--- /dev/null
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Construct objects from configuration instructions.
+ *
+ * @copyright © 2014 Wikimedia Foundation and contributors
+ */
+class ObjectFactory {
+
+ /**
+ * Instantiate an object based on a specification array.
+ *
+ * The specification array must contain a 'class' key with string value
+ * that specifies the class name to instantiate or a 'factory' key with
+ * a callable (is_callable() === true). It can optionally contain
+ * an 'args' key that provides arguments to pass to the
+ * constructor/callable.
+ *
+ * Values in the arguments collection which are Closure instances will be
+ * expanded by invoking them with no arguments before passing the
+ * resulting value on to the constructor/callable. This can be used to
+ * pass IDatabase instances or other live objects to the
+ * constructor/callable. This behavior can be suppressed by adding
+ * closure_expansion => false to the specification.
+ *
+ * The specification may also contain a 'calls' key that describes method
+ * calls to make on the newly created object before returning it. This
+ * pattern is often known as "setter injection". The value of this key is
+ * expected to be an associative array with method names as keys and
+ * argument lists as values. The argument list will be expanded (or not)
+ * in the same way as the 'args' key for the main object.
+ *
+ * @param array $spec Object specification
+ * @return object
+ * @throws InvalidArgumentException when object specification does not
+ * contain 'class' or 'factory' keys
+ * @throws ReflectionException when 'args' are supplied and 'class'
+ * constructor is non-public or non-existent
+ */
+ public static function getObjectFromSpec( $spec ) {
+ $args = isset( $spec['args'] ) ? $spec['args'] : [];
+ $expandArgs = !isset( $spec['closure_expansion'] ) ||
+ $spec['closure_expansion'] === true;
+
+ if ( $expandArgs ) {
+ $args = static::expandClosures( $args );
+ }
+
+ if ( isset( $spec['class'] ) ) {
+ $clazz = $spec['class'];
+ if ( !$args ) {
+ $obj = new $clazz();
+ } else {
+ $obj = static::constructClassInstance( $clazz, $args );
+ }
+ } elseif ( isset( $spec['factory'] ) ) {
+ $obj = call_user_func_array( $spec['factory'], $args );
+ } else {
+ throw new InvalidArgumentException(
+ 'Provided specification lacks both factory and class parameters.'
+ );
+ }
+
+ if ( isset( $spec['calls'] ) && is_array( $spec['calls'] ) ) {
+ // Call additional methods on the newly created object
+ foreach ( $spec['calls'] as $method => $margs ) {
+ if ( $expandArgs ) {
+ $margs = static::expandClosures( $margs );
+ }
+ call_user_func_array( [ $obj, $method ], $margs );
+ }
+ }
+
+ return $obj;
+ }
+
+ /**
+ * Iterate a list and call any closures it contains.
+ *
+ * @param array $list List of things
+ * @return array List with any Closures replaced with their output
+ */
+ protected static function expandClosures( $list ) {
+ return array_map( function ( $value ) {
+ if ( is_object( $value ) && $value instanceof Closure ) {
+ // If $value is a Closure, call it.
+ return $value();
+ } else {
+ return $value;
+ }
+ }, $list );
+ }
+
+ /**
+ * Construct an instance of the given class using the given arguments.
+ *
+ * PHP's `call_user_func_array()` doesn't work with object construction so
+ * we have to use other measures. Starting with PHP 5.6.0 we could use the
+ * "splat" operator (`...`) to unpack the array into an argument list.
+ * Sadly there is no way to conditionally include a syntax construct like
+ * a new operator in a way that allows older versions of PHP to still
+ * parse the file. Instead, we will try a loop unrolling technique that
+ * works for 0-10 arguments. If we are passed 11 or more arguments we will
+ * take the performance penalty of using
+ * `ReflectionClass::newInstanceArgs()` to construct the desired object.
+ *
+ * @param string $clazz Class name
+ * @param array $args Constructor arguments
+ * @return mixed Constructed instance
+ */
+ public static function constructClassInstance( $clazz, $args ) {
+ // $args should be a non-associative array; show nice error if that's not the case
+ if ( $args && array_keys( $args ) !== range( 0, count( $args ) - 1 ) ) {
+ throw new InvalidArgumentException( __METHOD__ . ': $args cannot be an associative array' );
+ }
+
+ // TODO: when PHP min version supported is >=5.6.0 replace this
+ // with `return new $clazz( ... $args );`.
+ $obj = null;
+ switch ( count( $args ) ) {
+ case 0:
+ $obj = new $clazz();
+ break;
+ case 1:
+ $obj = new $clazz( $args[0] );
+ break;
+ case 2:
+ $obj = new $clazz( $args[0], $args[1] );
+ break;
+ case 3:
+ $obj = new $clazz( $args[0], $args[1], $args[2] );
+ break;
+ case 4:
+ $obj = new $clazz( $args[0], $args[1], $args[2], $args[3] );
+ break;
+ case 5:
+ $obj = new $clazz(
+ $args[0], $args[1], $args[2], $args[3], $args[4]
+ );
+ break;
+ case 6:
+ $obj = new $clazz(
+ $args[0], $args[1], $args[2], $args[3], $args[4],
+ $args[5]
+ );
+ break;
+ case 7:
+ $obj = new $clazz(
+ $args[0], $args[1], $args[2], $args[3], $args[4],
+ $args[5], $args[6]
+ );
+ break;
+ case 8:
+ $obj = new $clazz(
+ $args[0], $args[1], $args[2], $args[3], $args[4],
+ $args[5], $args[6], $args[7]
+ );
+ break;
+ case 9:
+ $obj = new $clazz(
+ $args[0], $args[1], $args[2], $args[3], $args[4],
+ $args[5], $args[6], $args[7], $args[8]
+ );
+ break;
+ case 10:
+ $obj = new $clazz(
+ $args[0], $args[1], $args[2], $args[3], $args[4],
+ $args[5], $args[6], $args[7], $args[8], $args[9]
+ );
+ break;
+ default:
+ // Fall back to using ReflectionClass and curse the developer
+ // who decided that 11+ args was a reasonable method
+ // signature.
+ $ref = new ReflectionClass( $clazz );
+ $obj = $ref->newInstanceArgs( $args );
+ }
+ return $obj;
+ }
+}
scripts.mit.edu / autoinstallsdev / mediawiki.git / blobdiff