Allow to configure nproc

src/NProcFinder.php

@@ -22,14 +22,26 @@
 use const FILTER_VALIDATE_INT;
 
 /**
- * The number of processing units available. Usually matches the number of
- * logical cores.
+ * The number of (logical) cores.
  *
  * @see https://github.com/infection/infection/blob/fbd8c44/src/Resource/Processor/CpuCoresCountProvider.php#L69-L82
  * @see https://unix.stackexchange.com/questions/146051/number-of-processors-in-proc-cpuinfo
  */
 final class NProcFinder implements CpuCoreFinder
 {
+    /**
+     * @var bool
+     */
+    private $all;
+
+    /**
+     * @param bool $all If disabled will give the number of cores available for the current process only.
+     */
+    public function __construct(bool $all)
+    {
+        $this->all = $all;
+    }
+
     /**
      * @return positive-int|null
      */
@@ -40,7 +52,7 @@ public function find(): ?int
         }
 
         try {
-            $nproc = ShellExec::execute('nproc --all');
+            $nproc = ShellExec::execute('nproc'.($this->all ? ' --all' : ''));
         } catch (ExecException $nprocFailed) {
             return null;
         }