+/**
+ * Check whether a plugin is active.
+ *
+ * Only plugins installed in the plugins/ folder can be active.
+ *
+ * Plugins in the mu-plugins/ folder can't be "activated," so this function will
+ * return false for those plugins.
+ *
+ * @since 2.5.0
+ *
+ * @param string $plugin Base plugin path from plugins directory.
+ * @return bool True, if in the active plugins list. False, not in the list.
+ */
+function is_plugin_active( $plugin ) {
+ return in_array( $plugin, (array) get_option( 'active_plugins', array() ) ) || is_plugin_active_for_network( $plugin );
+}
+
+/**
+ * Check whether the plugin is inactive.
+ *
+ * Reverse of is_plugin_active(). Used as a callback.
+ *
+ * @since 3.1.0
+ * @see is_plugin_active()
+ *
+ * @param string $plugin Base plugin path from plugins directory.
+ * @return bool True if inactive. False if active.
+ */
+function is_plugin_inactive( $plugin ) {
+ return ! is_plugin_active( $plugin );
+}
+
+/**
+ * Check whether the plugin is active for the entire network.
+ *
+ * Only plugins installed in the plugins/ folder can be active.
+ *
+ * Plugins in the mu-plugins/ folder can't be "activated," so this function will
+ * return false for those plugins.
+ *
+ * @since 3.0.0
+ *
+ * @param string $plugin Base plugin path from plugins directory.
+ * @return bool True, if active for the network, otherwise false.
+ */
+function is_plugin_active_for_network( $plugin ) {
+ if ( !is_multisite() )
+ return false;
+
+ $plugins = get_site_option( 'active_sitewide_plugins');
+ if ( isset($plugins[$plugin]) )
+ return true;
+
+ return false;
+}
+
+/**
+ * Checks for "Network: true" in the plugin header to see if this should
+ * be activated only as a network wide plugin. The plugin would also work
+ * when Multisite is not enabled.
+ *
+ * Checks for "Site Wide Only: true" for backward compatibility.
+ *
+ * @since 3.0.0
+ *
+ * @param string $plugin Plugin to check
+ * @return bool True if plugin is network only, false otherwise.
+ */
+function is_network_only_plugin( $plugin ) {
+ $plugin_data = get_plugin_data( WP_PLUGIN_DIR . '/' . $plugin );
+ if ( $plugin_data )
+ return $plugin_data['Network'];
+ return false;
+}
+
+/**
+ * Attempts activation of plugin in a "sandbox" and redirects on success.
+ *
+ * A plugin that is already activated will not attempt to be activated again.
+ *
+ * The way it works is by setting the redirection to the error before trying to
+ * include the plugin file. If the plugin fails, then the redirection will not
+ * be overwritten with the success message. Also, the options will not be
+ * updated and the activation hook will not be called on plugin error.
+ *
+ * It should be noted that in no way the below code will actually prevent errors
+ * within the file. The code should not be used elsewhere to replicate the
+ * "sandbox", which uses redirection to work.
+ * {@source 13 1}
+ *
+ * If any errors are found or text is outputted, then it will be captured to
+ * ensure that the success redirection will update the error redirection.
+ *
+ * @since 2.5.0
+ *
+ * @param string $plugin Plugin path to main plugin file with plugin data.
+ * @param string $redirect Optional. URL to redirect to.
+ * @param bool $network_wide Optional. Whether to enable the plugin for all sites in the network
+ * or just the current site. Multisite only. Default false.
+ * @param bool $silent Optional. Whether to prevent calling activation hooks. Default false.
+ * @return WP_Error|null WP_Error on invalid file or null on success.
+ */
+function activate_plugin( $plugin, $redirect = '', $network_wide = false, $silent = false ) {
+ $plugin = plugin_basename( trim( $plugin ) );
+
+ if ( is_multisite() && ( $network_wide || is_network_only_plugin($plugin) ) ) {
+ $network_wide = true;
+ $current = get_site_option( 'active_sitewide_plugins', array() );
+ $_GET['networkwide'] = 1; // Back compat for plugins looking for this value.
+ } else {
+ $current = get_option( 'active_plugins', array() );
+ }
+
+ $valid = validate_plugin($plugin);
+ if ( is_wp_error($valid) )
+ return $valid;
+
+ if ( ( $network_wide && ! isset( $current[ $plugin ] ) ) || ( ! $network_wide && ! in_array( $plugin, $current ) ) ) {
+ if ( !empty($redirect) )
+ wp_redirect(add_query_arg('_error_nonce', wp_create_nonce('plugin-activation-error_' . $plugin), $redirect)); // we'll override this later if the plugin can be included without fatal error
+ ob_start();
+ wp_register_plugin_realpath( WP_PLUGIN_DIR . '/' . $plugin );
+ $_wp_plugin_file = $plugin;
+ include_once( WP_PLUGIN_DIR . '/' . $plugin );
+ $plugin = $_wp_plugin_file; // Avoid stomping of the $plugin variable in a plugin.
+
+ if ( ! $silent ) {
+ /**
+ * Fires before a plugin is activated.
+ *
+ * If a plugin is silently activated (such as during an update),
+ * this hook does not fire.
+ *
+ * @since 2.9.0
+ *
+ * @param string $plugin Plugin path to main plugin file with plugin data.
+ * @param bool $network_wide Whether to enable the plugin for all sites in the network
+ * or just the current site. Multisite only. Default is false.
+ */
+ do_action( 'activate_plugin', $plugin, $network_wide );
+
+ /**
+ * Fires as a specific plugin is being activated.
+ *
+ * This hook is the "activation" hook used internally by register_activation_hook().
+ * The dynamic portion of the hook name, `$plugin`, refers to the plugin basename.
+ *
+ * If a plugin is silently activated (such as during an update), this hook does not fire.
+ *
+ * @since 2.0.0
+ *
+ * @param bool $network_wide Whether to enable the plugin for all sites in the network
+ * or just the current site. Multisite only. Default is false.
+ */
+ do_action( 'activate_' . $plugin, $network_wide );
+ }
+
+ if ( $network_wide ) {
+ $current = get_site_option( 'active_sitewide_plugins', array() );
+ $current[$plugin] = time();
+ update_site_option( 'active_sitewide_plugins', $current );
+ } else {
+ $current = get_option( 'active_plugins', array() );