diff -r 07239de796bb -r e756a8c72c3d cms/drupal/modules/system/system.archiver.inc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cms/drupal/modules/system/system.archiver.inc	Fri Sep 08 12:04:06 2017 +0200
@@ -0,0 +1,139 @@
+<?php
+
+/**
+ * @file
+ * Archiver implementations provided by the system module.
+ */
+
+/**
+ * Archiver for .tar files.
+ */
+class ArchiverTar implements ArchiverInterface {
+
+  /**
+   * The underlying Archive_Tar instance that does the heavy lifting.
+   *
+   * @var Archive_Tar
+   */
+  protected $tar;
+
+  public function __construct($file_path) {
+    $this->tar = new Archive_Tar($file_path);
+  }
+
+  public function add($file_path) {
+    $this->tar->add($file_path);
+
+    return $this;
+  }
+
+  public function remove($file_path) {
+    // @todo Archive_Tar doesn't have a remove operation
+    // so we'll have to simulate it somehow, probably by
+    // creating a new archive with everything but the removed
+    // file.
+
+    return $this;
+  }
+
+  public function extract($path, Array $files = array()) {
+    if ($files) {
+      $this->tar->extractList($files, $path);
+    }
+    else {
+      $this->tar->extract($path);
+    }
+
+    return $this;
+  }
+
+  public function listContents() {
+    $files = array();
+    foreach ($this->tar->listContent() as $file_data) {
+      $files[] = $file_data['filename'];
+    }
+    return $files;
+  }
+
+  /**
+   * Retrieve the tar engine itself.
+   *
+   * In some cases it may be necessary to directly access the underlying
+   * Archive_Tar object for implementation-specific logic. This is for advanced
+   * use only as it is not shared by other implementations of ArchiveInterface.
+   *
+   * @return
+   *   The Archive_Tar object used by this object.
+   */
+  public function getArchive() {
+    return $this->tar;
+  }
+}
+
+/**
+ * Archiver for .zip files.
+ *
+ * @link http://php.net/zip
+ */
+class ArchiverZip implements ArchiverInterface {
+
+  /**
+   * The underlying ZipArchive instance that does the heavy lifting.
+   *
+   * @var ZipArchive
+   */
+  protected $zip;
+
+  public function __construct($file_path) {
+    $this->zip = new ZipArchive();
+    if ($this->zip->open($file_path) !== TRUE) {
+      // @todo: This should be an interface-specific exception some day.
+      throw new Exception(t('Cannot open %file_path', array('%file_path' => $file_path)));
+    }
+  }
+
+  public function add($file_path) {
+    $this->zip->addFile($file_path);
+
+    return $this;
+  }
+
+  public function remove($file_path) {
+    $this->zip->deleteName($file_path);
+
+    return $this;
+  }
+
+  public function extract($path, Array $files = array()) {
+    if ($files) {
+      $this->zip->extractTo($path, $files);
+    }
+    else {
+      $this->zip->extractTo($path);
+    }
+
+    return $this;
+  }
+
+  public function listContents() {
+    $files = array();
+    for ($i=0; $i < $this->zip->numFiles; $i++) {
+      $files[] = $this->zip->getNameIndex($i);
+    }
+    return $files;
+  }
+
+  /**
+   * Retrieve the zip engine itself.
+   *
+   * In some cases it may be necessary to directly access the underlying
+   * ZipArchive object for implementation-specific logic. This is for advanced
+   * use only as it is not shared by other implementations of ArchiveInterface.
+   *
+   * @return
+   *   The ZipArchive object used by this object.
+   */
+  public function getArchive() {
+    return $this->zip;
+  }
+}