Running plugin without shell_exec

Hi,

Thanks for this plugin! I’d like to use it on a hosting provider where the shell_exec function is disabled, so I’m unable to use it. I’ve created a patch that uses shell_exec only when it’s available:

--- opcache-reset.php   2025-12-15 02:33:08.000000000 +0100
+++ opcache-reset.php.new       2026-08-06 11:56:54.146880433 +0200
@@ -77,8 +77,10 @@
        }
 
        if ( $file_cache_dir && file_exists( $file_cache_dir ) ) {
-               // move it out of the way to avoid race conditions
-               shell_exec( "mv {$file_cache_dir} {$file_cache_dir}.rm" );
+               if ( function_exists( 'shell_exec' ) ) {
+                       // move it out of the way to avoid race conditions
+                       shell_exec( "mv {$file_cache_dir} {$file_cache_dir}.rm" );
+               }
        }
 
        // We are in PHP-FPM context and not file cache only
@@ -87,11 +89,13 @@
        }
 
        if ( $file_cache_dir ) {
-               if ( file_exists( "{$file_cache_dir}.rm" ) ) {
-                       shell_exec( "rm -rf {$file_cache_dir}.rm" );
+               if ( function_exists( 'shell_exec' ) ) {
+                       if ( file_exists( "{$file_cache_dir}.rm" ) ) {
+                               shell_exec( "rm -rf {$file_cache_dir}.rm" );
+                       }
+                       // make sure OPcache directory is re-created
+                       shell_exec( "mkdir -p {$file_cache_dir}" );
                }
-               // make sure OPcache directory is re-created
-               shell_exec( "mkdir -p {$file_cache_dir}" );
        }
 
        // Irrespective of the context, we should attempt to clear the memory-based OPCache, because this script may be called from CLI
@@ -105,11 +109,13 @@
        }
 
        // Try cachetool binary first.
-       $cachetool = trim( shell_exec( "PATH={$path} which cachetool 2>/dev/null" ) );
-       if ( $cachetool ) {
-               $cmd = 'php -d opcache.enable_cli=0 -d opcache.file_cache_only=0 -d opcache.file_cache=/tmp $(which cachetool) opcache:reset';
-               shell_exec( "PATH={$path} {$cmd} 2>&1" );
-               return;
+       if ( function_exists( 'shell_exec' ) ) {
+               $cachetool = trim( shell_exec( "PATH={$path} which cachetool 2>/dev/null" ) );
+               if ( $cachetool ) {
+                       $cmd = 'php -d opcache.enable_cli=0 -d opcache.file_cache_only=0 -d opcache.file_cache=/tmp $(which cachetool) opcache:reset';
+                       shell_exec( "PATH={$path} {$cmd} 2>&1" );
+                       return;
+               }
        }
 
        // Fallback: direct FastCGI if cachetool.yml exists.