From 4cc2a489d01a5cc69daf68bc5913ea80398a5d1a Mon Sep 17 00:00:00 2001
From: rhysd <lin90162@yahoo.co.jp>
Date: Sun, 15 Jan 2023 19:04:16 +0900
Subject: [PATCH] Remove unnecessary heap allocations in `PrettyPrinter::print`
 for style components

---
 src/pretty_printer.rs | 25 +++++++++++++------------
 src/style.rs          |  8 ++++++++
 2 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/src/pretty_printer.rs b/src/pretty_printer.rs
index 0d68ba40..bc89d4fc 100644
--- a/src/pretty_printer.rs
+++ b/src/pretty_printer.rs
@@ -10,7 +10,7 @@ use crate::{
     error::Result,
     input,
     line_range::{HighlightedLineRanges, LineRange, LineRanges},
-    style::{StyleComponent, StyleComponents},
+    style::StyleComponent,
     SyntaxMapping, WrappingMode,
 };
 
@@ -20,6 +20,7 @@ use crate::paging::PagingMode;
 #[derive(Default)]
 struct ActiveStyleComponents {
     header: bool,
+    #[cfg(feature = "git")]
     vcs_modification_markers: bool,
     grid: bool,
     rule: bool,
@@ -269,31 +270,31 @@ impl<'a> PrettyPrinter<'a> {
             .term_width
             .unwrap_or_else(|| Term::stdout().size().1 as usize);
 
-        let mut style_components = vec![];
+        self.config.style_components.clear();
         if self.active_style_components.grid {
-            style_components.push(StyleComponent::Grid);
+            self.config.style_components.insert(StyleComponent::Grid);
         }
         if self.active_style_components.rule {
-            style_components.push(StyleComponent::Rule);
+            self.config.style_components.insert(StyleComponent::Rule);
         }
         if self.active_style_components.header {
-            style_components.push(StyleComponent::Header);
+            self.config.style_components.insert(StyleComponent::Header);
         }
         if self.active_style_components.line_numbers {
-            style_components.push(StyleComponent::LineNumbers);
+            self.config
+                .style_components
+                .insert(StyleComponent::LineNumbers);
         }
         if self.active_style_components.snip {
-            style_components.push(StyleComponent::Snip);
+            self.config.style_components.insert(StyleComponent::Snip);
         }
+        #[cfg(feature = "git")]
         if self.active_style_components.vcs_modification_markers {
-            #[cfg(feature = "git")]
-            style_components.push(StyleComponent::Changes);
+            self.config.style_components.insert(StyleComponent::Changes);
         }
-        self.config.style_components = StyleComponents::new(&style_components);
 
         // Collect the inputs to print
-        let mut inputs: Vec<Input> = vec![];
-        std::mem::swap(&mut inputs, &mut self.inputs);
+        let inputs = std::mem::take(&mut self.inputs);
 
         // Run the controller
         let controller = Controller::new(&self.config, &self.assets);
diff --git a/src/style.rs b/src/style.rs
index 27ee33e8..0f83d1bc 100644
--- a/src/style.rs
+++ b/src/style.rs
@@ -129,4 +129,12 @@ impl StyleComponents {
     pub fn plain(&self) -> bool {
         self.0.iter().all(|c| c == &StyleComponent::Plain)
     }
+
+    pub fn insert(&mut self, component: StyleComponent) {
+        self.0.insert(component);
+    }
+
+    pub fn clear(&mut self) {
+        self.0.clear();
+    }
 }