From 1fba1b76ec005fefa76b8585c95a075bd7cfc5c2 Mon Sep 17 00:00:00 2001
From: Agustin Chiappe Berrini <jnieve@gmail.com>
Date: Sat, 18 Nov 2017 09:41:40 -0500
Subject: [PATCH] Reduce number of heap allocations
---
src/parser/shell_expand/mod.rs | 43 +++++++++++++++++++++++++++-------
1 file changed, 34 insertions(+), 9 deletions(-)
diff --git a/src/parser/shell_expand/mod.rs b/src/parser/shell_expand/mod.rs
index f16a4dfb..aa9171c5 100644
--- a/src/parser/shell_expand/mod.rs
+++ b/src/parser/shell_expand/mod.rs
@@ -50,15 +50,24 @@ fn expand_process<E: Expander>(
};
slice(current, output, selection)
} else {
- // TODO: Complete this so that we don't need any heap allocations.
- // All that we need is to shift bytes to the left when extra spaces are found.
- //
- // unsafe {
- // let bytes: &mut [u8] = output.as_bytes_mut();
- // bytes.iter_mut().filter(|b| **b == b'\n').for_each(|b| *b = b' ');
- // slice(current, str::from_utf8_unchecked(&bytes).trim(), selection)
- // }
- slice(current, &output.split_whitespace().collect::<Vec<&str>>().join(" "), selection)
+ let mut result = String::with_capacity(output.len());
+ let mut previous_char_was_whitespace = true;
+ output
+ .chars()
+ .for_each(|c| {
+ match c {
+ c if !char::is_whitespace(c) => {
+ result.push(c);
+ previous_char_was_whitespace = false;
+ },
+ c if char::is_whitespace(c) && !previous_char_was_whitespace => {
+ result.push(' ');
+ previous_char_was_whitespace = true;
+ },
+ _ => (),
+ }
+ });
+ slice(current, result.trim_right(), selection)
}
}
}
@@ -559,6 +568,22 @@ mod test {
}
}
+ struct CommandExpander;
+
+ impl Expander for CommandExpander {
+ fn command(&self, cmd: &str) -> Option<Value> {
+ Some(cmd.to_owned())
+ }
+ }
+
+ #[test]
+ fn expand_process_unquoted() {
+ let mut output = String::new();
+ let line = " Mary had\ta\u{2009}little \n\t lamb\t";
+ expand_process(&mut output, line, Select::All, &CommandExpander, false);
+ assert_eq!(output, "Mary had a little lamb");
+ }
+
#[test]
fn expand_variable_normal_variable() {
let input = "$FOO:NOT:$BAR";
--
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