Use lazy_static to cache datetime formats

One of those two date formats was re-compiled before any date was displayed. Now they are compiled only the first time they're used, and cached versions are used thereafter, resulting in a speedup.

2 files changed, 20 insertions, 12 deletions

diff --git a/src/main.rs b/src/main.rs
index 8c4761a..1e9f76c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,5 @@
 #![warn(trivial_casts, trivial_numeric_casts)]
-#![warn(unused_extern_crates, unused_qualifications)]
+#![warn(unused_qualifications)]
 #![warn(unused_results)]
 
 extern crate ansi_term;
@@ -15,9 +15,8 @@ extern crate term_grid;
 extern crate unicode_width;
 extern crate users;
 
-#[cfg(feature="git")]
-extern crate git2;
-
+#[cfg(feature="git")] extern crate git2;
+#[macro_use] extern crate lazy_static;
 
 use std::env;
 use std::path::{Component, Path};
diff --git a/src/output/details.rs b/src/output/details.rs
index 7e9775f..a7d1da9 100644
--- a/src/output/details.rs
+++ b/src/output/details.rs
@@ -129,13 +129,11 @@ use output::column::{Alignment, Column, Columns, Cell, SizeFormat};
 use ansi_term::{ANSIString, ANSIStrings, Style};
 
 use datetime::local::{LocalDateTime, DatePiece};
-use datetime::format::{DateFormat};
-use datetime::zoned::{TimeZone};
+use datetime::format::DateFormat;
+use datetime::zoned::TimeZone;
 
 use locale;
 
-use number_prefix::{binary_prefix, decimal_prefix, Prefixed, Standalone, PrefixNames};
-
 use users::{OSUsers, Users};
 use users::mock::MockUsers;
 
@@ -562,6 +560,8 @@ impl<U> Table<U> where U: Users {
     }
 
     fn render_size(&self, size: f::Size, size_format: SizeFormat) -> Cell {
+        use number_prefix::{binary_prefix, decimal_prefix, Prefixed, Standalone, PrefixNames};
+
         if let f::Size::Some(offset) = size {
             let result = match size_format {
                 SizeFormat::DecimalBytes  => decimal_prefix(offset as f64),
@@ -591,14 +591,14 @@ impl<U> Table<U> where U: Users {
     fn render_time(&self, timestamp: f::Time) -> Cell {
         let date = self.tz.at(LocalDateTime::at(timestamp.0 as i64));
 
-        let format = if date.year() == self.current_year {
-                DateFormat::parse("{2>:D} {:M} {2>:h}:{02>:m}").unwrap()
+        let datestamp = if date.year() == self.current_year {
+                DATE_AND_TIME.format(&date, &self.time)
             }
             else {
-                DateFormat::parse("{2>:D} {:M} {5>:Y}").unwrap()
+                DATE_AND_YEAR.format(&date, &self.time)
             };
 
-        Cell::paint(self.colours.date, &format.format(&date, &self.time))
+        Cell::paint(self.colours.date, &datestamp)
     }
 
     fn render_git_status(&self, git: f::Git) -> Cell {
@@ -753,6 +753,15 @@ impl TreePart {
 }
 
 
+lazy_static! {
+    static ref DATE_AND_TIME: DateFormat<'static> =
+        DateFormat::parse("{2>:D} {:M} {2>:h}:{02>:m}").unwrap();
+
+    static ref DATE_AND_YEAR: DateFormat<'static> =
+        DateFormat::parse("{2>:D} {:M} {5>:Y}").unwrap();
+}
+
+
 #[cfg(test)]
 pub mod test {
     pub use super::Table;