Added feature to not overwrite existing handlers if found in core application (#170)

* Added feature to not overwrite existing handlers

* Applied fix from StyleCI

* Removed redundent if conditional

* Update InjectHandlers.php

Co-authored-by: Taylor Otwell <[email protected]>

Author: jaxwilko

src/BuildProcess/InjectHandlers.php

@@ -30,10 +30,10 @@ public function __invoke()
             $this->files->copy($stubPath.'/runtime.php', $this->appPath.'/runtime.php');
         }
 
-        $this->files->copy($stubPath.'/cliRuntime.php', $this->appPath.'/cliRuntime.php');
-        $this->files->copy($stubPath.'/fpmRuntime.php', $this->appPath.'/fpmRuntime.php');
-        $this->files->copy($stubPath.'/httpRuntime.php', $this->appPath.'/httpRuntime.php');
-        $this->files->copy($stubPath.'/httpHandler.php', $this->appPath.'/httpHandler.php');
+        $this->copyMissing($stubPath.'/cliRuntime.php', $this->appPath.'/cliRuntime.php');
+        $this->copyMissing($stubPath.'/fpmRuntime.php', $this->appPath.'/fpmRuntime.php');
+        $this->copyMissing($stubPath.'/httpRuntime.php', $this->appPath.'/httpRuntime.php');
+        $this->copyMissing($stubPath.'/httpHandler.php', $this->appPath.'/httpHandler.php');
 
         if (Manifest::shouldSeparateVendor($this->environment)) {
             file_put_contents(
@@ -61,4 +61,18 @@ protected function configureHttpHandler($file)
             file_get_contents($file)
         );
     }
+
+    /**
+     * Copy a file to a new location if that file does not exist.
+     *
+     * @param  string  $from
+     * @param  string  $to
+     * @return void
+     */
+    protected function copyMissing($from, $to)
+    {
+        if (! $this->files->exists($to)) {
+            $this->files->copy($from, $to);
+        }
+    }
 }