_style(&mut self, style: String) {
-        self.map.insert(
-            QualName::new(None, ns!(), local_name!("style")),
-            style.into(),
-        );
+            .entry(QualName::new(None, ns!(), local_name!("style")))
     }
 }

css-inline/src/lib.rs

@@ -35,6 +35,7 @@ use indexmap::IndexMap;
 use smallvec::{smallvec, SmallVec};
 use std::{
     borrow::Cow,
+    collections::btree_map::Entry,
     io::{ErrorKind, Write},
 };
 
@@ -257,18 +258,22 @@ impl<'a> CSSInliner<'a> {
             };
             styles.sort_unstable_by(|_, (a, _), _, (b, _)| a.cmp(b));
             let attributes = &mut element.attributes;
-            if let Some(existing_style) = attributes.get_style_mut() {
-                merge_styles(existing_style, styles)?;
-            } else {
-                let mut final_styles = String::with_capacity(128);
-                for (name, (_, value)) in styles {
-                    final_styles.push_str(name.as_str());
-                    final_styles.push(':');
-                    replace_double_quotes!(final_styles, name, value);
-                    final_styles.push(';');
+            match attributes.get_style_entry() {
+                Entry::Vacant(entry) => {
+                    let mut final_styles = String::with_capacity(128);
+                    for (name, (_, value)) in styles {
+                        final_styles.push_str(name.as_str());
+                        final_styles.push(':');
+                        replace_double_quotes!(final_styles, name, value);
+                        final_styles.push(';');
+                    }
+                    entry.insert(final_styles.into());
                 }
-                attributes.set_style(final_styles);
-            };
+                Entry::Occupied(mut entry) => {
+                    let existing_style = entry.get_mut();
+                    merge_styles(existing_style, styles)?;
+                }
+            }
         }
         Ok(document)
     }