Add ability to prevent storing parsed CSS in transients

amp.php

@@ -13,6 +13,8 @@
  * @package AMP
  */
 
+use AmpProject\AmpWP\Services;
+
 define( 'AMP__FILE__', __FILE__ );
 define( 'AMP__DIR__', __DIR__ );
 define( 'AMP__VERSION', '1.5.0-alpha' );
@@ -268,14 +270,19 @@ function _amp_xdebug_admin_notice() {
 
 require_once AMP__DIR__ . '/vendor/autoload.php';
 
+Services::register();
+
 register_activation_hook( __FILE__, 'amp_activate' );
 
 /**
  * Handle activation of plugin.
  *
  * @since 0.2
+ *
+ * @param bool $network_wide Whether the activation was done network-wide.
  */
-function amp_activate() {
+function amp_activate( $network_wide = false ) {
+	Services::activate( $network_wide );
 	amp_after_setup_theme();
 	if ( ! did_action( 'amp_init' ) ) {
 		amp_init();
@@ -289,8 +296,11 @@ function amp_activate() {
  * Handle deactivation of plugin.
  *
  * @since 0.2
+ *
+ * @param bool $network_wide Whether the activation was done network-wide.
  */
-function amp_deactivate() {
+function amp_deactivate( $network_wide = false ) {
+	Services::deactivate( $network_wide );
 	// We need to manually remove the amp endpoint.
 	global $wp_rewrite;
 	foreach ( $wp_rewrite->endpoints as $index => $endpoint ) {

includes/amp-helper-functions.php

@@ -973,6 +973,17 @@ function amp_get_content_sanitizers( $post = null ) {
 		);
 	}
 
+	/**
+	 * Filters whether parsed CSS is allowed to be cached in transients.
+	 *
+	 * When this is filtered to be false, parsed CSS will not be stored in transients. This is important when there is
+	 * highly-variable CSS content in order to prevent filling up the wp_options table with an endless number of entries.
+	 *
+	 * @since 1.5.0
+	 * @param bool $transient_caching_allowed Transient caching allowed.
+	 */
+	$sanitizers['AMP_Style_Sanitizer']['allow_transient_caching'] = apply_filters( 'amp_parsed_css_transient_caching_allowed', true );
+
 	// Force style sanitizer and whitelist sanitizer to be at end.
 	foreach ( [ 'AMP_Style_Sanitizer', 'AMP_Meta_Sanitizer', 'AMP_Tag_And_Attribute_Sanitizer' ] as $class_name ) {
 		if ( isset( $sanitizers[ $class_name ] ) ) {

includes/sanitizers/class-amp-style-sanitizer.php

@@ -5,6 +5,8 @@
  * @package AMP
  */
 
+use AmpProject\AmpWP\BackgroundTask\MonitorCssTransientCaching;
+use AmpProject\AmpWP\Option;
 use AmpProject\AmpWP\RemoteRequest\CachedRemoteGetRequest;
 use AmpProject\AmpWP\RemoteRequest\WpHttpRemoteGetRequest;
 use AmpProject\DevMode;
@@ -122,6 +124,7 @@ class AMP_Style_Sanitizer extends AMP_Base_Sanitizer {
 	 *      @type string   $parsed_cache_variant       Additional value by which to vary parsed cache.
 	 *      @type string[] $focus_within_classes       Class names in selectors that should be replaced with :focus-within pseudo classes.
 	 *      @type string[] $low_priority_plugins       Plugin slugs of the plugins to deprioritize when hitting the CSS limit.
+	 *      @type bool     $allow_transient_caching    Whether to allow caching parsed CSS in transients. This may need to be disabled when there is highly-variable CSS content.
 	 * }
 	 */
 	protected $args;
@@ -143,6 +146,7 @@ class AMP_Style_Sanitizer extends AMP_Base_Sanitizer {
 		'parsed_cache_variant'      => null,
 		'focus_within_classes'      => [ 'focus' ],
 		'low_priority_plugins'      => [ 'query-monitor' ],
+		'allow_transient_caching'   => true,
 	];
 
 	/**
@@ -1484,10 +1488,11 @@ private function fetch_external_stylesheet( $url ) {
 	 * }
 	 */
 	private function get_parsed_stylesheet( $stylesheet, $options = [] ) {
-		$parsed      = null;
-		$cache_key   = null;
-		$cached      = true;
-		$cache_group = 'amp-parsed-stylesheet-v27'; // This should be bumped whenever the PHP-CSS-Parser is updated or parsed format is updated.
+		$parsed         = null;
+		$cache_key      = null;
+		$cached         = true;
+		$cache_group    = 'amp-parsed-stylesheet-v27'; // This should be bumped whenever the PHP-CSS-Parser is updated or parsed format is updated.
+		$use_transients = $this->should_use_transient_caching();
 
 		$cache_impacting_options = array_merge(
 			wp_array_slice_assoc(
@@ -1505,10 +1510,10 @@ private function get_parsed_stylesheet( $stylesheet, $options = [] ) {
 
 		$cache_key = md5( $stylesheet . wp_json_encode( $cache_impacting_options ) );
 
-		if ( wp_using_ext_object_cache() ) {
-			$parsed = wp_cache_get( $cache_key, $cache_group );
-		} else {
+		if ( $use_transients ) {
 			$parsed = get_transient( $cache_group . '-' . $cache_key );
+		} else {
+			$parsed = wp_cache_get( $cache_key, $cache_group );
 		}
 
 		/*
@@ -1534,18 +1539,39 @@ private function get_parsed_stylesheet( $stylesheet, $options = [] ) {
 			 * getting filled infinitely. On the other hand, if an external object cache is available then we don't
 			 * set an expiration because it should implement LRU cache expulsion policy.
 			 */
-			if ( wp_using_ext_object_cache() ) {
-				wp_cache_set( $cache_key, $parsed, $cache_group );
-			} else {
+			if ( $use_transients ) {
 				// The expiration is to ensure transient doesn't stick around forever since no LRU flushing like with external object cache.
 				set_transient( $cache_group . '-' . $cache_key, $parsed, MONTH_IN_SECONDS );
+			} else {
+				wp_cache_set( $cache_key, $parsed, $cache_group );
 			}
 		}
 
 		$parsed['cached'] = $cached;
 		return $parsed;
 	}
 
+	/**
+	 * Check whether transient caching for stylesheets should be used.
+	 *
+	 * @return bool Whether transient caching should be used.
+	 */
+	private function should_use_transient_caching() {
+		if ( wp_using_ext_object_cache() ) {
+			return false;
+		}
+
+		if ( ! $this->args['allow_transient_caching'] ) {
+			return false;
+		}
+
+		if ( AMP_Options_Manager::get_option( Option::DISABLE_CSS_TRANSIENT_CACHING, false ) ) {
+			return false;
+		}
+
+		return true;
+	}
+
 	/**
 	 * Parse imported stylesheet and replace the `@import` rule with the imported rules in the provided CSS list (in place).
 	 *