some code refactor

src/http.rs

@@ -13,7 +13,7 @@ pub fn is_url(path: &str) -> bool {
 }
 
 pub fn resolve_url(from: &str, to: &str) -> Result<String, ParseError> {
-    let mut result = "".to_string();
+    let mut result = String::new();
 
     if is_url(to) { // (anything, http://site.com/css/main.css)
         result = to.to_string();
@@ -51,9 +51,9 @@ pub fn resolve_url(from: &str, to: &str) -> Result<String, ParseError> {
 }
 
 pub fn url_is_data(url: &str) -> Result<bool, String> {
-    match Url::parse(&url) {
+    match Url::parse(url) {
         Ok(parsed_url) => Ok(parsed_url.scheme() == "data"),
-        Err(err) => return Err(format!("{}", err.to_string())),
+        Err(err) => return Err(format!("{}", err)),
     }
 }
 

src/utils.rs

@@ -17,12 +17,7 @@ pub fn data_to_dataurl(mime: &str, data: &[u8]) -> String {
 }
 
 fn detect_mimetype(data: &[u8]) -> String {
-    let detected_mimetype = data.sniff_mime_type();
-    if detected_mimetype != None {
-        detected_mimetype.unwrap().to_string()
-    } else {
-        "".to_string()
-    }
+    data.sniff_mime_type().unwrap_or("").to_string()
 }
 
 #[cfg(test)]
@@ -34,6 +29,9 @@ mod tests {
         let mime = "application/javascript";
         let data = "var word = 'hello';\nalert(word);\n";
         let datauri = data_to_dataurl(mime, data.as_bytes());
-        assert_eq!(&datauri, "data:application/javascript;base64,dmFyIHdvcmQgPSAnaGVsbG8nOwphbGVydCh3b3JkKTsK");
+        assert_eq!(
+            &datauri,
+            "data:application/javascript;base64,dmFyIHdvcmQgPSAnaGVsbG8nOwphbGVydCh3b3JkKTsK"
+        );
     }
 }