registration: Generalize CoreVersionChecker to VersionChecker

This allows us to put other requirements more easily into extension
registration, such as skins and/or extensions.

Bug: T117277
Change-Id: I3ec1b28b6af380621585cd61b38e5ebb8be9f9c7

4 files changed, 139 insertions, 84 deletions

diff --git a/includes/registration/CoreVersionChecker.php b/includes/registration/CoreVersionChecker.php
deleted file mode 100644
index f64d826da0d4..000000000000
--- a/includes/registration/CoreVersionChecker.php
+++ /dev/null
@@ -1,68 +0,0 @@
-<?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
- */
-
-use Composer\Semver\VersionParser;
-use Composer\Semver\Constraint\Constraint;
-
-/**
- * @since 1.26
- */
-class CoreVersionChecker {
-
-	/**
-	 * @var Constraint|bool representing $wgVersion
-	 */
-	private $coreVersion = false;
-
-	/**
-	 * @var VersionParser
-	 */
-	private $versionParser;
-
-	/**
-	 * @param string $coreVersion Current version of core
-	 */
-	public function __construct( $coreVersion ) {
-		$this->versionParser = new VersionParser();
-		try {
-			$this->coreVersion = new Constraint(
-				'==',
-				$this->versionParser->normalize( $coreVersion )
-			);
-		} catch ( UnexpectedValueException $e ) {
-			// Non-parsable version, don't fatal.
-		}
-	}
-
-	/**
-	 * Check that the provided constraint is compatible with the current version of core
-	 *
-	 * @param string $constraint Something like ">= 1.26"
-	 * @return bool
-	 */
-	public function check( $constraint ) {
-		if ( $this->coreVersion === false ) {
-			// Couldn't parse the core version, so we can't check anything
-			return true;
-		}
-
-		return $this->versionParser->parseConstraints( $constraint )
-			->matches( $this->coreVersion );
-	}
-}
diff --git a/includes/registration/ExtensionProcessor.php b/includes/registration/ExtensionProcessor.php
index d9671324fef9..1212f9972cba 100644
--- a/includes/registration/ExtensionProcessor.php
+++ b/includes/registration/ExtensionProcessor.php
@@ -216,13 +216,7 @@ class ExtensionProcessor implements Processor {
 	}
 
 	public function getRequirements( array $info ) {
-		$requirements = [];
-		$key = ExtensionRegistry::MEDIAWIKI_CORE;
-		if ( isset( $info['requires'][$key] ) ) {
-			$requirements[$key] = $info['requires'][$key];
-		}
-
-		return $requirements;
+		return isset( $info['requires'] ) ? $info['requires'] : [];
 	}
 
 	protected function extractHooks( array $info ) {
diff --git a/includes/registration/ExtensionRegistry.php b/includes/registration/ExtensionRegistry.php
index 70dc6248f0ad..0521f3b263fd 100644
--- a/includes/registration/ExtensionRegistry.php
+++ b/includes/registration/ExtensionRegistry.php
@@ -204,7 +204,8 @@ class ExtensionRegistry {
 		$autoloaderPaths = [];
 		$processor = new ExtensionProcessor();
 		$incompatible = [];
-		$coreVersionParser = new CoreVersionChecker( $wgVersion );
+		$versionParser = new VersionChecker();
+		$versionParser->setCoreVersion( $wgVersion );
 		foreach ( $queue as $path => $mtime ) {
 			$json = file_get_contents( $path );
 			if ( $json === false ) {
@@ -217,14 +218,14 @@ class ExtensionRegistry {
 
 			// Check any constraints against MediaWiki core
 			$requires = $processor->getRequirements( $info );
-			if ( isset( $requires[self::MEDIAWIKI_CORE] )
-				&& !$coreVersionParser->check( $requires[self::MEDIAWIKI_CORE] )
-			) {
-				// Doesn't match, mark it as incompatible.
-				$incompatible[] = "{$info['name']} is not compatible with the current "
-					. "MediaWiki core (version {$wgVersion}), it requires: " . $requires[self::MEDIAWIKI_CORE]
-					. '.';
-				continue;
+			if ( $requires ) {
+				$versionCheck = $versionParser->checkArray(
+					[ $info['name'] => $requires ]
+				);
+				$incompatible = array_merge( $incompatible, $versionCheck );
+				if ( $versionCheck ) {
+					continue;
+				}
 			}
 
 			if ( !isset( $info['manifest_version'] ) ) {
diff --git a/includes/registration/VersionChecker.php b/includes/registration/VersionChecker.php
new file mode 100644
index 000000000000..b61a10e4b2e8
--- /dev/null
+++ b/includes/registration/VersionChecker.php
@@ -0,0 +1,128 @@
+<?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
+ *
+ * @author Legoktm
+ * @author Florian Schmidt
+ */
+
+use Composer\Semver\VersionParser;
+use Composer\Semver\Constraint\Constraint;
+
+/**
+ * Provides functions to check a set of extensions with dependencies against
+ * a set of loaded extensions and given version information.
+ *
+ * @since 1.29
+ */
+class VersionChecker {
+	/**
+	 * @var Constraint|bool representing $wgVersion
+	 */
+	private $coreVersion = false;
+
+	/**
+	 * @var VersionParser
+	 */
+	private $versionParser;
+
+	public function __construct() {
+		$this->versionParser = new VersionParser();
+	}
+
+	/**
+	 * Set MediaWiki core version.
+	 *
+	 * @param string $coreVersion Current version of core
+	 * @return VersionChecker $this
+	 */
+	public function setCoreVersion( $coreVersion ) {
+		try {
+			$this->coreVersion = new Constraint(
+				'==',
+				$this->versionParser->normalize( $coreVersion )
+			);
+			$this->coreVersion->setPrettyString( $coreVersion );
+		} catch ( UnexpectedValueException $e ) {
+			// Non-parsable version, don't fatal.
+		}
+
+		return $this;
+	}
+
+	/**
+	 * Check all given dependencies if they are compatible with the named
+	 * installed extensions in the $credits array.
+	 *
+	 * Example $extDependencies:
+	 *	{
+	 *		'GoogleAPIClient' => {
+	 *			'MediaWiki' => '>= 1.25.0'
+	 *		}
+	 *	}
+	 *
+	 * @param array $extDependencies All extensions that depend on other ones
+	 * @return array
+	 */
+	public function checkArray( array $extDependencies ) {
+		$errors = [];
+		foreach ( $extDependencies as $extension => $dependencies ) {
+			foreach ( $dependencies as $dependencyType => $values ) {
+				switch ( $dependencyType ) {
+					case ExtensionRegistry::MEDIAWIKI_CORE:
+						$errors = array_merge(
+							$errors,
+							$this->handleMediaWikiDependency( $values, $extension )
+						);
+						break;
+					default:
+						throw new UnexpectedValueException( 'Dependency type ' . $dependencyType .
+							' unknown in ' . $extension );
+				}
+			}
+		}
+
+		return $errors;
+	}
+
+	/**
+	 * Handle a dependency to MediaWiki core. It will check, if a MediaWiki version constraint was
+	 * set with self::setCoreVersion before this call (if not, it will return an empty array) and
+	 * checks the version constraint given against it.
+	 *
+	 * @param string $constraint The required version constraint for this dependency
+	 * @param string $checkedExt The Extension, which depends on this dependency
+	 * @return array An empty array, if MediaWiki version is compatible with $constraint, an array
+	 *  with an error message, otherwise.
+	 */
+	private function handleMediaWikiDependency( $constraint, $checkedExt ) {
+		if ( $this->coreVersion === false ) {
+			// Couldn't parse the core version, so we can't check anything
+			return [];
+		}
+
+		// if the installed and required version are compatible, return an empty array
+		if ( $this->versionParser->parseConstraints( $constraint )
+			->matches( $this->coreVersion ) ) {
+			return [];
+		}
+		// otherwise mark this as incompatible.
+		return [ "{$checkedExt} is not compatible with the current "
+		         . "MediaWiki core (version {$this->coreVersion->getPrettyString()}), it requires: "
+		         . $constraint . '.' ];
+	}
+}