feat: allow configuring number of threads that rayon uses

Author: Tommypop2

crates/c2pdf-gui/src/main.rs

@@ -127,6 +127,7 @@ fn app_view() -> impl IntoView {
             12.0,
             None,
             &logger_for_thread,
+						None
           );
           doc_subset.lock().unwrap().to_document(&mut doc);
           let f = File::create(path_for_thread.join("output.pdf")).unwrap();

crates/c2pdf/src/bin/c2pdf.rs

@@ -6,6 +6,7 @@ use c2pdf::logging::Logger;
 use core::f32;
 use printpdf::*;
 use std::fs::File;
+use std::num::NonZeroU8;
 use std::path::PathBuf;
 use std::time::Instant;
 // This makes `FromArgs` happy
@@ -65,6 +66,10 @@ struct Arguments {
   /// text to add to (the top of) every page
   #[argh(option)]
   page_text: Option<String>,
+
+  /// number of threads to use for processing
+  #[argh(option)]
+  threads: Option<NonZeroU8>,
 }
 fn main() {
   // Parse args
@@ -98,6 +103,7 @@ fn main() {
     args.font_size,
     args.page_text,
     &logger,
+    args.threads,
   );
   doc_subset.lock().unwrap().to_document(&mut doc);
   let num_pages = doc.pages.len();

crates/c2pdf/src/lib/lib.rs

@@ -8,6 +8,7 @@
 
 use std::{
   cmp::Ordering,
+  num::NonZeroU8,
   path::PathBuf,
   sync::{Arc, Mutex},
 };
@@ -43,6 +44,7 @@ impl CodeToPdf {
     font_size: f32,
     page_text: Option<String>,
     logger: &Logger,
+    threads: Option<NonZeroU8>,
   ) -> (Arc<Mutex<DocumentSubset>>, usize) {
     let doc_subset = DocumentSubset::default();
     let ss = two_face::syntax::extra_newlines();
@@ -75,7 +77,13 @@ impl CodeToPdf {
     let local_highlighter_config = ThreadLocal::<Arc<Mutex<HighlighterConfig>>>::new();
 
     let doc_subset = Arc::new(Mutex::new(doc_subset));
-
+    if let Some(threads) = threads {
+			// Build the global threadpool with the correct number of threads
+      rayon::ThreadPoolBuilder::new()
+        .num_threads(u8::from(threads) as usize)
+        .build_global()
+        .unwrap();
+    }
     walker.enumerate().par_bridge().for_each(|(i, result)| {
       // let mut doc = PdfDocument::new(&args.name);
       let c2pdf_mutex = local_c2pdf.get_or(|| {