Merge #2982

2982: perf: regex new is expensive r=yangby-cryptape,zhangsoledad a=driftluo ### What problem does this PR solve? regex new is expensive，reinitialization every time enter the function is not a good strategy ### What is changed and how it works? use once_cell to wrapper regex ### Release note ```release-note Title Only: Include only the PR title in the release note. ``` Co-authored-by: driftluo <[email protected]>
nervosnetwork · Aug 26, 2021 · 2ca6aa1 · 2ca6aa1
2 parents 35aa766 + ab7e580
commit 2ca6aa1
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Showing 3 changed files with 13 additions and 15 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/util/Cargo.toml b/util/Cargo.toml
@@ -12,6 +12,7 @@ repository = "https://github.com/nervosnetwork/ckb"
 parking_lot = "0.11"
 linked-hash-map = "0.5"
 regex = "1.1.6"
+once_cell = "1.8.0"
 
 [dev-dependencies]
 ckb-fixed-hash = { path = "fixed-hash", version = "= 0.100.0-pre" }

diff --git a/util/src/strings.rs b/util/src/strings.rs
@@ -18,24 +18,18 @@ use regex::Regex;
 /// ```
 pub fn check_if_identifier_is_valid(ident: &str) -> Result<(), String> {
     const IDENT_PATTERN: &str = r#"^[0-9a-zA-Z_-]+$"#;
+    static RE: once_cell::sync::OnceCell<Regex> = once_cell::sync::OnceCell::new();
+    // IDENT_PATTERN is a correct regular expression, so unwrap here
+    let re = RE.get_or_init(|| Regex::new(IDENT_PATTERN).unwrap());
+
     if ident.is_empty() {
         return Err("the identifier shouldn't be empty".to_owned());
     }
-    match Regex::new(IDENT_PATTERN) {
-        Ok(re) => {
-            if !re.is_match(&ident) {
-                return Err(format!(
-                    "invaild identifier \"{}\", the identifier pattern is \"{}\"",
-                    ident, IDENT_PATTERN
-                ));
-            }
-        }
-        Err(err) => {
-            return Err(format!(
-                "invalid regular expression \"{}\": {}",
-                IDENT_PATTERN, err
-            ));
-        }
+    if !re.is_match(ident) {
+        return Err(format!(
+            "Invalid identifier \"{}\", the identifier pattern is \"{}\"",
+            ident, IDENT_PATTERN
+        ));
     }
     Ok(())
 }