1 files changed, 90 insertions, 0 deletions
diff --git a/lib/Analyzer/SequenceOperationsAnalyzer.php b/lib/Analyzer/SequenceOperationsAnalyzer.php
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+++ b/lib/Analyzer/SequenceOperationsAnalyzer.php
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+<?php
+
+/**
+ * @copyright Copyright (c) 2018 Matthias Held <matthias.held@uni-konstanz.de>
+ * @author Matthias Held <matthias.held@uni-konstanz.de>
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace OCA\RansomwareDetection\Analyzer;
+
+use OCA\RansomwareDetection\Monitor;
+
+class SequenceOperationsAnalyzer
+{
+    /**
+     * Sequence operation class.
+     *
+     * @var int
+     */
+    const NO_WRITE_AND_DELETE = 0;
+    const ONLY_WRITE = 1;
+    const ONLY_DELETE = 2;
+    const EQUAL_WRITE_AND_DELETE = 3;
+    const DIFF_WRITE_AND_DELETE = 4;
+
+    /**
+     * Classifies the operations in a sequence.
+     *
+     * @param array $sequence
+     *
+     * @return int
+     */
+    public function analyze($sequence)
+    {
+        $numberOfWrittenFiles = 0;
+        $numberOfDeletedFiles = 0;
+        $numberOfRenamedFiles = 0;
+
+        $sequenceClass = self::NO_WRITE_AND_DELETE;
+
+        foreach ($sequence as $fileOperation) {
+            switch ($fileOperation->getCommand()) {
+                case Monitor::WRITE:
+                    $numberOfWrittenFiles++;
+                    break;
+                case Monitor::READ:
+                    break;
+                case Monitor::RENAME:
+                    $numberOfRenamedFiles++;
+                    break;
+                case Monitor::DELETE:
+                    $numberOfDeletedFiles++;
+                    break;
+                default:
+                    break;
+            }
+        }
+
+        if ($numberOfWrittenFiles > 0) {
+            if ($numberOfDeletedFiles > 0) {
+                if ($numberOfWrittenFiles === $numberOfDeletedFiles) {
+                    $sequenceClass = self::EQUAL_WRITE_AND_DELETE;
+                } else {
+                    $sequenceClass = self::DIFF_WRITE_AND_DELETE;
+                }
+            } else {
+                $sequenceClass = self::ONLY_WRITE;
+            }
+        } else {
+            if ($numberOfDeletedFiles > 0) {
+                $sequenceClass = self::ONLY_DELETE;
+            }
+        }
+
+        return $sequenceClass;
+    }
+}