perf: Use Formatter.write_str instead of write! macro in the Display trait implementation for InlineError

Stranger6667 · Stranger6667 · commit 42cd5477b200 · 2020-08-13T11:36:39.000+02:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Performance
+
+- Use `Formatter.write_str` instead of `write!` macro in the `Display` trait implementation for `InlineError`. [#85](https://github.com/Stranger6667/css-inline/issues/85)
+
 ## [0.5.0] - 2020-08-07
 
 ### Added
diff --git a/benches/inliner.rs b/benches/inliner.rs
@@ -1,5 +1,5 @@
 use criterion::{black_box, criterion_group, criterion_main, Criterion};
-use css_inline::inline;
+use css_inline::{inline, InlineError};
 
 fn simple(c: &mut Criterion) {
     let html = black_box(
@@ -25,6 +25,11 @@ fn simple(c: &mut Criterion) {
     c.bench_function("simple HTML", |b| b.iter(|| inline(html).unwrap()));
 }
 
+fn error_formatting(c: &mut Criterion) {
+    let error = black_box(InlineError::ParseError("Error description".to_string()));
+    c.bench_function("error formatting", |b| b.iter(|| format!("{}", error)));
+}
+
 fn merging(c: &mut Criterion) {
     let html = black_box(
         r#"<html>
@@ -156,5 +161,5 @@ BEGIN FOOTER
     c.bench_function("big email", |b| b.iter(|| inline(html).unwrap()));
 }
 
-criterion_group!(benches, simple, merging, big_email);
+criterion_group!(benches, simple, merging, big_email, error_formatting);
 criterion_main!(benches);
diff --git a/src/error.rs b/src/error.rs
@@ -34,9 +34,9 @@ impl Error for InlineError {}
 impl Display for InlineError {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
-            InlineError::IO(error) => write!(f, "{}", error),
-            InlineError::Network(error) => write!(f, "{}", error),
-            InlineError::ParseError(error) => write!(f, "{}", error),
+            InlineError::IO(error) => f.write_str(error.to_string().as_str()),
+            InlineError::Network(error) => f.write_str(error.to_string().as_str()),
+            InlineError::ParseError(error) => f.write_str(error.as_str()),
         }
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -34,9 +34,9 @@ impl Error for InlineError {}`
`34`	`34`	`impl Display for InlineError {`
`35`	`35`	`fn fmt(&self, f: &mut Formatter) -> fmt::Result {`
`36`	`36`	`match self {`
`37`		`- InlineError::IO(error) => write!(f, "{}", error),`
`38`		`- InlineError::Network(error) => write!(f, "{}", error),`
`39`		`- InlineError::ParseError(error) => write!(f, "{}", error),`
	`37`	`+ InlineError::IO(error) => f.write_str(error.to_string().as_str()),`
	`38`	`+ InlineError::Network(error) => f.write_str(error.to_string().as_str()),`
	`39`	`+ InlineError::ParseError(error) => f.write_str(error.as_str()),`
`40`	`40`	`}`
`41`	`41`	`}`
`42`	`42`	`}`