remove APC support

APC is only supported up to PHP 5.5. As Cachify now requires PHP 5.6 or
later, there is no point in maintaining legacy APC support.

We already ignore unavailable backends silently with fallback to DB, so
just removing it does not make it worse here.

README.md

@@ -1,12 +1,12 @@
 # Cachify #
-Smart, efficient cache solution for WordPress. Use DB, HDD, APC, Redis or Memcached for storing your blog pages. Make WordPress faster!
+Smart, efficient cache solution for WordPress. Use DB, HDD, Redis or Memcached for storing your blog pages. Make WordPress faster!
 
 ## Description ##
-*Cachify* optimizes your page loads by caching posts, pages and custom post types as static content. You can choose between caching via database, on the web server’s hard drive (HDD), Memcached (only on Nginx), Redis or — thanks to APC (Alternative PHP Cache) — directly in the web server’s system cache. Whenever a page or post is loaded, it can be pulled directly from the cache. The amount of database queries and PHP requests will dramatically decrease towards zero, depending on the caching method you chose.
+*Cachify* optimizes your page loads by caching posts, pages and custom post types as static content. You can choose between caching via database, on the web server’s hard drive (HDD), Memcached (only on Nginx) or Redis. Whenever a page or post is loaded, it can be pulled directly from the cache. The amount of database queries and PHP requests will dramatically decrease towards zero, depending on the caching method you chose.
 
 ### Features ###
 * Works with custom post types.
-* Caching methods: DB, HDD, APC, Redis and Memcached.
+* Caching methods: DB, HDD, Redis and Memcached.
 * “Flush Cache” button in the WordPress toolbar.
 * Ready for WordPress Multisite.
 * Optional compression of HTML markup.
@@ -41,7 +41,6 @@ Smart, efficient cache solution for WordPress. Use DB, HDD, APC, Redis or Memcac
 ### Requirements ###
 * PHP 5.6 or greater
 * WordPress 4.7 or greater
-* APC 3.1.4 or greater (optional)
 * Memcached in Nginx (optional)
 * Redis (optional, via the phpredis module)
 

cachify.php

@@ -1,7 +1,7 @@
 <?php
 /**
  * Plugin Name: Cachify
- * Description: Easy to use WordPress caching plugin. Serving static blog pages from database, disk, Memcached, Redis or APC.
+ * Description: Easy to use WordPress caching plugin. Serving static blog pages from database, disk, Memcached or Redis.
  * Author:      pluginkollektiv
  * Author URI:  https://pluginkollektiv.org
  * Plugin URI:  https://cachify.pluginkollektiv.org
@@ -91,7 +91,7 @@
  * @param string $class_name the class name.
  */
 function cachify_autoload( $class_name ) {
-	if ( in_array( $class_name, array( 'Cachify', 'Cachify_APC', 'Cachify_Backend', 'Cachify_CLI', 'Cachify_DB', 'Cachify_HDD', 'Cachify_MEMCACHED', 'Cachify_REDIS' ), true ) ) {
+	if ( in_array( $class_name, array( 'Cachify', 'Cachify_Backend', 'Cachify_CLI', 'Cachify_DB', 'Cachify_HDD', 'Cachify_MEMCACHED', 'Cachify_REDIS' ), true ) ) {
 		require_once sprintf(
 			'%s/inc/class-%s.php',
 			CACHIFY_DIR,

inc/class-cachify.php

@@ -48,7 +48,7 @@ final class Cachify {
 	 * @since 2.0.9
 	 */
 	const METHOD_DB  = 0;
-	const METHOD_APC = 1;
+	const METHOD_APC = 1;  // No longer available.
 	const METHOD_HDD = 2;
 	const METHOD_MMC = 3;
 	const METHOD_REDIS = 4;
@@ -389,12 +389,8 @@ private static function _set_default_vars() {
 		/* Options */
 		self::$options = self::_get_options();
 
-		/* APC */
-		if ( self::METHOD_APC === self::$options['use_apc'] && Cachify_APC::is_available() ) {
-			self::$method = new Cachify_APC();
-
-			/* HDD */
-		} elseif ( self::METHOD_HDD === self::$options['use_apc'] && Cachify_HDD::is_available() ) {
+		/* HDD */
+		if ( self::METHOD_HDD === self::$options['use_apc'] && Cachify_HDD::is_available() ) {
 			self::$method = new Cachify_HDD();
 
 			/* MEMCACHED */
@@ -1499,9 +1495,6 @@ public static function flush_total_cache( $clear_all_methods = false ) {
 			/* DB */
 			Cachify_DB::clear_cache();
 
-			/* APC */
-			Cachify_APC::clear_cache();
-
 			/* HDD */
 			Cachify_HDD::clear_cache();
 
@@ -1706,17 +1699,11 @@ private static function _method_select() {
 		/* Defaults */
 		$methods = array(
 			self::METHOD_DB  => esc_html__( 'Database', 'cachify' ),
-			self::METHOD_APC => esc_html__( 'APC', 'cachify' ),
 			self::METHOD_HDD => esc_html__( 'Hard disk', 'cachify' ),
 			self::METHOD_MMC => esc_html__( 'Memcached', 'cachify' ),
 			self::METHOD_REDIS => esc_html__( 'Redis', 'cachify' ),
 		);
 
-		/* APC */
-		if ( ! Cachify_APC::is_available() ) {
-			unset( $methods[1] );
-		}
-
 		/* Memcached? */
 		if ( ! Cachify_MEMCACHED::is_available() ) {
 			unset( $methods[3] );
@@ -1786,7 +1773,7 @@ public static function validate_options( $data ) {
 		self::flush_total_cache( true );
 
 		/* Notification */
-		if ( self::$options['use_apc'] !== $data['use_apc'] && $data['use_apc'] >= self::METHOD_APC && self::METHOD_REDIS != $data['use_apc'] ) {
+		if ( self::$options['use_apc'] !== $data['use_apc'] && $data['use_apc'] >= self::METHOD_HDD && self::METHOD_REDIS != $data['use_apc'] ) {
 			add_settings_error(
 				'cachify_method_tip',
 				'cachify_method_tip',
@@ -1883,12 +1870,6 @@ private static function _get_tabs( $options ) {
 				'name' => __( 'Setup', 'cachify' ),
 				'page' => 'setup/cachify.hdd.' . ( self::$is_nginx ? 'nginx' : 'htaccess' ) . '.php',
 			);
-		} elseif ( self::METHOD_APC === $options['use_apc'] ) {
-			/* Setup tab for APC */
-			$tabs['setup'] = array(
-				'name' => __( 'Setup', 'cachify' ),
-				'page' => 'setup/cachify.apc.' . ( self::$is_nginx ? 'nginx' : 'htaccess' ) . '.php',
-			);
 		} elseif ( self::METHOD_MMC === $options['use_apc'] && self::$is_nginx ) {
 			/* Setup tab for Memcached */
 			$tabs['setup'] = array(