When deleting a file, delete all transformations of the file

Summary:
Fixes T3143. When a user deletes a file, delete all transforms of the file too. In particular, this means that deleting an image deletes all the thumbnails of the image.

In most cases, this aligns with user expectations. The only sort of weird case I can come up with is that memes are transformations of the source macro image, so deleting grumpycat will delete all the hilarious grumpycat memes. This seems not-too-unreasonable, though, and desirable if someone accidentally uploads an inappropriate image which is promptly turned into a meme.

Test Plan:
Added a unit test which covers both inbound and outbound transformations.

Uploaded a file and deleted it, verified its thumbnail was also deleted.

Reviewers: chad, btrahan, joseph.kampf

Reviewed By: btrahan

CC: aran, joseph.kampf

Maniphest Tasks: T3143

Differential Revision: https://secure.phabricator.com/D5879

src/applications/files/query/PhabricatorFileQuery.php

@@ -24,6 +24,38 @@ final class PhabricatorFileQuery
     return $this;
   }
 
+  /**
+   * Select files which are transformations of some other file. For example,
+   * you can use this query to find previously generated thumbnails of an image
+   * file.
+   *
+   * As a parameter, provide a list of transformation specifications. Each
+   * specification is a dictionary with the keys `originalPHID` and `transform`.
+   * The `originalPHID` is the PHID of the original file (the file which was
+   * transformed) and the `transform` is the name of the transform to query
+   * for. If you pass `true` as the `transform`, all transformations of the
+   * file will be selected.
+   *
+   * For example:
+   *
+   *   array(
+   *     array(
+   *       'originalPHID' => 'PHID-FILE-aaaa',
+   *       'transform'    => 'sepia',
+   *     ),
+   *     array(
+   *       'originalPHID' => 'PHID-FILE-bbbb',
+   *       'transform'    => true,
+   *     ),
+   *   )
+   *
+   * This selects the `"sepia"` transformation of the file with PHID
+   * `PHID-FILE-aaaa` and all transformations of the file with PHID
+   * `PHID-FILE-bbbb`.
+   *
+   * @param list<dict>  List of transform specifications, described above.
+   * @return this
+   */
   public function withTransforms(array $specs) {
     foreach ($specs as $spec) {
       if (!is_array($spec) ||
@@ -50,7 +82,7 @@ final class PhabricatorFileQuery
 
     $data = queryfx_all(
       $conn_r,
-      'SELECT * FROM %T f %Q %Q %Q %Q',
+      'SELECT f.* FROM %T f %Q %Q %Q %Q',
       $table->getTableName(),
       $this->buildJoinClause($conn_r),
       $this->buildWhereClause($conn_r),
@@ -108,11 +140,18 @@ final class PhabricatorFileQuery
     if ($this->transforms) {
       $clauses = array();
       foreach ($this->transforms as $transform) {
-        $clauses[] = qsprintf(
-          $conn_r,
-          '(t.originalPHID = %s AND t.transform = %s)',
-          $transform['originalPHID'],
-          $transform['transform']);
+        if ($transform['transform'] === true) {
+          $clauses[] = qsprintf(
+            $conn_r,
+            '(t.originalPHID = %s)',
+            $transform['originalPHID']);
+        } else {
+          $clauses[] = qsprintf(
+            $conn_r,
+            '(t.originalPHID = %s AND t.transform = %s)',
+            $transform['originalPHID'],
+            $transform['transform']);
+        }
       }
       $where[] = qsprintf($conn_r, '(%Q)', implode(') OR (', $clauses));
     }