<?php
namespace Composer\Util;
use Composer\Package\Link;
use Composer\Package\PackageInterface;
class PackageSorter
{
/**
* Sorts packages by dependency weight
*
* Packages of equal weight retain the original order
*
* @param array $packages
* @return array
*/
public static function sortPackages(array $packages) {
$usageList = array();
foreach ($packages as $package) { /** @var PackageInterface $package */
foreach (array_merge($package->getRequires(), $package->getDevRequires()) as $link) { /** @var Link $link */
$target = $link->getTarget();
$usageList[$target][] = $package->getName();
}
}
$computing = array();
$computed = array();
$computeImportance = function ($name) use (&$computeImportance, &$computing, &$computed, $usageList) {
// reusing computed importance
if (isset($computed[$name])) {
return $computed[$name];
}
// canceling circular dependency
if (isset($computing[$name])) {
return 0;
}
$computing[$name] = true;
$weight = 0;
if (isset($usageList[$name])) {
foreach ($usageList[$name] as $user) {
$weight -= 1 - $computeImportance($user);
}
}
unset($computing[$name]);
$computed[$name] = $weight;
return $weight;
};
$weightList = array();
foreach ($packages as $name => $package) {
$weight = $computeImportance($name);
$weightList[$name] = $weight;
}
$stable_sort = function (&$array) {
static $transform, $restore;
$i = 0;
if (!$transform) {
$transform = function (&$v, $k) use (&$i) {
$v = array($v, ++$i, $k, $v);
};
$restore = function (&$v) {
$v = $v[3];
};
}
array_walk($array, $transform);
asort($array);
array_walk($array, $restore);
};
$stable_sort($weightList);
$sortedPackages = array();
foreach (array_keys($weightList) as $name) {
$sortedPackages[] = $packages[$name];
}
return $sortedPackages;
}
}