Jetpack: Introduce helper for sharing code between modules

- Shared code will live in /lib
- It'll be loadable via 'require_lib()' calls

Author: mcsf

class.jetpack.php

@@ -226,13 +226,15 @@ private function Jetpack() {
 		add_action( 'customize_controls_enqueue_scripts', array( $this, 'devicepx' ) );
 		add_action( 'admin_enqueue_scripts', array( $this, 'devicepx' ) );
 
+		add_filter( 'jetpack_require_lib_dir', array( $this, 'require_lib_dir' ) );
+
 		// add_action( 'jetpack_admin_menu', array( $this, 'admin_menu_modules' ) );
 
 		add_action( 'jetpack_activate_module', array( $this, 'activate_module_actions' ) );
 
 		/**
 		 * These actions run checks to load additional files.
-		 * They check for external files or plugins, so thef need to run as late as possible.
+		 * They check for external files or plugins, so they need to run as late as possible.
 		 */
 		add_action( 'plugins_loaded', array( $this, 'check_open_graph' ),       999 );
 		add_action( 'plugins_loaded', array( $this, 'check_rest_api_compat' ), 1000 );
@@ -299,6 +301,16 @@ function devicepx() {
 		wp_enqueue_script( 'devicepx', ( is_ssl() ? 'https' : 'http' ) . '://s0.wp.com/wp-content/js/devicepx-jetpack.js', array(), gmdate( 'oW' ), true );
 	}
 
+	/*
+	 * Returns the location of Jetpack's lib directory. This filter is applied  
+	 * in require_lib(). 
+	 * 
+	 * @filter require_lib_dir  
+	 */ 
+	function require_lib_dir( $lib_dir ) { 
+		return JETPACK__PLUGIN_DIR . 'lib'; 
+	} 
+
 	/**
 	 * Is Jetpack active?
 	 */

jetpack.php

@@ -50,6 +50,7 @@
 require_once( JETPACK__PLUGIN_DIR . 'functions.compat.php'            );
 require_once( JETPACK__PLUGIN_DIR . 'functions.gallery.php'           );
 require_once( JETPACK__PLUGIN_DIR . 'functions.twitter-cards.php'     );
+require_once( JETPACK__PLUGIN_DIR . 'require-lib.php'                 ); 
 
 register_activation_hook( __FILE__, array( 'Jetpack', 'plugin_activation' ) );
 register_deactivation_hook( __FILE__, array( 'Jetpack', 'plugin_deactivation' ) );

readme.txt

@@ -1,5 +1,5 @@
 === Jetpack by WordPress.com ===
-Contributors: automattic, alternatekev, andy, apeatling, azaozz, barry, beaulebens, blobaugh, cfinke, chellycat, danielbachhuber, daniloercoli, designsimply, eoigal, ethitter, gibrown, georgestephanis, hew, hugobaeta, iammattthomas, jblz, jeherve, jkudish, Joen, johnjamesjacoby, jshreve, lancewillett, martinremy, matt, matveb, mdawaffe, migueluy, nickmomrik, pento, stephdau, tmoorewp, Viper007Bond, westi, yoavf
+Contributors: automattic, alternatekev, andy, apeatling, azaozz, barry, beaulebens, blobaugh, cfinke, chellycat, danielbachhuber, daniloercoli, designsimply, eoigal, ethitter, gibrown, georgestephanis, hew, hugobaeta, iammattthomas, jblz, jeherve, jkudish, Joen, johnjamesjacoby, jshreve, lancewillett, martinremy, matt, matveb, mcsf, mdawaffe, migueluy, nickmomrik, pento, stephdau, tmoorewp, Viper007Bond, westi, yoavf
 Tags: WordPress.com, statistics, stats, views, tweets, twitter, widget, gravatar, hovercards, profile, equations, latex, math, maths, youtube, shortcode, archives, audio, blip, bliptv, dailymotion, digg, flickr, googlevideo, google, googlemaps, kyte, kytetv, livevideo, redlasso, rockyou, rss, scribd, slide, slideshare, soundcloud, vimeo, shortlinks, wp.me, subscriptions, notifications, notes, json, api, rest, mosaic, gallery, slideshow
 Requires at least: 3.5
 Tested up to: 3.6

require-lib.php

@@ -0,0 +1,23 @@
+<?php
+
+function jetpack_require_lib( $slug ) {
+	if ( !preg_match( '|^[a-z0-9/_.-]+$|i', $slug ) ) {
+		trigger_error( "Cannot load a library with invalid slug $slug.", E_USER_ERROR );
+		return;
+	}
+	$basename = basename( $slug );
+	$lib_dir = WP_CONTENT_DIR . '/lib';
+	$lib_dir = apply_filters( 'jetpack_require_lib_dir', $lib_dir );
+	$choices = array(
+		"$lib_dir/$slug.php",
+		"$lib_dir/$slug/0-load.php",
+		"$lib_dir/$slug/$basename.php",
+	);
+	foreach( $choices as $file_name ) {
+		if ( is_readable( $file_name ) ) {
+			require_once $file_name;
+			return;
+		}
+	}
+	trigger_error( "Cannot find a library with slug $slug.", E_USER_ERROR );
+}