Cleanup most of the DIY extension detection/dl() code into nice clean wfDl()

config/Installer.php

@@ -333,7 +333,7 @@ error_reporting( 0 );
 $phpdatabases = array();
 foreach (array_keys($ourdb) as $db) {
 	$compname = $ourdb[$db]['compile'];
-	if( extension_loaded( $compname ) || ( mw_have_dl() && dl( "{$compname}." . PHP_SHLIB_SUFFIX ) ) ) {
+	if( wfDl( $compname ) ) {
 		array_push($phpdatabases, $db);
 		$ourdb[$db]['havedriver'] = 1;
 	}

includes/GlobalFunctions.php

@@ -2304,6 +2304,30 @@ function wfIniGetBool( $setting ) {
 		|| preg_match( "/^\s*[+-]?0*[1-9]/", $val ); // approx C atoi() function
 }
 
+/**
+ * Wrapper function for PHP's dl(). This doesn't work in most situations from
+ * PHP 5.3 onward, and is usually disabled in shared environments anyway.
+ *
+ * @param $extension String A PHP extension. The file suffix (.so or .dll)
+ *                          should be omitted
+ * @return Bool - Whether or not the extension is loaded
+ */
+function wfDl( $extension ) {
+	if( extension_loaded( $extension ) ) {
+		return true;
+	}
+
+	$canDl = ( function_exists( 'dl' ) && is_callable( 'dl' )
+		&& wfIniGetBool( 'enable_dl' ) && !wfIniGetBool( 'safe_mode' ) );
+
+	if( $canDl ) {
+		wfSuppressWarnings();
+		dl( $extension . '.' . PHP_SHLIB_SUFFIX );
+		wfRestoreWarnings();
+	}
+	return extension_loaded( $extension );
+}
+
 /**
  * Execute a shell command, with time and memory limits mirrored from the PHP
  * configuration if supported.

includes/MimeMagic.php

@@ -102,7 +102,7 @@ END_STRING
 global $wgLoadFileinfoExtension;
 
 if ($wgLoadFileinfoExtension) {
-	if(!extension_loaded('fileinfo')) dl('fileinfo.' . PHP_SHLIB_SUFFIX);
+	wfDl( 'fileinfo' );
 }
 
 /**

includes/db/DatabaseIbm_db2.php

@@ -484,9 +484,8 @@ class DatabaseIbm_db2 extends DatabaseBase {
 		wfProfileIn( __METHOD__ );
 		
 		// Load IBM DB2 driver if missing
-		if (!@extension_loaded('ibm_db2')) {
-			@dl('ibm_db2.so');
-		}
+		wfDl( 'ibm_db2' );
+
 		// Test for IBM DB2 support, to avoid suppressed fatal error
 		if ( !function_exists( 'db2_connect' ) ) {
 			$error = "DB2 functions missing, have you enabled the ibm_db2 extension for PHP?\n";

includes/db/DatabaseMysql.php

@@ -26,9 +26,7 @@ class DatabaseMysql extends DatabaseBase {
 
 		# Test for missing mysql.so
 		# First try to load it
-		if (!@extension_loaded('mysql')) {
-			@dl('mysql.so');
-		}
+		wfDl( 'mysql' );
 
 		# Fail now
 		# Otherwise we get a suppressed fatal error, which is very hard to track down

includes/diff/DifferenceInterface.php

@@ -657,7 +657,7 @@ CONTROL;
 		else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 			wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 			wfSuppressWarnings();
-			dl( 'php_wikidiff2.so' );
+			wfDl( 'wikidiff2' );
 			wfRestoreWarnings();
 			wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 		}

includes/installer/Installer.php

@@ -38,6 +38,7 @@ abstract class Installer {
 		'wgLogo',
 		'wgShellLocale',
 		'wgSecretKey',
+		'wgExternalDiffEngine',
 	);
 
 	/**
@@ -350,16 +351,6 @@ abstract class Installer {
 			$this->setVar( $name, $value );
 		}
 	}
-
-	/**
-	 * Returns true if dl() can be used
-	 */
-	function haveDl() {
-		return function_exists( 'dl' )
-			&& is_callable( 'dl' )
-			&& wfIniGetBool( 'enable_dl' )
-			&& !wfIniGetBool( 'safe_mode' );
-	}
 	
 	/** Check if we're installing the latest version */
 	function envLatestVersion() {

includes/installer/InstallerDBType.php

@@ -128,8 +128,7 @@ abstract class InstallerDBType {
 	 */
 	function checkExtension( $name ) {
 		wfSuppressWarnings();
-		$compiled = extension_loaded( $name )
-			|| ( $this->parent->haveDl() && dl( $name . '.' . PHP_SHLIB_SUFFIX ) );
+		$compiled = wfDl( $name );
 		wfRestoreWarnings();
 		return $compiled;
 	}

maintenance/backup.inc

@@ -146,7 +146,7 @@ class BackupDumper {
 					break;
 				case "force-normal":
 					if ( !function_exists( 'utf8_normalize' ) ) {
-						dl( "php_utfnormal.so" );
+						wfDl( "php_utfnormal.so" );
 						if ( !function_exists( 'utf8_normalize' ) ) {
 							wfDie( "Failed to load UTF-8 normalization extension. " .
 								"Install or remove --force-normal parameter to use slower code.\n" );