1 files changed, 80 insertions, 0 deletions
diff --git a/lib/private/App/CompareVersion.php b/lib/private/App/CompareVersion.php
new file mode 100644
index 00000000000..7edc3e565b1
--- /dev/null
+++ b/lib/private/App/CompareVersion.php
@@ -0,0 +1,80 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2018 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OC\App;
+
+use InvalidArgumentException;
+use function explode;
+
+class CompareVersion {
+	private const REGEX_MAJOR = '/^\d+$/';
+	private const REGEX_MAJOR_MINOR = '/^\d+\.\d+$/';
+	private const REGEX_MAJOR_MINOR_PATCH = '/^\d+\.\d+\.\d+(?!\.\d+)/';
+	private const REGEX_ACTUAL = '/^\d+(\.\d+){1,2}/';
+
+	/**
+	 * Checks if the given server version fulfills the given (app) version requirements.
+	 *
+	 * Version requirements can be 'major.minor.patch', 'major.minor' or just 'major',
+	 * so '13.0.1', '13.0' and '13' are valid.
+	 *
+	 * @param string $actual version as major.minor.patch notation
+	 * @param string $required version where major is required and minor and patch are optional
+	 * @param string $comparator passed to `version_compare`
+	 * @return bool whether the requirement is fulfilled
+	 * @throws InvalidArgumentException if versions specified in an invalid format
+	 */
+	public function isCompatible(string $actual, string $required,
+		string $comparator = '>='): bool {
+		if (!preg_match(self::REGEX_ACTUAL, $actual, $matches)) {
+			throw new InvalidArgumentException("version specification $actual is invalid");
+		}
+		$cleanActual = $matches[0];
+
+		if (preg_match(self::REGEX_MAJOR, $required) === 1) {
+			return $this->compareMajor($cleanActual, $required, $comparator);
+		} elseif (preg_match(self::REGEX_MAJOR_MINOR, $required) === 1) {
+			return $this->compareMajorMinor($cleanActual, $required, $comparator);
+		} elseif (preg_match(self::REGEX_MAJOR_MINOR_PATCH, $required) === 1) {
+			return $this->compareMajorMinorPatch($cleanActual, $required, $comparator);
+		} else {
+			throw new InvalidArgumentException("required version $required is invalid");
+		}
+	}
+
+	private function compareMajor(string $actual, string $required,
+		string $comparator) {
+		$actualMajor = explode('.', $actual)[0];
+		$requiredMajor = explode('.', $required)[0];
+
+		return version_compare($actualMajor, $requiredMajor, $comparator);
+	}
+
+	private function compareMajorMinor(string $actual, string $required,
+		string $comparator) {
+		$actualMajor = explode('.', $actual)[0];
+		$actualMinor = explode('.', $actual)[1];
+		$requiredMajor = explode('.', $required)[0];
+		$requiredMinor = explode('.', $required)[1];
+
+		return version_compare("$actualMajor.$actualMinor",
+			"$requiredMajor.$requiredMinor", $comparator);
+	}
+
+	private function compareMajorMinorPatch($actual, $required, $comparator) {
+		$actualMajor = explode('.', $actual)[0];
+		$actualMinor = explode('.', $actual)[1];
+		$actualPatch = explode('.', $actual)[2];
+		$requiredMajor = explode('.', $required)[0];
+		$requiredMinor = explode('.', $required)[1];
+		$requiredPatch = explode('.', $required)[2];
+
+		return version_compare("$actualMajor.$actualMinor.$actualPatch",
+			"$requiredMajor.$requiredMinor.$requiredPatch", $comparator);
+	}
+}