Use lazy_static to not recompile regex every timeHEADmaster

This introduces lazy_static as a new dependency so that the regex does
not have to be compiled every time the function is called.

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

3 files changed, 6 insertions, 2 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 74352a4..a0d85dd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -12,6 +12,7 @@ dependencies = [
 name = "annotate-rust"
 version = "0.1.0"
 dependencies = [
+ "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.40 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/Cargo.toml b/Cargo.toml
index e229d66..00514e4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,3 +9,4 @@ regex = "1.1.9"
 syn = { version = "0.15.39", default-features = false, features = ["full", "parsing", "visit", "extra-traits"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
+lazy_static = "1.3"
diff --git a/src/git.rs b/src/git.rs
index daaceb0..68afd52 100644
--- a/src/git.rs
+++ b/src/git.rs
@@ -32,13 +32,15 @@ pub fn crawl_git_tree<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
 }
 
 pub fn parse_ls_tree_output<'a>(output: &'a [u8]) -> Result<Vec<Blob<'a>>, Utf8Error> {
-    let re = Regex::new(r"^[^ ]+ [^ ]+ ([^\t]+)\t(.+)$").unwrap();
+    lazy_static::lazy_static! {
+        static ref RE: Regex = Regex::new(r"^[^ ]+ [^ ]+ ([^\t]+)\t(.+)$").unwrap();
+    }
 
     output.split(|byte| *byte == 0)
         .map(str::from_utf8)
         .filter_map(|r_l| match r_l {
             Err(e) => Some(Err(e)),
-            Ok(l) => re.captures(l).map(Ok),
+            Ok(l) => RE.captures(l).map(Ok),
         })
         .map(|r_captures| r_captures.map(|captures| Blob {
             object: captures.get(1).unwrap().as_str(),